diff options
Diffstat (limited to 'drivers/block')
| -rw-r--r-- | drivers/block/Kconfig | 12 | ||||
| -rw-r--r-- | drivers/block/Kconfig.iosched | 69 | ||||
| -rw-r--r-- | drivers/block/Makefile | 14 | ||||
| -rw-r--r-- | drivers/block/as-iosched.c | 1985 | ||||
| -rw-r--r-- | drivers/block/cfq-iosched.c | 2428 | ||||
| -rw-r--r-- | drivers/block/deadline-iosched.c | 878 | ||||
| -rw-r--r-- | drivers/block/elevator.c | 802 | ||||
| -rw-r--r-- | drivers/block/genhd.c | 726 | ||||
| -rw-r--r-- | drivers/block/ioctl.c | 275 | ||||
| -rw-r--r-- | drivers/block/ll_rw_blk.c | 3613 | ||||
| -rw-r--r-- | drivers/block/noop-iosched.c | 46 | ||||
| -rw-r--r-- | drivers/block/scsi_ioctl.c | 589 |
12 files changed, 0 insertions, 11437 deletions
diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig index 51b0af1..7b1cd93 100644 --- a/drivers/block/Kconfig +++ b/drivers/block/Kconfig @@ -409,16 +409,6 @@ config BLK_DEV_INITRD for details. -#XXX - it makes sense to enable this only for 32-bit subarch's, not for x86_64 -#for instance. -config LBD - bool "Support for Large Block Devices" - depends on X86 || (MIPS && 32BIT) || PPC32 || ARCH_S390_31 || SUPERH || UML - help - Say Y here if you want to attach large (bigger than 2TB) discs to - your machine, or if you want to have a raid or loopback device - bigger than 2TB. Otherwise say N. - config CDROM_PKTCDVD tristate "Packet writing on CD/DVD media" depends on !UML @@ -455,8 +445,6 @@ config CDROM_PKTCDVD_WCACHE source "drivers/s390/block/Kconfig" -source "drivers/block/Kconfig.iosched" - config ATA_OVER_ETH tristate "ATA over Ethernet support" depends on NET diff --git a/drivers/block/Kconfig.iosched b/drivers/block/Kconfig.iosched deleted file mode 100644 index 5b90d2f..0000000 --- a/drivers/block/Kconfig.iosched +++ /dev/null @@ -1,69 +0,0 @@ - -menu "IO Schedulers" - -config IOSCHED_NOOP - bool - default y - ---help--- - The no-op I/O scheduler is a minimal scheduler that does basic merging - and sorting. Its main uses include non-disk based block devices like - memory devices, and specialised software or hardware environments - that do their own scheduling and require only minimal assistance from - the kernel. - -config IOSCHED_AS - tristate "Anticipatory I/O scheduler" - default y - ---help--- - The anticipatory I/O scheduler is the default disk scheduler. It is - generally a good choice for most environments, but is quite large and - complex when compared to the deadline I/O scheduler, it can also be - slower in some cases especially some database loads. - -config IOSCHED_DEADLINE - tristate "Deadline I/O scheduler" - default y - ---help--- - The deadline I/O scheduler is simple and compact, and is often as - good as the anticipatory I/O scheduler, and in some database - workloads, better. In the case of a single process performing I/O to - a disk at any one time, its behaviour is almost identical to the - anticipatory I/O scheduler and so is a good choice. - -config IOSCHED_CFQ - tristate "CFQ I/O scheduler" - default y - ---help--- - The CFQ I/O scheduler tries to distribute bandwidth equally - among all processes in the system. It should provide a fair - working environment, suitable for desktop systems. - -choice - prompt "Default I/O scheduler" - default DEFAULT_AS - help - Select the I/O scheduler which will be used by default for all - block devices. - - config DEFAULT_AS - bool "Anticipatory" if IOSCHED_AS - - config DEFAULT_DEADLINE - bool "Deadline" if IOSCHED_DEADLINE - - config DEFAULT_CFQ - bool "CFQ" if IOSCHED_CFQ - - config DEFAULT_NOOP - bool "No-op" - -endchoice - -config DEFAULT_IOSCHED - string - default "anticipatory" if DEFAULT_AS - default "deadline" if DEFAULT_DEADLINE - default "cfq" if DEFAULT_CFQ - default "noop" if DEFAULT_NOOP - -endmenu diff --git a/drivers/block/Makefile b/drivers/block/Makefile index 1cf09a1..3ec1f8d 100644 --- a/drivers/block/Makefile +++ b/drivers/block/Makefile @@ -4,21 +4,7 @@ # 12 June 2000, Christoph Hellwig <hch@infradead.org> # Rewritten to use lists instead of if-statements. # -# Note : at this point, these files are compiled on all systems. -# In the future, some of these should be built conditionally. -# - -# -# NOTE that ll_rw_blk.c must come early in linkage order - it starts the -# kblockd threads -# - -obj-y := elevator.o ll_rw_blk.o ioctl.o genhd.o scsi_ioctl.o -obj-$(CONFIG_IOSCHED_NOOP) += noop-iosched.o -obj-$(CONFIG_IOSCHED_AS) += as-iosched.o -obj-$(CONFIG_IOSCHED_DEADLINE) += deadline-iosched.o -obj-$(CONFIG_IOSCHED_CFQ) += cfq-iosched.o obj-$(CONFIG_MAC_FLOPPY) += swim3.o obj-$(CONFIG_BLK_DEV_FD) += floppy.o obj-$(CONFIG_BLK_DEV_FD98) += floppy98.o diff --git a/drivers/block/as-iosched.c b/drivers/block/as-iosched.c deleted file mode 100644 index c6744ff..0000000 --- a/drivers/block/as-iosched.c +++ /dev/null @@ -1,1985 +0,0 @@ -/* - * linux/drivers/block/as-iosched.c - * - * Anticipatory & deadline i/o scheduler. - * - * Copyright (C) 2002 Jens Axboe <axboe@suse.de> - * Nick Piggin <piggin@cyberone.com.au> - * - */ -#include <linux/kernel.h> -#include <linux/fs.h> -#include <linux/blkdev.h> -#include <linux/elevator.h> -#include <linux/bio.h> -#include <linux/config.h> -#include <linux/module.h> -#include <linux/slab.h> -#include <linux/init.h> -#include <linux/compiler.h> -#include <linux/hash.h> -#include <linux/rbtree.h> -#include <linux/interrupt.h> - -#define REQ_SYNC 1 -#define REQ_ASYNC 0 - -/* - * See Documentation/block/as-iosched.txt - */ - -/* - * max time before a read is submitted. - */ -#define default_read_expire (HZ / 8) - -/* - * ditto for writes, these limits are not hard, even - * if the disk is capable of satisfying them. - */ -#define default_write_expire (HZ / 4) - -/* - * read_batch_expire describes how long we will allow a stream of reads to - * persist before looking to see whether it is time to switch over to writes. - */ -#define default_read_batch_expire (HZ / 2) - -/* - * write_batch_expire describes how long we want a stream of writes to run for. - * This is not a hard limit, but a target we set for the auto-tuning thingy. - * See, the problem is: we can send a lot of writes to disk cache / TCQ in - * a short amount of time... - */ -#define default_write_batch_expire (HZ / 8) - -/* - * max time we may wait to anticipate a read (default around 6ms) - */ -#define default_antic_expire ((HZ / 150) ? HZ / 150 : 1) - -/* - * Keep track of up to 20ms thinktimes. We can go as big as we like here, - * however huge values tend to interfere and not decay fast enough. A program - * might be in a non-io phase of operation. Waiting on user input for example, - * or doing a lengthy computation. A small penalty can be justified there, and - * will still catch out those processes that constantly have large thinktimes. - */ -#define MAX_THINKTIME (HZ/50UL) - -/* Bits in as_io_context.state */ -enum as_io_states { - AS_TASK_RUNNING=0, /* Process has not exitted */ - AS_TASK_IOSTARTED, /* Process has started some IO */ - AS_TASK_IORUNNING, /* Process has completed some IO */ -}; - -enum anticipation_status { - ANTIC_OFF=0, /* Not anticipating (normal operation) */ - ANTIC_WAIT_REQ, /* The last read has not yet completed */ - ANTIC_WAIT_NEXT, /* Currently anticipating a request vs - last read (which has completed) */ - ANTIC_FINISHED, /* Anticipating but have found a candidate - * or timed out */ -}; - -struct as_data { - /* - * run time data - */ - - struct request_queue *q; /* the "owner" queue */ - - /* - * requests (as_rq s) are present on both sort_list and fifo_list - */ - struct rb_root sort_list[2]; - struct list_head fifo_list[2]; - - struct as_rq *next_arq[2]; /* next in sort order */ - sector_t last_sector[2]; /* last REQ_SYNC & REQ_ASYNC sectors */ - struct list_head *hash; /* request hash */ - - unsigned long exit_prob; /* probability a task will exit while - being waited on */ - unsigned long new_ttime_total; /* mean thinktime on new proc */ - unsigned long new_ttime_mean; - u64 new_seek_total; /* mean seek on new proc */ - sector_t new_seek_mean; - - unsigned long current_batch_expires; - unsigned long last_check_fifo[2]; - int changed_batch; /* 1: waiting for old batch to end */ - int new_batch; /* 1: waiting on first read complete */ - int batch_data_dir; /* current batch REQ_SYNC / REQ_ASYNC */ - int write_batch_count; /* max # of reqs in a write batch */ - int current_write_count; /* how many requests left this batch */ - int write_batch_idled; /* has the write batch gone idle? */ - mempool_t *arq_pool; - - enum anticipation_status antic_status; - unsigned long antic_start; /* jiffies: when it started */ - struct timer_list antic_timer; /* anticipatory scheduling timer */ - struct work_struct antic_work; /* Deferred unplugging */ - struct io_context *io_context; /* Identify the expected process */ - int ioc_finished; /* IO associated with io_context is finished */ - int nr_dispatched; - - /* - * settings that change how the i/o scheduler behaves - */ - unsigned long fifo_expire[2]; - unsigned long batch_expire[2]; - unsigned long antic_expire; -}; - -#define list_entry_fifo(ptr) list_entry((ptr), struct as_rq, fifo) - -/* - * per-request data. - */ -enum arq_state { - AS_RQ_NEW=0, /* New - not referenced and not on any lists */ - AS_RQ_QUEUED, /* In the request queue. It belongs to the - scheduler */ - AS_RQ_DISPATCHED, /* On the dispatch list. It belongs to the - driver now */ - AS_RQ_PRESCHED, /* Debug poisoning for requests being used */ - AS_RQ_REMOVED, - AS_RQ_MERGED, - AS_RQ_POSTSCHED, /* when they shouldn't be */ -}; - -struct as_rq { - /* - * rbtree index, key is the starting offset - */ - struct rb_node rb_node; - sector_t rb_key; - - struct request *request; - - struct io_context *io_context; /* The submitting task */ - - /* - * request hash, key is the ending offset (for back merge lookup) - */ - struct list_head hash; - unsigned int on_hash; - - /* - * expire fifo - */ - struct list_head fifo; - unsigned long expires; - - unsigned int is_sync; - enum arq_state state; -}; - -#define RQ_DATA(rq) ((struct as_rq *) (rq)->elevator_private) - -static kmem_cache_t *arq_pool; - -/* - * IO Context helper functions - */ - -/* Called to deallocate the as_io_context */ -static void free_as_io_context(struct as_io_context *aic) -{ - kfree(aic); -} - -/* Called when the task exits */ -static void exit_as_io_context(struct as_io_context *aic) -{ - WARN_ON(!test_bit(AS_TASK_RUNNING, &aic->state)); - clear_bit(AS_TASK_RUNNING, &aic->state); -} - -static struct as_io_context *alloc_as_io_context(void) -{ - struct as_io_context *ret; - - ret = kmalloc(sizeof(*ret), GFP_ATOMIC); - if (ret) { - ret->dtor = free_as_io_context; - ret->exit = exit_as_io_context; - ret->state = 1 << AS_TASK_RUNNING; - atomic_set(&ret->nr_queued, 0); - atomic_set(&ret->nr_dispatched, 0); - spin_lock_init(&ret->lock); - ret->ttime_total = 0; - ret->ttime_samples = 0; - ret->ttime_mean = 0; - ret->seek_total = 0; - ret->seek_samples = 0; - ret->seek_mean = 0; - } - - return ret; -} - -/* - * If the current task has no AS IO context then create one and initialise it. - * Then take a ref on the task's io context and return it. - */ -static struct io_context *as_get_io_context(void) -{ - struct io_context *ioc = get_io_context(GFP_ATOMIC); - if (ioc && !ioc->aic) { - ioc->aic = alloc_as_io_context(); - if (!ioc->aic) { - put_io_context(ioc); - ioc = NULL; - } - } - return ioc; -} - -static void as_put_io_context(struct as_rq *arq) -{ - struct as_io_context *aic; - - if (unlikely(!arq->io_context)) - return; - - aic = arq->io_context->aic; - - if (arq->is_sync == REQ_SYNC && aic) { - spin_lock(&aic->lock); - set_bit(AS_TASK_IORUNNING, &aic->state); - aic->last_end_request = jiffies; - spin_unlock(&aic->lock); - } - - put_io_context(arq->io_context); -} - -/* - * the back merge hash support functions - */ -static const int as_hash_shift = 6; -#define AS_HASH_BLOCK(sec) ((sec) >> 3) -#define AS_HASH_FN(sec) (hash_long(AS_HASH_BLOCK((sec)), as_hash_shift)) -#define AS_HASH_ENTRIES (1 << as_hash_shift) -#define rq_hash_key(rq) ((rq)->sector + (rq)->nr_sectors) -#define list_entry_hash(ptr) list_entry((ptr), struct as_rq, hash) - -static inline void __as_del_arq_hash(struct as_rq *arq) -{ - arq->on_hash = 0; - list_del_init(&arq->hash); -} - -static inline void as_del_arq_hash(struct as_rq *arq) -{ - if (arq->on_hash) - __as_del_arq_hash(arq); -} - -static void as_add_arq_hash(struct as_data *ad, struct as_rq *arq) -{ - struct request *rq = arq->request; - - BUG_ON(arq->on_hash); - - arq->on_hash = 1; - list_add(&arq->hash, &ad->hash[AS_HASH_FN(rq_hash_key(rq))]); -} - -/* - * move hot entry to front of chain - */ -static inline void as_hot_arq_hash(struct as_data *ad, struct as_rq *arq) -{ - struct request *rq = arq->request; - struct list_head *head = &ad->hash[AS_HASH_FN(rq_hash_key(rq))]; - - if (!arq->on_hash) { - WARN_ON(1); - return; - } - - if (arq->hash.prev != head) { - list_del(&arq->hash); - list_add(&arq->hash, head); - } -} - -static struct request *as_find_arq_hash(struct as_data *ad, sector_t offset) -{ - struct list_head *hash_list = &ad->hash[AS_HASH_FN(offset)]; - struct list_head *entry, *next = hash_list->next; - - while ((entry = next) != hash_list) { - struct as_rq *arq = list_entry_hash(entry); - struct request *__rq = arq->request; - - next = entry->next; - - BUG_ON(!arq->on_hash); - - if (!rq_mergeable(__rq)) { - as_del_arq_hash(arq); - continue; - } - - if (rq_hash_key(__rq) == offset) - return __rq; - } - - return NULL; -} - -/* - * rb tree support functions - */ -#define RB_NONE (2) -#define RB_EMPTY(root) ((root)->rb_node == NULL) -#define ON_RB(node) ((node)->rb_color != RB_NONE) -#define RB_CLEAR(node) ((node)->rb_color = RB_NONE) -#define rb_entry_arq(node) rb_entry((node), struct as_rq, rb_node) -#define ARQ_RB_ROOT(ad, arq) (&(ad)->sort_list[(arq)->is_sync]) -#define rq_rb_key(rq) (rq)->sector - -/* - * as_find_first_arq finds the first (lowest sector numbered) request - * for the specified data_dir. Used to sweep back to the start of the disk - * (1-way elevator) after we process the last (highest sector) request. - */ -static struct as_rq *as_find_first_arq(struct as_data *ad, int data_dir) -{ - struct rb_node *n = ad->sort_list[data_dir].rb_node; - - if (n == NULL) - return NULL; - - for (;;) { - if (n->rb_left == NULL) - return rb_entry_arq(n); - - n = n->rb_left; - } -} - -/* - * Add the request to the rb tree if it is unique. If there is an alias (an - * existing request against the same sector), which can happen when using - * direct IO, then return the alias. - */ -static struct as_rq *as_add_arq_rb(struct as_data *ad, struct as_rq *arq) -{ - struct rb_node **p = &ARQ_RB_ROOT(ad, arq)->rb_node; - struct rb_node *parent = NULL; - struct as_rq *__arq; - struct request *rq = arq->request; - - arq->rb_key = rq_rb_key(rq); - - while (*p) { - parent = *p; - __arq = rb_entry_arq(parent); - - if (arq->rb_key < __arq->rb_key) - p = &(*p)->rb_left; - else if (arq->rb_key > __arq->rb_key) - p = &(*p)->rb_right; - else - return __arq; - } - - rb_link_node(&arq->rb_node, parent, p); - rb_insert_color(&arq->rb_node, ARQ_RB_ROOT(ad, arq)); - - return NULL; -} - -static inline void as_del_arq_rb(struct as_data *ad, struct as_rq *arq) -{ - if (!ON_RB(&arq->rb_node)) { - WARN_ON(1); - return; - } - - rb_erase(&arq->rb_node, ARQ_RB_ROOT(ad, arq)); - RB_CLEAR(&arq->rb_node); -} - -static struct request * -as_find_arq_rb(struct as_data *ad, sector_t sector, int data_dir) -{ - struct rb_node *n = ad->sort_list[data_dir].rb_node; - struct as_rq *arq; - - while (n) { - arq = rb_entry_arq(n); - - if (sector < arq->rb_key) - n = n->rb_left; - else if (sector > arq->rb_key) - n = n->rb_right; - else - return arq->request; - } - - return NULL; -} - -/* - * IO Scheduler proper - */ - -#define MAXBACK (1024 * 1024) /* - * Maximum distance the disk will go backward - * for a request. - */ - -#define BACK_PENALTY 2 - -/* - * as_choose_req selects the preferred one of two requests of the same data_dir - * ignoring time - eg. timeouts, which is the job of as_dispatch_request - */ -static struct as_rq * -as_choose_req(struct as_data *ad, struct as_rq *arq1, struct as_rq *arq2) -{ - int data_dir; - sector_t last, s1, s2, d1, d2; - int r1_wrap=0, r2_wrap=0; /* requests are behind the disk head */ - const sector_t maxback = MAXBACK; - - if (arq1 == NULL || arq1 == arq2) - return arq2; - if (arq2 == NULL) - return arq1; - - data_dir = arq1->is_sync; - - last = ad->last_sector[data_dir]; - s1 = arq1->request->sector; - s2 = arq2->request->sector; - - BUG_ON(data_dir != arq2->is_sync); - - /* - * Strict one way elevator _except_ in the case where we allow - * short backward seeks which are biased as twice the cost of a - * similar forward seek. - */ - if (s1 >= last) - d1 = s1 - last; - else if (s1+maxback >= last) - d1 = (last - s1)*BACK_PENALTY; - else { - r1_wrap = 1; - d1 = 0; /* shut up, gcc */ - } - - if (s2 >= last) - d2 = s2 - last; - else if (s2+maxback >= last) - d2 = (last - s2)*BACK_PENALTY; - else { - r2_wrap = 1; - d2 = 0; - } - - /* Found required data */ - if (!r1_wrap && r2_wrap) - return arq1; - else if (!r2_wrap && r1_wrap) - return arq2; - else if (r1_wrap && r2_wrap) { - /* both behind the head */ - if (s1 <= s2) - return arq1; - else - return arq2; - } - - /* Both requests in front of the head */ - if (d1 < d2) - return arq1; - else if (d2 < d1) - return arq2; - else { - if (s1 >= s2) - return arq1; - else - return arq2; - } -} - -/* - * as_find_next_arq finds the next request after @prev in elevator order. - * this with as_choose_req form the basis for how the scheduler chooses - * what request to process next. Anticipation works on top of this. - */ -static struct as_rq *as_find_next_arq(struct as_data *ad, struct as_rq *last) -{ - const int data_dir = last->is_sync; - struct as_rq *ret; - struct rb_node *rbnext = rb_next(&last->rb_node); - struct rb_node *rbprev = rb_prev(&last->rb_node); - struct as_rq *arq_next, *arq_prev; - - BUG_ON(!ON_RB(&last->rb_node)); - - if (rbprev) - arq_prev = rb_entry_arq(rbprev); - else - arq_prev = NULL; - - if (rbnext) - arq_next = rb_entry_arq(rbnext); - else { - arq_next = as_find_first_arq(ad, data_dir); - if (arq_next == last) - arq_next = NULL; - } - - ret = as_choose_req(ad, arq_next, arq_prev); - - return ret; -} - -/* - * anticipatory scheduling functions follow - */ - -/* - * as_antic_expired tells us when we have anticipated too long. - * The funny "absolute difference" math on the elapsed time is to handle - * jiffy wraps, and disks which have been idle for 0x80000000 jiffies. - */ -static int as_antic_expired(struct as_data *ad) -{ - long delta_jif; - - delta_jif = jiffies - ad->antic_start; - if (unlikely(delta_jif < 0)) - delta_jif = -delta_jif; - if (delta_jif < ad->antic_expire) - return 0; - - return 1; -} - -/* - * as_antic_waitnext starts anticipating that a nice request will soon be - * submitted. See also as_antic_waitreq - */ -static void as_antic_waitnext(struct as_data *ad) -{ - unsigned long timeout; - - BUG_ON(ad->antic_status != ANTIC_OFF - && ad->antic_status != ANTIC_WAIT_REQ); - - timeout = ad->antic_start + ad->antic_expire; - - mod_timer(&ad->antic_timer, timeout); - - ad->antic_status = ANTIC_WAIT_NEXT; -} - -/* - * as_antic_waitreq starts anticipating. We don't start timing the anticipation - * until the request that we're anticipating on has finished. This means we - * are timing from when the candidate process wakes up hopefully. - */ -static void as_antic_waitreq(struct as_data *ad) -{ - BUG_ON(ad->antic_status == ANTIC_FINISHED); - if (ad->antic_status == ANTIC_OFF) { - if (!ad->io_context || ad->ioc_finished) - as_antic_waitnext(ad); - else - ad->antic_status = ANTIC_WAIT_REQ; - } -} - -/* - * This is called directly by the functions in this file to stop anticipation. - * We kill the timer and schedule a call to the request_fn asap. - */ -static void as_antic_stop(struct as_data *ad) -{ - int status = ad->antic_status; - - if (status == ANTIC_WAIT_REQ || status == ANTIC_WAIT_NEXT) { - if (status == ANTIC_WAIT_NEXT) - del_timer(&ad->antic_timer); - ad->antic_status = ANTIC_FINISHED; - /* see as_work_handler */ - kblockd_schedule_work(&ad->antic_work); - } -} - -/* - * as_antic_timeout is the timer function set by as_antic_waitnext. - */ -static void as_antic_timeout(unsigned long data) -{ - struct request_queue *q = (struct request_queue *)data; - struct as_data *ad = q->elevator->elevator_data; - unsigned long flags; - - spin_lock_irqsave(q->queue_lock, flags); - if (ad->antic_status == ANTIC_WAIT_REQ - || ad->antic_status == ANTIC_WAIT_NEXT) { - struct as_io_context *aic = ad->io_context->aic; - - ad->antic_status = ANTIC_FINISHED; - kblockd_schedule_work(&ad->antic_work); - - if (aic->ttime_samples == 0) { - /* process anticipated on has exitted or timed out*/ - ad->exit_prob = (7*ad->exit_prob + 256)/8; - } - } - spin_unlock_irqrestore(q->queue_lock, flags); -} - -/* - * as_close_req decides if one request is considered "close" to the - * previous one issued. - */ -static int as_close_req(struct as_data *ad, struct as_rq *arq) -{ - unsigned long delay; /* milliseconds */ - sector_t last = ad->last_sector[ad->batch_data_dir]; - sector_t next = arq->request->sector; - sector_t delta; /* acceptable close offset (in sectors) */ - - if (ad->antic_status == ANTIC_OFF || !ad->ioc_finished) - delay = 0; - else - delay = ((jiffies - ad->antic_start) * 1000) / HZ; - - if (delay <= 1) - delta = 64; - else if (delay <= 20 && delay <= ad->antic_expire) - delta = 64 << (delay-1); - else - return 1; - - return (last - (delta>>1) <= next) && (next <= last + delta); -} - -/* - * as_can_break_anticipation returns true if we have been anticipating this - * request. - * - * It also returns true if the process against which we are anticipating - * submits a write - that's presumably an fsync, O_SYNC write, etc. We want to - * dispatch it ASAP, because we know that application will not be submitting - * any new reads. - * - * If the task which has submitted the request has exitted, break anticipation. - * - * If this task has queued some other IO, do not enter enticipation. - */ -static int as_can_break_anticipation(struct as_data *ad, struct as_rq *arq) -{ - struct io_context *ioc; - struct as_io_context *aic; - sector_t s; - - ioc = ad->io_context; - BUG_ON(!ioc); - - if (arq && ioc == arq->io_context) { - /* request from same process */ - return 1; - } - - if (ad->ioc_finished && as_antic_expired(ad)) { - /* - * In this situation status should really be FINISHED, - * however the timer hasn't had the chance to run yet. - */ - return 1; - } - - aic = ioc->aic; - if (!aic) - return 0; - - if (!test_bit(AS_TASK_RUNNING, &aic->state)) { - /* process anticipated on has exitted */ - if (aic->ttime_samples == 0) - ad->exit_prob = (7*ad->exit_prob + 256)/8; - return 1; - } - - if (atomic_read(&aic->nr_queued) > 0) { - /* process has more requests queued */ - return 1; - } - - if (atomic_read(&aic->nr_dispatched) > 0) { - /* process has more requests dispatched */ - return 1; - } - - if (arq && arq->is_sync == REQ_SYNC && as_close_req(ad, arq)) { - /* - * Found a close request that is not one of ours. - * - * This makes close requests from another process reset - * our thinktime delay. Is generally useful when there are - * two or more cooperating processes working in the same - * area. - */ - spin_lock(&aic->lock); - aic->last_end_request = jiffies; - spin_unlock(&aic->lock); - return 1; - } - - - if (aic->ttime_samples == 0) { - if (ad->new_ttime_mean > ad->antic_expire) - return 1; - if (ad->exit_prob > 128) - return 1; - } else if (aic->ttime_mean > ad->antic_expire) { - /* the process thinks too much between requests */ - return 1; - } - - if (!arq) - return 0; - - if (ad->last_sector[REQ_SYNC] < arq->request->sector) - s = arq->request->sector - ad->last_sector[REQ_SYNC]; - else - s = ad->last_sector[REQ_SYNC] - arq->request->sector; - - if (aic->seek_samples == 0) { - /* - * Process has just started IO. Use past statistics to - * guage success possibility - */ - if (ad->new_seek_mean > s) { - /* this request is better than what we're expecting */ - return 1; - } - - } else { - if (aic->seek_mean > s) { - /* this request is better than what we're expecting */ - return 1; - } - } - - return 0; -} - -/* - * as_can_anticipate indicates weather we should either run arq - * or keep anticipating a better request. - */ -static int as_can_anticipate(struct as_data *ad, struct as_rq *arq) -{ - if (!ad->io_context) - /* - * Last request submitted was a write - */ - return 0; - - if (ad->antic_status == ANTIC_FINISHED) - /* - * Don't restart if we have just finished. Run the next request - */ - return 0; - - if (as_can_break_anticipation(ad, arq)) - /* - * This request is a good candidate. Don't keep anticipating, - * run it. - */ - return 0; - - /* - * OK from here, we haven't finished, and don't have a decent request! - * Status is either ANTIC_OFF so start waiting, - * ANTIC_WAIT_REQ so continue waiting for request to finish - * or ANTIC_WAIT_NEXT so continue waiting for an acceptable request. - * - */ - - return 1; -} - -static void as_update_thinktime(struct as_data *ad, struct as_io_context *aic, unsigned long ttime) -{ - /* fixed point: 1.0 == 1<<8 */ - if (aic->ttime_samples == 0) { - ad->new_ttime_total = (7*ad->new_ttime_total + 256*ttime) / 8; - ad->new_ttime_mean = ad->new_ttime_total / 256; - - ad->exit_prob = (7*ad->exit_prob)/8; - } - aic->ttime_samples = (7*aic->ttime_samples + 256) / 8; - aic->ttime_total = (7*aic->ttime_total + 256*ttime) / 8; - aic->ttime_mean = (aic->ttime_total + 128) / aic->ttime_samples; -} - -static void as_update_seekdist(struct as_data *ad, struct as_io_context *aic, sector_t sdist) -{ - u64 total; - - if (aic->seek_samples == 0) { - ad->new_seek_total = (7*ad->new_seek_total + 256*(u64)sdist)/8; - ad->new_seek_mean = ad->new_seek_total / 256; - } - - /* - * Don't allow the seek distance to get too large from the - * odd fragment, pagein, etc - */ - if (aic->seek_samples <= 60) /* second&third seek */ - sdist = min(sdist, (aic->seek_mean * 4) + 2*1024*1024); - else - sdist = min(sdist, (aic->seek_mean * 4) + 2*1024*64); - - aic->seek_samples = (7*aic->seek_samples + 256) / 8; - aic->seek_total = (7*aic->seek_total + (u64)256*sdist) / 8; - total = aic->seek_total + (aic->seek_samples/2); - do_div(total, aic->seek_samples); - aic->seek_mean = (sector_t)total; -} - -/* - * as_update_iohist keeps a decaying histogram of IO thinktimes, and - * updates @aic->ttime_mean based on that. It is called when a new - * request is queued. - */ -static void as_update_iohist(struct as_data *ad, struct as_io_context *aic, struct request *rq) -{ - struct as_rq *arq = RQ_DATA(rq); - int data_dir = arq->is_sync; - unsigned long thinktime; - sector_t seek_dist; - - if (aic == NULL) - return; - - if (data_dir == REQ_SYNC) { - unsigned long in_flight = atomic_read(&aic->nr_queued) - + atomic_read(&aic->nr_dispatched); - spin_lock(&aic->lock); - if (test_bit(AS_TASK_IORUNNING, &aic->state) || - test_bit(AS_TASK_IOSTARTED, &aic->state)) { - /* Calculate read -> read thinktime */ - if (test_bit(AS_TASK_IORUNNING, &aic->state) - && in_flight == 0) { - thinktime = jiffies - aic->last_end_request; - thinktime = min(thinktime, MAX_THINKTIME-1); - } else - thinktime = 0; - as_update_thinktime(ad, aic, thinktime); - - /* Calculate read -> read seek distance */ - if (aic->last_request_pos < rq->sector) - seek_dist = rq->sector - aic->last_request_pos; - else - seek_dist = aic->last_request_pos - rq->sector; - as_update_seekdist(ad, aic, seek_dist); - } - aic->last_request_pos = rq->sector + rq->nr_sectors; - set_bit(AS_TASK_IOSTARTED, &aic->state); - spin_unlock(&aic->lock); - } -} - -/* - * as_update_arq must be called whenever a request (arq) is added to - * the sort_list. This function keeps caches up to date, and checks if the - * request might be one we are "anticipating" - */ -static void as_update_arq(struct as_data *ad, struct as_rq *arq) -{ - const int data_dir = arq->is_sync; - - /* keep the next_arq cache up to date */ - ad->next_arq[data_dir] = as_choose_req(ad, arq, ad->next_arq[data_dir]); - - /* - * have we been anticipating this request? - * or does it come from the same process as the one we are anticipating - * for? - */ - if (ad->antic_status == ANTIC_WAIT_REQ - || ad->antic_status == ANTIC_WAIT_NEXT) { - if (as_can_break_anticipation(ad, arq)) - as_antic_stop(ad); - } -} - -/* - * Gathers timings and resizes the write batch automatically - */ -static void update_write_batch(struct as_data *ad) -{ - unsigned long batch = ad->batch_expire[REQ_ASYNC]; - long write_time; - - write_time = (jiffies - ad->current_batch_expires) + batch; - if (write_time < 0) - write_time = 0; - - if (write_time > batch && !ad->write_batch_idled) { - if (write_time > batch * 3) - ad->write_batch_count /= 2; - else - ad->write_batch_count--; - } else if (write_time < batch && ad->current_write_count == 0) { - if (batch > write_time * 3) - ad->write_batch_count *= 2; - else - ad->write_batch_count++; - } - - if (ad->write_batch_count < 1) - ad->write_batch_count = 1; -} - -/* - * as_completed_request is to be called when a request has completed and - * returned something to the requesting process, be it an error or data. - */ -static void as_completed_request(request_queue_t *q, struct request *rq) -{ - struct as_data *ad = q->elevator->elevator_data; - struct as_rq *arq = RQ_DATA(rq); - - WARN_ON(!list_empty(&rq->queuelist)); - - if (arq->state != AS_RQ_REMOVED) { - printk("arq->state %d\n", arq->state); - WARN_ON(1); - goto out; - } - - if (ad->changed_batch && ad->nr_dispatched == 1) { - kblockd_schedule_work(&ad->antic_work); - ad->changed_batch = 0; - - if (ad->batch_data_dir == REQ_SYNC) - ad->new_batch = 1; - } - WARN_ON(ad->nr_dispatched == 0); - ad->nr_dispatched--; - - /* - * Start counting the batch from when a request of that direction is - * actually serviced. This should help devices with big TCQ windows - * and writeback caches - */ - if (ad->new_batch && ad->batch_data_dir == arq->is_sync) { - update_write_batch(ad); - ad->current_batch_expires = jiffies + - ad->batch_expire[REQ_SYNC]; - ad->new_batch = 0; - } - - if (ad->io_context == arq->io_context && ad->io_context) { - ad->antic_start = jiffies; - ad->ioc_finished = 1; - if (ad->antic_status == ANTIC_WAIT_REQ) { - /* - * We were waiting on this request, now anticipate - * the next one - */ - as_antic_waitnext(ad); - } - } - - as_put_io_context(arq); -out: - arq->state = AS_RQ_POSTSCHED; -} - -/* - * as_remove_queued_request removes a request from the pre dispatch queue - * without updating refcounts. It is expected the caller will drop the - * reference unless it replaces the request at somepart of the elevator - * (ie. the dispatch queue) - */ -static void as_remove_queued_request(request_queue_t *q, struct request *rq) -{ - struct as_rq *arq = RQ_DATA(rq); - const int data_dir = arq->is_sync; - struct as_data *ad = q->elevator->elevator_data; - - WARN_ON(arq->state != AS_RQ_QUEUED); - - if (arq->io_context && arq->io_context->aic) { - BUG_ON(!atomic_read(&arq->io_context->aic->nr_queued)); - atomic_dec(&arq->io_context->aic->nr_queued); - } - - /* - * Update the "next_arq" cache if we are about to remove its - * entry - */ - if (ad->next_arq[data_dir] == arq) - ad->next_arq[data_dir] = as_find_next_arq(ad, arq); - - list_del_init(&arq->fifo); - as_del_arq_hash(arq); - as_del_arq_rb(ad, arq); -} - -/* - * as_fifo_expired returns 0 if there are no expired reads on the fifo, - * 1 otherwise. It is ratelimited so that we only perform the check once per - * `fifo_expire' interval. Otherwise a large number of expired requests - * would create a hopeless seekstorm. - * - * See as_antic_expired comment. - */ -static int as_fifo_expired(struct as_data *ad, int adir) -{ - struct as_rq *arq; - long delta_jif; - - delta_jif = jiffies - ad->last_check_fifo[adir]; - if (unlikely(delta_jif < 0)) - delta_jif = -delta_jif; - if (delta_jif < ad->fifo_expire[adir]) - return 0; - - ad->last_check_fifo[adir] = jiffies; - - if (list_empty(&ad->fifo_list[adir])) - return 0; - - arq = list_entry_fifo(ad->fifo_list[adir].next); - - return time_after(jiffies, arq->expires); -} - -/* - * as_batch_expired returns true if the current batch has expired. A batch - * is a set of reads or a set of writes. - */ -static inline int as_batch_expired(struct as_data *ad) -{ - if (ad->changed_batch || ad->new_batch) - return 0; - - if (ad->batch_data_dir == REQ_SYNC) - /* TODO! add a check so a complete fifo gets written? */ - return time_after(jiffies, ad->current_batch_expires); - - return time_after(jiffies, ad->current_batch_expires) - || ad->current_write_count == 0; -} - -/* - * move an entry to dispatch queue - */ -static void as_move_to_dispatch(struct as_data *ad, struct as_rq *arq) -{ - struct request *rq = arq->request; - const int data_dir = arq->is_sync; - - BUG_ON(!ON_RB(&arq->rb_node)); - - as_antic_stop(ad); - ad->antic_status = ANTIC_OFF; - - /* - * This has to be set in order to be correctly updated by - * as_find_next_arq - */ - ad->last_sector[data_dir] = rq->sector + rq->nr_sectors; - - if (data_dir == REQ_SYNC) { - /* In case we have to anticipate after this */ - copy_io_context(&ad->io_context, &arq->io_context); - } else { - if (ad->io_context) { - put_io_context(ad->io_context); - ad->io_context = NULL; - } - - if (ad->current_write_count != 0) - ad->current_write_count--; - } - ad->ioc_finished = 0; - - ad->next_arq[data_dir] = as_find_next_arq(ad, arq); - - /* - * take it off the sort and fifo list, add to dispatch queue - */ - while (!list_empty(&rq->queuelist)) { - struct request *__rq = list_entry_rq(rq->queuelist.next); - struct as_rq *__arq = RQ_DATA(__rq); - - list_del(&__rq->queuelist); - - elv_dispatch_add_tail(ad->q, __rq); - - if (__arq->io_context && __arq->io_context->aic) - atomic_inc(&__arq->io_context->aic->nr_dispatched); - - WARN_ON(__arq->state != AS_RQ_QUEUED); - __arq->state = AS_RQ_DISPATCHED; - - ad->nr_dispatched++; - } - - as_remove_queued_request(ad->q, rq); - WARN_ON(arq->state != AS_RQ_QUEUED); - - elv_dispatch_sort(ad->q, rq); - - arq->state = AS_RQ_DISPATCHED; - if (arq->io_context && arq->io_context->aic) - atomic_inc(&arq->io_context->aic->nr_dispatched); - ad->nr_dispatched++; -} - -/* - * as_dispatch_request selects the best request according to - * read/write expire, batch expire, etc, and moves it to the dispatch - * queue. Returns 1 if a request was found, 0 otherwise. - */ -static int as_dispatch_request(request_queue_t *q, int force) -{ - struct as_data *ad = q->elevator->elevator_data; - struct as_rq *arq; - const int reads = !list_empty(&ad->fifo_list[REQ_SYNC]); - const int writes = !list_empty(&ad->fifo_list[REQ_ASYNC]); - - if (unlikely(force)) { - /* - * Forced dispatch, accounting is useless. Reset - * accounting states and dump fifo_lists. Note that - * batch_data_dir is reset to REQ_SYNC to avoid - * screwing write batch accounting as write batch - * accounting occurs on W->R transition. - */ - int dispatched = 0; - - ad->batch_data_dir = REQ_SYNC; - ad->changed_batch = 0; - ad->new_batch = 0; - - while (ad->next_arq[REQ_SYNC]) { - as_move_to_dispatch(ad, ad->next_arq[REQ_SYNC]); - dispatched++; - } - ad->last_check_fifo[REQ_SYNC] = jiffies; - - while (ad->next_arq[REQ_ASYNC]) { - as_move_to_dispatch(ad, ad->next_arq[REQ_ASYNC]); - dispatched++; - } - ad->last_check_fifo[REQ_ASYNC] = jiffies; - - return dispatched; - } - - /* Signal that the write batch was uncontended, so we can't time it */ - if (ad->batch_data_dir == REQ_ASYNC && !reads) { - if (ad->current_write_count == 0 || !writes) - ad->write_batch_idled = 1; - } - - if (!(reads || writes) - || ad->antic_status == ANTIC_WAIT_REQ - || ad->antic_status == ANTIC_WAIT_NEXT - || ad->changed_batch) - return 0; - - if (!(reads && writes && as_batch_expired(ad)) ) { - /* - * batch is still running or no reads or no writes - */ - arq = ad->next_arq[ad->batch_data_dir]; - - if (ad->batch_data_dir == REQ_SYNC && ad->antic_expire) { - if (as_fifo_expired(ad, REQ_SYNC)) - goto fifo_expired; - - if (as_can_anticipate(ad, arq)) { - as_antic_waitreq(ad); - return 0; - } - } - - if (arq) { - /* we have a "next request" */ - if (reads && !writes) - ad->current_batch_expires = - jiffies + ad->batch_expire[REQ_SYNC]; - goto dispatch_request; - } - } - - /* - * at this point we are not running a batch. select the appropriate - * data direction (read / write) - */ - - if (reads) { - BUG_ON(RB_EMPTY(&ad->sort_list[REQ_SYNC])); - - if (writes && ad->batch_data_dir == REQ_SYNC) - /* - * Last batch was a read, switch to writes - */ - goto dispatch_writes; - - if (ad->batch_data_dir == REQ_ASYNC) { - WARN_ON(ad->new_batch); - ad->changed_batch = 1; - } - ad->batch_data_dir = REQ_SYNC; - arq = list_entry_fifo(ad->fifo_list[ad->batch_data_dir].next); - ad->last_check_fifo[ad->batch_data_dir] = jiffies; - goto dispatch_request; - } - - /* - * the last batch was a read - */ - - if (writes) { -dispatch_writes: - BUG_ON(RB_EMPTY(&ad->sort_list[REQ_ASYNC])); - - if (ad->batch_data_dir == REQ_SYNC) { - ad->changed_batch = 1; - - /* - * new_batch might be 1 when the queue runs out of - * reads. A subsequent submission of a write might - * cause a change of batch before the read is finished. - */ - ad->new_batch = 0; - } - ad->batch_data_dir = REQ_ASYNC; - ad->current_write_count = ad->write_batch_count; - ad->write_batch_idled = 0; - arq = ad->next_arq[ad->batch_data_dir]; - goto dispatch_request; - } - - BUG(); - return 0; - -dispatch_request: - /* - * If a request has expired, service it. - */ - - if (as_fifo_expired(ad, ad->batch_data_dir)) { -fifo_expired: - arq = list_entry_fifo(ad->fifo_list[ad->batch_data_dir].next); - BUG_ON(arq == NULL); - } - - if (ad->changed_batch) { - WARN_ON(ad->new_batch); - - if (ad->nr_dispatched) - return 0; - - if (ad->batch_data_dir == REQ_ASYNC) - ad->current_batch_expires = jiffies + - ad->batch_expire[REQ_ASYNC]; - else - ad->new_batch = 1; - - ad->changed_batch = 0; - } - - /* - * arq is the selected appropriate request. - */ - as_move_to_dispatch(ad, arq); - - return 1; -} - -/* - * Add arq to a list behind alias - */ -static inline void -as_add_aliased_request(struct as_data *ad, struct as_rq *arq, struct as_rq *alias) -{ - struct request *req = arq->request; - struct list_head *insert = alias->request->queuelist.prev; - - /* - * Transfer list of aliases - */ - while (!list_empty(&req->queuelist)) { - struct request *__rq = list_entry_rq(req->queuelist.next); - struct as_rq *__arq = RQ_DATA(__rq); - - list_move_tail(&__rq->queuelist, &alias->request->queuelist); - - WARN_ON(__arq->state != AS_RQ_QUEUED); - } - - /* - * Another request with the same start sector on the rbtree. - * Link this request to that sector. They are untangled in - * as_move_to_dispatch - */ - list_add(&arq->request->queuelist, insert); - - /* - * Don't want to have to handle merges. - */ - as_del_arq_hash(arq); - arq->request->flags |= REQ_NOMERGE; -} - -/* - * add arq to rbtree and fifo - */ -static void as_add_request(request_queue_t *q, struct request *rq) -{ - struct as_data *ad = q->elevator->elevator_data; - struct as_rq *arq = RQ_DATA(rq); - struct as_rq *alias; - int data_dir; - - if (arq->state != AS_RQ_PRESCHED) { - printk("arq->state: %d\n", arq->state); - WARN_ON(1); - } - arq->state = AS_RQ_NEW; - - if (rq_data_dir(arq->request) == READ - || current->flags&PF_SYNCWRITE) - arq->is_sync = 1; - else - arq->is_sync = 0; - data_dir = arq->is_sync; - - arq->io_context = as_get_io_context(); - - if (arq->io_context) { - as_update_iohist(ad, arq->io_context->aic, arq->request); - atomic_inc(&arq->io_context->aic->nr_queued); - } - - alias = as_add_arq_rb(ad, arq); - if (!alias) { - /* - * set expire time (only used for reads) and add to fifo list - */ - arq->expires = jiffies + ad->fifo_expire[data_dir]; - list_add_tail(&arq->fifo, &ad->fifo_list[data_dir]); - - if (rq_mergeable(arq->request)) - as_add_arq_hash(ad, arq); - as_update_arq(ad, arq); /* keep state machine up to date */ - - } else { - as_add_aliased_request(ad, arq, alias); - - /* - * have we been anticipating this request? - * or does it come from the same process as the one we are - * anticipating for? - */ - if (ad->antic_status == ANTIC_WAIT_REQ - || ad->antic_status == ANTIC_WAIT_NEXT) { - if (as_can_break_anticipation(ad, arq)) - as_antic_stop(ad); - } - } - - arq->state = AS_RQ_QUEUED; -} - -static void as_activate_request(request_queue_t *q, struct request *rq) -{ - struct as_rq *arq = RQ_DATA(rq); - - WARN_ON(arq->state != AS_RQ_DISPATCHED); - arq->state = AS_RQ_REMOVED; - if (arq->io_context && arq->io_context->aic) - atomic_dec(&arq->io_context->aic->nr_dispatched); -} - -static void as_deactivate_request(request_queue_t *q, struct request *rq) -{ - struct as_rq *arq = RQ_DATA(rq); - - WARN_ON(arq->state != AS_RQ_REMOVED); - arq->state = AS_RQ_DISPATCHED; - if (arq->io_context && arq->io_context->aic) - atomic_inc(&arq->io_context->aic->nr_dispatched); -} - -/* - * as_queue_empty tells us if there are requests left in the device. It may - * not be the case that a driver can get the next request even if the queue - * is not empty - it is used in the block layer to check for plugging and - * merging opportunities - */ -static int as_queue_empty(request_queue_t *q) -{ - struct as_data *ad = q->elevator->elevator_data; - - return list_empty(&ad->fifo_list[REQ_ASYNC]) - && list_empty(&ad->fifo_list[REQ_SYNC]); -} - -static struct request * -as_former_request(request_queue_t *q, struct request *rq) -{ - struct as_rq *arq = RQ_DATA(rq); - struct rb_node *rbprev = rb_prev(&arq->rb_node); - struct request *ret = NULL; - - if (rbprev) - ret = rb_entry_arq(rbprev)->request; - - return ret; -} - -static struct request * -as_latter_request(request_queue_t *q, struct request *rq) -{ - struct as_rq *arq = RQ_DATA(rq); - struct rb_node *rbnext = rb_next(&arq->rb_node); - struct request *ret = NULL; - - if (rbnext) - ret = rb_entry_arq(rbnext)->request; - - return ret; -} - -static int -as_merge(request_queue_t *q, struct request **req, struct bio *bio) -{ - struct as_data *ad = q->elevator->elevator_data; - sector_t rb_key = bio->bi_sector + bio_sectors(bio); - struct request *__rq; - int ret; - - /* - * see if the merge hash can satisfy a back merge - */ - __rq = as_find_arq_hash(ad, bio->bi_sector); - if (__rq) { - BUG_ON(__rq->sector + __rq->nr_sectors != bio->bi_sector); - - if (elv_rq_merge_ok(__rq, bio)) { - ret = ELEVATOR_BACK_MERGE; - goto out; - } - } - - /* - * check for front merge - */ - __rq = as_find_arq_rb(ad, rb_key, bio_data_dir(bio)); - if (__rq) { - BUG_ON(rb_key != rq_rb_key(__rq)); - - if (elv_rq_merge_ok(__rq, bio)) { - ret = ELEVATOR_FRONT_MERGE; - goto out; - } - } - - return ELEVATOR_NO_MERGE; -out: - if (ret) { - if (rq_mergeable(__rq)) - as_hot_arq_hash(ad, RQ_DATA(__rq)); - } - *req = __rq; - return ret; -} - -static void as_merged_request(request_queue_t *q, struct request *req) -{ - struct as_data *ad = q->elevator->elevator_data; - struct as_rq *arq = RQ_DATA(req); - - /* - * hash always needs to be repositioned, key is end sector - */ - as_del_arq_hash(arq); - as_add_arq_hash(ad, arq); - - /* - * if the merge was a front merge, we need to reposition request - */ - if (rq_rb_key(req) != arq->rb_key) { - struct as_rq *alias, *next_arq = NULL; - - if (ad->next_arq[arq->is_sync] == arq) - next_arq = as_find_next_arq(ad, arq); - - /* - * Note! We should really be moving any old aliased requests - * off this request and try to insert them into the rbtree. We - * currently don't bother. Ditto the next function. - */ - as_del_arq_rb(ad, arq); - if ((alias = as_add_arq_rb(ad, arq)) ) { - list_del_init(&arq->fifo); - as_add_aliased_request(ad, arq, alias); - if (next_arq) - ad->next_arq[arq->is_sync] = next_arq; - } - /* - * Note! At this stage of this and the next function, our next - * request may not be optimal - eg the request may have "grown" - * behind the disk head. We currently don't bother adjusting. - */ - } -} - -static void -as_merged_requests(request_queue_t *q, struct request *req, - struct request *next) -{ - struct as_data *ad = q->elevator->elevator_data; - struct as_rq *arq = RQ_DATA(req); - struct as_rq *anext = RQ_DATA(next); - - BUG_ON(!arq); - BUG_ON(!anext); - - /* - * reposition arq (this is the merged request) in hash, and in rbtree - * in case of a front merge - */ - as_del_arq_hash(arq); - as_add_arq_hash(ad, arq); - - if (rq_rb_key(req) != arq->rb_key) { - struct as_rq *alias, *next_arq = NULL; - - if (ad->next_arq[arq->is_sync] == arq) - next_arq = as_find_next_arq(ad, arq); - - as_del_arq_rb(ad, arq); - if ((alias = as_add_arq_rb(ad, arq)) ) { - list_del_init(&arq->fifo); - as_add_aliased_request(ad, arq, alias); - if (next_arq) - ad->next_arq[arq->is_sync] = next_arq; - } - } - - /* - * if anext expires before arq, assign its expire time to arq - * and move into anext position (anext will be deleted) in fifo - */ - if (!list_empty(&arq->fifo) && !list_empty(&anext->fifo)) { - if (time_before(anext->expires, arq->expires)) { - list_move(&arq->fifo, &anext->fifo); - arq->expires = anext->expires; - /* - * Don't copy here but swap, because when anext is - * removed below, it must contain the unused context - */ - swap_io_context(&arq->io_context, &anext->io_context); - } - } - - /* - * Transfer list of aliases - */ - while (!list_empty(&next->queuelist)) { - struct request *__rq = list_entry_rq(next->queuelist.next); - struct as_rq *__arq = RQ_DATA(__rq); - - list_move_tail(&__rq->queuelist, &req->queuelist); - - WARN_ON(__arq->state != AS_RQ_QUEUED); - } - - /* - * kill knowledge of next, this one is a goner - */ - as_remove_queued_request(q, next); - as_put_io_context(anext); - - anext->state = AS_RQ_MERGED; -} - -/* - * This is executed in a "deferred" process context, by kblockd. It calls the - * driver's request_fn so the driver can submit that request. - * - * IMPORTANT! This guy will reenter the elevator, so set up all queue global - * state before calling, and don't rely on any state over calls. - * - * FIXME! dispatch queue is not a queue at all! - */ -static void as_work_handler(void *data) -{ - struct request_queue *q = data; - unsigned long flags; - - spin_lock_irqsave(q->queue_lock, flags); - if (!as_queue_empty(q)) - q->request_fn(q); - spin_unlock_irqrestore(q->queue_lock, flags); -} - -static void as_put_request(request_queue_t *q, struct request *rq) -{ - struct as_data *ad = q->elevator->elevator_data; - struct as_rq *arq = RQ_DATA(rq); - - if (!arq) { - WARN_ON(1); - return; - } - - if (unlikely(arq->state != AS_RQ_POSTSCHED && - arq->state != AS_RQ_PRESCHED && - arq->state != AS_RQ_MERGED)) { - printk("arq->state %d\n", arq->state); - WARN_ON(1); - } - - mempool_free(arq, ad->arq_pool); - rq->elevator_private = NULL; -} - -static int as_set_request(request_queue_t *q, struct request *rq, - struct bio *bio, gfp_t gfp_mask) -{ - struct as_data *ad = q->elevator->elevator_data; - struct as_rq *arq = mempool_alloc(ad->arq_pool, gfp_mask); - - if (arq) { - memset(arq, 0, sizeof(*arq)); - RB_CLEAR(&arq->rb_node); - arq->request = rq; - arq->state = AS_RQ_PRESCHED; - arq->io_context = NULL; - INIT_LIST_HEAD(&arq->hash); - arq->on_hash = 0; - INIT_LIST_HEAD(&arq->fifo); - rq->elevator_private = arq; - return 0; - } - - return 1; -} - -static int as_may_queue(request_queue_t *q, int rw, struct bio *bio) -{ - int ret = ELV_MQUEUE_MAY; - struct as_data *ad = q->elevator->elevator_data; - struct io_context *ioc; - if (ad->antic_status == ANTIC_WAIT_REQ || - ad->antic_status == ANTIC_WAIT_NEXT) { - ioc = as_get_io_context(); - if (ad->io_context == ioc) - ret = ELV_MQUEUE_MUST; - put_io_context(ioc); - } - - return ret; -} - -static void as_exit_queue(elevator_t *e) -{ - struct as_data *ad = e->elevator_data; - - del_timer_sync(&ad->antic_timer); - kblockd_flush(); - - BUG_ON(!list_empty(&ad->fifo_list[REQ_SYNC])); - BUG_ON(!list_empty(&ad->fifo_list[REQ_ASYNC])); - - mempool_destroy(ad->arq_pool); - put_io_context(ad->io_context); - kfree(ad->hash); - kfree(ad); -} - -/* - * initialize elevator private data (as_data), and alloc a arq for - * each request on the free lists - */ -static int as_init_queue(request_queue_t *q, elevator_t *e) -{ - struct as_data *ad; - int i; - - if (!arq_pool) - return -ENOMEM; - - ad = kmalloc_node(sizeof(*ad), GFP_KERNEL, q->node); - if (!ad) - return -ENOMEM; - memset(ad, 0, sizeof(*ad)); - - ad->q = q; /* Identify what queue the data belongs to */ - - ad->hash = kmalloc_node(sizeof(struct list_head)*AS_HASH_ENTRIES, - GFP_KERNEL, q->node); - if (!ad->hash) { - kfree(ad); - return -ENOMEM; - } - - ad->arq_pool = mempool_create_node(BLKDEV_MIN_RQ, mempool_alloc_slab, - mempool_free_slab, arq_pool, q->node); - if (!ad->arq_pool) { - kfree(ad->hash); - kfree(ad); - return -ENOMEM; - } - - /* anticipatory scheduling helpers */ - ad->antic_timer.function = as_antic_timeout; - ad->antic_timer.data = (unsigned long)q; - init_timer(&ad->antic_timer); - INIT_WORK(&ad->antic_work, as_work_handler, q); - - for (i = 0; i < AS_HASH_ENTRIES; i++) - INIT_LIST_HEAD(&ad->hash[i]); - - INIT_LIST_HEAD(&ad->fifo_list[REQ_SYNC]); - INIT_LIST_HEAD(&ad->fifo_list[REQ_ASYNC]); - ad->sort_list[REQ_SYNC] = RB_ROOT; - ad->sort_list[REQ_ASYNC] = RB_ROOT; - ad->fifo_expire[REQ_SYNC] = default_read_expire; - ad->fifo_expire[REQ_ASYNC] = default_write_expire; - ad->antic_expire = default_antic_expire; - ad->batch_expire[REQ_SYNC] = default_read_batch_expire; - ad->batch_expire[REQ_ASYNC] = default_write_batch_expire; - e->elevator_data = ad; - - ad->current_batch_expires = jiffies + ad->batch_expire[REQ_SYNC]; - ad->write_batch_count = ad->batch_expire[REQ_ASYNC] / 10; - if (ad->write_batch_count < 2) - ad->write_batch_count = 2; - - return 0; -} - -/* - * sysfs parts below - */ -struct as_fs_entry { - struct attribute attr; - ssize_t (*show)(struct as_data *, char *); - ssize_t (*store)(struct as_data *, const char *, size_t); -}; - -static ssize_t -as_var_show(unsigned int var, char *page) -{ - return sprintf(page, "%d\n", var); -} - -static ssize_t -as_var_store(unsigned long *var, const char *page, size_t count) -{ - char *p = (char *) page; - - *var = simple_strtoul(p, &p, 10); - return count; -} - -static ssize_t as_est_show(struct as_data *ad, char *page) -{ - int pos = 0; - - pos += sprintf(page+pos, "%lu %% exit probability\n", 100*ad->exit_prob/256); - pos += sprintf(page+pos, "%lu ms new thinktime\n", ad->new_ttime_mean); - pos += sprintf(page+pos, "%llu sectors new seek distance\n", (unsigned long long)ad->new_seek_mean); - - return pos; -} - -#define SHOW_FUNCTION(__FUNC, __VAR) \ -static ssize_t __FUNC(struct as_data *ad, char *page) \ -{ \ - return as_var_show(jiffies_to_msecs((__VAR)), (page)); \ -} -SHOW_FUNCTION(as_readexpire_show, ad->fifo_expire[REQ_SYNC]); -SHOW_FUNCTION(as_writeexpire_show, ad->fifo_expire[REQ_ASYNC]); -SHOW_FUNCTION(as_anticexpire_show, ad->antic_expire); -SHOW_FUNCTION(as_read_batchexpire_show, ad->batch_expire[REQ_SYNC]); -SHOW_FUNCTION(as_write_batchexpire_show, ad->batch_expire[REQ_ASYNC]); -#undef SHOW_FUNCTION - -#define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX) \ -static ssize_t __FUNC(struct as_data *ad, const char *page, size_t count) \ -{ \ - int ret = as_var_store(__PTR, (page), count); \ - if (*(__PTR) < (MIN)) \ - *(__PTR) = (MIN); \ - else if (*(__PTR) > (MAX)) \ - *(__PTR) = (MAX); \ - *(__PTR) = msecs_to_jiffies(*(__PTR)); \ - return ret; \ -} -STORE_FUNCTION(as_readexpire_store, &ad->fifo_expire[REQ_SYNC], 0, INT_MAX); -STORE_FUNCTION(as_writeexpire_store, &ad->fifo_expire[REQ_ASYNC], 0, INT_MAX); -STORE_FUNCTION(as_anticexpire_store, &ad->antic_expire, 0, INT_MAX); -STORE_FUNCTION(as_read_batchexpire_store, - &ad->batch_expire[REQ_SYNC], 0, INT_MAX); -STORE_FUNCTION(as_write_batchexpire_store, - &ad->batch_expire[REQ_ASYNC], 0, INT_MAX); -#undef STORE_FUNCTION - -static struct as_fs_entry as_est_entry = { - .attr = {.name = "est_time", .mode = S_IRUGO }, - .show = as_est_show, -}; -static struct as_fs_entry as_readexpire_entry = { - .attr = {.name = "read_expire", .mode = S_IRUGO | S_IWUSR }, - .show = as_readexpire_show, - .store = as_readexpire_store, -}; -static struct as_fs_entry as_writeexpire_entry = { - .attr = {.name = "write_expire", .mode = S_IRUGO | S_IWUSR }, - .show = as_writeexpire_show, - .store = as_writeexpire_store, -}; -static struct as_fs_entry as_anticexpire_entry = { - .attr = {.name = "antic_expire", .mode = S_IRUGO | S_IWUSR }, - .show = as_anticexpire_show, - .store = as_anticexpire_store, -}; -static struct as_fs_entry as_read_batchexpire_entry = { - .attr = {.name = "read_batch_expire", .mode = S_IRUGO | S_IWUSR }, - .show = as_read_batchexpire_show, - .store = as_read_batchexpire_store, -}; -static struct as_fs_entry as_write_batchexpire_entry = { - .attr = {.name = "write_batch_expire", .mode = S_IRUGO | S_IWUSR }, - .show = as_write_batchexpire_show, - .store = as_write_batchexpire_store, -}; - -static struct attribute *default_attrs[] = { - &as_est_entry.attr, - &as_readexpire_entry.attr, - &as_writeexpire_entry.attr, - &as_anticexpire_entry.attr, - &as_read_batchexpire_entry.attr, - &as_write_batchexpire_entry.attr, - NULL, -}; - -#define to_as(atr) container_of((atr), struct as_fs_entry, attr) - -static ssize_t -as_attr_show(struct kobject *kobj, struct attribute *attr, char *page) -{ - elevator_t *e = container_of(kobj, elevator_t, kobj); - struct as_fs_entry *entry = to_as(attr); - - if (!entry->show) - return -EIO; - - return entry->show(e->elevator_data, page); -} - -static ssize_t -as_attr_store(struct kobject *kobj, struct attribute *attr, - const char *page, size_t length) -{ - elevator_t *e = container_of(kobj, elevator_t, kobj); - struct as_fs_entry *entry = to_as(attr); - - if (!entry->store) - return -EIO; - - return entry->store(e->elevator_data, page, length); -} - -static struct sysfs_ops as_sysfs_ops = { - .show = as_attr_show, - .store = as_attr_store, -}; - -static struct kobj_type as_ktype = { - .sysfs_ops = &as_sysfs_ops, - .default_attrs = default_attrs, -}; - -static struct elevator_type iosched_as = { - .ops = { - .elevator_merge_fn = as_merge, - .elevator_merged_fn = as_merged_request, - .elevator_merge_req_fn = as_merged_requests, - .elevator_dispatch_fn = as_dispatch_request, - .elevator_add_req_fn = as_add_request, - .elevator_activate_req_fn = as_activate_request, - .elevator_deactivate_req_fn = as_deactivate_request, - .elevator_queue_empty_fn = as_queue_empty, - .elevator_completed_req_fn = as_completed_request, - .elevator_former_req_fn = as_former_request, - .elevator_latter_req_fn = as_latter_request, - .elevator_set_req_fn = as_set_request, - .elevator_put_req_fn = as_put_request, - .elevator_may_queue_fn = as_may_queue, - .elevator_init_fn = as_init_queue, - .elevator_exit_fn = as_exit_queue, - }, - - .elevator_ktype = &as_ktype, - .elevator_name = "anticipatory", - .elevator_owner = THIS_MODULE, -}; - -static int __init as_init(void) -{ - int ret; - - arq_pool = kmem_cache_create("as_arq", sizeof(struct as_rq), - 0, 0, NULL, NULL); - if (!arq_pool) - return -ENOMEM; - - ret = elv_register(&iosched_as); - if (!ret) { - /* - * don't allow AS to get unregistered, since we would have - * to browse all tasks in the system and release their - * as_io_context first - */ - __module_get(THIS_MODULE); - return 0; - } - - kmem_cache_destroy(arq_pool); - return ret; -} - -static void __exit as_exit(void) -{ - elv_unregister(&iosched_as); - kmem_cache_destroy(arq_pool); -} - -module_init(as_init); -module_exit(as_exit); - -MODULE_AUTHOR("Nick Piggin"); -MODULE_LICENSE("GPL"); -MODULE_DESCRIPTION("anticipatory IO scheduler"); diff --git a/drivers/block/cfq-iosched.c b/drivers/block/cfq-iosched.c deleted file mode 100644 index ecacca9..0000000 --- a/drivers/block/cfq-iosched.c +++ /dev/null @@ -1,2428 +0,0 @@ -/* - * linux/drivers/block/cfq-iosched.c - * - * CFQ, or complete fairness queueing, disk scheduler. - * - * Based on ideas from a previously unfinished io - * scheduler (round robin per-process disk scheduling) and Andrea Arcangeli. - * - * Copyright (C) 2003 Jens Axboe <axboe@suse.de> - */ -#include <linux/kernel.h> -#include <linux/fs.h> -#include <linux/blkdev.h> -#include <linux/elevator.h> -#include <linux/bio.h> -#include <linux/config.h> -#include <linux/module.h> -#include <linux/slab.h> -#include <linux/init.h> -#include <linux/compiler.h> -#include <linux/hash.h> -#include <linux/rbtree.h> -#include <linux/mempool.h> -#include <linux/ioprio.h> -#include <linux/writeback.h> - -/* - * tunables - */ -static int cfq_quantum = 4; /* max queue in one round of service */ -static int cfq_queued = 8; /* minimum rq allocate limit per-queue*/ -static int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 }; -static int cfq_back_max = 16 * 1024; /* maximum backwards seek, in KiB */ -static int cfq_back_penalty = 2; /* penalty of a backwards seek */ - -static int cfq_slice_sync = HZ / 10; -static int cfq_slice_async = HZ / 25; -static int cfq_slice_async_rq = 2; -static int cfq_slice_idle = HZ / 100; - -#define CFQ_IDLE_GRACE (HZ / 10) -#define CFQ_SLICE_SCALE (5) - -#define CFQ_KEY_ASYNC (0) -#define CFQ_KEY_ANY (0xffff) - -/* - * disable queueing at the driver/hardware level - */ -static int cfq_max_depth = 2; - -/* - * for the hash of cfqq inside the cfqd - */ -#define CFQ_QHASH_SHIFT 6 -#define CFQ_QHASH_ENTRIES (1 << CFQ_QHASH_SHIFT) -#define list_entry_qhash(entry) hlist_entry((entry), struct cfq_queue, cfq_hash) - -/* - * for the hash of crq inside the cfqq - */ -#define CFQ_MHASH_SHIFT 6 -#define CFQ_MHASH_BLOCK(sec) ((sec) >> 3) -#define CFQ_MHASH_ENTRIES (1 << CFQ_MHASH_SHIFT) -#define CFQ_MHASH_FN(sec) hash_long(CFQ_MHASH_BLOCK(sec), CFQ_MHASH_SHIFT) -#define rq_hash_key(rq) ((rq)->sector + (rq)->nr_sectors) -#define list_entry_hash(ptr) hlist_entry((ptr), struct cfq_rq, hash) - -#define list_entry_cfqq(ptr) list_entry((ptr), struct cfq_queue, cfq_list) -#define list_entry_fifo(ptr) list_entry((ptr), struct request, queuelist) - -#define RQ_DATA(rq) (rq)->elevator_private - -/* - * rb-tree defines - */ -#define RB_NONE (2) -#define RB_EMPTY(node) ((node)->rb_node == NULL) -#define RB_CLEAR_COLOR(node) (node)->rb_color = RB_NONE -#define RB_CLEAR(node) do { \ - (node)->rb_parent = NULL; \ - RB_CLEAR_COLOR((node)); \ - (node)->rb_right = NULL; \ - (node)->rb_left = NULL; \ -} while (0) -#define RB_CLEAR_ROOT(root) ((root)->rb_node = NULL) -#define rb_entry_crq(node) rb_entry((node), struct cfq_rq, rb_node) -#define rq_rb_key(rq) (rq)->sector - -static kmem_cache_t *crq_pool; -static kmem_cache_t *cfq_pool; -static kmem_cache_t *cfq_ioc_pool; - -#define CFQ_PRIO_LISTS IOPRIO_BE_NR -#define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE) -#define cfq_class_be(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_BE) -#define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT) - -#define ASYNC (0) -#define SYNC (1) - -#define cfq_cfqq_dispatched(cfqq) \ - ((cfqq)->on_dispatch[ASYNC] + (cfqq)->on_dispatch[SYNC]) - -#define cfq_cfqq_class_sync(cfqq) ((cfqq)->key != CFQ_KEY_ASYNC) - -#define cfq_cfqq_sync(cfqq) \ - (cfq_cfqq_class_sync(cfqq) || (cfqq)->on_dispatch[SYNC]) - -/* - * Per block device queue structure - */ -struct cfq_data { - atomic_t ref; - request_queue_t *queue; - - /* - * rr list of queues with requests and the count of them - */ - struct list_head rr_list[CFQ_PRIO_LISTS]; - struct list_head busy_rr; - struct list_head cur_rr; - struct list_head idle_rr; - unsigned int busy_queues; - - /* - * non-ordered list of empty cfqq's - */ - struct list_head empty_list; - - /* - * cfqq lookup hash - */ - struct hlist_head *cfq_hash; - - /* - * global crq hash for all queues - */ - struct hlist_head *crq_hash; - - unsigned int max_queued; - - mempool_t *crq_pool; - - int rq_in_driver; - - /* - * schedule slice state info - */ - /* - * idle window management - */ - struct timer_list idle_slice_timer; - struct work_struct unplug_work; - - struct cfq_queue *active_queue; - struct cfq_io_context *active_cic; - int cur_prio, cur_end_prio; - unsigned int dispatch_slice; - - struct timer_list idle_class_timer; - - sector_t last_sector; - unsigned long last_end_request; - - unsigned int rq_starved; - - /* - * tunables, see top of file - */ - unsigned int cfq_quantum; - unsigned int cfq_queued; - unsigned int cfq_fifo_expire[2]; - unsigned int cfq_back_penalty; - unsigned int cfq_back_max; - unsigned int cfq_slice[2]; - unsigned int cfq_slice_async_rq; - unsigned int cfq_slice_idle; - unsigned int cfq_max_depth; -}; - -/* - * Per process-grouping structure - */ -struct cfq_queue { - /* reference count */ - atomic_t ref; - /* parent cfq_data */ - struct cfq_data *cfqd; - /* cfqq lookup hash */ - struct hlist_node cfq_hash; - /* hash key */ - unsigned int key; - /* on either rr or empty list of cfqd */ - struct list_head cfq_list; - /* sorted list of pending requests */ - struct rb_root sort_list; - /* if fifo isn't expired, next request to serve */ - struct cfq_rq *next_crq; - /* requests queued in sort_list */ - int queued[2]; - /* currently allocated requests */ - int allocated[2]; - /* fifo list of requests in sort_list */ - struct list_head fifo; - - unsigned long slice_start; - unsigned long slice_end; - unsigned long slice_left; - unsigned long service_last; - - /* number of requests that are on the dispatch list */ - int on_dispatch[2]; - - /* io prio of this group */ - unsigned short ioprio, org_ioprio; - unsigned short ioprio_class, org_ioprio_class; - - /* various state flags, see below */ - unsigned int flags; -}; - -struct cfq_rq { - struct rb_node rb_node; - sector_t rb_key; - struct request *request; - struct hlist_node hash; - - struct cfq_queue *cfq_queue; - struct cfq_io_context *io_context; - - unsigned int crq_flags; -}; - -enum cfqq_state_flags { - CFQ_CFQQ_FLAG_on_rr = 0, - CFQ_CFQQ_FLAG_wait_request, - CFQ_CFQQ_FLAG_must_alloc, - CFQ_CFQQ_FLAG_must_alloc_slice, - CFQ_CFQQ_FLAG_must_dispatch, - CFQ_CFQQ_FLAG_fifo_expire, - CFQ_CFQQ_FLAG_idle_window, - CFQ_CFQQ_FLAG_prio_changed, - CFQ_CFQQ_FLAG_expired, -}; - -#define CFQ_CFQQ_FNS(name) \ -static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \ -{ \ - cfqq->flags |= (1 << CFQ_CFQQ_FLAG_##name); \ -} \ -static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \ -{ \ - cfqq->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \ -} \ -static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \ -{ \ - return (cfqq->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \ -} - -CFQ_CFQQ_FNS(on_rr); -CFQ_CFQQ_FNS(wait_request); -CFQ_CFQQ_FNS(must_alloc); -CFQ_CFQQ_FNS(must_alloc_slice); -CFQ_CFQQ_FNS(must_dispatch); -CFQ_CFQQ_FNS(fifo_expire); -CFQ_CFQQ_FNS(idle_window); -CFQ_CFQQ_FNS(prio_changed); -CFQ_CFQQ_FNS(expired); -#undef CFQ_CFQQ_FNS - -enum cfq_rq_state_flags { - CFQ_CRQ_FLAG_is_sync = 0, -}; - -#define CFQ_CRQ_FNS(name) \ -static inline void cfq_mark_crq_##name(struct cfq_rq *crq) \ -{ \ - crq->crq_flags |= (1 << CFQ_CRQ_FLAG_##name); \ -} \ -static inline void cfq_clear_crq_##name(struct cfq_rq *crq) \ -{ \ - crq->crq_flags &= ~(1 << CFQ_CRQ_FLAG_##name); \ -} \ -static inline int cfq_crq_##name(const struct cfq_rq *crq) \ -{ \ - return (crq->crq_flags & (1 << CFQ_CRQ_FLAG_##name)) != 0; \ -} - -CFQ_CRQ_FNS(is_sync); -#undef CFQ_CRQ_FNS - -static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned int, unsigned short); -static void cfq_dispatch_insert(request_queue_t *, struct cfq_rq *); -static void cfq_put_cfqd(struct cfq_data *cfqd); - -#define process_sync(tsk) ((tsk)->flags & PF_SYNCWRITE) - -/* - * lots of deadline iosched dupes, can be abstracted later... - */ -static inline void cfq_del_crq_hash(struct cfq_rq *crq) -{ - hlist_del_init(&crq->hash); -} - -static inline void cfq_add_crq_hash(struct cfq_data *cfqd, struct cfq_rq *crq) -{ - const int hash_idx = CFQ_MHASH_FN(rq_hash_key(crq->request)); - - hlist_add_head(&crq->hash, &cfqd->crq_hash[hash_idx]); -} - -static struct request *cfq_find_rq_hash(struct cfq_data *cfqd, sector_t offset) -{ - struct hlist_head *hash_list = &cfqd->crq_hash[CFQ_MHASH_FN(offset)]; - struct hlist_node *entry, *next; - - hlist_for_each_safe(entry, next, hash_list) { - struct cfq_rq *crq = list_entry_hash(entry); - struct request *__rq = crq->request; - - if (!rq_mergeable(__rq)) { - cfq_del_crq_hash(crq); - continue; - } - - if (rq_hash_key(__rq) == offset) - return __rq; - } - - return NULL; -} - -/* - * scheduler run of queue, if there are requests pending and no one in the - * driver that will restart queueing - */ -static inline void cfq_schedule_dispatch(struct cfq_data *cfqd) -{ - if (!cfqd->rq_in_driver && cfqd->busy_queues) - kblockd_schedule_work(&cfqd->unplug_work); -} - -static int cfq_queue_empty(request_queue_t *q) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - - return !cfqd->busy_queues; -} - -/* - * Lifted from AS - choose which of crq1 and crq2 that is best served now. - * We choose the request that is closest to the head right now. Distance - * behind the head are penalized and only allowed to a certain extent. - */ -static struct cfq_rq * -cfq_choose_req(struct cfq_data *cfqd, struct cfq_rq *crq1, struct cfq_rq *crq2) -{ - sector_t last, s1, s2, d1 = 0, d2 = 0; - int r1_wrap = 0, r2_wrap = 0; /* requests are behind the disk head */ - unsigned long back_max; - - if (crq1 == NULL || crq1 == crq2) - return crq2; - if (crq2 == NULL) - return crq1; - - if (cfq_crq_is_sync(crq1) && !cfq_crq_is_sync(crq2)) - return crq1; - else if (cfq_crq_is_sync(crq2) && !cfq_crq_is_sync(crq1)) - return crq2; - - s1 = crq1->request->sector; - s2 = crq2->request->sector; - - last = cfqd->last_sector; - - /* - * by definition, 1KiB is 2 sectors - */ - back_max = cfqd->cfq_back_max * 2; - - /* - * Strict one way elevator _except_ in the case where we allow - * short backward seeks which are biased as twice the cost of a - * similar forward seek. - */ - if (s1 >= last) - d1 = s1 - last; - else if (s1 + back_max >= last) - d1 = (last - s1) * cfqd->cfq_back_penalty; - else - r1_wrap = 1; - - if (s2 >= last) - d2 = s2 - last; - else if (s2 + back_max >= last) - d2 = (last - s2) * cfqd->cfq_back_penalty; - else - r2_wrap = 1; - - /* Found required data */ - if (!r1_wrap && r2_wrap) - return crq1; - else if (!r2_wrap && r1_wrap) - return crq2; - else if (r1_wrap && r2_wrap) { - /* both behind the head */ - if (s1 <= s2) - return crq1; - else - return crq2; - } - - /* Both requests in front of the head */ - if (d1 < d2) - return crq1; - else if (d2 < d1) - return crq2; - else { - if (s1 >= s2) - return crq1; - else - return crq2; - } -} - -/* - * would be nice to take fifo expire time into account as well - */ -static struct cfq_rq * -cfq_find_next_crq(struct cfq_data *cfqd, struct cfq_queue *cfqq, - struct cfq_rq *last) -{ - struct cfq_rq *crq_next = NULL, *crq_prev = NULL; - struct rb_node *rbnext, *rbprev; - - if (!(rbnext = rb_next(&last->rb_node))) { - rbnext = rb_first(&cfqq->sort_list); - if (rbnext == &last->rb_node) - rbnext = NULL; - } - - rbprev = rb_prev(&last->rb_node); - - if (rbprev) - crq_prev = rb_entry_crq(rbprev); - if (rbnext) - crq_next = rb_entry_crq(rbnext); - - return cfq_choose_req(cfqd, crq_next, crq_prev); -} - -static void cfq_update_next_crq(struct cfq_rq *crq) -{ - struct cfq_queue *cfqq = crq->cfq_queue; - - if (cfqq->next_crq == crq) - cfqq->next_crq = cfq_find_next_crq(cfqq->cfqd, cfqq, crq); -} - -static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted) -{ - struct cfq_data *cfqd = cfqq->cfqd; - struct list_head *list, *entry; - - BUG_ON(!cfq_cfqq_on_rr(cfqq)); - - list_del(&cfqq->cfq_list); - - if (cfq_class_rt(cfqq)) - list = &cfqd->cur_rr; - else if (cfq_class_idle(cfqq)) - list = &cfqd->idle_rr; - else { - /* - * if cfqq has requests in flight, don't allow it to be - * found in cfq_set_active_queue before it has finished them. - * this is done to increase fairness between a process that - * has lots of io pending vs one that only generates one - * sporadically or synchronously - */ - if (cfq_cfqq_dispatched(cfqq)) - list = &cfqd->busy_rr; - else - list = &cfqd->rr_list[cfqq->ioprio]; - } - - /* - * if queue was preempted, just add to front to be fair. busy_rr - * isn't sorted. - */ - if (preempted || list == &cfqd->busy_rr) { - list_add(&cfqq->cfq_list, list); - return; - } - - /* - * sort by when queue was last serviced - */ - entry = list; - while ((entry = entry->prev) != list) { - struct cfq_queue *__cfqq = list_entry_cfqq(entry); - - if (!__cfqq->service_last) - break; - if (time_before(__cfqq->service_last, cfqq->service_last)) - break; - } - - list_add(&cfqq->cfq_list, entry); -} - -/* - * add to busy list of queues for service, trying to be fair in ordering - * the pending list according to last request service - */ -static inline void -cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) -{ - BUG_ON(cfq_cfqq_on_rr(cfqq)); - cfq_mark_cfqq_on_rr(cfqq); - cfqd->busy_queues++; - - cfq_resort_rr_list(cfqq, 0); -} - -static inline void -cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) -{ - BUG_ON(!cfq_cfqq_on_rr(cfqq)); - cfq_clear_cfqq_on_rr(cfqq); - list_move(&cfqq->cfq_list, &cfqd->empty_list); - - BUG_ON(!cfqd->busy_queues); - cfqd->busy_queues--; -} - -/* - * rb tree support functions - */ -static inline void cfq_del_crq_rb(struct cfq_rq *crq) -{ - struct cfq_queue *cfqq = crq->cfq_queue; - struct cfq_data *cfqd = cfqq->cfqd; - const int sync = cfq_crq_is_sync(crq); - - BUG_ON(!cfqq->queued[sync]); - cfqq->queued[sync]--; - - cfq_update_next_crq(crq); - - rb_erase(&crq->rb_node, &cfqq->sort_list); - RB_CLEAR_COLOR(&crq->rb_node); - - if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY(&cfqq->sort_list)) - cfq_del_cfqq_rr(cfqd, cfqq); -} - -static struct cfq_rq * -__cfq_add_crq_rb(struct cfq_rq *crq) -{ - struct rb_node **p = &crq->cfq_queue->sort_list.rb_node; - struct rb_node *parent = NULL; - struct cfq_rq *__crq; - - while (*p) { - parent = *p; - __crq = rb_entry_crq(parent); - - if (crq->rb_key < __crq->rb_key) - p = &(*p)->rb_left; - else if (crq->rb_key > __crq->rb_key) - p = &(*p)->rb_right; - else - return __crq; - } - - rb_link_node(&crq->rb_node, parent, p); - return NULL; -} - -static void cfq_add_crq_rb(struct cfq_rq *crq) -{ - struct cfq_queue *cfqq = crq->cfq_queue; - struct cfq_data *cfqd = cfqq->cfqd; - struct request *rq = crq->request; - struct cfq_rq *__alias; - - crq->rb_key = rq_rb_key(rq); - cfqq->queued[cfq_crq_is_sync(crq)]++; - - /* - * looks a little odd, but the first insert might return an alias. - * if that happens, put the alias on the dispatch list - */ - while ((__alias = __cfq_add_crq_rb(crq)) != NULL) - cfq_dispatch_insert(cfqd->queue, __alias); - - rb_insert_color(&crq->rb_node, &cfqq->sort_list); - - if (!cfq_cfqq_on_rr(cfqq)) - cfq_add_cfqq_rr(cfqd, cfqq); - - /* - * check if this request is a better next-serve candidate - */ - cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq); -} - -static inline void -cfq_reposition_crq_rb(struct cfq_queue *cfqq, struct cfq_rq *crq) -{ - rb_erase(&crq->rb_node, &cfqq->sort_list); - cfqq->queued[cfq_crq_is_sync(crq)]--; - - cfq_add_crq_rb(crq); -} - -static struct request *cfq_find_rq_rb(struct cfq_data *cfqd, sector_t sector) - -{ - struct cfq_queue *cfqq = cfq_find_cfq_hash(cfqd, current->pid, CFQ_KEY_ANY); - struct rb_node *n; - - if (!cfqq) - goto out; - - n = cfqq->sort_list.rb_node; - while (n) { - struct cfq_rq *crq = rb_entry_crq(n); - - if (sector < crq->rb_key) - n = n->rb_left; - else if (sector > crq->rb_key) - n = n->rb_right; - else - return crq->request; - } - -out: - return NULL; -} - -static void cfq_activate_request(request_queue_t *q, struct request *rq) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - - cfqd->rq_in_driver++; -} - -static void cfq_deactivate_request(request_queue_t *q, struct request *rq) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - - WARN_ON(!cfqd->rq_in_driver); - cfqd->rq_in_driver--; -} - -static void cfq_remove_request(struct request *rq) -{ - struct cfq_rq *crq = RQ_DATA(rq); - - list_del_init(&rq->queuelist); - cfq_del_crq_rb(crq); - cfq_del_crq_hash(crq); -} - -static int -cfq_merge(request_queue_t *q, struct request **req, struct bio *bio) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - struct request *__rq; - int ret; - - __rq = cfq_find_rq_hash(cfqd, bio->bi_sector); - if (__rq && elv_rq_merge_ok(__rq, bio)) { - ret = ELEVATOR_BACK_MERGE; - goto out; - } - - __rq = cfq_find_rq_rb(cfqd, bio->bi_sector + bio_sectors(bio)); - if (__rq && elv_rq_merge_ok(__rq, bio)) { - ret = ELEVATOR_FRONT_MERGE; - goto out; - } - - return ELEVATOR_NO_MERGE; -out: - *req = __rq; - return ret; -} - -static void cfq_merged_request(request_queue_t *q, struct request *req) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - struct cfq_rq *crq = RQ_DATA(req); - - cfq_del_crq_hash(crq); - cfq_add_crq_hash(cfqd, crq); - - if (rq_rb_key(req) != crq->rb_key) { - struct cfq_queue *cfqq = crq->cfq_queue; - - cfq_update_next_crq(crq); - cfq_reposition_crq_rb(cfqq, crq); - } -} - -static void -cfq_merged_requests(request_queue_t *q, struct request *rq, - struct request *next) -{ - cfq_merged_request(q, rq); - - /* - * reposition in fifo if next is older than rq - */ - if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) && - time_before(next->start_time, rq->start_time)) - list_move(&rq->queuelist, &next->queuelist); - - cfq_remove_request(next); -} - -static inline void -__cfq_set_active_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) -{ - if (cfqq) { - /* - * stop potential idle class queues waiting service - */ - del_timer(&cfqd->idle_class_timer); - - cfqq->slice_start = jiffies; - cfqq->slice_end = 0; - cfqq->slice_left = 0; - cfq_clear_cfqq_must_alloc_slice(cfqq); - cfq_clear_cfqq_fifo_expire(cfqq); - cfq_clear_cfqq_expired(cfqq); - } - - cfqd->active_queue = cfqq; -} - -/* - * 0 - * 0,1 - * 0,1,2 - * 0,1,2,3 - * 0,1,2,3,4 - * 0,1,2,3,4,5 - * 0,1,2,3,4,5,6 - * 0,1,2,3,4,5,6,7 - */ -static int cfq_get_next_prio_level(struct cfq_data *cfqd) -{ - int prio, wrap; - - prio = -1; - wrap = 0; - do { - int p; - - for (p = cfqd->cur_prio; p <= cfqd->cur_end_prio; p++) { - if (!list_empty(&cfqd->rr_list[p])) { - prio = p; - break; - } - } - - if (prio != -1) - break; - cfqd->cur_prio = 0; - if (++cfqd->cur_end_prio == CFQ_PRIO_LISTS) { - cfqd->cur_end_prio = 0; - if (wrap) - break; - wrap = 1; - } - } while (1); - - if (unlikely(prio == -1)) - return -1; - - BUG_ON(prio >= CFQ_PRIO_LISTS); - - list_splice_init(&cfqd->rr_list[prio], &cfqd->cur_rr); - - cfqd->cur_prio = prio + 1; - if (cfqd->cur_prio > cfqd->cur_end_prio) { - cfqd->cur_end_prio = cfqd->cur_prio; - cfqd->cur_prio = 0; - } - if (cfqd->cur_end_prio == CFQ_PRIO_LISTS) { - cfqd->cur_prio = 0; - cfqd->cur_end_prio = 0; - } - - return prio; -} - -static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd) -{ - struct cfq_queue *cfqq; - - /* - * if current queue is expired but not done with its requests yet, - * wait for that to happen - */ - if ((cfqq = cfqd->active_queue) != NULL) { - if (cfq_cfqq_expired(cfqq) && cfq_cfqq_dispatched(cfqq)) - return NULL; - } - - /* - * if current list is non-empty, grab first entry. if it is empty, - * get next prio level and grab first entry then if any are spliced - */ - if (!list_empty(&cfqd->cur_rr) || cfq_get_next_prio_level(cfqd) != -1) - cfqq = list_entry_cfqq(cfqd->cur_rr.next); - - /* - * if we have idle queues and no rt or be queues had pending - * requests, either allow immediate service if the grace period - * has passed or arm the idle grace timer - */ - if (!cfqq && !list_empty(&cfqd->idle_rr)) { - unsigned long end = cfqd->last_end_request + CFQ_IDLE_GRACE; - - if (time_after_eq(jiffies, end)) - cfqq = list_entry_cfqq(cfqd->idle_rr.next); - else - mod_timer(&cfqd->idle_class_timer, end); - } - - __cfq_set_active_queue(cfqd, cfqq); - return cfqq; -} - -/* - * current cfqq expired its slice (or was too idle), select new one - */ -static void -__cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, - int preempted) -{ - unsigned long now = jiffies; - - if (cfq_cfqq_wait_request(cfqq)) - del_timer(&cfqd->idle_slice_timer); - - if (!preempted && !cfq_cfqq_dispatched(cfqq)) - cfqq->service_last = now; - - cfq_clear_cfqq_must_dispatch(cfqq); - cfq_clear_cfqq_wait_request(cfqq); - - /* - * store what was left of this slice, if the queue idled out - * or was preempted - */ - if (time_after(now, cfqq->slice_end)) - cfqq->slice_left = now - cfqq->slice_end; - else - cfqq->slice_left = 0; - - if (cfq_cfqq_on_rr(cfqq)) - cfq_resort_rr_list(cfqq, preempted); - - if (cfqq == cfqd->active_queue) - cfqd->active_queue = NULL; - - if (cfqd->active_cic) { - put_io_context(cfqd->active_cic->ioc); - cfqd->active_cic = NULL; - } - - cfqd->dispatch_slice = 0; -} - -static inline void cfq_slice_expired(struct cfq_data *cfqd, int preempted) -{ - struct cfq_queue *cfqq = cfqd->active_queue; - - if (cfqq) { - /* - * use deferred expiry, if there are requests in progress as - * not to disturb the slice of the next queue - */ - if (cfq_cfqq_dispatched(cfqq)) - cfq_mark_cfqq_expired(cfqq); - else - __cfq_slice_expired(cfqd, cfqq, preempted); - } -} - -static int cfq_arm_slice_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq) - -{ - WARN_ON(!RB_EMPTY(&cfqq->sort_list)); - WARN_ON(cfqq != cfqd->active_queue); - - /* - * idle is disabled, either manually or by past process history - */ - if (!cfqd->cfq_slice_idle) - return 0; - if (!cfq_cfqq_idle_window(cfqq)) - return 0; - /* - * task has exited, don't wait - */ - if (cfqd->active_cic && !cfqd->active_cic->ioc->task) - return 0; - - cfq_mark_cfqq_must_dispatch(cfqq); - cfq_mark_cfqq_wait_request(cfqq); - - if (!timer_pending(&cfqd->idle_slice_timer)) { - unsigned long slice_left = min(cfqq->slice_end - 1, (unsigned long) cfqd->cfq_slice_idle); - - cfqd->idle_slice_timer.expires = jiffies + slice_left; - add_timer(&cfqd->idle_slice_timer); - } - - return 1; -} - -static void cfq_dispatch_insert(request_queue_t *q, struct cfq_rq *crq) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - struct cfq_queue *cfqq = crq->cfq_queue; - - cfqq->next_crq = cfq_find_next_crq(cfqd, cfqq, crq); - cfq_remove_request(crq->request); - cfqq->on_dispatch[cfq_crq_is_sync(crq)]++; - elv_dispatch_sort(q, crq->request); -} - -/* - * return expired entry, or NULL to just start from scratch in rbtree - */ -static inline struct cfq_rq *cfq_check_fifo(struct cfq_queue *cfqq) -{ - struct cfq_data *cfqd = cfqq->cfqd; - struct request *rq; - struct cfq_rq *crq; - - if (cfq_cfqq_fifo_expire(cfqq)) - return NULL; - - if (!list_empty(&cfqq->fifo)) { - int fifo = cfq_cfqq_class_sync(cfqq); - - crq = RQ_DATA(list_entry_fifo(cfqq->fifo.next)); - rq = crq->request; - if (time_after(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo])) { - cfq_mark_cfqq_fifo_expire(cfqq); - return crq; - } - } - - return NULL; -} - -/* - * Scale schedule slice based on io priority. Use the sync time slice only - * if a queue is marked sync and has sync io queued. A sync queue with async - * io only, should not get full sync slice length. - */ -static inline int -cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) -{ - const int base_slice = cfqd->cfq_slice[cfq_cfqq_sync(cfqq)]; - - WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); - - return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - cfqq->ioprio)); -} - -static inline void -cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) -{ - cfqq->slice_end = cfq_prio_to_slice(cfqd, cfqq) + jiffies; -} - -static inline int -cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq) -{ - const int base_rq = cfqd->cfq_slice_async_rq; - - WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); - - return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio)); -} - -/* - * get next queue for service - */ -static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd, int force) -{ - unsigned long now = jiffies; - struct cfq_queue *cfqq; - - cfqq = cfqd->active_queue; - if (!cfqq) - goto new_queue; - - if (cfq_cfqq_expired(cfqq)) - goto new_queue; - - /* - * slice has expired - */ - if (!cfq_cfqq_must_dispatch(cfqq) && time_after(now, cfqq->slice_end)) - goto expire; - - /* - * if queue has requests, dispatch one. if not, check if - * enough slice is left to wait for one - */ - if (!RB_EMPTY(&cfqq->sort_list)) - goto keep_queue; - else if (!force && cfq_cfqq_class_sync(cfqq) && - time_before(now, cfqq->slice_end)) { - if (cfq_arm_slice_timer(cfqd, cfqq)) - return NULL; - } - -expire: - cfq_slice_expired(cfqd, 0); -new_queue: - cfqq = cfq_set_active_queue(cfqd); -keep_queue: - return cfqq; -} - -static int -__cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq, - int max_dispatch) -{ - int dispatched = 0; - - BUG_ON(RB_EMPTY(&cfqq->sort_list)); - - do { - struct cfq_rq *crq; - - /* - * follow expired path, else get first next available - */ - if ((crq = cfq_check_fifo(cfqq)) == NULL) - crq = cfqq->next_crq; - - /* - * finally, insert request into driver dispatch list - */ - cfq_dispatch_insert(cfqd->queue, crq); - - cfqd->dispatch_slice++; - dispatched++; - - if (!cfqd->active_cic) { - atomic_inc(&crq->io_context->ioc->refcount); - cfqd->active_cic = crq->io_context; - } - - if (RB_EMPTY(&cfqq->sort_list)) - break; - - } while (dispatched < max_dispatch); - - /* - * if slice end isn't set yet, set it. if at least one request was - * sync, use the sync time slice value - */ - if (!cfqq->slice_end) - cfq_set_prio_slice(cfqd, cfqq); - - /* - * expire an async queue immediately if it has used up its slice. idle - * queue always expire after 1 dispatch round. - */ - if ((!cfq_cfqq_sync(cfqq) && - cfqd->dispatch_slice >= cfq_prio_to_maxrq(cfqd, cfqq)) || - cfq_class_idle(cfqq)) - cfq_slice_expired(cfqd, 0); - - return dispatched; -} - -static int -cfq_dispatch_requests(request_queue_t *q, int force) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - struct cfq_queue *cfqq; - - if (!cfqd->busy_queues) - return 0; - - cfqq = cfq_select_queue(cfqd, force); - if (cfqq) { - int max_dispatch; - - /* - * if idle window is disabled, allow queue buildup - */ - if (!cfq_cfqq_idle_window(cfqq) && - cfqd->rq_in_driver >= cfqd->cfq_max_depth) - return 0; - - cfq_clear_cfqq_must_dispatch(cfqq); - cfq_clear_cfqq_wait_request(cfqq); - del_timer(&cfqd->idle_slice_timer); - - if (!force) { - max_dispatch = cfqd->cfq_quantum; - if (cfq_class_idle(cfqq)) - max_dispatch = 1; - } else - max_dispatch = INT_MAX; - - return __cfq_dispatch_requests(cfqd, cfqq, max_dispatch); - } - - return 0; -} - -/* - * task holds one reference to the queue, dropped when task exits. each crq - * in-flight on this queue also holds a reference, dropped when crq is freed. - * - * queue lock must be held here. - */ -static void cfq_put_queue(struct cfq_queue *cfqq) -{ - struct cfq_data *cfqd = cfqq->cfqd; - - BUG_ON(atomic_read(&cfqq->ref) <= 0); - - if (!atomic_dec_and_test(&cfqq->ref)) - return; - - BUG_ON(rb_first(&cfqq->sort_list)); - BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]); - BUG_ON(cfq_cfqq_on_rr(cfqq)); - - if (unlikely(cfqd->active_queue == cfqq)) { - __cfq_slice_expired(cfqd, cfqq, 0); - cfq_schedule_dispatch(cfqd); - } - - cfq_put_cfqd(cfqq->cfqd); - - /* - * it's on the empty list and still hashed - */ - list_del(&cfqq->cfq_list); - hlist_del(&cfqq->cfq_hash); - kmem_cache_free(cfq_pool, cfqq); -} - -static inline struct cfq_queue * -__cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned int prio, - const int hashval) -{ - struct hlist_head *hash_list = &cfqd->cfq_hash[hashval]; - struct hlist_node *entry, *next; - - hlist_for_each_safe(entry, next, hash_list) { - struct cfq_queue *__cfqq = list_entry_qhash(entry); - const unsigned short __p = IOPRIO_PRIO_VALUE(__cfqq->ioprio_class, __cfqq->ioprio); - - if (__cfqq->key == key && (__p == prio || prio == CFQ_KEY_ANY)) - return __cfqq; - } - - return NULL; -} - -static struct cfq_queue * -cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned short prio) -{ - return __cfq_find_cfq_hash(cfqd, key, prio, hash_long(key, CFQ_QHASH_SHIFT)); -} - -static void cfq_free_io_context(struct cfq_io_context *cic) -{ - struct cfq_io_context *__cic; - struct list_head *entry, *next; - - list_for_each_safe(entry, next, &cic->list) { - __cic = list_entry(entry, struct cfq_io_context, list); - kmem_cache_free(cfq_ioc_pool, __cic); - } - - kmem_cache_free(cfq_ioc_pool, cic); -} - -/* - * Called with interrupts disabled - */ -static void cfq_exit_single_io_context(struct cfq_io_context *cic) -{ - struct cfq_data *cfqd = cic->cfqq->cfqd; - request_queue_t *q = cfqd->queue; - - WARN_ON(!irqs_disabled()); - - spin_lock(q->queue_lock); - - if (unlikely(cic->cfqq == cfqd->active_queue)) { - __cfq_slice_expired(cfqd, cic->cfqq, 0); - cfq_schedule_dispatch(cfqd); - } - - cfq_put_queue(cic->cfqq); - cic->cfqq = NULL; - spin_unlock(q->queue_lock); -} - -/* - * Another task may update the task cic list, if it is doing a queue lookup - * on its behalf. cfq_cic_lock excludes such concurrent updates - */ -static void cfq_exit_io_context(struct cfq_io_context *cic) -{ - struct cfq_io_context *__cic; - struct list_head *entry; - unsigned long flags; - - local_irq_save(flags); - - /* - * put the reference this task is holding to the various queues - */ - list_for_each(entry, &cic->list) { - __cic = list_entry(entry, struct cfq_io_context, list); - cfq_exit_single_io_context(__cic); - } - - cfq_exit_single_io_context(cic); - local_irq_restore(flags); -} - -static struct cfq_io_context * -cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) -{ - struct cfq_io_context *cic = kmem_cache_alloc(cfq_ioc_pool, gfp_mask); - - if (cic) { - INIT_LIST_HEAD(&cic->list); - cic->cfqq = NULL; - cic->key = NULL; - cic->last_end_request = jiffies; - cic->ttime_total = 0; - cic->ttime_samples = 0; - cic->ttime_mean = 0; - cic->dtor = cfq_free_io_context; - cic->exit = cfq_exit_io_context; - } - - return cic; -} - -static void cfq_init_prio_data(struct cfq_queue *cfqq) -{ - struct task_struct *tsk = current; - int ioprio_class; - - if (!cfq_cfqq_prio_changed(cfqq)) - return; - - ioprio_class = IOPRIO_PRIO_CLASS(tsk->ioprio); - switch (ioprio_class) { - default: - printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class); - case IOPRIO_CLASS_NONE: - /* - * no prio set, place us in the middle of the BE classes - */ - cfqq->ioprio = task_nice_ioprio(tsk); - cfqq->ioprio_class = IOPRIO_CLASS_BE; - break; - case IOPRIO_CLASS_RT: - cfqq->ioprio = task_ioprio(tsk); - cfqq->ioprio_class = IOPRIO_CLASS_RT; - break; - case IOPRIO_CLASS_BE: - cfqq->ioprio = task_ioprio(tsk); - cfqq->ioprio_class = IOPRIO_CLASS_BE; - break; - case IOPRIO_CLASS_IDLE: - cfqq->ioprio_class = IOPRIO_CLASS_IDLE; - cfqq->ioprio = 7; - cfq_clear_cfqq_idle_window(cfqq); - break; - } - - /* - * keep track of original prio settings in case we have to temporarily - * elevate the priority of this queue - */ - cfqq->org_ioprio = cfqq->ioprio; - cfqq->org_ioprio_class = cfqq->ioprio_class; - - if (cfq_cfqq_on_rr(cfqq)) - cfq_resort_rr_list(cfqq, 0); - - cfq_clear_cfqq_prio_changed(cfqq); -} - -static inline void changed_ioprio(struct cfq_queue *cfqq) -{ - if (cfqq) { - struct cfq_data *cfqd = cfqq->cfqd; - - spin_lock(cfqd->queue->queue_lock); - cfq_mark_cfqq_prio_changed(cfqq); - cfq_init_prio_data(cfqq); - spin_unlock(cfqd->queue->queue_lock); - } -} - -/* - * callback from sys_ioprio_set, irqs are disabled - */ -static int cfq_ioc_set_ioprio(struct io_context *ioc, unsigned int ioprio) -{ - struct cfq_io_context *cic = ioc->cic; - - changed_ioprio(cic->cfqq); - - list_for_each_entry(cic, &cic->list, list) - changed_ioprio(cic->cfqq); - - return 0; -} - -static struct cfq_queue * -cfq_get_queue(struct cfq_data *cfqd, unsigned int key, unsigned short ioprio, - gfp_t gfp_mask) -{ - const int hashval = hash_long(key, CFQ_QHASH_SHIFT); - struct cfq_queue *cfqq, *new_cfqq = NULL; - -retry: - cfqq = __cfq_find_cfq_hash(cfqd, key, ioprio, hashval); - - if (!cfqq) { - if (new_cfqq) { - cfqq = new_cfqq; - new_cfqq = NULL; - } else if (gfp_mask & __GFP_WAIT) { - spin_unlock_irq(cfqd->queue->queue_lock); - new_cfqq = kmem_cache_alloc(cfq_pool, gfp_mask); - spin_lock_irq(cfqd->queue->queue_lock); - goto retry; - } else { - cfqq = kmem_cache_alloc(cfq_pool, gfp_mask); - if (!cfqq) - goto out; - } - - memset(cfqq, 0, sizeof(*cfqq)); - - INIT_HLIST_NODE(&cfqq->cfq_hash); - INIT_LIST_HEAD(&cfqq->cfq_list); - RB_CLEAR_ROOT(&cfqq->sort_list); - INIT_LIST_HEAD(&cfqq->fifo); - - cfqq->key = key; - hlist_add_head(&cfqq->cfq_hash, &cfqd->cfq_hash[hashval]); - atomic_set(&cfqq->ref, 0); - cfqq->cfqd = cfqd; - atomic_inc(&cfqd->ref); - cfqq->service_last = 0; - /* - * set ->slice_left to allow preemption for a new process - */ - cfqq->slice_left = 2 * cfqd->cfq_slice_idle; - cfq_mark_cfqq_idle_window(cfqq); - cfq_mark_cfqq_prio_changed(cfqq); - cfq_init_prio_data(cfqq); - } - - if (new_cfqq) - kmem_cache_free(cfq_pool, new_cfqq); - - atomic_inc(&cfqq->ref); -out: - WARN_ON((gfp_mask & __GFP_WAIT) && !cfqq); - return cfqq; -} - -/* - * Setup general io context and cfq io context. There can be several cfq - * io contexts per general io context, if this process is doing io to more - * than one device managed by cfq. Note that caller is holding a reference to - * cfqq, so we don't need to worry about it disappearing - */ -static struct cfq_io_context * -cfq_get_io_context(struct cfq_data *cfqd, pid_t pid, gfp_t gfp_mask) -{ - struct io_context *ioc = NULL; - struct cfq_io_context *cic; - - might_sleep_if(gfp_mask & __GFP_WAIT); - - ioc = get_io_context(gfp_mask); - if (!ioc) - return NULL; - - if ((cic = ioc->cic) == NULL) { - cic = cfq_alloc_io_context(cfqd, gfp_mask); - - if (cic == NULL) - goto err; - - /* - * manually increment generic io_context usage count, it - * cannot go away since we are already holding one ref to it - */ - ioc->cic = cic; - ioc->set_ioprio = cfq_ioc_set_ioprio; - cic->ioc = ioc; - cic->key = cfqd; - atomic_inc(&cfqd->ref); - } else { - struct cfq_io_context *__cic; - - /* - * the first cic on the list is actually the head itself - */ - if (cic->key == cfqd) - goto out; - - /* - * cic exists, check if we already are there. linear search - * should be ok here, the list will usually not be more than - * 1 or a few entries long - */ - list_for_each_entry(__cic, &cic->list, list) { - /* - * this process is already holding a reference to - * this queue, so no need to get one more - */ - if (__cic->key == cfqd) { - cic = __cic; - goto out; - } - } - - /* - * nope, process doesn't have a cic assoicated with this - * cfqq yet. get a new one and add to list - */ - __cic = cfq_alloc_io_context(cfqd, gfp_mask); - if (__cic == NULL) - goto err; - - __cic->ioc = ioc; - __cic->key = cfqd; - atomic_inc(&cfqd->ref); - list_add(&__cic->list, &cic->list); - cic = __cic; - } - -out: - return cic; -err: - put_io_context(ioc); - return NULL; -} - -static void -cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic) -{ - unsigned long elapsed, ttime; - - /* - * if this context already has stuff queued, thinktime is from - * last queue not last end - */ -#if 0 - if (time_after(cic->last_end_request, cic->last_queue)) - elapsed = jiffies - cic->last_end_request; - else - elapsed = jiffies - cic->last_queue; -#else - elapsed = jiffies - cic->last_end_request; -#endif - - ttime = min(elapsed, 2UL * cfqd->cfq_slice_idle); - - cic->ttime_samples = (7*cic->ttime_samples + 256) / 8; - cic->ttime_total = (7*cic->ttime_total + 256*ttime) / 8; - cic->ttime_mean = (cic->ttime_total + 128) / cic->ttime_samples; -} - -#define sample_valid(samples) ((samples) > 80) - -/* - * Disable idle window if the process thinks too long or seeks so much that - * it doesn't matter - */ -static void -cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, - struct cfq_io_context *cic) -{ - int enable_idle = cfq_cfqq_idle_window(cfqq); - - if (!cic->ioc->task || !cfqd->cfq_slice_idle) - enable_idle = 0; - else if (sample_valid(cic->ttime_samples)) { - if (cic->ttime_mean > cfqd->cfq_slice_idle) - enable_idle = 0; - else - enable_idle = 1; - } - - if (enable_idle) - cfq_mark_cfqq_idle_window(cfqq); - else - cfq_clear_cfqq_idle_window(cfqq); -} - - -/* - * Check if new_cfqq should preempt the currently active queue. Return 0 for - * no or if we aren't sure, a 1 will cause a preempt. - */ -static int -cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, - struct cfq_rq *crq) -{ - struct cfq_queue *cfqq = cfqd->active_queue; - - if (cfq_class_idle(new_cfqq)) - return 0; - - if (!cfqq) - return 1; - - if (cfq_class_idle(cfqq)) - return 1; - if (!cfq_cfqq_wait_request(new_cfqq)) - return 0; - /* - * if it doesn't have slice left, forget it - */ - if (new_cfqq->slice_left < cfqd->cfq_slice_idle) - return 0; - if (cfq_crq_is_sync(crq) && !cfq_cfqq_sync(cfqq)) - return 1; - - return 0; -} - -/* - * cfqq preempts the active queue. if we allowed preempt with no slice left, - * let it have half of its nominal slice. - */ -static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) -{ - struct cfq_queue *__cfqq, *next; - - list_for_each_entry_safe(__cfqq, next, &cfqd->cur_rr, cfq_list) - cfq_resort_rr_list(__cfqq, 1); - - if (!cfqq->slice_left) - cfqq->slice_left = cfq_prio_to_slice(cfqd, cfqq) / 2; - - cfqq->slice_end = cfqq->slice_left + jiffies; - __cfq_slice_expired(cfqd, cfqq, 1); - __cfq_set_active_queue(cfqd, cfqq); -} - -/* - * should really be a ll_rw_blk.c helper - */ -static void cfq_start_queueing(struct cfq_data *cfqd, struct cfq_queue *cfqq) -{ - request_queue_t *q = cfqd->queue; - - if (!blk_queue_plugged(q)) - q->request_fn(q); - else - __generic_unplug_device(q); -} - -/* - * Called when a new fs request (crq) is added (to cfqq). Check if there's - * something we should do about it - */ -static void -cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, - struct cfq_rq *crq) -{ - struct cfq_io_context *cic; - - cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq); - - /* - * we never wait for an async request and we don't allow preemption - * of an async request. so just return early - */ - if (!cfq_crq_is_sync(crq)) - return; - - cic = crq->io_context; - - cfq_update_io_thinktime(cfqd, cic); - cfq_update_idle_window(cfqd, cfqq, cic); - - cic->last_queue = jiffies; - - if (cfqq == cfqd->active_queue) { - /* - * if we are waiting for a request for this queue, let it rip - * immediately and flag that we must not expire this queue - * just now - */ - if (cfq_cfqq_wait_request(cfqq)) { - cfq_mark_cfqq_must_dispatch(cfqq); - del_timer(&cfqd->idle_slice_timer); - cfq_start_queueing(cfqd, cfqq); - } - } else if (cfq_should_preempt(cfqd, cfqq, crq)) { - /* - * not the active queue - expire current slice if it is - * idle and has expired it's mean thinktime or this new queue - * has some old slice time left and is of higher priority - */ - cfq_preempt_queue(cfqd, cfqq); - cfq_mark_cfqq_must_dispatch(cfqq); - cfq_start_queueing(cfqd, cfqq); - } -} - -static void cfq_insert_request(request_queue_t *q, struct request *rq) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - struct cfq_rq *crq = RQ_DATA(rq); - struct cfq_queue *cfqq = crq->cfq_queue; - - cfq_init_prio_data(cfqq); - - cfq_add_crq_rb(crq); - - list_add_tail(&rq->queuelist, &cfqq->fifo); - - if (rq_mergeable(rq)) - cfq_add_crq_hash(cfqd, crq); - - cfq_crq_enqueued(cfqd, cfqq, crq); -} - -static void cfq_completed_request(request_queue_t *q, struct request *rq) -{ - struct cfq_rq *crq = RQ_DATA(rq); - struct cfq_queue *cfqq = crq->cfq_queue; - struct cfq_data *cfqd = cfqq->cfqd; - const int sync = cfq_crq_is_sync(crq); - unsigned long now; - - now = jiffies; - - WARN_ON(!cfqd->rq_in_driver); - WARN_ON(!cfqq->on_dispatch[sync]); - cfqd->rq_in_driver--; - cfqq->on_dispatch[sync]--; - - if (!cfq_class_idle(cfqq)) - cfqd->last_end_request = now; - - if (!cfq_cfqq_dispatched(cfqq)) { - if (cfq_cfqq_on_rr(cfqq)) { - cfqq->service_last = now; - cfq_resort_rr_list(cfqq, 0); - } - if (cfq_cfqq_expired(cfqq)) { - __cfq_slice_expired(cfqd, cfqq, 0); - cfq_schedule_dispatch(cfqd); - } - } - - if (cfq_crq_is_sync(crq)) - crq->io_context->last_end_request = now; -} - -static struct request * -cfq_former_request(request_queue_t *q, struct request *rq) -{ - struct cfq_rq *crq = RQ_DATA(rq); - struct rb_node *rbprev = rb_prev(&crq->rb_node); - - if (rbprev) - return rb_entry_crq(rbprev)->request; - - return NULL; -} - -static struct request * -cfq_latter_request(request_queue_t *q, struct request *rq) -{ - struct cfq_rq *crq = RQ_DATA(rq); - struct rb_node *rbnext = rb_next(&crq->rb_node); - - if (rbnext) - return rb_entry_crq(rbnext)->request; - - return NULL; -} - -/* - * we temporarily boost lower priority queues if they are holding fs exclusive - * resources. they are boosted to normal prio (CLASS_BE/4) - */ -static void cfq_prio_boost(struct cfq_queue *cfqq) -{ - const int ioprio_class = cfqq->ioprio_class; - const int ioprio = cfqq->ioprio; - - if (has_fs_excl()) { - /* - * boost idle prio on transactions that would lock out other - * users of the filesystem - */ - if (cfq_class_idle(cfqq)) - cfqq->ioprio_class = IOPRIO_CLASS_BE; - if (cfqq->ioprio > IOPRIO_NORM) - cfqq->ioprio = IOPRIO_NORM; - } else { - /* - * check if we need to unboost the queue - */ - if (cfqq->ioprio_class != cfqq->org_ioprio_class) - cfqq->ioprio_class = cfqq->org_ioprio_class; - if (cfqq->ioprio != cfqq->org_ioprio) - cfqq->ioprio = cfqq->org_ioprio; - } - - /* - * refile between round-robin lists if we moved the priority class - */ - if ((ioprio_class != cfqq->ioprio_class || ioprio != cfqq->ioprio) && - cfq_cfqq_on_rr(cfqq)) - cfq_resort_rr_list(cfqq, 0); -} - -static inline pid_t cfq_queue_pid(struct task_struct *task, int rw) -{ - if (rw == READ || process_sync(task)) - return task->pid; - - return CFQ_KEY_ASYNC; -} - -static inline int -__cfq_may_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq, - struct task_struct *task, int rw) -{ -#if 1 - if ((cfq_cfqq_wait_request(cfqq) || cfq_cfqq_must_alloc(cfqq)) && - !cfq_cfqq_must_alloc_slice(cfqq)) { - cfq_mark_cfqq_must_alloc_slice(cfqq); - return ELV_MQUEUE_MUST; - } - - return ELV_MQUEUE_MAY; -#else - if (!cfqq || task->flags & PF_MEMALLOC) - return ELV_MQUEUE_MAY; - if (!cfqq->allocated[rw] || cfq_cfqq_must_alloc(cfqq)) { - if (cfq_cfqq_wait_request(cfqq)) - return ELV_MQUEUE_MUST; - - /* - * only allow 1 ELV_MQUEUE_MUST per slice, otherwise we - * can quickly flood the queue with writes from a single task - */ - if (rw == READ || !cfq_cfqq_must_alloc_slice(cfqq)) { - cfq_mark_cfqq_must_alloc_slice(cfqq); - return ELV_MQUEUE_MUST; - } - - return ELV_MQUEUE_MAY; - } - if (cfq_class_idle(cfqq)) - return ELV_MQUEUE_NO; - if (cfqq->allocated[rw] >= cfqd->max_queued) { - struct io_context *ioc = get_io_context(GFP_ATOMIC); - int ret = ELV_MQUEUE_NO; - - if (ioc && ioc->nr_batch_requests) - ret = ELV_MQUEUE_MAY; - - put_io_context(ioc); - return ret; - } - - return ELV_MQUEUE_MAY; -#endif -} - -static int cfq_may_queue(request_queue_t *q, int rw, struct bio *bio) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - struct task_struct *tsk = current; - struct cfq_queue *cfqq; - - /* - * don't force setup of a queue from here, as a call to may_queue - * does not necessarily imply that a request actually will be queued. - * so just lookup a possibly existing queue, or return 'may queue' - * if that fails - */ - cfqq = cfq_find_cfq_hash(cfqd, cfq_queue_pid(tsk, rw), tsk->ioprio); - if (cfqq) { - cfq_init_prio_data(cfqq); - cfq_prio_boost(cfqq); - - return __cfq_may_queue(cfqd, cfqq, tsk, rw); - } - - return ELV_MQUEUE_MAY; -} - -static void cfq_check_waiters(request_queue_t *q, struct cfq_queue *cfqq) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - struct request_list *rl = &q->rq; - - if (cfqq->allocated[READ] <= cfqd->max_queued || cfqd->rq_starved) { - smp_mb(); - if (waitqueue_active(&rl->wait[READ])) - wake_up(&rl->wait[READ]); - } - - if (cfqq->allocated[WRITE] <= cfqd->max_queued || cfqd->rq_starved) { - smp_mb(); - if (waitqueue_active(&rl->wait[WRITE])) - wake_up(&rl->wait[WRITE]); - } -} - -/* - * queue lock held here - */ -static void cfq_put_request(request_queue_t *q, struct request *rq) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - struct cfq_rq *crq = RQ_DATA(rq); - - if (crq) { - struct cfq_queue *cfqq = crq->cfq_queue; - const int rw = rq_data_dir(rq); - - BUG_ON(!cfqq->allocated[rw]); - cfqq->allocated[rw]--; - - put_io_context(crq->io_context->ioc); - - mempool_free(crq, cfqd->crq_pool); - rq->elevator_private = NULL; - - cfq_check_waiters(q, cfqq); - cfq_put_queue(cfqq); - } -} - -/* - * Allocate cfq data structures associated with this request. - */ -static int -cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio, - gfp_t gfp_mask) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - struct task_struct *tsk = current; - struct cfq_io_context *cic; - const int rw = rq_data_dir(rq); - pid_t key = cfq_queue_pid(tsk, rw); - struct cfq_queue *cfqq; - struct cfq_rq *crq; - unsigned long flags; - - might_sleep_if(gfp_mask & __GFP_WAIT); - - cic = cfq_get_io_context(cfqd, key, gfp_mask); - - spin_lock_irqsave(q->queue_lock, flags); - - if (!cic) - goto queue_fail; - - if (!cic->cfqq) { - cfqq = cfq_get_queue(cfqd, key, tsk->ioprio, gfp_mask); - if (!cfqq) - goto queue_fail; - - cic->cfqq = cfqq; - } else - cfqq = cic->cfqq; - - cfqq->allocated[rw]++; - cfq_clear_cfqq_must_alloc(cfqq); - cfqd->rq_starved = 0; - atomic_inc(&cfqq->ref); - spin_unlock_irqrestore(q->queue_lock, flags); - - crq = mempool_alloc(cfqd->crq_pool, gfp_mask); - if (crq) { - RB_CLEAR(&crq->rb_node); - crq->rb_key = 0; - crq->request = rq; - INIT_HLIST_NODE(&crq->hash); - crq->cfq_queue = cfqq; - crq->io_context = cic; - - if (rw == READ || process_sync(tsk)) - cfq_mark_crq_is_sync(crq); - else - cfq_clear_crq_is_sync(crq); - - rq->elevator_private = crq; - return 0; - } - - spin_lock_irqsave(q->queue_lock, flags); - cfqq->allocated[rw]--; - if (!(cfqq->allocated[0] + cfqq->allocated[1])) - cfq_mark_cfqq_must_alloc(cfqq); - cfq_put_queue(cfqq); -queue_fail: - if (cic) - put_io_context(cic->ioc); - /* - * mark us rq allocation starved. we need to kickstart the process - * ourselves if there are no pending requests that can do it for us. - * that would be an extremely rare OOM situation - */ - cfqd->rq_starved = 1; - cfq_schedule_dispatch(cfqd); - spin_unlock_irqrestore(q->queue_lock, flags); - return 1; -} - -static void cfq_kick_queue(void *data) -{ - request_queue_t *q = data; - struct cfq_data *cfqd = q->elevator->elevator_data; - unsigned long flags; - - spin_lock_irqsave(q->queue_lock, flags); - - if (cfqd->rq_starved) { - struct request_list *rl = &q->rq; - - /* - * we aren't guaranteed to get a request after this, but we - * have to be opportunistic - */ - smp_mb(); - if (waitqueue_active(&rl->wait[READ])) - wake_up(&rl->wait[READ]); - if (waitqueue_active(&rl->wait[WRITE])) - wake_up(&rl->wait[WRITE]); - } - - blk_remove_plug(q); - q->request_fn(q); - spin_unlock_irqrestore(q->queue_lock, flags); -} - -/* - * Timer running if the active_queue is currently idling inside its time slice - */ -static void cfq_idle_slice_timer(unsigned long data) -{ - struct cfq_data *cfqd = (struct cfq_data *) data; - struct cfq_queue *cfqq; - unsigned long flags; - - spin_lock_irqsave(cfqd->queue->queue_lock, flags); - - if ((cfqq = cfqd->active_queue) != NULL) { - unsigned long now = jiffies; - - /* - * expired - */ - if (time_after(now, cfqq->slice_end)) - goto expire; - - /* - * only expire and reinvoke request handler, if there are - * other queues with pending requests - */ - if (!cfqd->busy_queues) { - cfqd->idle_slice_timer.expires = min(now + cfqd->cfq_slice_idle, cfqq->slice_end); - add_timer(&cfqd->idle_slice_timer); - goto out_cont; - } - - /* - * not expired and it has a request pending, let it dispatch - */ - if (!RB_EMPTY(&cfqq->sort_list)) { - cfq_mark_cfqq_must_dispatch(cfqq); - goto out_kick; - } - } -expire: - cfq_slice_expired(cfqd, 0); -out_kick: - cfq_schedule_dispatch(cfqd); -out_cont: - spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); -} - -/* - * Timer running if an idle class queue is waiting for service - */ -static void cfq_idle_class_timer(unsigned long data) -{ - struct cfq_data *cfqd = (struct cfq_data *) data; - unsigned long flags, end; - - spin_lock_irqsave(cfqd->queue->queue_lock, flags); - - /* - * race with a non-idle queue, reset timer - */ - end = cfqd->last_end_request + CFQ_IDLE_GRACE; - if (!time_after_eq(jiffies, end)) { - cfqd->idle_class_timer.expires = end; - add_timer(&cfqd->idle_class_timer); - } else - cfq_schedule_dispatch(cfqd); - - spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); -} - -static void cfq_shutdown_timer_wq(struct cfq_data *cfqd) -{ - del_timer_sync(&cfqd->idle_slice_timer); - del_timer_sync(&cfqd->idle_class_timer); - blk_sync_queue(cfqd->queue); -} - -static void cfq_put_cfqd(struct cfq_data *cfqd) -{ - request_queue_t *q = cfqd->queue; - - if (!atomic_dec_and_test(&cfqd->ref)) - return; - - cfq_shutdown_timer_wq(cfqd); - blk_put_queue(q); - - mempool_destroy(cfqd->crq_pool); - kfree(cfqd->crq_hash); - kfree(cfqd->cfq_hash); - kfree(cfqd); -} - -static void cfq_exit_queue(elevator_t *e) -{ - struct cfq_data *cfqd = e->elevator_data; - - cfq_shutdown_timer_wq(cfqd); - cfq_put_cfqd(cfqd); -} - -static int cfq_init_queue(request_queue_t *q, elevator_t *e) -{ - struct cfq_data *cfqd; - int i; - - cfqd = kmalloc(sizeof(*cfqd), GFP_KERNEL); - if (!cfqd) - return -ENOMEM; - - memset(cfqd, 0, sizeof(*cfqd)); - - for (i = 0; i < CFQ_PRIO_LISTS; i++) - INIT_LIST_HEAD(&cfqd->rr_list[i]); - - INIT_LIST_HEAD(&cfqd->busy_rr); - INIT_LIST_HEAD(&cfqd->cur_rr); - INIT_LIST_HEAD(&cfqd->idle_rr); - INIT_LIST_HEAD(&cfqd->empty_list); - - cfqd->crq_hash = kmalloc(sizeof(struct hlist_head) * CFQ_MHASH_ENTRIES, GFP_KERNEL); - if (!cfqd->crq_hash) - goto out_crqhash; - - cfqd->cfq_hash = kmalloc(sizeof(struct hlist_head) * CFQ_QHASH_ENTRIES, GFP_KERNEL); - if (!cfqd->cfq_hash) - goto out_cfqhash; - - cfqd->crq_pool = mempool_create(BLKDEV_MIN_RQ, mempool_alloc_slab, mempool_free_slab, crq_pool); - if (!cfqd->crq_pool) - goto out_crqpool; - - for (i = 0; i < CFQ_MHASH_ENTRIES; i++) - INIT_HLIST_HEAD(&cfqd->crq_hash[i]); - for (i = 0; i < CFQ_QHASH_ENTRIES; i++) - INIT_HLIST_HEAD(&cfqd->cfq_hash[i]); - - e->elevator_data = cfqd; - - cfqd->queue = q; - atomic_inc(&q->refcnt); - - cfqd->max_queued = q->nr_requests / 4; - q->nr_batching = cfq_queued; - - init_timer(&cfqd->idle_slice_timer); - cfqd->idle_slice_timer.function = cfq_idle_slice_timer; - cfqd->idle_slice_timer.data = (unsigned long) cfqd; - - init_timer(&cfqd->idle_class_timer); - cfqd->idle_class_timer.function = cfq_idle_class_timer; - cfqd->idle_class_timer.data = (unsigned long) cfqd; - - INIT_WORK(&cfqd->unplug_work, cfq_kick_queue, q); - - atomic_set(&cfqd->ref, 1); - - cfqd->cfq_queued = cfq_queued; - cfqd->cfq_quantum = cfq_quantum; - cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0]; - cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1]; - cfqd->cfq_back_max = cfq_back_max; - cfqd->cfq_back_penalty = cfq_back_penalty; - cfqd->cfq_slice[0] = cfq_slice_async; - cfqd->cfq_slice[1] = cfq_slice_sync; - cfqd->cfq_slice_async_rq = cfq_slice_async_rq; - cfqd->cfq_slice_idle = cfq_slice_idle; - cfqd->cfq_max_depth = cfq_max_depth; - - return 0; -out_crqpool: - kfree(cfqd->cfq_hash); -out_cfqhash: - kfree(cfqd->crq_hash); -out_crqhash: - kfree(cfqd); - return -ENOMEM; -} - -static void cfq_slab_kill(void) -{ - if (crq_pool) - kmem_cache_destroy(crq_pool); - if (cfq_pool) - kmem_cache_destroy(cfq_pool); - if (cfq_ioc_pool) - kmem_cache_destroy(cfq_ioc_pool); -} - -static int __init cfq_slab_setup(void) -{ - crq_pool = kmem_cache_create("crq_pool", sizeof(struct cfq_rq), 0, 0, - NULL, NULL); - if (!crq_pool) - goto fail; - - cfq_pool = kmem_cache_create("cfq_pool", sizeof(struct cfq_queue), 0, 0, - NULL, NULL); - if (!cfq_pool) - goto fail; - - cfq_ioc_pool = kmem_cache_create("cfq_ioc_pool", - sizeof(struct cfq_io_context), 0, 0, NULL, NULL); - if (!cfq_ioc_pool) - goto fail; - - return 0; -fail: - cfq_slab_kill(); - return -ENOMEM; -} - -/* - * sysfs parts below --> - */ -struct cfq_fs_entry { - struct attribute attr; - ssize_t (*show)(struct cfq_data *, char *); - ssize_t (*store)(struct cfq_data *, const char *, size_t); -}; - -static ssize_t -cfq_var_show(unsigned int var, char *page) -{ - return sprintf(page, "%d\n", var); -} - -static ssize_t -cfq_var_store(unsigned int *var, const char *page, size_t count) -{ - char *p = (char *) page; - - *var = simple_strtoul(p, &p, 10); - return count; -} - -#define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ -static ssize_t __FUNC(struct cfq_data *cfqd, char *page) \ -{ \ - unsigned int __data = __VAR; \ - if (__CONV) \ - __data = jiffies_to_msecs(__data); \ - return cfq_var_show(__data, (page)); \ -} -SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0); -SHOW_FUNCTION(cfq_queued_show, cfqd->cfq_queued, 0); -SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1); -SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1); -SHOW_FUNCTION(cfq_back_max_show, cfqd->cfq_back_max, 0); -SHOW_FUNCTION(cfq_back_penalty_show, cfqd->cfq_back_penalty, 0); -SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1); -SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1); -SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1); -SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0); -SHOW_FUNCTION(cfq_max_depth_show, cfqd->cfq_max_depth, 0); -#undef SHOW_FUNCTION - -#define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ -static ssize_t __FUNC(struct cfq_data *cfqd, const char *page, size_t count) \ -{ \ - unsigned int __data; \ - int ret = cfq_var_store(&__data, (page), count); \ - if (__data < (MIN)) \ - __data = (MIN); \ - else if (__data > (MAX)) \ - __data = (MAX); \ - if (__CONV) \ - *(__PTR) = msecs_to_jiffies(__data); \ - else \ - *(__PTR) = __data; \ - return ret; \ -} -STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0); -STORE_FUNCTION(cfq_queued_store, &cfqd->cfq_queued, 1, UINT_MAX, 0); -STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1, UINT_MAX, 1); -STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1, UINT_MAX, 1); -STORE_FUNCTION(cfq_back_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0); -STORE_FUNCTION(cfq_back_penalty_store, &cfqd->cfq_back_penalty, 1, UINT_MAX, 0); -STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1); -STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1); -STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1); -STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, UINT_MAX, 0); -STORE_FUNCTION(cfq_max_depth_store, &cfqd->cfq_max_depth, 1, UINT_MAX, 0); -#undef STORE_FUNCTION - -static struct cfq_fs_entry cfq_quantum_entry = { - .attr = {.name = "quantum", .mode = S_IRUGO | S_IWUSR }, - .show = cfq_quantum_show, - .store = cfq_quantum_store, -}; -static struct cfq_fs_entry cfq_queued_entry = { - .attr = {.name = "queued", .mode = S_IRUGO | S_IWUSR }, - .show = cfq_queued_show, - .store = cfq_queued_store, -}; -static struct cfq_fs_entry cfq_fifo_expire_sync_entry = { - .attr = {.name = "fifo_expire_sync", .mode = S_IRUGO | S_IWUSR }, - .show = cfq_fifo_expire_sync_show, - .store = cfq_fifo_expire_sync_store, -}; -static struct cfq_fs_entry cfq_fifo_expire_async_entry = { - .attr = {.name = "fifo_expire_async", .mode = S_IRUGO | S_IWUSR }, - .show = cfq_fifo_expire_async_show, - .store = cfq_fifo_expire_async_store, -}; -static struct cfq_fs_entry cfq_back_max_entry = { - .attr = {.name = "back_seek_max", .mode = S_IRUGO | S_IWUSR }, - .show = cfq_back_max_show, - .store = cfq_back_max_store, -}; -static struct cfq_fs_entry cfq_back_penalty_entry = { - .attr = {.name = "back_seek_penalty", .mode = S_IRUGO | S_IWUSR }, - .show = cfq_back_penalty_show, - .store = cfq_back_penalty_store, -}; -static struct cfq_fs_entry cfq_slice_sync_entry = { - .attr = {.name = "slice_sync", .mode = S_IRUGO | S_IWUSR }, - .show = cfq_slice_sync_show, - .store = cfq_slice_sync_store, -}; -static struct cfq_fs_entry cfq_slice_async_entry = { - .attr = {.name = "slice_async", .mode = S_IRUGO | S_IWUSR }, - .show = cfq_slice_async_show, - .store = cfq_slice_async_store, -}; -static struct cfq_fs_entry cfq_slice_async_rq_entry = { - .attr = {.name = "slice_async_rq", .mode = S_IRUGO | S_IWUSR }, - .show = cfq_slice_async_rq_show, - .store = cfq_slice_async_rq_store, -}; -static struct cfq_fs_entry cfq_slice_idle_entry = { - .attr = {.name = "slice_idle", .mode = S_IRUGO | S_IWUSR }, - .show = cfq_slice_idle_show, - .store = cfq_slice_idle_store, -}; -static struct cfq_fs_entry cfq_max_depth_entry = { - .attr = {.name = "max_depth", .mode = S_IRUGO | S_IWUSR }, - .show = cfq_max_depth_show, - .store = cfq_max_depth_store, -}; - -static struct attribute *default_attrs[] = { - &cfq_quantum_entry.attr, - &cfq_queued_entry.attr, - &cfq_fifo_expire_sync_entry.attr, - &cfq_fifo_expire_async_entry.attr, - &cfq_back_max_entry.attr, - &cfq_back_penalty_entry.attr, - &cfq_slice_sync_entry.attr, - &cfq_slice_async_entry.attr, - &cfq_slice_async_rq_entry.attr, - &cfq_slice_idle_entry.attr, - &cfq_max_depth_entry.attr, - NULL, -}; - -#define to_cfq(atr) container_of((atr), struct cfq_fs_entry, attr) - -static ssize_t -cfq_attr_show(struct kobject *kobj, struct attribute *attr, char *page) -{ - elevator_t *e = container_of(kobj, elevator_t, kobj); - struct cfq_fs_entry *entry = to_cfq(attr); - - if (!entry->show) - return -EIO; - - return entry->show(e->elevator_data, page); -} - -static ssize_t -cfq_attr_store(struct kobject *kobj, struct attribute *attr, - const char *page, size_t length) -{ - elevator_t *e = container_of(kobj, elevator_t, kobj); - struct cfq_fs_entry *entry = to_cfq(attr); - - if (!entry->store) - return -EIO; - - return entry->store(e->elevator_data, page, length); -} - -static struct sysfs_ops cfq_sysfs_ops = { - .show = cfq_attr_show, - .store = cfq_attr_store, -}; - -static struct kobj_type cfq_ktype = { - .sysfs_ops = &cfq_sysfs_ops, - .default_attrs = default_attrs, -}; - -static struct elevator_type iosched_cfq = { - .ops = { - .elevator_merge_fn = cfq_merge, - .elevator_merged_fn = cfq_merged_request, - .elevator_merge_req_fn = cfq_merged_requests, - .elevator_dispatch_fn = cfq_dispatch_requests, - .elevator_add_req_fn = cfq_insert_request, - .elevator_activate_req_fn = cfq_activate_request, - .elevator_deactivate_req_fn = cfq_deactivate_request, - .elevator_queue_empty_fn = cfq_queue_empty, - .elevator_completed_req_fn = cfq_completed_request, - .elevator_former_req_fn = cfq_former_request, - .elevator_latter_req_fn = cfq_latter_request, - .elevator_set_req_fn = cfq_set_request, - .elevator_put_req_fn = cfq_put_request, - .elevator_may_queue_fn = cfq_may_queue, - .elevator_init_fn = cfq_init_queue, - .elevator_exit_fn = cfq_exit_queue, - }, - .elevator_ktype = &cfq_ktype, - .elevator_name = "cfq", - .elevator_owner = THIS_MODULE, -}; - -static int __init cfq_init(void) -{ - int ret; - - /* - * could be 0 on HZ < 1000 setups - */ - if (!cfq_slice_async) - cfq_slice_async = 1; - if (!cfq_slice_idle) - cfq_slice_idle = 1; - - if (cfq_slab_setup()) - return -ENOMEM; - - ret = elv_register(&iosched_cfq); - if (ret) - cfq_slab_kill(); - - return ret; -} - -static void __exit cfq_exit(void) -{ - elv_unregister(&iosched_cfq); - cfq_slab_kill(); -} - -module_init(cfq_init); -module_exit(cfq_exit); - -MODULE_AUTHOR("Jens Axboe"); -MODULE_LICENSE("GPL"); -MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler"); diff --git a/drivers/block/deadline-iosched.c b/drivers/block/deadline-iosched.c deleted file mode 100644 index 7929471..0000000 --- a/drivers/block/deadline-iosched.c +++ /dev/null @@ -1,878 +0,0 @@ -/* - * linux/drivers/block/deadline-iosched.c - * - * Deadline i/o scheduler. - * - * Copyright (C) 2002 Jens Axboe <axboe@suse.de> - */ -#include <linux/kernel.h> -#include <linux/fs.h> -#include <linux/blkdev.h> -#include <linux/elevator.h> -#include <linux/bio.h> -#include <linux/config.h> -#include <linux/module.h> -#include <linux/slab.h> -#include <linux/init.h> -#include <linux/compiler.h> -#include <linux/hash.h> -#include <linux/rbtree.h> - -/* - * See Documentation/block/deadline-iosched.txt - */ -static int read_expire = HZ / 2; /* max time before a read is submitted. */ -static int write_expire = 5 * HZ; /* ditto for writes, these limits are SOFT! */ -static int writes_starved = 2; /* max times reads can starve a write */ -static int fifo_batch = 16; /* # of sequential requests treated as one - by the above parameters. For throughput. */ - -static const int deadline_hash_shift = 5; -#define DL_HASH_BLOCK(sec) ((sec) >> 3) -#define DL_HASH_FN(sec) (hash_long(DL_HASH_BLOCK((sec)), deadline_hash_shift)) -#define DL_HASH_ENTRIES (1 << deadline_hash_shift) -#define rq_hash_key(rq) ((rq)->sector + (rq)->nr_sectors) -#define list_entry_hash(ptr) list_entry((ptr), struct deadline_rq, hash) -#define ON_HASH(drq) (drq)->on_hash - -struct deadline_data { - /* - * run time data - */ - - /* - * requests (deadline_rq s) are present on both sort_list and fifo_list - */ - struct rb_root sort_list[2]; - struct list_head fifo_list[2]; - - /* - * next in sort order. read, write or both are NULL - */ - struct deadline_rq *next_drq[2]; - struct list_head *hash; /* request hash */ - unsigned int batching; /* number of sequential requests made */ - sector_t last_sector; /* head position */ - unsigned int starved; /* times reads have starved writes */ - - /* - * settings that change how the i/o scheduler behaves - */ - int fifo_expire[2]; - int fifo_batch; - int writes_starved; - int front_merges; - - mempool_t *drq_pool; -}; - -/* - * pre-request data. - */ -struct deadline_rq { - /* - * rbtree index, key is the starting offset - */ - struct rb_node rb_node; - sector_t rb_key; - - struct request *request; - - /* - * request hash, key is the ending offset (for back merge lookup) - */ - struct list_head hash; - char on_hash; - - /* - * expire fifo - */ - struct list_head fifo; - unsigned long expires; -}; - -static void deadline_move_request(struct deadline_data *dd, struct deadline_rq *drq); - -static kmem_cache_t *drq_pool; - -#define RQ_DATA(rq) ((struct deadline_rq *) (rq)->elevator_private) - -/* - * the back merge hash support functions - */ -static inline void __deadline_del_drq_hash(struct deadline_rq *drq) -{ - drq->on_hash = 0; - list_del_init(&drq->hash); -} - -static inline void deadline_del_drq_hash(struct deadline_rq *drq) -{ - if (ON_HASH(drq)) - __deadline_del_drq_hash(drq); -} - -static inline void -deadline_add_drq_hash(struct deadline_data *dd, struct deadline_rq *drq) -{ - struct request *rq = drq->request; - - BUG_ON(ON_HASH(drq)); - - drq->on_hash = 1; - list_add(&drq->hash, &dd->hash[DL_HASH_FN(rq_hash_key(rq))]); -} - -/* - * move hot entry to front of chain - */ -static inline void -deadline_hot_drq_hash(struct deadline_data *dd, struct deadline_rq *drq) -{ - struct request *rq = drq->request; - struct list_head *head = &dd->hash[DL_HASH_FN(rq_hash_key(rq))]; - - if (ON_HASH(drq) && drq->hash.prev != head) { - list_del(&drq->hash); - list_add(&drq->hash, head); - } -} - -static struct request * -deadline_find_drq_hash(struct deadline_data *dd, sector_t offset) -{ - struct list_head *hash_list = &dd->hash[DL_HASH_FN(offset)]; - struct list_head *entry, *next = hash_list->next; - - while ((entry = next) != hash_list) { - struct deadline_rq *drq = list_entry_hash(entry); - struct request *__rq = drq->request; - - next = entry->next; - - BUG_ON(!ON_HASH(drq)); - - if (!rq_mergeable(__rq)) { - __deadline_del_drq_hash(drq); - continue; - } - - if (rq_hash_key(__rq) == offset) - return __rq; - } - - return NULL; -} - -/* - * rb tree support functions - */ -#define RB_NONE (2) -#define RB_EMPTY(root) ((root)->rb_node == NULL) -#define ON_RB(node) ((node)->rb_color != RB_NONE) -#define RB_CLEAR(node) ((node)->rb_color = RB_NONE) -#define rb_entry_drq(node) rb_entry((node), struct deadline_rq, rb_node) -#define DRQ_RB_ROOT(dd, drq) (&(dd)->sort_list[rq_data_dir((drq)->request)]) -#define rq_rb_key(rq) (rq)->sector - -static struct deadline_rq * -__deadline_add_drq_rb(struct deadline_data *dd, struct deadline_rq *drq) -{ - struct rb_node **p = &DRQ_RB_ROOT(dd, drq)->rb_node; - struct rb_node *parent = NULL; - struct deadline_rq *__drq; - - while (*p) { - parent = *p; - __drq = rb_entry_drq(parent); - - if (drq->rb_key < __drq->rb_key) - p = &(*p)->rb_left; - else if (drq->rb_key > __drq->rb_key) - p = &(*p)->rb_right; - else - return __drq; - } - - rb_link_node(&drq->rb_node, parent, p); - return NULL; -} - -static void -deadline_add_drq_rb(struct deadline_data *dd, struct deadline_rq *drq) -{ - struct deadline_rq *__alias; - - drq->rb_key = rq_rb_key(drq->request); - -retry: - __alias = __deadline_add_drq_rb(dd, drq); - if (!__alias) { - rb_insert_color(&drq->rb_node, DRQ_RB_ROOT(dd, drq)); - return; - } - - deadline_move_request(dd, __alias); - goto retry; -} - -static inline void -deadline_del_drq_rb(struct deadline_data *dd, struct deadline_rq *drq) -{ - const int data_dir = rq_data_dir(drq->request); - - if (dd->next_drq[data_dir] == drq) { - struct rb_node *rbnext = rb_next(&drq->rb_node); - - dd->next_drq[data_dir] = NULL; - if (rbnext) - dd->next_drq[data_dir] = rb_entry_drq(rbnext); - } - - BUG_ON(!ON_RB(&drq->rb_node)); - rb_erase(&drq->rb_node, DRQ_RB_ROOT(dd, drq)); - RB_CLEAR(&drq->rb_node); -} - -static struct request * -deadline_find_drq_rb(struct deadline_data *dd, sector_t sector, int data_dir) -{ - struct rb_node *n = dd->sort_list[data_dir].rb_node; - struct deadline_rq *drq; - - while (n) { - drq = rb_entry_drq(n); - - if (sector < drq->rb_key) - n = n->rb_left; - else if (sector > drq->rb_key) - n = n->rb_right; - else - return drq->request; - } - - return NULL; -} - -/* - * deadline_find_first_drq finds the first (lowest sector numbered) request - * for the specified data_dir. Used to sweep back to the start of the disk - * (1-way elevator) after we process the last (highest sector) request. - */ -static struct deadline_rq * -deadline_find_first_drq(struct deadline_data *dd, int data_dir) -{ - struct rb_node *n = dd->sort_list[data_dir].rb_node; - - for (;;) { - if (n->rb_left == NULL) - return rb_entry_drq(n); - - n = n->rb_left; - } -} - -/* - * add drq to rbtree and fifo - */ -static void -deadline_add_request(struct request_queue *q, struct request *rq) -{ - struct deadline_data *dd = q->elevator->elevator_data; - struct deadline_rq *drq = RQ_DATA(rq); - - const int data_dir = rq_data_dir(drq->request); - - deadline_add_drq_rb(dd, drq); - /* - * set expire time (only used for reads) and add to fifo list - */ - drq->expires = jiffies + dd->fifo_expire[data_dir]; - list_add_tail(&drq->fifo, &dd->fifo_list[data_dir]); - - if (rq_mergeable(rq)) - deadline_add_drq_hash(dd, drq); -} - -/* - * remove rq from rbtree, fifo, and hash - */ -static void deadline_remove_request(request_queue_t *q, struct request *rq) -{ - struct deadline_rq *drq = RQ_DATA(rq); - struct deadline_data *dd = q->elevator->elevator_data; - - list_del_init(&drq->fifo); - deadline_del_drq_rb(dd, drq); - deadline_del_drq_hash(drq); -} - -static int -deadline_merge(request_queue_t *q, struct request **req, struct bio *bio) -{ - struct deadline_data *dd = q->elevator->elevator_data; - struct request *__rq; - int ret; - - /* - * see if the merge hash can satisfy a back merge - */ - __rq = deadline_find_drq_hash(dd, bio->bi_sector); - if (__rq) { - BUG_ON(__rq->sector + __rq->nr_sectors != bio->bi_sector); - - if (elv_rq_merge_ok(__rq, bio)) { - ret = ELEVATOR_BACK_MERGE; - goto out; - } - } - - /* - * check for front merge - */ - if (dd->front_merges) { - sector_t rb_key = bio->bi_sector + bio_sectors(bio); - - __rq = deadline_find_drq_rb(dd, rb_key, bio_data_dir(bio)); - if (__rq) { - BUG_ON(rb_key != rq_rb_key(__rq)); - - if (elv_rq_merge_ok(__rq, bio)) { - ret = ELEVATOR_FRONT_MERGE; - goto out; - } - } - } - - return ELEVATOR_NO_MERGE; -out: - if (ret) - deadline_hot_drq_hash(dd, RQ_DATA(__rq)); - *req = __rq; - return ret; -} - -static void deadline_merged_request(request_queue_t *q, struct request *req) -{ - struct deadline_data *dd = q->elevator->elevator_data; - struct deadline_rq *drq = RQ_DATA(req); - - /* - * hash always needs to be repositioned, key is end sector - */ - deadline_del_drq_hash(drq); - deadline_add_drq_hash(dd, drq); - - /* - * if the merge was a front merge, we need to reposition request - */ - if (rq_rb_key(req) != drq->rb_key) { - deadline_del_drq_rb(dd, drq); - deadline_add_drq_rb(dd, drq); - } -} - -static void -deadline_merged_requests(request_queue_t *q, struct request *req, - struct request *next) -{ - struct deadline_data *dd = q->elevator->elevator_data; - struct deadline_rq *drq = RQ_DATA(req); - struct deadline_rq *dnext = RQ_DATA(next); - - BUG_ON(!drq); - BUG_ON(!dnext); - - /* - * reposition drq (this is the merged request) in hash, and in rbtree - * in case of a front merge - */ - deadline_del_drq_hash(drq); - deadline_add_drq_hash(dd, drq); - - if (rq_rb_key(req) != drq->rb_key) { - deadline_del_drq_rb(dd, drq); - deadline_add_drq_rb(dd, drq); - } - - /* - * if dnext expires before drq, assign its expire time to drq - * and move into dnext position (dnext will be deleted) in fifo - */ - if (!list_empty(&drq->fifo) && !list_empty(&dnext->fifo)) { - if (time_before(dnext->expires, drq->expires)) { - list_move(&drq->fifo, &dnext->fifo); - drq->expires = dnext->expires; - } - } - - /* - * kill knowledge of next, this one is a goner - */ - deadline_remove_request(q, next); -} - -/* - * move request from sort list to dispatch queue. - */ -static inline void -deadline_move_to_dispatch(struct deadline_data *dd, struct deadline_rq *drq) -{ - request_queue_t *q = drq->request->q; - - deadline_remove_request(q, drq->request); - elv_dispatch_add_tail(q, drq->request); -} - -/* - * move an entry to dispatch queue - */ -static void -deadline_move_request(struct deadline_data *dd, struct deadline_rq *drq) -{ - const int data_dir = rq_data_dir(drq->request); - struct rb_node *rbnext = rb_next(&drq->rb_node); - - dd->next_drq[READ] = NULL; - dd->next_drq[WRITE] = NULL; - - if (rbnext) - dd->next_drq[data_dir] = rb_entry_drq(rbnext); - - dd->last_sector = drq->request->sector + drq->request->nr_sectors; - - /* - * take it off the sort and fifo list, move - * to dispatch queue - */ - deadline_move_to_dispatch(dd, drq); -} - -#define list_entry_fifo(ptr) list_entry((ptr), struct deadline_rq, fifo) - -/* - * deadline_check_fifo returns 0 if there are no expired reads on the fifo, - * 1 otherwise. Requires !list_empty(&dd->fifo_list[data_dir]) - */ -static inline int deadline_check_fifo(struct deadline_data *dd, int ddir) -{ - struct deadline_rq *drq = list_entry_fifo(dd->fifo_list[ddir].next); - - /* - * drq is expired! - */ - if (time_after(jiffies, drq->expires)) - return 1; - - return 0; -} - -/* - * deadline_dispatch_requests selects the best request according to - * read/write expire, fifo_batch, etc - */ -static int deadline_dispatch_requests(request_queue_t *q, int force) -{ - struct deadline_data *dd = q->elevator->elevator_data; - const int reads = !list_empty(&dd->fifo_list[READ]); - const int writes = !list_empty(&dd->fifo_list[WRITE]); - struct deadline_rq *drq; - int data_dir; - - /* - * batches are currently reads XOR writes - */ - if (dd->next_drq[WRITE]) - drq = dd->next_drq[WRITE]; - else - drq = dd->next_drq[READ]; - - if (drq) { - /* we have a "next request" */ - - if (dd->last_sector != drq->request->sector) - /* end the batch on a non sequential request */ - dd->batching += dd->fifo_batch; - - if (dd->batching < dd->fifo_batch) - /* we are still entitled to batch */ - goto dispatch_request; - } - - /* - * at this point we are not running a batch. select the appropriate - * data direction (read / write) - */ - - if (reads) { - BUG_ON(RB_EMPTY(&dd->sort_list[READ])); - - if (writes && (dd->starved++ >= dd->writes_starved)) - goto dispatch_writes; - - data_dir = READ; - - goto dispatch_find_request; - } - - /* - * there are either no reads or writes have been starved - */ - - if (writes) { -dispatch_writes: - BUG_ON(RB_EMPTY(&dd->sort_list[WRITE])); - - dd->starved = 0; - - data_dir = WRITE; - - goto dispatch_find_request; - } - - return 0; - -dispatch_find_request: - /* - * we are not running a batch, find best request for selected data_dir - */ - if (deadline_check_fifo(dd, data_dir)) { - /* An expired request exists - satisfy it */ - dd->batching = 0; - drq = list_entry_fifo(dd->fifo_list[data_dir].next); - - } else if (dd->next_drq[data_dir]) { - /* - * The last req was the same dir and we have a next request in - * sort order. No expired requests so continue on from here. - */ - drq = dd->next_drq[data_dir]; - } else { - /* - * The last req was the other direction or we have run out of - * higher-sectored requests. Go back to the lowest sectored - * request (1 way elevator) and start a new batch. - */ - dd->batching = 0; - drq = deadline_find_first_drq(dd, data_dir); - } - -dispatch_request: - /* - * drq is the selected appropriate request. - */ - dd->batching++; - deadline_move_request(dd, drq); - - return 1; -} - -static int deadline_queue_empty(request_queue_t *q) -{ - struct deadline_data *dd = q->elevator->elevator_data; - - return list_empty(&dd->fifo_list[WRITE]) - && list_empty(&dd->fifo_list[READ]); -} - -static struct request * -deadline_former_request(request_queue_t *q, struct request *rq) -{ - struct deadline_rq *drq = RQ_DATA(rq); - struct rb_node *rbprev = rb_prev(&drq->rb_node); - - if (rbprev) - return rb_entry_drq(rbprev)->request; - - return NULL; -} - -static struct request * -deadline_latter_request(request_queue_t *q, struct request *rq) -{ - struct deadline_rq *drq = RQ_DATA(rq); - struct rb_node *rbnext = rb_next(&drq->rb_node); - - if (rbnext) - return rb_entry_drq(rbnext)->request; - - return NULL; -} - -static void deadline_exit_queue(elevator_t *e) -{ - struct deadline_data *dd = e->elevator_data; - - BUG_ON(!list_empty(&dd->fifo_list[READ])); - BUG_ON(!list_empty(&dd->fifo_list[WRITE])); - - mempool_destroy(dd->drq_pool); - kfree(dd->hash); - kfree(dd); -} - -/* - * initialize elevator private data (deadline_data), and alloc a drq for - * each request on the free lists - */ -static int deadline_init_queue(request_queue_t *q, elevator_t *e) -{ - struct deadline_data *dd; - int i; - - if (!drq_pool) - return -ENOMEM; - - dd = kmalloc_node(sizeof(*dd), GFP_KERNEL, q->node); - if (!dd) - return -ENOMEM; - memset(dd, 0, sizeof(*dd)); - - dd->hash = kmalloc_node(sizeof(struct list_head)*DL_HASH_ENTRIES, - GFP_KERNEL, q->node); - if (!dd->hash) { - kfree(dd); - return -ENOMEM; - } - - dd->drq_pool = mempool_create_node(BLKDEV_MIN_RQ, mempool_alloc_slab, - mempool_free_slab, drq_pool, q->node); - if (!dd->drq_pool) { - kfree(dd->hash); - kfree(dd); - return -ENOMEM; - } - - for (i = 0; i < DL_HASH_ENTRIES; i++) - INIT_LIST_HEAD(&dd->hash[i]); - - INIT_LIST_HEAD(&dd->fifo_list[READ]); - INIT_LIST_HEAD(&dd->fifo_list[WRITE]); - dd->sort_list[READ] = RB_ROOT; - dd->sort_list[WRITE] = RB_ROOT; - dd->fifo_expire[READ] = read_expire; - dd->fifo_expire[WRITE] = write_expire; - dd->writes_starved = writes_starved; - dd->front_merges = 1; - dd->fifo_batch = fifo_batch; - e->elevator_data = dd; - return 0; -} - -static void deadline_put_request(request_queue_t *q, struct request *rq) -{ - struct deadline_data *dd = q->elevator->elevator_data; - struct deadline_rq *drq = RQ_DATA(rq); - - mempool_free(drq, dd->drq_pool); - rq->elevator_private = NULL; -} - -static int -deadline_set_request(request_queue_t *q, struct request *rq, struct bio *bio, - gfp_t gfp_mask) -{ - struct deadline_data *dd = q->elevator->elevator_data; - struct deadline_rq *drq; - - drq = mempool_alloc(dd->drq_pool, gfp_mask); - if (drq) { - memset(drq, 0, sizeof(*drq)); - RB_CLEAR(&drq->rb_node); - drq->request = rq; - - INIT_LIST_HEAD(&drq->hash); - drq->on_hash = 0; - - INIT_LIST_HEAD(&drq->fifo); - - rq->elevator_private = drq; - return 0; - } - - return 1; -} - -/* - * sysfs parts below - */ -struct deadline_fs_entry { - struct attribute attr; - ssize_t (*show)(struct deadline_data *, char *); - ssize_t (*store)(struct deadline_data *, const char *, size_t); -}; - -static ssize_t -deadline_var_show(int var, char *page) -{ - return sprintf(page, "%d\n", var); -} - -static ssize_t -deadline_var_store(int *var, const char *page, size_t count) -{ - char *p = (char *) page; - - *var = simple_strtol(p, &p, 10); - return count; -} - -#define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ -static ssize_t __FUNC(struct deadline_data *dd, char *page) \ -{ \ - int __data = __VAR; \ - if (__CONV) \ - __data = jiffies_to_msecs(__data); \ - return deadline_var_show(__data, (page)); \ -} -SHOW_FUNCTION(deadline_readexpire_show, dd->fifo_expire[READ], 1); -SHOW_FUNCTION(deadline_writeexpire_show, dd->fifo_expire[WRITE], 1); -SHOW_FUNCTION(deadline_writesstarved_show, dd->writes_starved, 0); -SHOW_FUNCTION(deadline_frontmerges_show, dd->front_merges, 0); -SHOW_FUNCTION(deadline_fifobatch_show, dd->fifo_batch, 0); -#undef SHOW_FUNCTION - -#define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ -static ssize_t __FUNC(struct deadline_data *dd, const char *page, size_t count) \ -{ \ - int __data; \ - int ret = deadline_var_store(&__data, (page), count); \ - if (__data < (MIN)) \ - __data = (MIN); \ - else if (__data > (MAX)) \ - __data = (MAX); \ - if (__CONV) \ - *(__PTR) = msecs_to_jiffies(__data); \ - else \ - *(__PTR) = __data; \ - return ret; \ -} -STORE_FUNCTION(deadline_readexpire_store, &dd->fifo_expire[READ], 0, INT_MAX, 1); -STORE_FUNCTION(deadline_writeexpire_store, &dd->fifo_expire[WRITE], 0, INT_MAX, 1); -STORE_FUNCTION(deadline_writesstarved_store, &dd->writes_starved, INT_MIN, INT_MAX, 0); -STORE_FUNCTION(deadline_frontmerges_store, &dd->front_merges, 0, 1, 0); -STORE_FUNCTION(deadline_fifobatch_store, &dd->fifo_batch, 0, INT_MAX, 0); -#undef STORE_FUNCTION - -static struct deadline_fs_entry deadline_readexpire_entry = { - .attr = {.name = "read_expire", .mode = S_IRUGO | S_IWUSR }, - .show = deadline_readexpire_show, - .store = deadline_readexpire_store, -}; -static struct deadline_fs_entry deadline_writeexpire_entry = { - .attr = {.name = "write_expire", .mode = S_IRUGO | S_IWUSR }, - .show = deadline_writeexpire_show, - .store = deadline_writeexpire_store, -}; -static struct deadline_fs_entry deadline_writesstarved_entry = { - .attr = {.name = "writes_starved", .mode = S_IRUGO | S_IWUSR }, - .show = deadline_writesstarved_show, - .store = deadline_writesstarved_store, -}; -static struct deadline_fs_entry deadline_frontmerges_entry = { - .attr = {.name = "front_merges", .mode = S_IRUGO | S_IWUSR }, - .show = deadline_frontmerges_show, - .store = deadline_frontmerges_store, -}; -static struct deadline_fs_entry deadline_fifobatch_entry = { - .attr = {.name = "fifo_batch", .mode = S_IRUGO | S_IWUSR }, - .show = deadline_fifobatch_show, - .store = deadline_fifobatch_store, -}; - -static struct attribute *default_attrs[] = { - &deadline_readexpire_entry.attr, - &deadline_writeexpire_entry.attr, - &deadline_writesstarved_entry.attr, - &deadline_frontmerges_entry.attr, - &deadline_fifobatch_entry.attr, - NULL, -}; - -#define to_deadline(atr) container_of((atr), struct deadline_fs_entry, attr) - -static ssize_t -deadline_attr_show(struct kobject *kobj, struct attribute *attr, char *page) -{ - elevator_t *e = container_of(kobj, elevator_t, kobj); - struct deadline_fs_entry *entry = to_deadline(attr); - - if (!entry->show) - return -EIO; - - return entry->show(e->elevator_data, page); -} - -static ssize_t -deadline_attr_store(struct kobject *kobj, struct attribute *attr, - const char *page, size_t length) -{ - elevator_t *e = container_of(kobj, elevator_t, kobj); - struct deadline_fs_entry *entry = to_deadline(attr); - - if (!entry->store) - return -EIO; - - return entry->store(e->elevator_data, page, length); -} - -static struct sysfs_ops deadline_sysfs_ops = { - .show = deadline_attr_show, - .store = deadline_attr_store, -}; - -static struct kobj_type deadline_ktype = { - .sysfs_ops = &deadline_sysfs_ops, - .default_attrs = default_attrs, -}; - -static struct elevator_type iosched_deadline = { - .ops = { - .elevator_merge_fn = deadline_merge, - .elevator_merged_fn = deadline_merged_request, - .elevator_merge_req_fn = deadline_merged_requests, - .elevator_dispatch_fn = deadline_dispatch_requests, - .elevator_add_req_fn = deadline_add_request, - .elevator_queue_empty_fn = deadline_queue_empty, - .elevator_former_req_fn = deadline_former_request, - .elevator_latter_req_fn = deadline_latter_request, - .elevator_set_req_fn = deadline_set_request, - .elevator_put_req_fn = deadline_put_request, - .elevator_init_fn = deadline_init_queue, - .elevator_exit_fn = deadline_exit_queue, - }, - - .elevator_ktype = &deadline_ktype, - .elevator_name = "deadline", - .elevator_owner = THIS_MODULE, -}; - -static int __init deadline_init(void) -{ - int ret; - - drq_pool = kmem_cache_create("deadline_drq", sizeof(struct deadline_rq), - 0, 0, NULL, NULL); - - if (!drq_pool) - return -ENOMEM; - - ret = elv_register(&iosched_deadline); - if (ret) - kmem_cache_destroy(drq_pool); - - return ret; -} - -static void __exit deadline_exit(void) -{ - kmem_cache_destroy(drq_pool); - elv_unregister(&iosched_deadline); -} - -module_init(deadline_init); -module_exit(deadline_exit); - -MODULE_AUTHOR("Jens Axboe"); -MODULE_LICENSE("GPL"); -MODULE_DESCRIPTION("deadline IO scheduler"); diff --git a/drivers/block/elevator.c b/drivers/block/elevator.c deleted file mode 100644 index d4a49a3..0000000 --- a/drivers/block/elevator.c +++ /dev/null @@ -1,802 +0,0 @@ -/* - * linux/drivers/block/elevator.c - * - * Block device elevator/IO-scheduler. - * - * Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE - * - * 30042000 Jens Axboe <axboe@suse.de> : - * - * Split the elevator a bit so that it is possible to choose a different - * one or even write a new "plug in". There are three pieces: - * - elevator_fn, inserts a new request in the queue list - * - elevator_merge_fn, decides whether a new buffer can be merged with - * an existing request - * - elevator_dequeue_fn, called when a request is taken off the active list - * - * 20082000 Dave Jones <davej@suse.de> : - * Removed tests for max-bomb-segments, which was breaking elvtune - * when run without -bN - * - * Jens: - * - Rework again to work with bio instead of buffer_heads - * - loose bi_dev comparisons, partition handling is right now - * - completely modularize elevator setup and teardown - * - */ -#include <linux/kernel.h> -#include <linux/fs.h> -#include <linux/blkdev.h> -#include <linux/elevator.h> -#include <linux/bio.h> -#include <linux/config.h> -#include <linux/module.h> -#include <linux/slab.h> -#include <linux/init.h> -#include <linux/compiler.h> -#include <linux/delay.h> - -#include <asm/uaccess.h> - -static DEFINE_SPINLOCK(elv_list_lock); -static LIST_HEAD(elv_list); - -/* - * can we safely merge with this request? - */ -inline int elv_rq_merge_ok(struct request *rq, struct bio *bio) -{ - if (!rq_mergeable(rq)) - return 0; - - /* - * different data direction or already started, don't merge - */ - if (bio_data_dir(bio) != rq_data_dir(rq)) - return 0; - - /* - * same device and no special stuff set, merge is ok - */ - if (rq->rq_disk == bio->bi_bdev->bd_disk && - !rq->waiting && !rq->special) - return 1; - - return 0; -} -EXPORT_SYMBOL(elv_rq_merge_ok); - -inline int elv_try_merge(struct request *__rq, struct bio *bio) -{ - int ret = ELEVATOR_NO_MERGE; - - /* - * we can merge and sequence is ok, check if it's possible - */ - if (elv_rq_merge_ok(__rq, bio)) { - if (__rq->sector + __rq->nr_sectors == bio->bi_sector) - ret = ELEVATOR_BACK_MERGE; - else if (__rq->sector - bio_sectors(bio) == bio->bi_sector) - ret = ELEVATOR_FRONT_MERGE; - } - - return ret; -} -EXPORT_SYMBOL(elv_try_merge); - -static struct elevator_type *elevator_find(const char *name) -{ - struct elevator_type *e = NULL; - struct list_head *entry; - - list_for_each(entry, &elv_list) { - struct elevator_type *__e; - - __e = list_entry(entry, struct elevator_type, list); - - if (!strcmp(__e->elevator_name, name)) { - e = __e; - break; - } - } - - return e; -} - -static void elevator_put(struct elevator_type *e) -{ - module_put(e->elevator_owner); -} - -static struct elevator_type *elevator_get(const char *name) -{ - struct elevator_type *e; - - spin_lock_irq(&elv_list_lock); - - e = elevator_find(name); - if (e && !try_module_get(e->elevator_owner)) - e = NULL; - - spin_unlock_irq(&elv_list_lock); - - return e; -} - -static int elevator_attach(request_queue_t *q, struct elevator_type *e, - struct elevator_queue *eq) -{ - int ret = 0; - - memset(eq, 0, sizeof(*eq)); - eq->ops = &e->ops; - eq->elevator_type = e; - - q->elevator = eq; - - if (eq->ops->elevator_init_fn) - ret = eq->ops->elevator_init_fn(q, eq); - - return ret; -} - -static char chosen_elevator[16]; - -static void elevator_setup_default(void) -{ - struct elevator_type *e; - - /* - * If default has not been set, use the compiled-in selection. - */ - if (!chosen_elevator[0]) - strcpy(chosen_elevator, CONFIG_DEFAULT_IOSCHED); - - /* - * If the given scheduler is not available, fall back to no-op. - */ - if (!(e = elevator_find(chosen_elevator))) - strcpy(chosen_elevator, "noop"); - elevator_put(e); -} - -static int __init elevator_setup(char *str) -{ - strncpy(chosen_elevator, str, sizeof(chosen_elevator) - 1); - return 0; -} - -__setup("elevator=", elevator_setup); - -int elevator_init(request_queue_t *q, char *name) -{ - struct elevator_type *e = NULL; - struct elevator_queue *eq; - int ret = 0; - - INIT_LIST_HEAD(&q->queue_head); - q->last_merge = NULL; - q->end_sector = 0; - q->boundary_rq = NULL; - - elevator_setup_default(); - - if (!name) - name = chosen_elevator; - - e = elevator_get(name); - if (!e) - return -EINVAL; - - eq = kmalloc(sizeof(struct elevator_queue), GFP_KERNEL); - if (!eq) { - elevator_put(e->elevator_type); - return -ENOMEM; - } - - ret = elevator_attach(q, e, eq); - if (ret) { - kfree(eq); - elevator_put(e->elevator_type); - } - - return ret; -} - -void elevator_exit(elevator_t *e) -{ - if (e->ops->elevator_exit_fn) - e->ops->elevator_exit_fn(e); - - elevator_put(e->elevator_type); - e->elevator_type = NULL; - kfree(e); -} - -/* - * Insert rq into dispatch queue of q. Queue lock must be held on - * entry. If sort != 0, rq is sort-inserted; otherwise, rq will be - * appended to the dispatch queue. To be used by specific elevators. - */ -void elv_dispatch_sort(request_queue_t *q, struct request *rq) -{ - sector_t boundary; - struct list_head *entry; - - if (q->last_merge == rq) - q->last_merge = NULL; - - boundary = q->end_sector; - - list_for_each_prev(entry, &q->queue_head) { - struct request *pos = list_entry_rq(entry); - - if (pos->flags & (REQ_SOFTBARRIER|REQ_HARDBARRIER|REQ_STARTED)) - break; - if (rq->sector >= boundary) { - if (pos->sector < boundary) - continue; - } else { - if (pos->sector >= boundary) - break; - } - if (rq->sector >= pos->sector) - break; - } - - list_add(&rq->queuelist, entry); -} - -int elv_merge(request_queue_t *q, struct request **req, struct bio *bio) -{ - elevator_t *e = q->elevator; - int ret; - - if (q->last_merge) { - ret = elv_try_merge(q->last_merge, bio); - if (ret != ELEVATOR_NO_MERGE) { - *req = q->last_merge; - return ret; - } - } - - if (e->ops->elevator_merge_fn) - return e->ops->elevator_merge_fn(q, req, bio); - - return ELEVATOR_NO_MERGE; -} - -void elv_merged_request(request_queue_t *q, struct request *rq) -{ - elevator_t *e = q->elevator; - - if (e->ops->elevator_merged_fn) - e->ops->elevator_merged_fn(q, rq); - - q->last_merge = rq; -} - -void elv_merge_requests(request_queue_t *q, struct request *rq, - struct request *next) -{ - elevator_t *e = q->elevator; - - if (e->ops->elevator_merge_req_fn) - e->ops->elevator_merge_req_fn(q, rq, next); - - q->last_merge = rq; -} - -void elv_requeue_request(request_queue_t *q, struct request *rq) -{ - elevator_t *e = q->elevator; - - /* - * it already went through dequeue, we need to decrement the - * in_flight count again - */ - if (blk_account_rq(rq)) { - q->in_flight--; - if (blk_sorted_rq(rq) && e->ops->elevator_deactivate_req_fn) - e->ops->elevator_deactivate_req_fn(q, rq); - } - - rq->flags &= ~REQ_STARTED; - - /* - * if this is the flush, requeue the original instead and drop the flush - */ - if (rq->flags & REQ_BAR_FLUSH) { - clear_bit(QUEUE_FLAG_FLUSH, &q->queue_flags); - rq = rq->end_io_data; - } - - __elv_add_request(q, rq, ELEVATOR_INSERT_FRONT, 0); -} - -void __elv_add_request(request_queue_t *q, struct request *rq, int where, - int plug) -{ - if (rq->flags & (REQ_SOFTBARRIER | REQ_HARDBARRIER)) { - /* - * barriers implicitly indicate back insertion - */ - if (where == ELEVATOR_INSERT_SORT) - where = ELEVATOR_INSERT_BACK; - - /* - * this request is scheduling boundary, update end_sector - */ - if (blk_fs_request(rq)) { - q->end_sector = rq_end_sector(rq); - q->boundary_rq = rq; - } - } else if (!(rq->flags & REQ_ELVPRIV) && where == ELEVATOR_INSERT_SORT) - where = ELEVATOR_INSERT_BACK; - - if (plug) - blk_plug_device(q); - - rq->q = q; - - switch (where) { - case ELEVATOR_INSERT_FRONT: - rq->flags |= REQ_SOFTBARRIER; - - list_add(&rq->queuelist, &q->queue_head); - break; - - case ELEVATOR_INSERT_BACK: - rq->flags |= REQ_SOFTBARRIER; - - while (q->elevator->ops->elevator_dispatch_fn(q, 1)) - ; - list_add_tail(&rq->queuelist, &q->queue_head); - /* - * We kick the queue here for the following reasons. - * - The elevator might have returned NULL previously - * to delay requests and returned them now. As the - * queue wasn't empty before this request, ll_rw_blk - * won't run the queue on return, resulting in hang. - * - Usually, back inserted requests won't be merged - * with anything. There's no point in delaying queue - * processing. - */ - blk_remove_plug(q); - q->request_fn(q); - break; - - case ELEVATOR_INSERT_SORT: - BUG_ON(!blk_fs_request(rq)); - rq->flags |= REQ_SORTED; - if (q->last_merge == NULL && rq_mergeable(rq)) - q->last_merge = rq; - /* - * Some ioscheds (cfq) run q->request_fn directly, so - * rq cannot be accessed after calling - * elevator_add_req_fn. - */ - q->elevator->ops->elevator_add_req_fn(q, rq); - break; - - default: - printk(KERN_ERR "%s: bad insertion point %d\n", - __FUNCTION__, where); - BUG(); - } - - if (blk_queue_plugged(q)) { - int nrq = q->rq.count[READ] + q->rq.count[WRITE] - - q->in_flight; - - if (nrq >= q->unplug_thresh) - __generic_unplug_device(q); - } -} - -void elv_add_request(request_queue_t *q, struct request *rq, int where, - int plug) -{ - unsigned long flags; - - spin_lock_irqsave(q->queue_lock, flags); - __elv_add_request(q, rq, where, plug); - spin_unlock_irqrestore(q->queue_lock, flags); -} - -static inline struct request *__elv_next_request(request_queue_t *q) -{ - struct request *rq; - - if (unlikely(list_empty(&q->queue_head) && - !q->elevator->ops->elevator_dispatch_fn(q, 0))) - return NULL; - - rq = list_entry_rq(q->queue_head.next); - - /* - * if this is a barrier write and the device has to issue a - * flush sequence to support it, check how far we are - */ - if (blk_fs_request(rq) && blk_barrier_rq(rq)) { - BUG_ON(q->ordered == QUEUE_ORDERED_NONE); - - if (q->ordered == QUEUE_ORDERED_FLUSH && - !blk_barrier_preflush(rq)) - rq = blk_start_pre_flush(q, rq); - } - - return rq; -} - -struct request *elv_next_request(request_queue_t *q) -{ - struct request *rq; - int ret; - - while ((rq = __elv_next_request(q)) != NULL) { - if (!(rq->flags & REQ_STARTED)) { - elevator_t *e = q->elevator; - - /* - * This is the first time the device driver - * sees this request (possibly after - * requeueing). Notify IO scheduler. - */ - if (blk_sorted_rq(rq) && - e->ops->elevator_activate_req_fn) - e->ops->elevator_activate_req_fn(q, rq); - - /* - * just mark as started even if we don't start - * it, a request that has been delayed should - * not be passed by new incoming requests - */ - rq->flags |= REQ_STARTED; - } - - if (!q->boundary_rq || q->boundary_rq == rq) { - q->end_sector = rq_end_sector(rq); - q->boundary_rq = NULL; - } - - if ((rq->flags & REQ_DONTPREP) || !q->prep_rq_fn) - break; - - ret = q->prep_rq_fn(q, rq); - if (ret == BLKPREP_OK) { - break; - } else if (ret == BLKPREP_DEFER) { - /* - * the request may have been (partially) prepped. - * we need to keep this request in the front to - * avoid resource deadlock. REQ_STARTED will - * prevent other fs requests from passing this one. - */ - rq = NULL; - break; - } else if (ret == BLKPREP_KILL) { - int nr_bytes = rq->hard_nr_sectors << 9; - - if (!nr_bytes) - nr_bytes = rq->data_len; - - blkdev_dequeue_request(rq); - rq->flags |= REQ_QUIET; - end_that_request_chunk(rq, 0, nr_bytes); - end_that_request_last(rq); - } else { - printk(KERN_ERR "%s: bad return=%d\n", __FUNCTION__, - ret); - break; - } - } - - return rq; -} - -void elv_dequeue_request(request_queue_t *q, struct request *rq) -{ - BUG_ON(list_empty(&rq->queuelist)); - - list_del_init(&rq->queuelist); - - /* - * the time frame between a request being removed from the lists - * and to it is freed is accounted as io that is in progress at - * the driver side. - */ - if (blk_account_rq(rq)) - q->in_flight++; -} - -int elv_queue_empty(request_queue_t *q) -{ - elevator_t *e = q->elevator; - - if (!list_empty(&q->queue_head)) - return 0; - - if (e->ops->elevator_queue_empty_fn) - return e->ops->elevator_queue_empty_fn(q); - - return 1; -} - -struct request *elv_latter_request(request_queue_t *q, struct request *rq) -{ - struct list_head *next; - - elevator_t *e = q->elevator; - - if (e->ops->elevator_latter_req_fn) - return e->ops->elevator_latter_req_fn(q, rq); - - next = rq->queuelist.next; - if (next != &q->queue_head && next != &rq->queuelist) - return list_entry_rq(next); - - return NULL; -} - -struct request *elv_former_request(request_queue_t *q, struct request *rq) -{ - struct list_head *prev; - - elevator_t *e = q->elevator; - - if (e->ops->elevator_former_req_fn) - return e->ops->elevator_former_req_fn(q, rq); - - prev = rq->queuelist.prev; - if (prev != &q->queue_head && prev != &rq->queuelist) - return list_entry_rq(prev); - - return NULL; -} - -int elv_set_request(request_queue_t *q, struct request *rq, struct bio *bio, - gfp_t gfp_mask) -{ - elevator_t *e = q->elevator; - - if (e->ops->elevator_set_req_fn) - return e->ops->elevator_set_req_fn(q, rq, bio, gfp_mask); - - rq->elevator_private = NULL; - return 0; -} - -void elv_put_request(request_queue_t *q, struct request *rq) -{ - elevator_t *e = q->elevator; - - if (e->ops->elevator_put_req_fn) - e->ops->elevator_put_req_fn(q, rq); -} - -int elv_may_queue(request_queue_t *q, int rw, struct bio *bio) -{ - elevator_t *e = q->elevator; - - if (e->ops->elevator_may_queue_fn) - return e->ops->elevator_may_queue_fn(q, rw, bio); - - return ELV_MQUEUE_MAY; -} - -void elv_completed_request(request_queue_t *q, struct request *rq) -{ - elevator_t *e = q->elevator; - - /* - * request is released from the driver, io must be done - */ - if (blk_account_rq(rq)) { - q->in_flight--; - if (blk_sorted_rq(rq) && e->ops->elevator_completed_req_fn) - e->ops->elevator_completed_req_fn(q, rq); - } -} - -int elv_register_queue(struct request_queue *q) -{ - elevator_t *e = q->elevator; - - e->kobj.parent = kobject_get(&q->kobj); - if (!e->kobj.parent) - return -EBUSY; - - snprintf(e->kobj.name, KOBJ_NAME_LEN, "%s", "iosched"); - e->kobj.ktype = e->elevator_type->elevator_ktype; - - return kobject_register(&e->kobj); -} - -void elv_unregister_queue(struct request_queue *q) -{ - if (q) { - elevator_t *e = q->elevator; - kobject_unregister(&e->kobj); - kobject_put(&q->kobj); - } -} - -int elv_register(struct elevator_type *e) -{ - spin_lock_irq(&elv_list_lock); - if (elevator_find(e->elevator_name)) - BUG(); - list_add_tail(&e->list, &elv_list); - spin_unlock_irq(&elv_list_lock); - - printk(KERN_INFO "io scheduler %s registered", e->elevator_name); - if (!strcmp(e->elevator_name, chosen_elevator)) - printk(" (default)"); - printk("\n"); - return 0; -} -EXPORT_SYMBOL_GPL(elv_register); - -void elv_unregister(struct elevator_type *e) -{ - struct task_struct *g, *p; - - /* - * Iterate every thread in the process to remove the io contexts. - */ - read_lock(&tasklist_lock); - do_each_thread(g, p) { - struct io_context *ioc = p->io_context; - if (ioc && ioc->cic) { - ioc->cic->exit(ioc->cic); - ioc->cic->dtor(ioc->cic); - ioc->cic = NULL; - } - if (ioc && ioc->aic) { - ioc->aic->exit(ioc->aic); - ioc->aic->dtor(ioc->aic); - ioc->aic = NULL; - } - } while_each_thread(g, p); - read_unlock(&tasklist_lock); - - spin_lock_irq(&elv_list_lock); - list_del_init(&e->list); - spin_unlock_irq(&elv_list_lock); -} -EXPORT_SYMBOL_GPL(elv_unregister); - -/* - * switch to new_e io scheduler. be careful not to introduce deadlocks - - * we don't free the old io scheduler, before we have allocated what we - * need for the new one. this way we have a chance of going back to the old - * one, if the new one fails init for some reason. - */ -static void elevator_switch(request_queue_t *q, struct elevator_type *new_e) -{ - elevator_t *old_elevator, *e; - - /* - * Allocate new elevator - */ - e = kmalloc(sizeof(elevator_t), GFP_KERNEL); - if (!e) - goto error; - - /* - * Turn on BYPASS and drain all requests w/ elevator private data - */ - spin_lock_irq(q->queue_lock); - - set_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags); - - while (q->elevator->ops->elevator_dispatch_fn(q, 1)) - ; - - while (q->rq.elvpriv) { - spin_unlock_irq(q->queue_lock); - msleep(10); - spin_lock_irq(q->queue_lock); - } - - spin_unlock_irq(q->queue_lock); - - /* - * unregister old elevator data - */ - elv_unregister_queue(q); - old_elevator = q->elevator; - - /* - * attach and start new elevator - */ - if (elevator_attach(q, new_e, e)) - goto fail; - - if (elv_register_queue(q)) - goto fail_register; - - /* - * finally exit old elevator and turn off BYPASS. - */ - elevator_exit(old_elevator); - clear_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags); - return; - -fail_register: - /* - * switch failed, exit the new io scheduler and reattach the old - * one again (along with re-adding the sysfs dir) - */ - elevator_exit(e); - e = NULL; -fail: - q->elevator = old_elevator; - elv_register_queue(q); - clear_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags); - kfree(e); -error: - elevator_put(new_e); - printk(KERN_ERR "elevator: switch to %s failed\n",new_e->elevator_name); -} - -ssize_t elv_iosched_store(request_queue_t *q, const char *name, size_t count) -{ - char elevator_name[ELV_NAME_MAX]; - struct elevator_type *e; - - memset(elevator_name, 0, sizeof(elevator_name)); - strncpy(elevator_name, name, sizeof(elevator_name)); - - if (elevator_name[strlen(elevator_name) - 1] == '\n') - elevator_name[strlen(elevator_name) - 1] = '\0'; - - e = elevator_get(elevator_name); - if (!e) { - printk(KERN_ERR "elevator: type %s not found\n", elevator_name); - return -EINVAL; - } - - if (!strcmp(elevator_name, q->elevator->elevator_type->elevator_name)) { - elevator_put(e); - return count; - } - - elevator_switch(q, e); - return count; -} - -ssize_t elv_iosched_show(request_queue_t *q, char *name) -{ - elevator_t *e = q->elevator; - struct elevator_type *elv = e->elevator_type; - struct list_head *entry; - int len = 0; - - spin_lock_irq(q->queue_lock); - list_for_each(entry, &elv_list) { - struct elevator_type *__e; - - __e = list_entry(entry, struct elevator_type, list); - if (!strcmp(elv->elevator_name, __e->elevator_name)) - len += sprintf(name+len, "[%s] ", elv->elevator_name); - else - len += sprintf(name+len, "%s ", __e->elevator_name); - } - spin_unlock_irq(q->queue_lock); - - len += sprintf(len+name, "\n"); - return len; -} - -EXPORT_SYMBOL(elv_dispatch_sort); -EXPORT_SYMBOL(elv_add_request); -EXPORT_SYMBOL(__elv_add_request); -EXPORT_SYMBOL(elv_requeue_request); -EXPORT_SYMBOL(elv_next_request); -EXPORT_SYMBOL(elv_dequeue_request); -EXPORT_SYMBOL(elv_queue_empty); -EXPORT_SYMBOL(elv_completed_request); -EXPORT_SYMBOL(elevator_exit); -EXPORT_SYMBOL(elevator_init); diff --git a/drivers/block/genhd.c b/drivers/block/genhd.c deleted file mode 100644 index 54aec4a..0000000 --- a/drivers/block/genhd.c +++ /dev/null @@ -1,726 +0,0 @@ -/* - * gendisk handling - */ - -#include <linux/config.h> -#include <linux/module.h> -#include <linux/fs.h> -#include <linux/genhd.h> -#include <linux/kernel.h> -#include <linux/blkdev.h> -#include <linux/init.h> -#include <linux/spinlock.h> -#include <linux/seq_file.h> -#include <linux/slab.h> -#include <linux/kmod.h> -#include <linux/kobj_map.h> -#include <linux/buffer_head.h> - -#define MAX_PROBE_HASH 255 /* random */ - -static struct subsystem block_subsys; - -static DECLARE_MUTEX(block_subsys_sem); - -/* - * Can be deleted altogether. Later. - * - */ -static struct blk_major_name { - struct blk_major_name *next; - int major; - char name[16]; -} *major_names[MAX_PROBE_HASH]; - -/* index in the above - for now: assume no multimajor ranges */ -static inline int major_to_index(int major) -{ - return major % MAX_PROBE_HASH; -} - -#ifdef CONFIG_PROC_FS -/* get block device names in somewhat random order */ -int get_blkdev_list(char *p, int used) -{ - struct blk_major_name *n; - int i, len; - - len = snprintf(p, (PAGE_SIZE-used), "\nBlock devices:\n"); - - down(&block_subsys_sem); - for (i = 0; i < ARRAY_SIZE(major_names); i++) { - for (n = major_names[i]; n; n = n->next) { - /* - * If the curent string plus the 5 extra characters - * in the line would run us off the page, then we're done - */ - if ((len + used + strlen(n->name) + 5) >= PAGE_SIZE) - goto page_full; - len += sprintf(p+len, "%3d %s\n", - n->major, n->name); - } - } -page_full: - up(&block_subsys_sem); - - return len; -} -#endif - -int register_blkdev(unsigned int major, const char *name) -{ - struct blk_major_name **n, *p; - int index, ret = 0; - - down(&block_subsys_sem); - - /* temporary */ - if (major == 0) { - for (index = ARRAY_SIZE(major_names)-1; index > 0; index--) { - if (major_names[index] == NULL) - break; - } - - if (index == 0) { - printk("register_blkdev: failed to get major for %s\n", - name); - ret = -EBUSY; - goto out; - } - major = index; - ret = major; - } - - p = kmalloc(sizeof(struct blk_major_name), GFP_KERNEL); - if (p == NULL) { - ret = -ENOMEM; - goto out; - } - - p->major = major; - strlcpy(p->name, name, sizeof(p->name)); - p->next = NULL; - index = major_to_index(major); - - for (n = &major_names[index]; *n; n = &(*n)->next) { - if ((*n)->major == major) - break; - } - if (!*n) - *n = p; - else - ret = -EBUSY; - - if (ret < 0) { - printk("register_blkdev: cannot get major %d for %s\n", - major, name); - kfree(p); - } -out: - up(&block_subsys_sem); - return ret; -} - -EXPORT_SYMBOL(register_blkdev); - -/* todo: make void - error printk here */ -int unregister_blkdev(unsigned int major, const char *name) -{ - struct blk_major_name **n; - struct blk_major_name *p = NULL; - int index = major_to_index(major); - int ret = 0; - - down(&block_subsys_sem); - for (n = &major_names[index]; *n; n = &(*n)->next) - if ((*n)->major == major) - break; - if (!*n || strcmp((*n)->name, name)) - ret = -EINVAL; - else { - p = *n; - *n = p->next; - } - up(&block_subsys_sem); - kfree(p); - - return ret; -} - -EXPORT_SYMBOL(unregister_blkdev); - -static struct kobj_map *bdev_map; - -/* - * Register device numbers dev..(dev+range-1) - * range must be nonzero - * The hash chain is sorted on range, so that subranges can override. - */ -void blk_register_region(dev_t dev, unsigned long range, struct module *module, - struct kobject *(*probe)(dev_t, int *, void *), - int (*lock)(dev_t, void *), void *data) -{ - kobj_map(bdev_map, dev, range, module, probe, lock, data); -} - -EXPORT_SYMBOL(blk_register_region); - -void blk_unregister_region(dev_t dev, unsigned long range) -{ - kobj_unmap(bdev_map, dev, range); -} - -EXPORT_SYMBOL(blk_unregister_region); - -static struct kobject *exact_match(dev_t dev, int *part, void *data) -{ - struct gendisk *p = data; - return &p->kobj; -} - -static int exact_lock(dev_t dev, void *data) -{ - struct gendisk *p = data; - - if (!get_disk(p)) - return -1; - return 0; -} - -/** - * add_disk - add partitioning information to kernel list - * @disk: per-device partitioning information - * - * This function registers the partitioning information in @disk - * with the kernel. - */ -void add_disk(struct gendisk *disk) -{ - disk->flags |= GENHD_FL_UP; - blk_register_region(MKDEV(disk->major, disk->first_minor), - disk->minors, NULL, exact_match, exact_lock, disk); - register_disk(disk); - blk_register_queue(disk); -} - -EXPORT_SYMBOL(add_disk); -EXPORT_SYMBOL(del_gendisk); /* in partitions/check.c */ - -void unlink_gendisk(struct gendisk *disk) -{ - blk_unregister_queue(disk); - blk_unregister_region(MKDEV(disk->major, disk->first_minor), - disk->minors); -} - -#define to_disk(obj) container_of(obj,struct gendisk,kobj) - -/** - * get_gendisk - get partitioning information for a given device - * @dev: device to get partitioning information for - * - * This function gets the structure containing partitioning - * information for the given device @dev. - */ -struct gendisk *get_gendisk(dev_t dev, int *part) -{ - struct kobject *kobj = kobj_lookup(bdev_map, dev, part); - return kobj ? to_disk(kobj) : NULL; -} - -#ifdef CONFIG_PROC_FS -/* iterator */ -static void *part_start(struct seq_file *part, loff_t *pos) -{ - struct list_head *p; - loff_t l = *pos; - - down(&block_subsys_sem); - list_for_each(p, &block_subsys.kset.list) - if (!l--) - return list_entry(p, struct gendisk, kobj.entry); - return NULL; -} - -static void *part_next(struct seq_file *part, void *v, loff_t *pos) -{ - struct list_head *p = ((struct gendisk *)v)->kobj.entry.next; - ++*pos; - return p==&block_subsys.kset.list ? NULL : - list_entry(p, struct gendisk, kobj.entry); -} - -static void part_stop(struct seq_file *part, void *v) -{ - up(&block_subsys_sem); -} - -static int show_partition(struct seq_file *part, void *v) -{ - struct gendisk *sgp = v; - int n; - char buf[BDEVNAME_SIZE]; - - if (&sgp->kobj.entry == block_subsys.kset.list.next) - seq_puts(part, "major minor #blocks name\n\n"); - - /* Don't show non-partitionable removeable devices or empty devices */ - if (!get_capacity(sgp) || - (sgp->minors == 1 && (sgp->flags & GENHD_FL_REMOVABLE))) - return 0; - if (sgp->flags & GENHD_FL_SUPPRESS_PARTITION_INFO) - return 0; - - /* show the full disk and all non-0 size partitions of it */ - seq_printf(part, "%4d %4d %10llu %s\n", - sgp->major, sgp->first_minor, - (unsigned long long)get_capacity(sgp) >> 1, - disk_name(sgp, 0, buf)); - for (n = 0; n < sgp->minors - 1; n++) { - if (!sgp->part[n]) - continue; - if (sgp->part[n]->nr_sects == 0) - continue; - seq_printf(part, "%4d %4d %10llu %s\n", - sgp->major, n + 1 + sgp->first_minor, - (unsigned long long)sgp->part[n]->nr_sects >> 1 , - disk_name(sgp, n + 1, buf)); - } - - return 0; -} - -struct seq_operations partitions_op = { - .start =part_start, - .next = part_next, - .stop = part_stop, - .show = show_partition -}; -#endif - - -extern int blk_dev_init(void); - -static struct kobject *base_probe(dev_t dev, int *part, void *data) -{ - if (request_module("block-major-%d-%d", MAJOR(dev), MINOR(dev)) > 0) - /* Make old-style 2.4 aliases work */ - request_module("block-major-%d", MAJOR(dev)); - return NULL; -} - -static int __init genhd_device_init(void) -{ - bdev_map = kobj_map_init(base_probe, &block_subsys_sem); - blk_dev_init(); - subsystem_register(&block_subsys); - return 0; -} - -subsys_initcall(genhd_device_init); - - - -/* - * kobject & sysfs bindings for block devices - */ -static ssize_t disk_attr_show(struct kobject *kobj, struct attribute *attr, - char *page) -{ - struct gendisk *disk = to_disk(kobj); - struct disk_attribute *disk_attr = - container_of(attr,struct disk_attribute,attr); - ssize_t ret = -EIO; - - if (disk_attr->show) - ret = disk_attr->show(disk,page); - return ret; -} - -static ssize_t disk_attr_store(struct kobject * kobj, struct attribute * attr, - const char *page, size_t count) -{ - struct gendisk *disk = to_disk(kobj); - struct disk_attribute *disk_attr = - container_of(attr,struct disk_attribute,attr); - ssize_t ret = 0; - - if (disk_attr->store) - ret = disk_attr->store(disk, page, count); - return ret; -} - -static struct sysfs_ops disk_sysfs_ops = { - .show = &disk_attr_show, - .store = &disk_attr_store, -}; - -static ssize_t disk_uevent_store(struct gendisk * disk, - const char *buf, size_t count) -{ - kobject_hotplug(&disk->kobj, KOBJ_ADD); - return count; -} -static ssize_t disk_dev_read(struct gendisk * disk, char *page) -{ - dev_t base = MKDEV(disk->major, disk->first_minor); - return print_dev_t(page, base); -} -static ssize_t disk_range_read(struct gendisk * disk, char *page) -{ - return sprintf(page, "%d\n", disk->minors); -} -static ssize_t disk_removable_read(struct gendisk * disk, char *page) -{ - return sprintf(page, "%d\n", - (disk->flags & GENHD_FL_REMOVABLE ? 1 : 0)); - -} -static ssize_t disk_size_read(struct gendisk * disk, char *page) -{ - return sprintf(page, "%llu\n", (unsigned long long)get_capacity(disk)); -} - -static ssize_t disk_stats_read(struct gendisk * disk, char *page) -{ - preempt_disable(); - disk_round_stats(disk); - preempt_enable(); - return sprintf(page, - "%8u %8u %8llu %8u " - "%8u %8u %8llu %8u " - "%8u %8u %8u" - "\n", - disk_stat_read(disk, ios[0]), disk_stat_read(disk, merges[0]), - (unsigned long long)disk_stat_read(disk, sectors[0]), - jiffies_to_msecs(disk_stat_read(disk, ticks[0])), - disk_stat_read(disk, ios[1]), disk_stat_read(disk, merges[1]), - (unsigned long long)disk_stat_read(disk, sectors[1]), - jiffies_to_msecs(disk_stat_read(disk, ticks[1])), - disk->in_flight, - jiffies_to_msecs(disk_stat_read(disk, io_ticks)), - jiffies_to_msecs(disk_stat_read(disk, time_in_queue))); -} -static struct disk_attribute disk_attr_uevent = { - .attr = {.name = "uevent", .mode = S_IWUSR }, - .store = disk_uevent_store -}; -static struct disk_attribute disk_attr_dev = { - .attr = {.name = "dev", .mode = S_IRUGO }, - .show = disk_dev_read -}; -static struct disk_attribute disk_attr_range = { - .attr = {.name = "range", .mode = S_IRUGO }, - .show = disk_range_read -}; -static struct disk_attribute disk_attr_removable = { - .attr = {.name = "removable", .mode = S_IRUGO }, - .show = disk_removable_read -}; -static struct disk_attribute disk_attr_size = { - .attr = {.name = "size", .mode = S_IRUGO }, - .show = disk_size_read -}; -static struct disk_attribute disk_attr_stat = { - .attr = {.name = "stat", .mode = S_IRUGO }, - .show = disk_stats_read -}; - -static struct attribute * default_attrs[] = { - &disk_attr_uevent.attr, - &disk_attr_dev.attr, - &disk_attr_range.attr, - &disk_attr_removable.attr, - &disk_attr_size.attr, - &disk_attr_stat.attr, - NULL, -}; - -static void disk_release(struct kobject * kobj) -{ - struct gendisk *disk = to_disk(kobj); - kfree(disk->random); - kfree(disk->part); - free_disk_stats(disk); - kfree(disk); -} - -static struct kobj_type ktype_block = { - .release = disk_release, - .sysfs_ops = &disk_sysfs_ops, - .default_attrs = default_attrs, -}; - -extern struct kobj_type ktype_part; - -static int block_hotplug_filter(struct kset *kset, struct kobject *kobj) -{ - struct kobj_type *ktype = get_ktype(kobj); - - return ((ktype == &ktype_block) || (ktype == &ktype_part)); -} - -static int block_hotplug(struct kset *kset, struct kobject *kobj, char **envp, - int num_envp, char *buffer, int buffer_size) -{ - struct kobj_type *ktype = get_ktype(kobj); - struct device *physdev; - struct gendisk *disk; - struct hd_struct *part; - int length = 0; - int i = 0; - - if (ktype == &ktype_block) { - disk = container_of(kobj, struct gendisk, kobj); - add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size, - &length, "MINOR=%u", disk->first_minor); - } else if (ktype == &ktype_part) { - disk = container_of(kobj->parent, struct gendisk, kobj); - part = container_of(kobj, struct hd_struct, kobj); - add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size, - &length, "MINOR=%u", - disk->first_minor + part->partno); - } else - return 0; - - add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size, &length, - "MAJOR=%u", disk->major); - - /* add physical device, backing this device */ - physdev = disk->driverfs_dev; - if (physdev) { - char *path = kobject_get_path(&physdev->kobj, GFP_KERNEL); - - add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size, - &length, "PHYSDEVPATH=%s", path); - kfree(path); - - if (physdev->bus) - add_hotplug_env_var(envp, num_envp, &i, - buffer, buffer_size, &length, - "PHYSDEVBUS=%s", - physdev->bus->name); - - if (physdev->driver) - add_hotplug_env_var(envp, num_envp, &i, - buffer, buffer_size, &length, - "PHYSDEVDRIVER=%s", - physdev->driver->name); - } - - /* terminate, set to next free slot, shrink available space */ - envp[i] = NULL; - envp = &envp[i]; - num_envp -= i; - buffer = &buffer[length]; - buffer_size -= length; - - return 0; -} - -static struct kset_hotplug_ops block_hotplug_ops = { - .filter = block_hotplug_filter, - .hotplug = block_hotplug, -}; - -/* declare block_subsys. */ -static decl_subsys(block, &ktype_block, &block_hotplug_ops); - - -/* - * aggregate disk stat collector. Uses the same stats that the sysfs - * entries do, above, but makes them available through one seq_file. - * Watching a few disks may be efficient through sysfs, but watching - * all of them will be more efficient through this interface. - * - * The output looks suspiciously like /proc/partitions with a bunch of - * extra fields. - */ - -/* iterator */ -static void *diskstats_start(struct seq_file *part, loff_t *pos) -{ - loff_t k = *pos; - struct list_head *p; - - down(&block_subsys_sem); - list_for_each(p, &block_subsys.kset.list) - if (!k--) - return list_entry(p, struct gendisk, kobj.entry); - return NULL; -} - -static void *diskstats_next(struct seq_file *part, void *v, loff_t *pos) -{ - struct list_head *p = ((struct gendisk *)v)->kobj.entry.next; - ++*pos; - return p==&block_subsys.kset.list ? NULL : - list_entry(p, struct gendisk, kobj.entry); -} - -static void diskstats_stop(struct seq_file *part, void *v) -{ - up(&block_subsys_sem); -} - -static int diskstats_show(struct seq_file *s, void *v) -{ - struct gendisk *gp = v; - char buf[BDEVNAME_SIZE]; - int n = 0; - - /* - if (&sgp->kobj.entry == block_subsys.kset.list.next) - seq_puts(s, "major minor name" - " rio rmerge rsect ruse wio wmerge " - "wsect wuse running use aveq" - "\n\n"); - */ - - preempt_disable(); - disk_round_stats(gp); - preempt_enable(); - seq_printf(s, "%4d %4d %s %u %u %llu %u %u %u %llu %u %u %u %u\n", - gp->major, n + gp->first_minor, disk_name(gp, n, buf), - disk_stat_read(gp, ios[0]), disk_stat_read(gp, merges[0]), - (unsigned long long)disk_stat_read(gp, sectors[0]), - jiffies_to_msecs(disk_stat_read(gp, ticks[0])), - disk_stat_read(gp, ios[1]), disk_stat_read(gp, merges[1]), - (unsigned long long)disk_stat_read(gp, sectors[1]), - jiffies_to_msecs(disk_stat_read(gp, ticks[1])), - gp->in_flight, - jiffies_to_msecs(disk_stat_read(gp, io_ticks)), - jiffies_to_msecs(disk_stat_read(gp, time_in_queue))); - - /* now show all non-0 size partitions of it */ - for (n = 0; n < gp->minors - 1; n++) { - struct hd_struct *hd = gp->part[n]; - - if (hd && hd->nr_sects) - seq_printf(s, "%4d %4d %s %u %u %u %u\n", - gp->major, n + gp->first_minor + 1, - disk_name(gp, n + 1, buf), - hd->ios[0], hd->sectors[0], - hd->ios[1], hd->sectors[1]); - } - - return 0; -} - -struct seq_operations diskstats_op = { - .start = diskstats_start, - .next = diskstats_next, - .stop = diskstats_stop, - .show = diskstats_show -}; - -struct gendisk *alloc_disk(int minors) -{ - return alloc_disk_node(minors, -1); -} - -struct gendisk *alloc_disk_node(int minors, int node_id) -{ - struct gendisk *disk; - - disk = kmalloc_node(sizeof(struct gendisk), GFP_KERNEL, node_id); - if (disk) { - memset(disk, 0, sizeof(struct gendisk)); - if (!init_disk_stats(disk)) { - kfree(disk); - return NULL; - } - if (minors > 1) { - int size = (minors - 1) * sizeof(struct hd_struct *); - disk->part = kmalloc_node(size, GFP_KERNEL, node_id); - if (!disk->part) { - kfree(disk); - return NULL; - } - memset(disk->part, 0, size); - } - disk->minors = minors; - kobj_set_kset_s(disk,block_subsys); - kobject_init(&disk->kobj); - rand_initialize_disk(disk); - } - return disk; -} - -EXPORT_SYMBOL(alloc_disk); -EXPORT_SYMBOL(alloc_disk_node); - -struct kobject *get_disk(struct gendisk *disk) -{ - struct module *owner; - struct kobject *kobj; - - if (!disk->fops) - return NULL; - owner = disk->fops->owner; - if (owner && !try_module_get(owner)) - return NULL; - kobj = kobject_get(&disk->kobj); - if (kobj == NULL) { - module_put(owner); - return NULL; - } - return kobj; - -} - -EXPORT_SYMBOL(get_disk); - -void put_disk(struct gendisk *disk) -{ - if (disk) - kobject_put(&disk->kobj); -} - -EXPORT_SYMBOL(put_disk); - -void set_device_ro(struct block_device *bdev, int flag) -{ - if (bdev->bd_contains != bdev) - bdev->bd_part->policy = flag; - else - bdev->bd_disk->policy = flag; -} - -EXPORT_SYMBOL(set_device_ro); - -void set_disk_ro(struct gendisk *disk, int flag) -{ - int i; - disk->policy = flag; - for (i = 0; i < disk->minors - 1; i++) - if (disk->part[i]) disk->part[i]->policy = flag; -} - -EXPORT_SYMBOL(set_disk_ro); - -int bdev_read_only(struct block_device *bdev) -{ - if (!bdev) - return 0; - else if (bdev->bd_contains != bdev) - return bdev->bd_part->policy; - else - return bdev->bd_disk->policy; -} - -EXPORT_SYMBOL(bdev_read_only); - -int invalidate_partition(struct gendisk *disk, int index) -{ - int res = 0; - struct block_device *bdev = bdget_disk(disk, index); - if (bdev) { - fsync_bdev(bdev); - res = __invalidate_device(bdev); - bdput(bdev); - } - return res; -} - -EXPORT_SYMBOL(invalidate_partition); diff --git a/drivers/block/ioctl.c b/drivers/block/ioctl.c deleted file mode 100644 index 6e27847..0000000 --- a/drivers/block/ioctl.c +++ /dev/null @@ -1,275 +0,0 @@ -#include <linux/sched.h> /* for capable() */ -#include <linux/blkdev.h> -#include <linux/blkpg.h> -#include <linux/backing-dev.h> -#include <linux/buffer_head.h> -#include <linux/smp_lock.h> -#include <asm/uaccess.h> - -static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user *arg) -{ - struct block_device *bdevp; - struct gendisk *disk; - struct blkpg_ioctl_arg a; - struct blkpg_partition p; - long long start, length; - int part; - int i; - - if (!capable(CAP_SYS_ADMIN)) - return -EACCES; - if (copy_from_user(&a, arg, sizeof(struct blkpg_ioctl_arg))) - return -EFAULT; - if (copy_from_user(&p, a.data, sizeof(struct blkpg_partition))) - return -EFAULT; - disk = bdev->bd_disk; - if (bdev != bdev->bd_contains) - return -EINVAL; - part = p.pno; - if (part <= 0 || part >= disk->minors) - return -EINVAL; - switch (a.op) { - case BLKPG_ADD_PARTITION: - start = p.start >> 9; - length = p.length >> 9; - /* check for fit in a hd_struct */ - if (sizeof(sector_t) == sizeof(long) && - sizeof(long long) > sizeof(long)) { - long pstart = start, plength = length; - if (pstart != start || plength != length - || pstart < 0 || plength < 0) - return -EINVAL; - } - /* partition number in use? */ - down(&bdev->bd_sem); - if (disk->part[part - 1]) { - up(&bdev->bd_sem); - return -EBUSY; - } - /* overlap? */ - for (i = 0; i < disk->minors - 1; i++) { - struct hd_struct *s = disk->part[i]; - - if (!s) - continue; - if (!(start+length <= s->start_sect || - start >= s->start_sect + s->nr_sects)) { - up(&bdev->bd_sem); - return -EBUSY; - } - } - /* all seems OK */ - add_partition(disk, part, start, length); - up(&bdev->bd_sem); - return 0; - case BLKPG_DEL_PARTITION: - if (!disk->part[part-1]) - return -ENXIO; - if (disk->part[part - 1]->nr_sects == 0) - return -ENXIO; - bdevp = bdget_disk(disk, part); - if (!bdevp) - return -ENOMEM; - down(&bdevp->bd_sem); - if (bdevp->bd_openers) { - up(&bdevp->bd_sem); - bdput(bdevp); - return -EBUSY; - } - /* all seems OK */ - fsync_bdev(bdevp); - invalidate_bdev(bdevp, 0); - - down(&bdev->bd_sem); - delete_partition(disk, part); - up(&bdev->bd_sem); - up(&bdevp->bd_sem); - bdput(bdevp); - - return 0; - default: - return -EINVAL; - } -} - -static int blkdev_reread_part(struct block_device *bdev) -{ - struct gendisk *disk = bdev->bd_disk; - int res; - - if (disk->minors == 1 || bdev != bdev->bd_contains) - return -EINVAL; - if (!capable(CAP_SYS_ADMIN)) - return -EACCES; - if (down_trylock(&bdev->bd_sem)) - return -EBUSY; - res = rescan_partitions(disk, bdev); - up(&bdev->bd_sem); - return res; -} - -static int put_ushort(unsigned long arg, unsigned short val) -{ - return put_user(val, (unsigned short __user *)arg); -} - -static int put_int(unsigned long arg, int val) -{ - return put_user(val, (int __user *)arg); -} - -static int put_long(unsigned long arg, long val) -{ - return put_user(val, (long __user *)arg); -} - -static int put_ulong(unsigned long arg, unsigned long val) -{ - return put_user(val, (unsigned long __user *)arg); -} - -static int put_u64(unsigned long arg, u64 val) -{ - return put_user(val, (u64 __user *)arg); -} - -static int blkdev_locked_ioctl(struct file *file, struct block_device *bdev, - unsigned cmd, unsigned long arg) -{ - struct backing_dev_info *bdi; - int ret, n; - - switch (cmd) { - case BLKRAGET: - case BLKFRAGET: - if (!arg) - return -EINVAL; - bdi = blk_get_backing_dev_info(bdev); - if (bdi == NULL) - return -ENOTTY; - return put_long(arg, (bdi->ra_pages * PAGE_CACHE_SIZE) / 512); - case BLKROGET: - return put_int(arg, bdev_read_only(bdev) != 0); - case BLKBSZGET: /* get the logical block size (cf. BLKSSZGET) */ - return put_int(arg, block_size(bdev)); - case BLKSSZGET: /* get block device hardware sector size */ - return put_int(arg, bdev_hardsect_size(bdev)); - case BLKSECTGET: - return put_ushort(arg, bdev_get_queue(bdev)->max_sectors); - case BLKRASET: - case BLKFRASET: - if(!capable(CAP_SYS_ADMIN)) - return -EACCES; - bdi = blk_get_backing_dev_info(bdev); - if (bdi == NULL) - return -ENOTTY; - bdi->ra_pages = (arg * 512) / PAGE_CACHE_SIZE; - return 0; - case BLKBSZSET: - /* set the logical block size */ - if (!capable(CAP_SYS_ADMIN)) - return -EACCES; - if (!arg) - return -EINVAL; - if (get_user(n, (int __user *) arg)) - return -EFAULT; - if (bd_claim(bdev, file) < 0) - return -EBUSY; - ret = set_blocksize(bdev, n); - bd_release(bdev); - return ret; - case BLKPG: - return blkpg_ioctl(bdev, (struct blkpg_ioctl_arg __user *) arg); - case BLKRRPART: - return blkdev_reread_part(bdev); - case BLKGETSIZE: - if ((bdev->bd_inode->i_size >> 9) > ~0UL) - return -EFBIG; - return put_ulong(arg, bdev->bd_inode->i_size >> 9); - case BLKGETSIZE64: - return put_u64(arg, bdev->bd_inode->i_size); - } - return -ENOIOCTLCMD; -} - -static int blkdev_driver_ioctl(struct inode *inode, struct file *file, - struct gendisk *disk, unsigned cmd, unsigned long arg) -{ - int ret; - if (disk->fops->unlocked_ioctl) - return disk->fops->unlocked_ioctl(file, cmd, arg); - - if (disk->fops->ioctl) { - lock_kernel(); - ret = disk->fops->ioctl(inode, file, cmd, arg); - unlock_kernel(); - return ret; - } - - return -ENOTTY; -} - -int blkdev_ioctl(struct inode *inode, struct file *file, unsigned cmd, - unsigned long arg) -{ - struct block_device *bdev = inode->i_bdev; - struct gendisk *disk = bdev->bd_disk; - int ret, n; - - switch(cmd) { - case BLKFLSBUF: - if (!capable(CAP_SYS_ADMIN)) - return -EACCES; - - ret = blkdev_driver_ioctl(inode, file, disk, cmd, arg); - /* -EINVAL to handle old uncorrected drivers */ - if (ret != -EINVAL && ret != -ENOTTY) - return ret; - - lock_kernel(); - fsync_bdev(bdev); - invalidate_bdev(bdev, 0); - unlock_kernel(); - return 0; - - case BLKROSET: - ret = blkdev_driver_ioctl(inode, file, disk, cmd, arg); - /* -EINVAL to handle old uncorrected drivers */ - if (ret != -EINVAL && ret != -ENOTTY) - return ret; - if (!capable(CAP_SYS_ADMIN)) - return -EACCES; - if (get_user(n, (int __user *)(arg))) - return -EFAULT; - lock_kernel(); - set_device_ro(bdev, n); - unlock_kernel(); - return 0; - } - - lock_kernel(); - ret = blkdev_locked_ioctl(file, bdev, cmd, arg); - unlock_kernel(); - if (ret != -ENOIOCTLCMD) - return ret; - - return blkdev_driver_ioctl(inode, file, disk, cmd, arg); -} - -/* Most of the generic ioctls are handled in the normal fallback path. - This assumes the blkdev's low level compat_ioctl always returns - ENOIOCTLCMD for unknown ioctls. */ -long compat_blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg) -{ - struct block_device *bdev = file->f_dentry->d_inode->i_bdev; - struct gendisk *disk = bdev->bd_disk; - int ret = -ENOIOCTLCMD; - if (disk->fops->compat_ioctl) { - lock_kernel(); - ret = disk->fops->compat_ioctl(file, cmd, arg); - unlock_kernel(); - } - return ret; -} - -EXPORT_SYMBOL_GPL(blkdev_ioctl); diff --git a/drivers/block/ll_rw_blk.c b/drivers/block/ll_rw_blk.c deleted file mode 100644 index 2747741..0000000 --- a/drivers/block/ll_rw_blk.c +++ /dev/null @@ -1,3613 +0,0 @@ -/* - * linux/drivers/block/ll_rw_blk.c - * - * Copyright (C) 1991, 1992 Linus Torvalds - * Copyright (C) 1994, Karl Keyte: Added support for disk statistics - * Elevator latency, (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE - * Queue request tables / lock, selectable elevator, Jens Axboe <axboe@suse.de> - * kernel-doc documentation started by NeilBrown <neilb@cse.unsw.edu.au> - July2000 - * bio rewrite, highmem i/o, etc, Jens Axboe <axboe@suse.de> - may 2001 - */ - -/* - * This handles all read/write requests to block devices - */ -#include <linux/config.h> -#include <linux/kernel.h> -#include <linux/module.h> -#include <linux/backing-dev.h> -#include <linux/bio.h> -#include <linux/blkdev.h> -#include <linux/highmem.h> -#include <linux/mm.h> -#include <linux/kernel_stat.h> -#include <linux/string.h> -#include <linux/init.h> -#include <linux/bootmem.h> /* for max_pfn/max_low_pfn */ -#include <linux/completion.h> -#include <linux/slab.h> -#include <linux/swap.h> -#include <linux/writeback.h> -#include <linux/blkdev.h> - -/* - * for max sense size - */ -#include <scsi/scsi_cmnd.h> - -static void blk_unplug_work(void *data); -static void blk_unplug_timeout(unsigned long data); -static void drive_stat_acct(struct request *rq, int nr_sectors, int new_io); - -/* - * For the allocated request tables - */ -static kmem_cache_t *request_cachep; - -/* - * For queue allocation - */ -static kmem_cache_t *requestq_cachep; - -/* - * For io context allocations - */ -static kmem_cache_t *iocontext_cachep; - -static wait_queue_head_t congestion_wqh[2] = { - __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[0]), - __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[1]) - }; - -/* - * Controlling structure to kblockd - */ -static struct workqueue_struct *kblockd_workqueue; - -unsigned long blk_max_low_pfn, blk_max_pfn; - -EXPORT_SYMBOL(blk_max_low_pfn); -EXPORT_SYMBOL(blk_max_pfn); - -/* Amount of time in which a process may batch requests */ -#define BLK_BATCH_TIME (HZ/50UL) - -/* Number of requests a "batching" process may submit */ -#define BLK_BATCH_REQ 32 - -/* - * Return the threshold (number of used requests) at which the queue is - * considered to be congested. It include a little hysteresis to keep the - * context switch rate down. - */ -static inline int queue_congestion_on_threshold(struct request_queue *q) -{ - return q->nr_congestion_on; -} - -/* - * The threshold at which a queue is considered to be uncongested - */ -static inline int queue_congestion_off_threshold(struct request_queue *q) -{ - return q->nr_congestion_off; -} - -static void blk_queue_congestion_threshold(struct request_queue *q) -{ - int nr; - - nr = q->nr_requests - (q->nr_requests / 8) + 1; - if (nr > q->nr_requests) - nr = q->nr_requests; - q->nr_congestion_on = nr; - - nr = q->nr_requests - (q->nr_requests / 8) - (q->nr_requests / 16) - 1; - if (nr < 1) - nr = 1; - q->nr_congestion_off = nr; -} - -/* - * A queue has just exitted congestion. Note this in the global counter of - * congested queues, and wake up anyone who was waiting for requests to be - * put back. - */ -static void clear_queue_congested(request_queue_t *q, int rw) -{ - enum bdi_state bit; - wait_queue_head_t *wqh = &congestion_wqh[rw]; - - bit = (rw == WRITE) ? BDI_write_congested : BDI_read_congested; - clear_bit(bit, &q->backing_dev_info.state); - smp_mb__after_clear_bit(); - if (waitqueue_active(wqh)) - wake_up(wqh); -} - -/* - * A queue has just entered congestion. Flag that in the queue's VM-visible - * state flags and increment the global gounter of congested queues. - */ -static void set_queue_congested(request_queue_t *q, int rw) -{ - enum bdi_state bit; - - bit = (rw == WRITE) ? BDI_write_congested : BDI_read_congested; - set_bit(bit, &q->backing_dev_info.state); -} - -/** - * blk_get_backing_dev_info - get the address of a queue's backing_dev_info - * @bdev: device - * - * Locates the passed device's request queue and returns the address of its - * backing_dev_info - * - * Will return NULL if the request queue cannot be located. - */ -struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev) -{ - struct backing_dev_info *ret = NULL; - request_queue_t *q = bdev_get_queue(bdev); - - if (q) - ret = &q->backing_dev_info; - return ret; -} - -EXPORT_SYMBOL(blk_get_backing_dev_info); - -void blk_queue_activity_fn(request_queue_t *q, activity_fn *fn, void *data) -{ - q->activity_fn = fn; - q->activity_data = data; -} - -EXPORT_SYMBOL(blk_queue_activity_fn); - -/** - * blk_queue_prep_rq - set a prepare_request function for queue - * @q: queue - * @pfn: prepare_request function - * - * It's possible for a queue to register a prepare_request callback which - * is invoked before the request is handed to the request_fn. The goal of - * the function is to prepare a request for I/O, it can be used to build a - * cdb from the request data for instance. - * - */ -void blk_queue_prep_rq(request_queue_t *q, prep_rq_fn *pfn) -{ - q->prep_rq_fn = pfn; -} - -EXPORT_SYMBOL(blk_queue_prep_rq); - -/** - * blk_queue_merge_bvec - set a merge_bvec function for queue - * @q: queue - * @mbfn: merge_bvec_fn - * - * Usually queues have static limitations on the max sectors or segments that - * we can put in a request. Stacking drivers may have some settings that - * are dynamic, and thus we have to query the queue whether it is ok to - * add a new bio_vec to a bio at a given offset or not. If the block device - * has such limitations, it needs to register a merge_bvec_fn to control - * the size of bio's sent to it. Note that a block device *must* allow a - * single page to be added to an empty bio. The block device driver may want - * to use the bio_split() function to deal with these bio's. By default - * no merge_bvec_fn is defined for a queue, and only the fixed limits are - * honored. - */ -void blk_queue_merge_bvec(request_queue_t *q, merge_bvec_fn *mbfn) -{ - q->merge_bvec_fn = mbfn; -} - -EXPORT_SYMBOL(blk_queue_merge_bvec); - -/** - * blk_queue_make_request - define an alternate make_request function for a device - * @q: the request queue for the device to be affected - * @mfn: the alternate make_request function - * - * Description: - * The normal way for &struct bios to be passed to a device - * driver is for them to be collected into requests on a request - * queue, and then to allow the device driver to select requests - * off that queue when it is ready. This works well for many block - * devices. However some block devices (typically virtual devices - * such as md or lvm) do not benefit from the processing on the - * request queue, and are served best by having the requests passed - * directly to them. This can be achieved by providing a function - * to blk_queue_make_request(). - * - * Caveat: - * The driver that does this *must* be able to deal appropriately - * with buffers in "highmemory". This can be accomplished by either calling - * __bio_kmap_atomic() to get a temporary kernel mapping, or by calling - * blk_queue_bounce() to create a buffer in normal memory. - **/ -void blk_queue_make_request(request_queue_t * q, make_request_fn * mfn) -{ - /* - * set defaults - */ - q->nr_requests = BLKDEV_MAX_RQ; - blk_queue_max_phys_segments(q, MAX_PHYS_SEGMENTS); - blk_queue_max_hw_segments(q, MAX_HW_SEGMENTS); - q->make_request_fn = mfn; - q->backing_dev_info.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE; - q->backing_dev_info.state = 0; - q->backing_dev_info.capabilities = BDI_CAP_MAP_COPY; - blk_queue_max_sectors(q, MAX_SECTORS); - blk_queue_hardsect_size(q, 512); - blk_queue_dma_alignment(q, 511); - blk_queue_congestion_threshold(q); - q->nr_batching = BLK_BATCH_REQ; - - q->unplug_thresh = 4; /* hmm */ - q->unplug_delay = (3 * HZ) / 1000; /* 3 milliseconds */ - if (q->unplug_delay == 0) - q->unplug_delay = 1; - - INIT_WORK(&q->unplug_work, blk_unplug_work, q); - - q->unplug_timer.function = blk_unplug_timeout; - q->unplug_timer.data = (unsigned long)q; - - /* - * by default assume old behaviour and bounce for any highmem page - */ - blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH); - - blk_queue_activity_fn(q, NULL, NULL); -} - -EXPORT_SYMBOL(blk_queue_make_request); - -static inline void rq_init(request_queue_t *q, struct request *rq) -{ - INIT_LIST_HEAD(&rq->queuelist); - - rq->errors = 0; - rq->rq_status = RQ_ACTIVE; - rq->bio = rq->biotail = NULL; - rq->ioprio = 0; - rq->buffer = NULL; - rq->ref_count = 1; - rq->q = q; - rq->waiting = NULL; - rq->special = NULL; - rq->data_len = 0; - rq->data = NULL; - rq->nr_phys_segments = 0; - rq->sense = NULL; - rq->end_io = NULL; - rq->end_io_data = NULL; -} - -/** - * blk_queue_ordered - does this queue support ordered writes - * @q: the request queue - * @flag: see below - * - * Description: - * For journalled file systems, doing ordered writes on a commit - * block instead of explicitly doing wait_on_buffer (which is bad - * for performance) can be a big win. Block drivers supporting this - * feature should call this function and indicate so. - * - **/ -void blk_queue_ordered(request_queue_t *q, int flag) -{ - switch (flag) { - case QUEUE_ORDERED_NONE: - if (q->flush_rq) - kmem_cache_free(request_cachep, q->flush_rq); - q->flush_rq = NULL; - q->ordered = flag; - break; - case QUEUE_ORDERED_TAG: - q->ordered = flag; - break; - case QUEUE_ORDERED_FLUSH: - q->ordered = flag; - if (!q->flush_rq) - q->flush_rq = kmem_cache_alloc(request_cachep, - GFP_KERNEL); - break; - default: - printk("blk_queue_ordered: bad value %d\n", flag); - break; - } -} - -EXPORT_SYMBOL(blk_queue_ordered); - -/** - * blk_queue_issue_flush_fn - set function for issuing a flush - * @q: the request queue - * @iff: the function to be called issuing the flush - * - * Description: - * If a driver supports issuing a flush command, the support is notified - * to the block layer by defining it through this call. - * - **/ -void blk_queue_issue_flush_fn(request_queue_t *q, issue_flush_fn *iff) -{ - q->issue_flush_fn = iff; -} - -EXPORT_SYMBOL(blk_queue_issue_flush_fn); - -/* - * Cache flushing for ordered writes handling - */ -static void blk_pre_flush_end_io(struct request *flush_rq) -{ - struct request *rq = flush_rq->end_io_data; - request_queue_t *q = rq->q; - - elv_completed_request(q, flush_rq); - - rq->flags |= REQ_BAR_PREFLUSH; - - if (!flush_rq->errors) - elv_requeue_request(q, rq); - else { - q->end_flush_fn(q, flush_rq); - clear_bit(QUEUE_FLAG_FLUSH, &q->queue_flags); - q->request_fn(q); - } -} - -static void blk_post_flush_end_io(struct request *flush_rq) -{ - struct request *rq = flush_rq->end_io_data; - request_queue_t *q = rq->q; - - elv_completed_request(q, flush_rq); - - rq->flags |= REQ_BAR_POSTFLUSH; - - q->end_flush_fn(q, flush_rq); - clear_bit(QUEUE_FLAG_FLUSH, &q->queue_flags); - q->request_fn(q); -} - -struct request *blk_start_pre_flush(request_queue_t *q, struct request *rq) -{ - struct request *flush_rq = q->flush_rq; - - BUG_ON(!blk_barrier_rq(rq)); - - if (test_and_set_bit(QUEUE_FLAG_FLUSH, &q->queue_flags)) - return NULL; - - rq_init(q, flush_rq); - flush_rq->elevator_private = NULL; - flush_rq->flags = REQ_BAR_FLUSH; - flush_rq->rq_disk = rq->rq_disk; - flush_rq->rl = NULL; - - /* - * prepare_flush returns 0 if no flush is needed, just mark both - * pre and post flush as done in that case - */ - if (!q->prepare_flush_fn(q, flush_rq)) { - rq->flags |= REQ_BAR_PREFLUSH | REQ_BAR_POSTFLUSH; - clear_bit(QUEUE_FLAG_FLUSH, &q->queue_flags); - return rq; - } - - /* - * some drivers dequeue requests right away, some only after io - * completion. make sure the request is dequeued. - */ - if (!list_empty(&rq->queuelist)) - blkdev_dequeue_request(rq); - - flush_rq->end_io_data = rq; - flush_rq->end_io = blk_pre_flush_end_io; - - __elv_add_request(q, flush_rq, ELEVATOR_INSERT_FRONT, 0); - return flush_rq; -} - -static void blk_start_post_flush(request_queue_t *q, struct request *rq) -{ - struct request *flush_rq = q->flush_rq; - - BUG_ON(!blk_barrier_rq(rq)); - - rq_init(q, flush_rq); - flush_rq->elevator_private = NULL; - flush_rq->flags = REQ_BAR_FLUSH; - flush_rq->rq_disk = rq->rq_disk; - flush_rq->rl = NULL; - - if (q->prepare_flush_fn(q, flush_rq)) { - flush_rq->end_io_data = rq; - flush_rq->end_io = blk_post_flush_end_io; - - __elv_add_request(q, flush_rq, ELEVATOR_INSERT_FRONT, 0); - q->request_fn(q); - } -} - -static inline int blk_check_end_barrier(request_queue_t *q, struct request *rq, - int sectors) -{ - if (sectors > rq->nr_sectors) - sectors = rq->nr_sectors; - - rq->nr_sectors -= sectors; - return rq->nr_sectors; -} - -static int __blk_complete_barrier_rq(request_queue_t *q, struct request *rq, - int sectors, int queue_locked) -{ - if (q->ordered != QUEUE_ORDERED_FLUSH) - return 0; - if (!blk_fs_request(rq) || !blk_barrier_rq(rq)) - return 0; - if (blk_barrier_postflush(rq)) - return 0; - - if (!blk_check_end_barrier(q, rq, sectors)) { - unsigned long flags = 0; - - if (!queue_locked) - spin_lock_irqsave(q->queue_lock, flags); - - blk_start_post_flush(q, rq); - - if (!queue_locked) - spin_unlock_irqrestore(q->queue_lock, flags); - } - - return 1; -} - -/** - * blk_complete_barrier_rq - complete possible barrier request - * @q: the request queue for the device - * @rq: the request - * @sectors: number of sectors to complete - * - * Description: - * Used in driver end_io handling to determine whether to postpone - * completion of a barrier request until a post flush has been done. This - * is the unlocked variant, used if the caller doesn't already hold the - * queue lock. - **/ -int blk_complete_barrier_rq(request_queue_t *q, struct request *rq, int sectors) -{ - return __blk_complete_barrier_rq(q, rq, sectors, 0); -} -EXPORT_SYMBOL(blk_complete_barrier_rq); - -/** - * blk_complete_barrier_rq_locked - complete possible barrier request - * @q: the request queue for the device - * @rq: the request - * @sectors: number of sectors to complete - * - * Description: - * See blk_complete_barrier_rq(). This variant must be used if the caller - * holds the queue lock. - **/ -int blk_complete_barrier_rq_locked(request_queue_t *q, struct request *rq, - int sectors) -{ - return __blk_complete_barrier_rq(q, rq, sectors, 1); -} -EXPORT_SYMBOL(blk_complete_barrier_rq_locked); - -/** - * blk_queue_bounce_limit - set bounce buffer limit for queue - * @q: the request queue for the device - * @dma_addr: bus address limit - * - * Description: - * Different hardware can have different requirements as to what pages - * it can do I/O directly to. A low level driver can call - * blk_queue_bounce_limit to have lower memory pages allocated as bounce - * buffers for doing I/O to pages residing above @page. By default - * the block layer sets this to the highest numbered "low" memory page. - **/ -void blk_queue_bounce_limit(request_queue_t *q, u64 dma_addr) -{ - unsigned long bounce_pfn = dma_addr >> PAGE_SHIFT; - - /* - * set appropriate bounce gfp mask -- unfortunately we don't have a - * full 4GB zone, so we have to resort to low memory for any bounces. - * ISA has its own < 16MB zone. - */ - if (bounce_pfn < blk_max_low_pfn) { - BUG_ON(dma_addr < BLK_BOUNCE_ISA); - init_emergency_isa_pool(); - q->bounce_gfp = GFP_NOIO | GFP_DMA; - } else - q->bounce_gfp = GFP_NOIO; - - q->bounce_pfn = bounce_pfn; -} - -EXPORT_SYMBOL(blk_queue_bounce_limit); - -/** - * blk_queue_max_sectors - set max sectors for a request for this queue - * @q: the request queue for the device - * @max_sectors: max sectors in the usual 512b unit - * - * Description: - * Enables a low level driver to set an upper limit on the size of - * received requests. - **/ -void blk_queue_max_sectors(request_queue_t *q, unsigned short max_sectors) -{ - if ((max_sectors << 9) < PAGE_CACHE_SIZE) { - max_sectors = 1 << (PAGE_CACHE_SHIFT - 9); - printk("%s: set to minimum %d\n", __FUNCTION__, max_sectors); - } - - q->max_sectors = q->max_hw_sectors = max_sectors; -} - -EXPORT_SYMBOL(blk_queue_max_sectors); - -/** - * blk_queue_max_phys_segments - set max phys segments for a request for this queue - * @q: the request queue for the device - * @max_segments: max number of segments - * - * Description: - * Enables a low level driver to set an upper limit on the number of - * physical data segments in a request. This would be the largest sized - * scatter list the driver could handle. - **/ -void blk_queue_max_phys_segments(request_queue_t *q, unsigned short max_segments) -{ - if (!max_segments) { - max_segments = 1; - printk("%s: set to minimum %d\n", __FUNCTION__, max_segments); - } - - q->max_phys_segments = max_segments; -} - -EXPORT_SYMBOL(blk_queue_max_phys_segments); - -/** - * blk_queue_max_hw_segments - set max hw segments for a request for this queue - * @q: the request queue for the device - * @max_segments: max number of segments - * - * Description: - * Enables a low level driver to set an upper limit on the number of - * hw data segments in a request. This would be the largest number of - * address/length pairs the host adapter can actually give as once - * to the device. - **/ -void blk_queue_max_hw_segments(request_queue_t *q, unsigned short max_segments) -{ - if (!max_segments) { - max_segments = 1; - printk("%s: set to minimum %d\n", __FUNCTION__, max_segments); - } - - q->max_hw_segments = max_segments; -} - -EXPORT_SYMBOL(blk_queue_max_hw_segments); - -/** - * blk_queue_max_segment_size - set max segment size for blk_rq_map_sg - * @q: the request queue for the device - * @max_size: max size of segment in bytes - * - * Description: - * Enables a low level driver to set an upper limit on the size of a - * coalesced segment - **/ -void blk_queue_max_segment_size(request_queue_t *q, unsigned int max_size) -{ - if (max_size < PAGE_CACHE_SIZE) { - max_size = PAGE_CACHE_SIZE; - printk("%s: set to minimum %d\n", __FUNCTION__, max_size); - } - - q->max_segment_size = max_size; -} - -EXPORT_SYMBOL(blk_queue_max_segment_size); - -/** - * blk_queue_hardsect_size - set hardware sector size for the queue - * @q: the request queue for the device - * @size: the hardware sector size, in bytes - * - * Description: - * This should typically be set to the lowest possible sector size - * that the hardware can operate on (possible without reverting to - * even internal read-modify-write operations). Usually the default - * of 512 covers most hardware. - **/ -void blk_queue_hardsect_size(request_queue_t *q, unsigned short size) -{ - q->hardsect_size = size; -} - -EXPORT_SYMBOL(blk_queue_hardsect_size); - -/* - * Returns the minimum that is _not_ zero, unless both are zero. - */ -#define min_not_zero(l, r) (l == 0) ? r : ((r == 0) ? l : min(l, r)) - -/** - * blk_queue_stack_limits - inherit underlying queue limits for stacked drivers - * @t: the stacking driver (top) - * @b: the underlying device (bottom) - **/ -void blk_queue_stack_limits(request_queue_t *t, request_queue_t *b) -{ - /* zero is "infinity" */ - t->max_sectors = t->max_hw_sectors = - min_not_zero(t->max_sectors,b->max_sectors); - - t->max_phys_segments = min(t->max_phys_segments,b->max_phys_segments); - t->max_hw_segments = min(t->max_hw_segments,b->max_hw_segments); - t->max_segment_size = min(t->max_segment_size,b->max_segment_size); - t->hardsect_size = max(t->hardsect_size,b->hardsect_size); -} - -EXPORT_SYMBOL(blk_queue_stack_limits); - -/** - * blk_queue_segment_boundary - set boundary rules for segment merging - * @q: the request queue for the device - * @mask: the memory boundary mask - **/ -void blk_queue_segment_boundary(request_queue_t *q, unsigned long mask) -{ - if (mask < PAGE_CACHE_SIZE - 1) { - mask = PAGE_CACHE_SIZE - 1; - printk("%s: set to minimum %lx\n", __FUNCTION__, mask); - } - - q->seg_boundary_mask = mask; -} - -EXPORT_SYMBOL(blk_queue_segment_boundary); - -/** - * blk_queue_dma_alignment - set dma length and memory alignment - * @q: the request queue for the device - * @mask: alignment mask - * - * description: - * set required memory and length aligment for direct dma transactions. - * this is used when buiding direct io requests for the queue. - * - **/ -void blk_queue_dma_alignment(request_queue_t *q, int mask) -{ - q->dma_alignment = mask; -} - -EXPORT_SYMBOL(blk_queue_dma_alignment); - -/** - * blk_queue_find_tag - find a request by its tag and queue - * - * @q: The request queue for the device - * @tag: The tag of the request - * - * Notes: - * Should be used when a device returns a tag and you want to match - * it with a request. - * - * no locks need be held. - **/ -struct request *blk_queue_find_tag(request_queue_t *q, int tag) -{ - struct blk_queue_tag *bqt = q->queue_tags; - - if (unlikely(bqt == NULL || tag >= bqt->real_max_depth)) - return NULL; - - return bqt->tag_index[tag]; -} - -EXPORT_SYMBOL(blk_queue_find_tag); - -/** - * __blk_queue_free_tags - release tag maintenance info - * @q: the request queue for the device - * - * Notes: - * blk_cleanup_queue() will take care of calling this function, if tagging - * has been used. So there's no need to call this directly. - **/ -static void __blk_queue_free_tags(request_queue_t *q) -{ - struct blk_queue_tag *bqt = q->queue_tags; - - if (!bqt) - return; - - if (atomic_dec_and_test(&bqt->refcnt)) { - BUG_ON(bqt->busy); - BUG_ON(!list_empty(&bqt->busy_list)); - - kfree(bqt->tag_index); - bqt->tag_index = NULL; - - kfree(bqt->tag_map); - bqt->tag_map = NULL; - - kfree(bqt); - } - - q->queue_tags = NULL; - q->queue_flags &= ~(1 << QUEUE_FLAG_QUEUED); -} - -/** - * blk_queue_free_tags - release tag maintenance info - * @q: the request queue for the device - * - * Notes: - * This is used to disabled tagged queuing to a device, yet leave - * queue in function. - **/ -void blk_queue_free_tags(request_queue_t *q) -{ - clear_bit(QUEUE_FLAG_QUEUED, &q->queue_flags); -} - -EXPORT_SYMBOL(blk_queue_free_tags); - -static int -init_tag_map(request_queue_t *q, struct blk_queue_tag *tags, int depth) -{ - struct request **tag_index; - unsigned long *tag_map; - int nr_ulongs; - - if (depth > q->nr_requests * 2) { - depth = q->nr_requests * 2; - printk(KERN_ERR "%s: adjusted depth to %d\n", - __FUNCTION__, depth); - } - - tag_index = kmalloc(depth * sizeof(struct request *), GFP_ATOMIC); - if (!tag_index) - goto fail; - - nr_ulongs = ALIGN(depth, BITS_PER_LONG) / BITS_PER_LONG; - tag_map = kmalloc(nr_ulongs * sizeof(unsigned long), GFP_ATOMIC); - if (!tag_map) - goto fail; - - memset(tag_index, 0, depth * sizeof(struct request *)); - memset(tag_map, 0, nr_ulongs * sizeof(unsigned long)); - tags->real_max_depth = depth; - tags->max_depth = depth; - tags->tag_index = tag_index; - tags->tag_map = tag_map; - - return 0; -fail: - kfree(tag_index); - return -ENOMEM; -} - -/** - * blk_queue_init_tags - initialize the queue tag info - * @q: the request queue for the device - * @depth: the maximum queue depth supported - * @tags: the tag to use - **/ -int blk_queue_init_tags(request_queue_t *q, int depth, - struct blk_queue_tag *tags) -{ - int rc; - - BUG_ON(tags && q->queue_tags && tags != q->queue_tags); - - if (!tags && !q->queue_tags) { - tags = kmalloc(sizeof(struct blk_queue_tag), GFP_ATOMIC); - if (!tags) - goto fail; - - if (init_tag_map(q, tags, depth)) - goto fail; - - INIT_LIST_HEAD(&tags->busy_list); - tags->busy = 0; - atomic_set(&tags->refcnt, 1); - } else if (q->queue_tags) { - if ((rc = blk_queue_resize_tags(q, depth))) - return rc; - set_bit(QUEUE_FLAG_QUEUED, &q->queue_flags); - return 0; - } else - atomic_inc(&tags->refcnt); - - /* - * assign it, all done - */ - q->queue_tags = tags; - q->queue_flags |= (1 << QUEUE_FLAG_QUEUED); - return 0; -fail: - kfree(tags); - return -ENOMEM; -} - -EXPORT_SYMBOL(blk_queue_init_tags); - -/** - * blk_queue_resize_tags - change the queueing depth - * @q: the request queue for the device - * @new_depth: the new max command queueing depth - * - * Notes: - * Must be called with the queue lock held. - **/ -int blk_queue_resize_tags(request_queue_t *q, int new_depth) -{ - struct blk_queue_tag *bqt = q->queue_tags; - struct request **tag_index; - unsigned long *tag_map; - int max_depth, nr_ulongs; - - if (!bqt) - return -ENXIO; - - /* - * if we already have large enough real_max_depth. just - * adjust max_depth. *NOTE* as requests with tag value - * between new_depth and real_max_depth can be in-flight, tag - * map can not be shrunk blindly here. - */ - if (new_depth <= bqt->real_max_depth) { - bqt->max_depth = new_depth; - return 0; - } - - /* - * save the old state info, so we can copy it back - */ - tag_index = bqt->tag_index; - tag_map = bqt->tag_map; - max_depth = bqt->real_max_depth; - - if (init_tag_map(q, bqt, new_depth)) - return -ENOMEM; - - memcpy(bqt->tag_index, tag_index, max_depth * sizeof(struct request *)); - nr_ulongs = ALIGN(max_depth, BITS_PER_LONG) / BITS_PER_LONG; - memcpy(bqt->tag_map, tag_map, nr_ulongs * sizeof(unsigned long)); - - kfree(tag_index); - kfree(tag_map); - return 0; -} - -EXPORT_SYMBOL(blk_queue_resize_tags); - -/** - * blk_queue_end_tag - end tag operations for a request - * @q: the request queue for the device - * @rq: the request that has completed - * - * Description: - * Typically called when end_that_request_first() returns 0, meaning - * all transfers have been done for a request. It's important to call - * this function before end_that_request_last(), as that will put the - * request back on the free list thus corrupting the internal tag list. - * - * Notes: - * queue lock must be held. - **/ -void blk_queue_end_tag(request_queue_t *q, struct request *rq) -{ - struct blk_queue_tag *bqt = q->queue_tags; - int tag = rq->tag; - - BUG_ON(tag == -1); - - if (unlikely(tag >= bqt->real_max_depth)) - /* - * This can happen after tag depth has been reduced. - * FIXME: how about a warning or info message here? - */ - return; - - if (unlikely(!__test_and_clear_bit(tag, bqt->tag_map))) { - printk(KERN_ERR "%s: attempt to clear non-busy tag (%d)\n", - __FUNCTION__, tag); - return; - } - - list_del_init(&rq->queuelist); - rq->flags &= ~REQ_QUEUED; - rq->tag = -1; - - if (unlikely(bqt->tag_index[tag] == NULL)) - printk(KERN_ERR "%s: tag %d is missing\n", - __FUNCTION__, tag); - - bqt->tag_index[tag] = NULL; - bqt->busy--; -} - -EXPORT_SYMBOL(blk_queue_end_tag); - -/** - * blk_queue_start_tag - find a free tag and assign it - * @q: the request queue for the device - * @rq: the block request that needs tagging - * - * Description: - * This can either be used as a stand-alone helper, or possibly be - * assigned as the queue &prep_rq_fn (in which case &struct request - * automagically gets a tag assigned). Note that this function - * assumes that any type of request can be queued! if this is not - * true for your device, you must check the request type before - * calling this function. The request will also be removed from - * the request queue, so it's the drivers responsibility to readd - * it if it should need to be restarted for some reason. - * - * Notes: - * queue lock must be held. - **/ -int blk_queue_start_tag(request_queue_t *q, struct request *rq) -{ - struct blk_queue_tag *bqt = q->queue_tags; - int tag; - - if (unlikely((rq->flags & REQ_QUEUED))) { - printk(KERN_ERR - "%s: request %p for device [%s] already tagged %d", - __FUNCTION__, rq, - rq->rq_disk ? rq->rq_disk->disk_name : "?", rq->tag); - BUG(); - } - - tag = find_first_zero_bit(bqt->tag_map, bqt->max_depth); - if (tag >= bqt->max_depth) - return 1; - - __set_bit(tag, bqt->tag_map); - - rq->flags |= REQ_QUEUED; - rq->tag = tag; - bqt->tag_index[tag] = rq; - blkdev_dequeue_request(rq); - list_add(&rq->queuelist, &bqt->busy_list); - bqt->busy++; - return 0; -} - -EXPORT_SYMBOL(blk_queue_start_tag); - -/** - * blk_queue_invalidate_tags - invalidate all pending tags - * @q: the request queue for the device - * - * Description: - * Hardware conditions may dictate a need to stop all pending requests. - * In this case, we will safely clear the block side of the tag queue and - * readd all requests to the request queue in the right order. - * - * Notes: - * queue lock must be held. - **/ -void blk_queue_invalidate_tags(request_queue_t *q) -{ - struct blk_queue_tag *bqt = q->queue_tags; - struct list_head *tmp, *n; - struct request *rq; - - list_for_each_safe(tmp, n, &bqt->busy_list) { - rq = list_entry_rq(tmp); - - if (rq->tag == -1) { - printk(KERN_ERR - "%s: bad tag found on list\n", __FUNCTION__); - list_del_init(&rq->queuelist); - rq->flags &= ~REQ_QUEUED; - } else - blk_queue_end_tag(q, rq); - - rq->flags &= ~REQ_STARTED; - __elv_add_request(q, rq, ELEVATOR_INSERT_BACK, 0); - } -} - -EXPORT_SYMBOL(blk_queue_invalidate_tags); - -static char *rq_flags[] = { - "REQ_RW", - "REQ_FAILFAST", - "REQ_SORTED", - "REQ_SOFTBARRIER", - "REQ_HARDBARRIER", - "REQ_CMD", - "REQ_NOMERGE", - "REQ_STARTED", - "REQ_DONTPREP", - "REQ_QUEUED", - "REQ_ELVPRIV", - "REQ_PC", - "REQ_BLOCK_PC", - "REQ_SENSE", - "REQ_FAILED", - "REQ_QUIET", - "REQ_SPECIAL", - "REQ_DRIVE_CMD", - "REQ_DRIVE_TASK", - "REQ_DRIVE_TASKFILE", - "REQ_PREEMPT", - "REQ_PM_SUSPEND", - "REQ_PM_RESUME", - "REQ_PM_SHUTDOWN", -}; - -void blk_dump_rq_flags(struct request *rq, char *msg) -{ - int bit; - - printk("%s: dev %s: flags = ", msg, - rq->rq_disk ? rq->rq_disk->disk_name : "?"); - bit = 0; - do { - if (rq->flags & (1 << bit)) - printk("%s ", rq_flags[bit]); - bit++; - } while (bit < __REQ_NR_BITS); - - printk("\nsector %llu, nr/cnr %lu/%u\n", (unsigned long long)rq->sector, - rq->nr_sectors, - rq->current_nr_sectors); - printk("bio %p, biotail %p, buffer %p, data %p, len %u\n", rq->bio, rq->biotail, rq->buffer, rq->data, rq->data_len); - - if (rq->flags & (REQ_BLOCK_PC | REQ_PC)) { - printk("cdb: "); - for (bit = 0; bit < sizeof(rq->cmd); bit++) - printk("%02x ", rq->cmd[bit]); - printk("\n"); - } -} - -EXPORT_SYMBOL(blk_dump_rq_flags); - -void blk_recount_segments(request_queue_t *q, struct bio *bio) -{ - struct bio_vec *bv, *bvprv = NULL; - int i, nr_phys_segs, nr_hw_segs, seg_size, hw_seg_size, cluster; - int high, highprv = 1; - - if (unlikely(!bio->bi_io_vec)) - return; - - cluster = q->queue_flags & (1 << QUEUE_FLAG_CLUSTER); - hw_seg_size = seg_size = nr_phys_segs = nr_hw_segs = 0; - bio_for_each_segment(bv, bio, i) { - /* - * the trick here is making sure that a high page is never - * considered part of another segment, since that might - * change with the bounce page. - */ - high = page_to_pfn(bv->bv_page) >= q->bounce_pfn; - if (high || highprv) - goto new_hw_segment; - if (cluster) { - if (seg_size + bv->bv_len > q->max_segment_size) - goto new_segment; - if (!BIOVEC_PHYS_MERGEABLE(bvprv, bv)) - goto new_segment; - if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bv)) - goto new_segment; - if (BIOVEC_VIRT_OVERSIZE(hw_seg_size + bv->bv_len)) - goto new_hw_segment; - - seg_size += bv->bv_len; - hw_seg_size += bv->bv_len; - bvprv = bv; - continue; - } -new_segment: - if (BIOVEC_VIRT_MERGEABLE(bvprv, bv) && - !BIOVEC_VIRT_OVERSIZE(hw_seg_size + bv->bv_len)) { - hw_seg_size += bv->bv_len; - } else { -new_hw_segment: - if (hw_seg_size > bio->bi_hw_front_size) - bio->bi_hw_front_size = hw_seg_size; - hw_seg_size = BIOVEC_VIRT_START_SIZE(bv) + bv->bv_len; - nr_hw_segs++; - } - - nr_phys_segs++; - bvprv = bv; - seg_size = bv->bv_len; - highprv = high; - } - if (hw_seg_size > bio->bi_hw_back_size) - bio->bi_hw_back_size = hw_seg_size; - if (nr_hw_segs == 1 && hw_seg_size > bio->bi_hw_front_size) - bio->bi_hw_front_size = hw_seg_size; - bio->bi_phys_segments = nr_phys_segs; - bio->bi_hw_segments = nr_hw_segs; - bio->bi_flags |= (1 << BIO_SEG_VALID); -} - - -static int blk_phys_contig_segment(request_queue_t *q, struct bio *bio, - struct bio *nxt) -{ - if (!(q->queue_flags & (1 << QUEUE_FLAG_CLUSTER))) - return 0; - - if (!BIOVEC_PHYS_MERGEABLE(__BVEC_END(bio), __BVEC_START(nxt))) - return 0; - if (bio->bi_size + nxt->bi_size > q->max_segment_size) - return 0; - - /* - * bio and nxt are contigous in memory, check if the queue allows - * these two to be merged into one - */ - if (BIO_SEG_BOUNDARY(q, bio, nxt)) - return 1; - - return 0; -} - -static int blk_hw_contig_segment(request_queue_t *q, struct bio *bio, - struct bio *nxt) -{ - if (unlikely(!bio_flagged(bio, BIO_SEG_VALID))) - blk_recount_segments(q, bio); - if (unlikely(!bio_flagged(nxt, BIO_SEG_VALID))) - blk_recount_segments(q, nxt); - if (!BIOVEC_VIRT_MERGEABLE(__BVEC_END(bio), __BVEC_START(nxt)) || - BIOVEC_VIRT_OVERSIZE(bio->bi_hw_front_size + bio->bi_hw_back_size)) - return 0; - if (bio->bi_size + nxt->bi_size > q->max_segment_size) - return 0; - - return 1; -} - -/* - * map a request to scatterlist, return number of sg entries setup. Caller - * must make sure sg can hold rq->nr_phys_segments entries - */ -int blk_rq_map_sg(request_queue_t *q, struct request *rq, struct scatterlist *sg) -{ - struct bio_vec *bvec, *bvprv; - struct bio *bio; - int nsegs, i, cluster; - - nsegs = 0; - cluster = q->queue_flags & (1 << QUEUE_FLAG_CLUSTER); - - /* - * for each bio in rq - */ - bvprv = NULL; - rq_for_each_bio(bio, rq) { - /* - * for each segment in bio - */ - bio_for_each_segment(bvec, bio, i) { - int nbytes = bvec->bv_len; - - if (bvprv && cluster) { - if (sg[nsegs - 1].length + nbytes > q->max_segment_size) - goto new_segment; - - if (!BIOVEC_PHYS_MERGEABLE(bvprv, bvec)) - goto new_segment; - if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bvec)) - goto new_segment; - - sg[nsegs - 1].length += nbytes; - } else { -new_segment: - memset(&sg[nsegs],0,sizeof(struct scatterlist)); - sg[nsegs].page = bvec->bv_page; - sg[nsegs].length = nbytes; - sg[nsegs].offset = bvec->bv_offset; - - nsegs++; - } - bvprv = bvec; - } /* segments in bio */ - } /* bios in rq */ - - return nsegs; -} - -EXPORT_SYMBOL(blk_rq_map_sg); - -/* - * the standard queue merge functions, can be overridden with device - * specific ones if so desired - */ - -static inline int ll_new_mergeable(request_queue_t *q, - struct request *req, - struct bio *bio) -{ - int nr_phys_segs = bio_phys_segments(q, bio); - - if (req->nr_phys_segments + nr_phys_segs > q->max_phys_segments) { - req->flags |= REQ_NOMERGE; - if (req == q->last_merge) - q->last_merge = NULL; - return 0; - } - - /* - * A hw segment is just getting larger, bump just the phys - * counter. - */ - req->nr_phys_segments += nr_phys_segs; - return 1; -} - -static inline int ll_new_hw_segment(request_queue_t *q, - struct request *req, - struct bio *bio) -{ - int nr_hw_segs = bio_hw_segments(q, bio); - int nr_phys_segs = bio_phys_segments(q, bio); - - if (req->nr_hw_segments + nr_hw_segs > q->max_hw_segments - || req->nr_phys_segments + nr_phys_segs > q->max_phys_segments) { - req->flags |= REQ_NOMERGE; - if (req == q->last_merge) - q->last_merge = NULL; - return 0; - } - - /* - * This will form the start of a new hw segment. Bump both - * counters. - */ - req->nr_hw_segments += nr_hw_segs; - req->nr_phys_segments += nr_phys_segs; - return 1; -} - -static int ll_back_merge_fn(request_queue_t *q, struct request *req, - struct bio *bio) -{ - int len; - - if (req->nr_sectors + bio_sectors(bio) > q->max_sectors) { - req->flags |= REQ_NOMERGE; - if (req == q->last_merge) - q->last_merge = NULL; - return 0; - } - if (unlikely(!bio_flagged(req->biotail, BIO_SEG_VALID))) - blk_recount_segments(q, req->biotail); - if (unlikely(!bio_flagged(bio, BIO_SEG_VALID))) - blk_recount_segments(q, bio); - len = req->biotail->bi_hw_back_size + bio->bi_hw_front_size; - if (BIOVEC_VIRT_MERGEABLE(__BVEC_END(req->biotail), __BVEC_START(bio)) && - !BIOVEC_VIRT_OVERSIZE(len)) { - int mergeable = ll_new_mergeable(q, req, bio); - - if (mergeable) { - if (req->nr_hw_segments == 1) - req->bio->bi_hw_front_size = len; - if (bio->bi_hw_segments == 1) - bio->bi_hw_back_size = len; - } - return mergeable; - } - - return ll_new_hw_segment(q, req, bio); -} - -static int ll_front_merge_fn(request_queue_t *q, struct request *req, - struct bio *bio) -{ - int len; - - if (req->nr_sectors + bio_sectors(bio) > q->max_sectors) { - req->flags |= REQ_NOMERGE; - if (req == q->last_merge) - q->last_merge = NULL; - return 0; - } - len = bio->bi_hw_back_size + req->bio->bi_hw_front_size; - if (unlikely(!bio_flagged(bio, BIO_SEG_VALID))) - blk_recount_segments(q, bio); - if (unlikely(!bio_flagged(req->bio, BIO_SEG_VALID))) - blk_recount_segments(q, req->bio); - if (BIOVEC_VIRT_MERGEABLE(__BVEC_END(bio), __BVEC_START(req->bio)) && - !BIOVEC_VIRT_OVERSIZE(len)) { - int mergeable = ll_new_mergeable(q, req, bio); - - if (mergeable) { - if (bio->bi_hw_segments == 1) - bio->bi_hw_front_size = len; - if (req->nr_hw_segments == 1) - req->biotail->bi_hw_back_size = len; - } - return mergeable; - } - - return ll_new_hw_segment(q, req, bio); -} - -static int ll_merge_requests_fn(request_queue_t *q, struct request *req, - struct request *next) -{ - int total_phys_segments; - int total_hw_segments; - - /* - * First check if the either of the requests are re-queued - * requests. Can't merge them if they are. - */ - if (req->special || next->special) - return 0; - - /* - * Will it become too large? - */ - if ((req->nr_sectors + next->nr_sectors) > q->max_sectors) - return 0; - - total_phys_segments = req->nr_phys_segments + next->nr_phys_segments; - if (blk_phys_contig_segment(q, req->biotail, next->bio)) - total_phys_segments--; - - if (total_phys_segments > q->max_phys_segments) - return 0; - - total_hw_segments = req->nr_hw_segments + next->nr_hw_segments; - if (blk_hw_contig_segment(q, req->biotail, next->bio)) { - int len = req->biotail->bi_hw_back_size + next->bio->bi_hw_front_size; - /* - * propagate the combined length to the end of the requests - */ - if (req->nr_hw_segments == 1) - req->bio->bi_hw_front_size = len; - if (next->nr_hw_segments == 1) - next->biotail->bi_hw_back_size = len; - total_hw_segments--; - } - - if (total_hw_segments > q->max_hw_segments) - return 0; - - /* Merge is OK... */ - req->nr_phys_segments = total_phys_segments; - req->nr_hw_segments = total_hw_segments; - return 1; -} - -/* - * "plug" the device if there are no outstanding requests: this will - * force the transfer to start only after we have put all the requests - * on the list. - * - * This is called with interrupts off and no requests on the queue and - * with the queue lock held. - */ -void blk_plug_device(request_queue_t *q) -{ - WARN_ON(!irqs_disabled()); - - /* - * don't plug a stopped queue, it must be paired with blk_start_queue() - * which will restart the queueing - */ - if (test_bit(QUEUE_FLAG_STOPPED, &q->queue_flags)) - return; - - if (!test_and_set_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags)) - mod_timer(&q->unplug_timer, jiffies + q->unplug_delay); -} - -EXPORT_SYMBOL(blk_plug_device); - -/* - * remove the queue from the plugged list, if present. called with - * queue lock held and interrupts disabled. - */ -int blk_remove_plug(request_queue_t *q) -{ - WARN_ON(!irqs_disabled()); - - if (!test_and_clear_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags)) - return 0; - - del_timer(&q->unplug_timer); - return 1; -} - -EXPORT_SYMBOL(blk_remove_plug); - -/* - * remove the plug and let it rip.. - */ -void __generic_unplug_device(request_queue_t *q) -{ - if (unlikely(test_bit(QUEUE_FLAG_STOPPED, &q->queue_flags))) - return; - - if (!blk_remove_plug(q)) - return; - - q->request_fn(q); -} -EXPORT_SYMBOL(__generic_unplug_device); - -/** - * generic_unplug_device - fire a request queue - * @q: The &request_queue_t in question - * - * Description: - * Linux uses plugging to build bigger requests queues before letting - * the device have at them. If a queue is plugged, the I/O scheduler - * is still adding and merging requests on the queue. Once the queue - * gets unplugged, the request_fn defined for the queue is invoked and - * transfers started. - **/ -void generic_unplug_device(request_queue_t *q) -{ - spin_lock_irq(q->queue_lock); - __generic_unplug_device(q); - spin_unlock_irq(q->queue_lock); -} -EXPORT_SYMBOL(generic_unplug_device); - -static void blk_backing_dev_unplug(struct backing_dev_info *bdi, - struct page *page) -{ - request_queue_t *q = bdi->unplug_io_data; - - /* - * devices don't necessarily have an ->unplug_fn defined - */ - if (q->unplug_fn) - q->unplug_fn(q); -} - -static void blk_unplug_work(void *data) -{ - request_queue_t *q = data; - - q->unplug_fn(q); -} - -static void blk_unplug_timeout(unsigned long data) -{ - request_queue_t *q = (request_queue_t *)data; - - kblockd_schedule_work(&q->unplug_work); -} - -/** - * blk_start_queue - restart a previously stopped queue - * @q: The &request_queue_t in question - * - * Description: - * blk_start_queue() will clear the stop flag on the queue, and call - * the request_fn for the queue if it was in a stopped state when - * entered. Also see blk_stop_queue(). Queue lock must be held. - **/ -void blk_start_queue(request_queue_t *q) -{ - clear_bit(QUEUE_FLAG_STOPPED, &q->queue_flags); - - /* - * one level of recursion is ok and is much faster than kicking - * the unplug handling - */ - if (!test_and_set_bit(QUEUE_FLAG_REENTER, &q->queue_flags)) { - q->request_fn(q); - clear_bit(QUEUE_FLAG_REENTER, &q->queue_flags); - } else { - blk_plug_device(q); - kblockd_schedule_work(&q->unplug_work); - } -} - -EXPORT_SYMBOL(blk_start_queue); - -/** - * blk_stop_queue - stop a queue - * @q: The &request_queue_t in question - * - * Description: - * The Linux block layer assumes that a block driver will consume all - * entries on the request queue when the request_fn strategy is called. - * Often this will not happen, because of hardware limitations (queue - * depth settings). If a device driver gets a 'queue full' response, - * or if it simply chooses not to queue more I/O at one point, it can - * call this function to prevent the request_fn from being called until - * the driver has signalled it's ready to go again. This happens by calling - * blk_start_queue() to restart queue operations. Queue lock must be held. - **/ -void blk_stop_queue(request_queue_t *q) -{ - blk_remove_plug(q); - set_bit(QUEUE_FLAG_STOPPED, &q->queue_flags); -} -EXPORT_SYMBOL(blk_stop_queue); - -/** - * blk_sync_queue - cancel any pending callbacks on a queue - * @q: the queue - * - * Description: - * The block layer may perform asynchronous callback activity - * on a queue, such as calling the unplug function after a timeout. - * A block device may call blk_sync_queue to ensure that any - * such activity is cancelled, thus allowing it to release resources - * the the callbacks might use. The caller must already have made sure - * that its ->make_request_fn will not re-add plugging prior to calling - * this function. - * - */ -void blk_sync_queue(struct request_queue *q) -{ - del_timer_sync(&q->unplug_timer); - kblockd_flush(); -} -EXPORT_SYMBOL(blk_sync_queue); - -/** - * blk_run_queue - run a single device queue - * @q: The queue to run - */ -void blk_run_queue(struct request_queue *q) -{ - unsigned long flags; - - spin_lock_irqsave(q->queue_lock, flags); - blk_remove_plug(q); - if (!elv_queue_empty(q)) - q->request_fn(q); - spin_unlock_irqrestore(q->queue_lock, flags); -} -EXPORT_SYMBOL(blk_run_queue); - -/** - * blk_cleanup_queue: - release a &request_queue_t when it is no longer needed - * @q: the request queue to be released - * - * Description: - * blk_cleanup_queue is the pair to blk_init_queue() or - * blk_queue_make_request(). It should be called when a request queue is - * being released; typically when a block device is being de-registered. - * Currently, its primary task it to free all the &struct request - * structures that were allocated to the queue and the queue itself. - * - * Caveat: - * Hopefully the low level driver will have finished any - * outstanding requests first... - **/ -void blk_cleanup_queue(request_queue_t * q) -{ - struct request_list *rl = &q->rq; - - if (!atomic_dec_and_test(&q->refcnt)) - return; - - if (q->elevator) - elevator_exit(q->elevator); - - blk_sync_queue(q); - - if (rl->rq_pool) - mempool_destroy(rl->rq_pool); - - if (q->queue_tags) - __blk_queue_free_tags(q); - - blk_queue_ordered(q, QUEUE_ORDERED_NONE); - - kmem_cache_free(requestq_cachep, q); -} - -EXPORT_SYMBOL(blk_cleanup_queue); - -static int blk_init_free_list(request_queue_t *q) -{ - struct request_list *rl = &q->rq; - - rl->count[READ] = rl->count[WRITE] = 0; - rl->starved[READ] = rl->starved[WRITE] = 0; - rl->elvpriv = 0; - init_waitqueue_head(&rl->wait[READ]); - init_waitqueue_head(&rl->wait[WRITE]); - - rl->rq_pool = mempool_create_node(BLKDEV_MIN_RQ, mempool_alloc_slab, - mempool_free_slab, request_cachep, q->node); - - if (!rl->rq_pool) - return -ENOMEM; - - return 0; -} - -static int __make_request(request_queue_t *, struct bio *); - -request_queue_t *blk_alloc_queue(gfp_t gfp_mask) -{ - return blk_alloc_queue_node(gfp_mask, -1); -} -EXPORT_SYMBOL(blk_alloc_queue); - -request_queue_t *blk_alloc_queue_node(gfp_t gfp_mask, int node_id) -{ - request_queue_t *q; - - q = kmem_cache_alloc_node(requestq_cachep, gfp_mask, node_id); - if (!q) - return NULL; - - memset(q, 0, sizeof(*q)); - init_timer(&q->unplug_timer); - atomic_set(&q->refcnt, 1); - - q->backing_dev_info.unplug_io_fn = blk_backing_dev_unplug; - q->backing_dev_info.unplug_io_data = q; - - return q; -} -EXPORT_SYMBOL(blk_alloc_queue_node); - -/** - * blk_init_queue - prepare a request queue for use with a block device - * @rfn: The function to be called to process requests that have been - * placed on the queue. - * @lock: Request queue spin lock - * - * Description: - * If a block device wishes to use the standard request handling procedures, - * which sorts requests and coalesces adjacent requests, then it must - * call blk_init_queue(). The function @rfn will be called when there - * are requests on the queue that need to be processed. If the device - * supports plugging, then @rfn may not be called immediately when requests - * are available on the queue, but may be called at some time later instead. - * Plugged queues are generally unplugged when a buffer belonging to one - * of the requests on the queue is needed, or due to memory pressure. - * - * @rfn is not required, or even expected, to remove all requests off the - * queue, but only as many as it can handle at a time. If it does leave - * requests on the queue, it is responsible for arranging that the requests - * get dealt with eventually. - * - * The queue spin lock must be held while manipulating the requests on the - * request queue. - * - * Function returns a pointer to the initialized request queue, or NULL if - * it didn't succeed. - * - * Note: - * blk_init_queue() must be paired with a blk_cleanup_queue() call - * when the block device is deactivated (such as at module unload). - **/ - -request_queue_t *blk_init_queue(request_fn_proc *rfn, spinlock_t *lock) -{ - return blk_init_queue_node(rfn, lock, -1); -} -EXPORT_SYMBOL(blk_init_queue); - -request_queue_t * -blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id) -{ - request_queue_t *q = blk_alloc_queue_node(GFP_KERNEL, node_id); - - if (!q) - return NULL; - - q->node = node_id; - if (blk_init_free_list(q)) - goto out_init; - - /* - * if caller didn't supply a lock, they get per-queue locking with - * our embedded lock - */ - if (!lock) { - spin_lock_init(&q->__queue_lock); - lock = &q->__queue_lock; - } - - q->request_fn = rfn; - q->back_merge_fn = ll_back_merge_fn; - q->front_merge_fn = ll_front_merge_fn; - q->merge_requests_fn = ll_merge_requests_fn; - q->prep_rq_fn = NULL; - q->unplug_fn = generic_unplug_device; - q->queue_flags = (1 << QUEUE_FLAG_CLUSTER); - q->queue_lock = lock; - - blk_queue_segment_boundary(q, 0xffffffff); - - blk_queue_make_request(q, __make_request); - blk_queue_max_segment_size(q, MAX_SEGMENT_SIZE); - - blk_queue_max_hw_segments(q, MAX_HW_SEGMENTS); - blk_queue_max_phys_segments(q, MAX_PHYS_SEGMENTS); - - /* - * all done - */ - if (!elevator_init(q, NULL)) { - blk_queue_congestion_threshold(q); - return q; - } - - blk_cleanup_queue(q); -out_init: - kmem_cache_free(requestq_cachep, q); - return NULL; -} -EXPORT_SYMBOL(blk_init_queue_node); - -int blk_get_queue(request_queue_t *q) -{ - if (likely(!test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) { - atomic_inc(&q->refcnt); - return 0; - } - - return 1; -} - -EXPORT_SYMBOL(blk_get_queue); - -static inline void blk_free_request(request_queue_t *q, struct request *rq) -{ - if (rq->flags & REQ_ELVPRIV) - elv_put_request(q, rq); - mempool_free(rq, q->rq.rq_pool); -} - -static inline struct request * -blk_alloc_request(request_queue_t *q, int rw, struct bio *bio, - int priv, gfp_t gfp_mask) -{ - struct request *rq = mempool_alloc(q->rq.rq_pool, gfp_mask); - - if (!rq) - return NULL; - - /* - * first three bits are identical in rq->flags and bio->bi_rw, - * see bio.h and blkdev.h - */ - rq->flags = rw; - - if (priv) { - if (unlikely(elv_set_request(q, rq, bio, gfp_mask))) { - mempool_free(rq, q->rq.rq_pool); - return NULL; - } - rq->flags |= REQ_ELVPRIV; - } - - return rq; -} - -/* - * ioc_batching returns true if the ioc is a valid batching request and - * should be given priority access to a request. - */ -static inline int ioc_batching(request_queue_t *q, struct io_context *ioc) -{ - if (!ioc) - return 0; - - /* - * Make sure the process is able to allocate at least 1 request - * even if the batch times out, otherwise we could theoretically - * lose wakeups. - */ - return ioc->nr_batch_requests == q->nr_batching || - (ioc->nr_batch_requests > 0 - && time_before(jiffies, ioc->last_waited + BLK_BATCH_TIME)); -} - -/* - * ioc_set_batching sets ioc to be a new "batcher" if it is not one. This - * will cause the process to be a "batcher" on all queues in the system. This - * is the behaviour we want though - once it gets a wakeup it should be given - * a nice run. - */ -static void ioc_set_batching(request_queue_t *q, struct io_context *ioc) -{ - if (!ioc || ioc_batching(q, ioc)) - return; - - ioc->nr_batch_requests = q->nr_batching; - ioc->last_waited = jiffies; -} - -static void __freed_request(request_queue_t *q, int rw) -{ - struct request_list *rl = &q->rq; - - if (rl->count[rw] < queue_congestion_off_threshold(q)) - clear_queue_congested(q, rw); - - if (rl->count[rw] + 1 <= q->nr_requests) { - if (waitqueue_active(&rl->wait[rw])) - wake_up(&rl->wait[rw]); - - blk_clear_queue_full(q, rw); - } -} - -/* - * A request has just been released. Account for it, update the full and - * congestion status, wake up any waiters. Called under q->queue_lock. - */ -static void freed_request(request_queue_t *q, int rw, int priv) -{ - struct request_list *rl = &q->rq; - - rl->count[rw]--; - if (priv) - rl->elvpriv--; - - __freed_request(q, rw); - - if (unlikely(rl->starved[rw ^ 1])) - __freed_request(q, rw ^ 1); -} - -#define blkdev_free_rq(list) list_entry((list)->next, struct request, queuelist) -/* - * Get a free request, queue_lock must be held. - * Returns NULL on failure, with queue_lock held. - * Returns !NULL on success, with queue_lock *not held*. - */ -static struct request *get_request(request_queue_t *q, int rw, struct bio *bio, - gfp_t gfp_mask) -{ - struct request *rq = NULL; - struct request_list *rl = &q->rq; - struct io_context *ioc = current_io_context(GFP_ATOMIC); - int priv; - - if (rl->count[rw]+1 >= q->nr_requests) { - /* - * The queue will fill after this allocation, so set it as - * full, and mark this process as "batching". This process - * will be allowed to complete a batch of requests, others - * will be blocked. - */ - if (!blk_queue_full(q, rw)) { - ioc_set_batching(q, ioc); - blk_set_queue_full(q, rw); - } - } - - switch (elv_may_queue(q, rw, bio)) { - case ELV_MQUEUE_NO: - goto rq_starved; - case ELV_MQUEUE_MAY: - break; - case ELV_MQUEUE_MUST: - goto get_rq; - } - - if (blk_queue_full(q, rw) && !ioc_batching(q, ioc)) { - /* - * The queue is full and the allocating process is not a - * "batcher", and not exempted by the IO scheduler - */ - goto out; - } - -get_rq: - /* - * Only allow batching queuers to allocate up to 50% over the defined - * limit of requests, otherwise we could have thousands of requests - * allocated with any setting of ->nr_requests - */ - if (rl->count[rw] >= (3 * q->nr_requests / 2)) - goto out; - - rl->count[rw]++; - rl->starved[rw] = 0; - if (rl->count[rw] >= queue_congestion_on_threshold(q)) - set_queue_congested(q, rw); - - priv = !test_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags); - if (priv) - rl->elvpriv++; - - spin_unlock_irq(q->queue_lock); - - rq = blk_alloc_request(q, rw, bio, priv, gfp_mask); - if (!rq) { - /* - * Allocation failed presumably due to memory. Undo anything - * we might have messed up. - * - * Allocating task should really be put onto the front of the - * wait queue, but this is pretty rare. - */ - spin_lock_irq(q->queue_lock); - freed_request(q, rw, priv); - - /* - * in the very unlikely event that allocation failed and no - * requests for this direction was pending, mark us starved - * so that freeing of a request in the other direction will - * notice us. another possible fix would be to split the - * rq mempool into READ and WRITE - */ -rq_starved: - if (unlikely(rl->count[rw] == 0)) - rl->starved[rw] = 1; - - goto out; - } - - if (ioc_batching(q, ioc)) - ioc->nr_batch_requests--; - - rq_init(q, rq); - rq->rl = rl; -out: - return rq; -} - -/* - * No available requests for this queue, unplug the device and wait for some - * requests to become available. - * - * Called with q->queue_lock held, and returns with it unlocked. - */ -static struct request *get_request_wait(request_queue_t *q, int rw, - struct bio *bio) -{ - struct request *rq; - - rq = get_request(q, rw, bio, GFP_NOIO); - while (!rq) { - DEFINE_WAIT(wait); - struct request_list *rl = &q->rq; - - prepare_to_wait_exclusive(&rl->wait[rw], &wait, - TASK_UNINTERRUPTIBLE); - - rq = get_request(q, rw, bio, GFP_NOIO); - - if (!rq) { - struct io_context *ioc; - - __generic_unplug_device(q); - spin_unlock_irq(q->queue_lock); - io_schedule(); - - /* - * After sleeping, we become a "batching" process and - * will be able to allocate at least one request, and - * up to a big batch of them for a small period time. - * See ioc_batching, ioc_set_batching - */ - ioc = current_io_context(GFP_NOIO); - ioc_set_batching(q, ioc); - - spin_lock_irq(q->queue_lock); - } - finish_wait(&rl->wait[rw], &wait); - } - - return rq; -} - -struct request *blk_get_request(request_queue_t *q, int rw, gfp_t gfp_mask) -{ - struct request *rq; - - BUG_ON(rw != READ && rw != WRITE); - - spin_lock_irq(q->queue_lock); - if (gfp_mask & __GFP_WAIT) { - rq = get_request_wait(q, rw, NULL); - } else { - rq = get_request(q, rw, NULL, gfp_mask); - if (!rq) - spin_unlock_irq(q->queue_lock); - } - /* q->queue_lock is unlocked at this point */ - - return rq; -} -EXPORT_SYMBOL(blk_get_request); - -/** - * blk_requeue_request - put a request back on queue - * @q: request queue where request should be inserted - * @rq: request to be inserted - * - * Description: - * Drivers often keep queueing requests until the hardware cannot accept - * more, when that condition happens we need to put the request back - * on the queue. Must be called with queue lock held. - */ -void blk_requeue_request(request_queue_t *q, struct request *rq) -{ - if (blk_rq_tagged(rq)) - blk_queue_end_tag(q, rq); - - elv_requeue_request(q, rq); -} - -EXPORT_SYMBOL(blk_requeue_request); - -/** - * blk_insert_request - insert a special request in to a request queue - * @q: request queue where request should be inserted - * @rq: request to be inserted - * @at_head: insert request at head or tail of queue - * @data: private data - * - * Description: - * Many block devices need to execute commands asynchronously, so they don't - * block the whole kernel from preemption during request execution. This is - * accomplished normally by inserting aritficial requests tagged as - * REQ_SPECIAL in to the corresponding request queue, and letting them be - * scheduled for actual execution by the request queue. - * - * We have the option of inserting the head or the tail of the queue. - * Typically we use the tail for new ioctls and so forth. We use the head - * of the queue for things like a QUEUE_FULL message from a device, or a - * host that is unable to accept a particular command. - */ -void blk_insert_request(request_queue_t *q, struct request *rq, - int at_head, void *data) -{ - int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK; - unsigned long flags; - - /* - * tell I/O scheduler that this isn't a regular read/write (ie it - * must not attempt merges on this) and that it acts as a soft - * barrier - */ - rq->flags |= REQ_SPECIAL | REQ_SOFTBARRIER; - - rq->special = data; - - spin_lock_irqsave(q->queue_lock, flags); - - /* - * If command is tagged, release the tag - */ - if (blk_rq_tagged(rq)) - blk_queue_end_tag(q, rq); - - drive_stat_acct(rq, rq->nr_sectors, 1); - __elv_add_request(q, rq, where, 0); - - if (blk_queue_plugged(q)) - __generic_unplug_device(q); - else - q->request_fn(q); - spin_unlock_irqrestore(q->queue_lock, flags); -} - -EXPORT_SYMBOL(blk_insert_request); - -/** - * blk_rq_map_user - map user data to a request, for REQ_BLOCK_PC usage - * @q: request queue where request should be inserted - * @rq: request structure to fill - * @ubuf: the user buffer - * @len: length of user data - * - * Description: - * Data will be mapped directly for zero copy io, if possible. Otherwise - * a kernel bounce buffer is used. - * - * A matching blk_rq_unmap_user() must be issued at the end of io, while - * still in process context. - * - * Note: The mapped bio may need to be bounced through blk_queue_bounce() - * before being submitted to the device, as pages mapped may be out of - * reach. It's the callers responsibility to make sure this happens. The - * original bio must be passed back in to blk_rq_unmap_user() for proper - * unmapping. - */ -int blk_rq_map_user(request_queue_t *q, struct request *rq, void __user *ubuf, - unsigned int len) -{ - unsigned long uaddr; - struct bio *bio; - int reading; - - if (len > (q->max_sectors << 9)) - return -EINVAL; - if (!len || !ubuf) - return -EINVAL; - - reading = rq_data_dir(rq) == READ; - - /* - * if alignment requirement is satisfied, map in user pages for - * direct dma. else, set up kernel bounce buffers - */ - uaddr = (unsigned long) ubuf; - if (!(uaddr & queue_dma_alignment(q)) && !(len & queue_dma_alignment(q))) - bio = bio_map_user(q, NULL, uaddr, len, reading); - else - bio = bio_copy_user(q, uaddr, len, reading); - - if (!IS_ERR(bio)) { - rq->bio = rq->biotail = bio; - blk_rq_bio_prep(q, rq, bio); - - rq->buffer = rq->data = NULL; - rq->data_len = len; - return 0; - } - - /* - * bio is the err-ptr - */ - return PTR_ERR(bio); -} - -EXPORT_SYMBOL(blk_rq_map_user); - -/** - * blk_rq_map_user_iov - map user data to a request, for REQ_BLOCK_PC usage - * @q: request queue where request should be inserted - * @rq: request to map data to - * @iov: pointer to the iovec - * @iov_count: number of elements in the iovec - * - * Description: - * Data will be mapped directly for zero copy io, if possible. Otherwise - * a kernel bounce buffer is used. - * - * A matching blk_rq_unmap_user() must be issued at the end of io, while - * still in process context. - * - * Note: The mapped bio may need to be bounced through blk_queue_bounce() - * before being submitted to the device, as pages mapped may be out of - * reach. It's the callers responsibility to make sure this happens. The - * original bio must be passed back in to blk_rq_unmap_user() for proper - * unmapping. - */ -int blk_rq_map_user_iov(request_queue_t *q, struct request *rq, - struct sg_iovec *iov, int iov_count) -{ - struct bio *bio; - - if (!iov || iov_count <= 0) - return -EINVAL; - - /* we don't allow misaligned data like bio_map_user() does. If the - * user is using sg, they're expected to know the alignment constraints - * and respect them accordingly */ - bio = bio_map_user_iov(q, NULL, iov, iov_count, rq_data_dir(rq)== READ); - if (IS_ERR(bio)) - return PTR_ERR(bio); - - rq->bio = rq->biotail = bio; - blk_rq_bio_prep(q, rq, bio); - rq->buffer = rq->data = NULL; - rq->data_len = bio->bi_size; - return 0; -} - -EXPORT_SYMBOL(blk_rq_map_user_iov); - -/** - * blk_rq_unmap_user - unmap a request with user data - * @bio: bio to be unmapped - * @ulen: length of user buffer - * - * Description: - * Unmap a bio previously mapped by blk_rq_map_user(). - */ -int blk_rq_unmap_user(struct bio *bio, unsigned int ulen) -{ - int ret = 0; - - if (bio) { - if (bio_flagged(bio, BIO_USER_MAPPED)) - bio_unmap_user(bio); - else - ret = bio_uncopy_user(bio); - } - - return 0; -} - -EXPORT_SYMBOL(blk_rq_unmap_user); - -/** - * blk_rq_map_kern - map kernel data to a request, for REQ_BLOCK_PC usage - * @q: request queue where request should be inserted - * @rq: request to fill - * @kbuf: the kernel buffer - * @len: length of user data - * @gfp_mask: memory allocation flags - */ -int blk_rq_map_kern(request_queue_t *q, struct request *rq, void *kbuf, - unsigned int len, gfp_t gfp_mask) -{ - struct bio *bio; - - if (len > (q->max_sectors << 9)) - return -EINVAL; - if (!len || !kbuf) - return -EINVAL; - - bio = bio_map_kern(q, kbuf, len, gfp_mask); - if (IS_ERR(bio)) - return PTR_ERR(bio); - - if (rq_data_dir(rq) == WRITE) - bio->bi_rw |= (1 << BIO_RW); - - rq->bio = rq->biotail = bio; - blk_rq_bio_prep(q, rq, bio); - - rq->buffer = rq->data = NULL; - rq->data_len = len; - return 0; -} - -EXPORT_SYMBOL(blk_rq_map_kern); - -/** - * blk_execute_rq_nowait - insert a request into queue for execution - * @q: queue to insert the request in - * @bd_disk: matching gendisk - * @rq: request to insert - * @at_head: insert request at head or tail of queue - * @done: I/O completion handler - * - * Description: - * Insert a fully prepared request at the back of the io scheduler queue - * for execution. Don't wait for completion. - */ -void blk_execute_rq_nowait(request_queue_t *q, struct gendisk *bd_disk, - struct request *rq, int at_head, - void (*done)(struct request *)) -{ - int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK; - - rq->rq_disk = bd_disk; - rq->flags |= REQ_NOMERGE; - rq->end_io = done; - elv_add_request(q, rq, where, 1); - generic_unplug_device(q); -} - -/** - * blk_execute_rq - insert a request into queue for execution - * @q: queue to insert the request in - * @bd_disk: matching gendisk - * @rq: request to insert - * @at_head: insert request at head or tail of queue - * - * Description: - * Insert a fully prepared request at the back of the io scheduler queue - * for execution and wait for completion. - */ -int blk_execute_rq(request_queue_t *q, struct gendisk *bd_disk, - struct request *rq, int at_head) -{ - DECLARE_COMPLETION(wait); - char sense[SCSI_SENSE_BUFFERSIZE]; - int err = 0; - - /* - * we need an extra reference to the request, so we can look at - * it after io completion - */ - rq->ref_count++; - - if (!rq->sense) { - memset(sense, 0, sizeof(sense)); - rq->sense = sense; - rq->sense_len = 0; - } - - rq->waiting = &wait; - blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq); - wait_for_completion(&wait); - rq->waiting = NULL; - - if (rq->errors) - err = -EIO; - - return err; -} - -EXPORT_SYMBOL(blk_execute_rq); - -/** - * blkdev_issue_flush - queue a flush - * @bdev: blockdev to issue flush for - * @error_sector: error sector - * - * Description: - * Issue a flush for the block device in question. Caller can supply - * room for storing the error offset in case of a flush error, if they - * wish to. Caller must run wait_for_completion() on its own. - */ -int blkdev_issue_flush(struct block_device *bdev, sector_t *error_sector) -{ - request_queue_t *q; - - if (bdev->bd_disk == NULL) - return -ENXIO; - - q = bdev_get_queue(bdev); - if (!q) - return -ENXIO; - if (!q->issue_flush_fn) - return -EOPNOTSUPP; - - return q->issue_flush_fn(q, bdev->bd_disk, error_sector); -} - -EXPORT_SYMBOL(blkdev_issue_flush); - -static void drive_stat_acct(struct request *rq, int nr_sectors, int new_io) -{ - int rw = rq_data_dir(rq); - - if (!blk_fs_request(rq) || !rq->rq_disk) - return; - - if (!new_io) { - __disk_stat_inc(rq->rq_disk, merges[rw]); - } else { - disk_round_stats(rq->rq_disk); - rq->rq_disk->in_flight++; - } -} - -/* - * add-request adds a request to the linked list. - * queue lock is held and interrupts disabled, as we muck with the - * request queue list. - */ -static inline void add_request(request_queue_t * q, struct request * req) -{ - drive_stat_acct(req, req->nr_sectors, 1); - - if (q->activity_fn) - q->activity_fn(q->activity_data, rq_data_dir(req)); - - /* - * elevator indicated where it wants this request to be - * inserted at elevator_merge time - */ - __elv_add_request(q, req, ELEVATOR_INSERT_SORT, 0); -} - -/* - * disk_round_stats() - Round off the performance stats on a struct - * disk_stats. - * - * The average IO queue length and utilisation statistics are maintained - * by observing the current state of the queue length and the amount of - * time it has been in this state for. - * - * Normally, that accounting is done on IO completion, but that can result - * in more than a second's worth of IO being accounted for within any one - * second, leading to >100% utilisation. To deal with that, we call this - * function to do a round-off before returning the results when reading - * /proc/diskstats. This accounts immediately for all queue usage up to - * the current jiffies and restarts the counters again. - */ -void disk_round_stats(struct gendisk *disk) -{ - unsigned long now = jiffies; - - if (now == disk->stamp) - return; - - if (disk->in_flight) { - __disk_stat_add(disk, time_in_queue, - disk->in_flight * (now - disk->stamp)); - __disk_stat_add(disk, io_ticks, (now - disk->stamp)); - } - disk->stamp = now; -} - -/* - * queue lock must be held - */ -static void __blk_put_request(request_queue_t *q, struct request *req) -{ - struct request_list *rl = req->rl; - - if (unlikely(!q)) - return; - if (unlikely(--req->ref_count)) - return; - - elv_completed_request(q, req); - - req->rq_status = RQ_INACTIVE; - req->rl = NULL; - - /* - * Request may not have originated from ll_rw_blk. if not, - * it didn't come out of our reserved rq pools - */ - if (rl) { - int rw = rq_data_dir(req); - int priv = req->flags & REQ_ELVPRIV; - - BUG_ON(!list_empty(&req->queuelist)); - - blk_free_request(q, req); - freed_request(q, rw, priv); - } -} - -void blk_put_request(struct request *req) -{ - unsigned long flags; - request_queue_t *q = req->q; - - /* - * Gee, IDE calls in w/ NULL q. Fix IDE and remove the - * following if (q) test. - */ - if (q) { - spin_lock_irqsave(q->queue_lock, flags); - __blk_put_request(q, req); - spin_unlock_irqrestore(q->queue_lock, flags); - } -} - -EXPORT_SYMBOL(blk_put_request); - -/** - * blk_end_sync_rq - executes a completion event on a request - * @rq: request to complete - */ -void blk_end_sync_rq(struct request *rq) -{ - struct completion *waiting = rq->waiting; - - rq->waiting = NULL; - __blk_put_request(rq->q, rq); - - /* - * complete last, if this is a stack request the process (and thus - * the rq pointer) could be invalid right after this complete() - */ - complete(waiting); -} -EXPORT_SYMBOL(blk_end_sync_rq); - -/** - * blk_congestion_wait - wait for a queue to become uncongested - * @rw: READ or WRITE - * @timeout: timeout in jiffies - * - * Waits for up to @timeout jiffies for a queue (any queue) to exit congestion. - * If no queues are congested then just wait for the next request to be - * returned. - */ -long blk_congestion_wait(int rw, long timeout) -{ - long ret; - DEFINE_WAIT(wait); - wait_queue_head_t *wqh = &congestion_wqh[rw]; - - prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE); - ret = io_schedule_timeout(timeout); - finish_wait(wqh, &wait); - return ret; -} - -EXPORT_SYMBOL(blk_congestion_wait); - -/* - * Has to be called with the request spinlock acquired - */ -static int attempt_merge(request_queue_t *q, struct request *req, - struct request *next) -{ - if (!rq_mergeable(req) || !rq_mergeable(next)) - return 0; - - /* - * not contigious - */ - if (req->sector + req->nr_sectors != next->sector) - return 0; - - if (rq_data_dir(req) != rq_data_dir(next) - || req->rq_disk != next->rq_disk - || next->waiting || next->special) - return 0; - - /* - * If we are allowed to merge, then append bio list - * from next to rq and release next. merge_requests_fn - * will have updated segment counts, update sector - * counts here. - */ - if (!q->merge_requests_fn(q, req, next)) - return 0; - - /* - * At this point we have either done a back merge - * or front merge. We need the smaller start_time of - * the merged requests to be the current request - * for accounting purposes. - */ - if (time_after(req->start_time, next->start_time)) - req->start_time = next->start_time; - - req->biotail->bi_next = next->bio; - req->biotail = next->biotail; - - req->nr_sectors = req->hard_nr_sectors += next->hard_nr_sectors; - - elv_merge_requests(q, req, next); - - if (req->rq_disk) { - disk_round_stats(req->rq_disk); - req->rq_disk->in_flight--; - } - - req->ioprio = ioprio_best(req->ioprio, next->ioprio); - - __blk_put_request(q, next); - return 1; -} - -static inline int attempt_back_merge(request_queue_t *q, struct request *rq) -{ - struct request *next = elv_latter_request(q, rq); - - if (next) - return attempt_merge(q, rq, next); - - return 0; -} - -static inline int attempt_front_merge(request_queue_t *q, struct request *rq) -{ - struct request *prev = elv_former_request(q, rq); - - if (prev) - return attempt_merge(q, prev, rq); - - return 0; -} - -/** - * blk_attempt_remerge - attempt to remerge active head with next request - * @q: The &request_queue_t belonging to the device - * @rq: The head request (usually) - * - * Description: - * For head-active devices, the queue can easily be unplugged so quickly - * that proper merging is not done on the front request. This may hurt - * performance greatly for some devices. The block layer cannot safely - * do merging on that first request for these queues, but the driver can - * call this function and make it happen any way. Only the driver knows - * when it is safe to do so. - **/ -void blk_attempt_remerge(request_queue_t *q, struct request *rq) -{ - unsigned long flags; - - spin_lock_irqsave(q->queue_lock, flags); - attempt_back_merge(q, rq); - spin_unlock_irqrestore(q->queue_lock, flags); -} - -EXPORT_SYMBOL(blk_attempt_remerge); - -static int __make_request(request_queue_t *q, struct bio *bio) -{ - struct request *req; - int el_ret, rw, nr_sectors, cur_nr_sectors, barrier, err, sync; - unsigned short prio; - sector_t sector; - - sector = bio->bi_sector; - nr_sectors = bio_sectors(bio); - cur_nr_sectors = bio_cur_sectors(bio); - prio = bio_prio(bio); - - rw = bio_data_dir(bio); - sync = bio_sync(bio); - - /* - * low level driver can indicate that it wants pages above a - * certain limit bounced to low memory (ie for highmem, or even - * ISA dma in theory) - */ - blk_queue_bounce(q, &bio); - - spin_lock_prefetch(q->queue_lock); - - barrier = bio_barrier(bio); - if (unlikely(barrier) && (q->ordered == QUEUE_ORDERED_NONE)) { - err = -EOPNOTSUPP; - goto end_io; - } - - spin_lock_irq(q->queue_lock); - - if (unlikely(barrier) || elv_queue_empty(q)) - goto get_rq; - - el_ret = elv_merge(q, &req, bio); - switch (el_ret) { - case ELEVATOR_BACK_MERGE: - BUG_ON(!rq_mergeable(req)); - - if (!q->back_merge_fn(q, req, bio)) - break; - - req->biotail->bi_next = bio; - req->biotail = bio; - req->nr_sectors = req->hard_nr_sectors += nr_sectors; - req->ioprio = ioprio_best(req->ioprio, prio); - drive_stat_acct(req, nr_sectors, 0); - if (!attempt_back_merge(q, req)) - elv_merged_request(q, req); - goto out; - - case ELEVATOR_FRONT_MERGE: - BUG_ON(!rq_mergeable(req)); - - if (!q->front_merge_fn(q, req, bio)) - break; - - bio->bi_next = req->bio; - req->bio = bio; - - /* - * may not be valid. if the low level driver said - * it didn't need a bounce buffer then it better - * not touch req->buffer either... - */ - req->buffer = bio_data(bio); - req->current_nr_sectors = cur_nr_sectors; - req->hard_cur_sectors = cur_nr_sectors; - req->sector = req->hard_sector = sector; - req->nr_sectors = req->hard_nr_sectors += nr_sectors; - req->ioprio = ioprio_best(req->ioprio, prio); - drive_stat_acct(req, nr_sectors, 0); - if (!attempt_front_merge(q, req)) - elv_merged_request(q, req); - goto out; - - /* ELV_NO_MERGE: elevator says don't/can't merge. */ - default: - ; - } - -get_rq: - /* - * Grab a free request. This is might sleep but can not fail. - * Returns with the queue unlocked. - */ - req = get_request_wait(q, rw, bio); - - /* - * After dropping the lock and possibly sleeping here, our request - * may now be mergeable after it had proven unmergeable (above). - * We don't worry about that case for efficiency. It won't happen - * often, and the elevators are able to handle it. - */ - - req->flags |= REQ_CMD; - - /* - * inherit FAILFAST from bio (for read-ahead, and explicit FAILFAST) - */ - if (bio_rw_ahead(bio) || bio_failfast(bio)) - req->flags |= REQ_FAILFAST; - - /* - * REQ_BARRIER implies no merging, but lets make it explicit - */ - if (unlikely(barrier)) - req->flags |= (REQ_HARDBARRIER | REQ_NOMERGE); - - req->errors = 0; - req->hard_sector = req->sector = sector; - req->hard_nr_sectors = req->nr_sectors = nr_sectors; - req->current_nr_sectors = req->hard_cur_sectors = cur_nr_sectors; - req->nr_phys_segments = bio_phys_segments(q, bio); - req->nr_hw_segments = bio_hw_segments(q, bio); - req->buffer = bio_data(bio); /* see ->buffer comment above */ - req->waiting = NULL; - req->bio = req->biotail = bio; - req->ioprio = prio; - req->rq_disk = bio->bi_bdev->bd_disk; - req->start_time = jiffies; - - spin_lock_irq(q->queue_lock); - if (elv_queue_empty(q)) - blk_plug_device(q); - add_request(q, req); -out: - if (sync) - __generic_unplug_device(q); - - spin_unlock_irq(q->queue_lock); - return 0; - -end_io: - bio_endio(bio, nr_sectors << 9, err); - return 0; -} - -/* - * If bio->bi_dev is a partition, remap the location - */ -static inline void blk_partition_remap(struct bio *bio) -{ - struct block_device *bdev = bio->bi_bdev; - - if (bdev != bdev->bd_contains) { - struct hd_struct *p = bdev->bd_part; - const int rw = bio_data_dir(bio); - - p->sectors[rw] += bio_sectors(bio); - p->ios[rw]++; - - bio->bi_sector += p->start_sect; - bio->bi_bdev = bdev->bd_contains; - } -} - -static void handle_bad_sector(struct bio *bio) -{ - char b[BDEVNAME_SIZE]; - - printk(KERN_INFO "attempt to access beyond end of device\n"); - printk(KERN_INFO "%s: rw=%ld, want=%Lu, limit=%Lu\n", - bdevname(bio->bi_bdev, b), - bio->bi_rw, - (unsigned long long)bio->bi_sector + bio_sectors(bio), - (long long)(bio->bi_bdev->bd_inode->i_size >> 9)); - - set_bit(BIO_EOF, &bio->bi_flags); -} - -/** - * generic_make_request: hand a buffer to its device driver for I/O - * @bio: The bio describing the location in memory and on the device. - * - * generic_make_request() is used to make I/O requests of block - * devices. It is passed a &struct bio, which describes the I/O that needs - * to be done. - * - * generic_make_request() does not return any status. The - * success/failure status of the request, along with notification of - * completion, is delivered asynchronously through the bio->bi_end_io - * function described (one day) else where. - * - * The caller of generic_make_request must make sure that bi_io_vec - * are set to describe the memory buffer, and that bi_dev and bi_sector are - * set to describe the device address, and the - * bi_end_io and optionally bi_private are set to describe how - * completion notification should be signaled. - * - * generic_make_request and the drivers it calls may use bi_next if this - * bio happens to be merged with someone else, and may change bi_dev and - * bi_sector for remaps as it sees fit. So the values of these fields - * should NOT be depended on after the call to generic_make_request. - */ -void generic_make_request(struct bio *bio) -{ - request_queue_t *q; - sector_t maxsector; - int ret, nr_sectors = bio_sectors(bio); - - might_sleep(); - /* Test device or partition size, when known. */ - maxsector = bio->bi_bdev->bd_inode->i_size >> 9; - if (maxsector) { - sector_t sector = bio->bi_sector; - - if (maxsector < nr_sectors || maxsector - nr_sectors < sector) { - /* - * This may well happen - the kernel calls bread() - * without checking the size of the device, e.g., when - * mounting a device. - */ - handle_bad_sector(bio); - goto end_io; - } - } - - /* - * Resolve the mapping until finished. (drivers are - * still free to implement/resolve their own stacking - * by explicitly returning 0) - * - * NOTE: we don't repeat the blk_size check for each new device. - * Stacking drivers are expected to know what they are doing. - */ - do { - char b[BDEVNAME_SIZE]; - - q = bdev_get_queue(bio->bi_bdev); - if (!q) { - printk(KERN_ERR - "generic_make_request: Trying to access " - "nonexistent block-device %s (%Lu)\n", - bdevname(bio->bi_bdev, b), - (long long) bio->bi_sector); -end_io: - bio_endio(bio, bio->bi_size, -EIO); - break; - } - - if (unlikely(bio_sectors(bio) > q->max_hw_sectors)) { - printk("bio too big device %s (%u > %u)\n", - bdevname(bio->bi_bdev, b), - bio_sectors(bio), - q->max_hw_sectors); - goto end_io; - } - - if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) - goto end_io; - - /* - * If this device has partitions, remap block n - * of partition p to block n+start(p) of the disk. - */ - blk_partition_remap(bio); - - ret = q->make_request_fn(q, bio); - } while (ret); -} - -EXPORT_SYMBOL(generic_make_request); - -/** - * submit_bio: submit a bio to the block device layer for I/O - * @rw: whether to %READ or %WRITE, or maybe to %READA (read ahead) - * @bio: The &struct bio which describes the I/O - * - * submit_bio() is very similar in purpose to generic_make_request(), and - * uses that function to do most of the work. Both are fairly rough - * interfaces, @bio must be presetup and ready for I/O. - * - */ -void submit_bio(int rw, struct bio *bio) -{ - int count = bio_sectors(bio); - - BIO_BUG_ON(!bio->bi_size); - BIO_BUG_ON(!bio->bi_io_vec); - bio->bi_rw |= rw; - if (rw & WRITE) - mod_page_state(pgpgout, count); - else - mod_page_state(pgpgin, count); - - if (unlikely(block_dump)) { - char b[BDEVNAME_SIZE]; - printk(KERN_DEBUG "%s(%d): %s block %Lu on %s\n", - current->comm, current->pid, - (rw & WRITE) ? "WRITE" : "READ", - (unsigned long long)bio->bi_sector, - bdevname(bio->bi_bdev,b)); - } - - generic_make_request(bio); -} - -EXPORT_SYMBOL(submit_bio); - -static void blk_recalc_rq_segments(struct request *rq) -{ - struct bio *bio, *prevbio = NULL; - int nr_phys_segs, nr_hw_segs; - unsigned int phys_size, hw_size; - request_queue_t *q = rq->q; - - if (!rq->bio) - return; - - phys_size = hw_size = nr_phys_segs = nr_hw_segs = 0; - rq_for_each_bio(bio, rq) { - /* Force bio hw/phys segs to be recalculated. */ - bio->bi_flags &= ~(1 << BIO_SEG_VALID); - - nr_phys_segs += bio_phys_segments(q, bio); - nr_hw_segs += bio_hw_segments(q, bio); - if (prevbio) { - int pseg = phys_size + prevbio->bi_size + bio->bi_size; - int hseg = hw_size + prevbio->bi_size + bio->bi_size; - - if (blk_phys_contig_segment(q, prevbio, bio) && - pseg <= q->max_segment_size) { - nr_phys_segs--; - phys_size += prevbio->bi_size + bio->bi_size; - } else - phys_size = 0; - - if (blk_hw_contig_segment(q, prevbio, bio) && - hseg <= q->max_segment_size) { - nr_hw_segs--; - hw_size += prevbio->bi_size + bio->bi_size; - } else - hw_size = 0; - } - prevbio = bio; - } - - rq->nr_phys_segments = nr_phys_segs; - rq->nr_hw_segments = nr_hw_segs; -} - -static void blk_recalc_rq_sectors(struct request *rq, int nsect) -{ - if (blk_fs_request(rq)) { - rq->hard_sector += nsect; - rq->hard_nr_sectors -= nsect; - - /* - * Move the I/O submission pointers ahead if required. - */ - if ((rq->nr_sectors >= rq->hard_nr_sectors) && - (rq->sector <= rq->hard_sector)) { - rq->sector = rq->hard_sector; - rq->nr_sectors = rq->hard_nr_sectors; - rq->hard_cur_sectors = bio_cur_sectors(rq->bio); - rq->current_nr_sectors = rq->hard_cur_sectors; - rq->buffer = bio_data(rq->bio); - } - - /* - * if total number of sectors is less than the first segment - * size, something has gone terribly wrong - */ - if (rq->nr_sectors < rq->current_nr_sectors) { - printk("blk: request botched\n"); - rq->nr_sectors = rq->current_nr_sectors; - } - } -} - -static int __end_that_request_first(struct request *req, int uptodate, - int nr_bytes) -{ - int total_bytes, bio_nbytes, error, next_idx = 0; - struct bio *bio; - - /* - * extend uptodate bool to allow < 0 value to be direct io error - */ - error = 0; - if (end_io_error(uptodate)) - error = !uptodate ? -EIO : uptodate; - - /* - * for a REQ_BLOCK_PC request, we want to carry any eventual - * sense key with us all the way through - */ - if (!blk_pc_request(req)) - req->errors = 0; - - if (!uptodate) { - if (blk_fs_request(req) && !(req->flags & REQ_QUIET)) - printk("end_request: I/O error, dev %s, sector %llu\n", - req->rq_disk ? req->rq_disk->disk_name : "?", - (unsigned long long)req->sector); - } - - if (blk_fs_request(req) && req->rq_disk) { - const int rw = rq_data_dir(req); - - __disk_stat_add(req->rq_disk, sectors[rw], nr_bytes >> 9); - } - - total_bytes = bio_nbytes = 0; - while ((bio = req->bio) != NULL) { - int nbytes; - - if (nr_bytes >= bio->bi_size) { - req->bio = bio->bi_next; - nbytes = bio->bi_size; - bio_endio(bio, nbytes, error); - next_idx = 0; - bio_nbytes = 0; - } else { - int idx = bio->bi_idx + next_idx; - - if (unlikely(bio->bi_idx >= bio->bi_vcnt)) { - blk_dump_rq_flags(req, "__end_that"); - printk("%s: bio idx %d >= vcnt %d\n", - __FUNCTION__, - bio->bi_idx, bio->bi_vcnt); - break; - } - - nbytes = bio_iovec_idx(bio, idx)->bv_len; - BIO_BUG_ON(nbytes > bio->bi_size); - - /* - * not a complete bvec done - */ - if (unlikely(nbytes > nr_bytes)) { - bio_nbytes += nr_bytes; - total_bytes += nr_bytes; - break; - } - - /* - * advance to the next vector - */ - next_idx++; - bio_nbytes += nbytes; - } - - total_bytes += nbytes; - nr_bytes -= nbytes; - - if ((bio = req->bio)) { - /* - * end more in this run, or just return 'not-done' - */ - if (unlikely(nr_bytes <= 0)) - break; - } - } - - /* - * completely done - */ - if (!req->bio) - return 0; - - /* - * if the request wasn't completed, update state - */ - if (bio_nbytes) { - bio_endio(bio, bio_nbytes, error); - bio->bi_idx += next_idx; - bio_iovec(bio)->bv_offset += nr_bytes; - bio_iovec(bio)->bv_len -= nr_bytes; - } - - blk_recalc_rq_sectors(req, total_bytes >> 9); - blk_recalc_rq_segments(req); - return 1; -} - -/** - * end_that_request_first - end I/O on a request - * @req: the request being processed - * @uptodate: 1 for success, 0 for I/O error, < 0 for specific error - * @nr_sectors: number of sectors to end I/O on - * - * Description: - * Ends I/O on a number of sectors attached to @req, and sets it up - * for the next range of segments (if any) in the cluster. - * - * Return: - * 0 - we are done with this request, call end_that_request_last() - * 1 - still buffers pending for this request - **/ -int end_that_request_first(struct request *req, int uptodate, int nr_sectors) -{ - return __end_that_request_first(req, uptodate, nr_sectors << 9); -} - -EXPORT_SYMBOL(end_that_request_first); - -/** - * end_that_request_chunk - end I/O on a request - * @req: the request being processed - * @uptodate: 1 for success, 0 for I/O error, < 0 for specific error - * @nr_bytes: number of bytes to complete - * - * Description: - * Ends I/O on a number of bytes attached to @req, and sets it up - * for the next range of segments (if any). Like end_that_request_first(), - * but deals with bytes instead of sectors. - * - * Return: - * 0 - we are done with this request, call end_that_request_last() - * 1 - still buffers pending for this request - **/ -int end_that_request_chunk(struct request *req, int uptodate, int nr_bytes) -{ - return __end_that_request_first(req, uptodate, nr_bytes); -} - -EXPORT_SYMBOL(end_that_request_chunk); - -/* - * queue lock must be held - */ -void end_that_request_last(struct request *req) -{ - struct gendisk *disk = req->rq_disk; - - if (unlikely(laptop_mode) && blk_fs_request(req)) - laptop_io_completion(); - - if (disk && blk_fs_request(req)) { - unsigned long duration = jiffies - req->start_time; - const int rw = rq_data_dir(req); - - __disk_stat_inc(disk, ios[rw]); - __disk_stat_add(disk, ticks[rw], duration); - disk_round_stats(disk); - disk->in_flight--; - } - if (req->end_io) - req->end_io(req); - else - __blk_put_request(req->q, req); -} - -EXPORT_SYMBOL(end_that_request_last); - -void end_request(struct request *req, int uptodate) -{ - if (!end_that_request_first(req, uptodate, req->hard_cur_sectors)) { - add_disk_randomness(req->rq_disk); - blkdev_dequeue_request(req); - end_that_request_last(req); - } -} - -EXPORT_SYMBOL(end_request); - -void blk_rq_bio_prep(request_queue_t *q, struct request *rq, struct bio *bio) -{ - /* first three bits are identical in rq->flags and bio->bi_rw */ - rq->flags |= (bio->bi_rw & 7); - - rq->nr_phys_segments = bio_phys_segments(q, bio); - rq->nr_hw_segments = bio_hw_segments(q, bio); - rq->current_nr_sectors = bio_cur_sectors(bio); - rq->hard_cur_sectors = rq->current_nr_sectors; - rq->hard_nr_sectors = rq->nr_sectors = bio_sectors(bio); - rq->buffer = bio_data(bio); - - rq->bio = rq->biotail = bio; -} - -EXPORT_SYMBOL(blk_rq_bio_prep); - -int kblockd_schedule_work(struct work_struct *work) -{ - return queue_work(kblockd_workqueue, work); -} - -EXPORT_SYMBOL(kblockd_schedule_work); - -void kblockd_flush(void) -{ - flush_workqueue(kblockd_workqueue); -} -EXPORT_SYMBOL(kblockd_flush); - -int __init blk_dev_init(void) -{ - kblockd_workqueue = create_workqueue("kblockd"); - if (!kblockd_workqueue) - panic("Failed to create kblockd\n"); - - request_cachep = kmem_cache_create("blkdev_requests", - sizeof(struct request), 0, SLAB_PANIC, NULL, NULL); - - requestq_cachep = kmem_cache_create("blkdev_queue", - sizeof(request_queue_t), 0, SLAB_PANIC, NULL, NULL); - - iocontext_cachep = kmem_cache_create("blkdev_ioc", - sizeof(struct io_context), 0, SLAB_PANIC, NULL, NULL); - - blk_max_low_pfn = max_low_pfn; - blk_max_pfn = max_pfn; - - return 0; -} - -/* - * IO Context helper functions - */ -void put_io_context(struct io_context *ioc) -{ - if (ioc == NULL) - return; - - BUG_ON(atomic_read(&ioc->refcount) == 0); - - if (atomic_dec_and_test(&ioc->refcount)) { - if (ioc->aic && ioc->aic->dtor) - ioc->aic->dtor(ioc->aic); - if (ioc->cic && ioc->cic->dtor) - ioc->cic->dtor(ioc->cic); - - kmem_cache_free(iocontext_cachep, ioc); - } -} -EXPORT_SYMBOL(put_io_context); - -/* Called by the exitting task */ -void exit_io_context(void) -{ - unsigned long flags; - struct io_context *ioc; - - local_irq_save(flags); - task_lock(current); - ioc = current->io_context; - current->io_context = NULL; - ioc->task = NULL; - task_unlock(current); - local_irq_restore(flags); - - if (ioc->aic && ioc->aic->exit) - ioc->aic->exit(ioc->aic); - if (ioc->cic && ioc->cic->exit) - ioc->cic->exit(ioc->cic); - - put_io_context(ioc); -} - -/* - * If the current task has no IO context then create one and initialise it. - * Otherwise, return its existing IO context. - * - * This returned IO context doesn't have a specifically elevated refcount, - * but since the current task itself holds a reference, the context can be - * used in general code, so long as it stays within `current` context. - */ -struct io_context *current_io_context(gfp_t gfp_flags) -{ - struct task_struct *tsk = current; - struct io_context *ret; - - ret = tsk->io_context; - if (likely(ret)) - return ret; - - ret = kmem_cache_alloc(iocontext_cachep, gfp_flags); - if (ret) { - atomic_set(&ret->refcount, 1); - ret->task = current; - ret->set_ioprio = NULL; - ret->last_waited = jiffies; /* doesn't matter... */ - ret->nr_batch_requests = 0; /* because this is 0 */ - ret->aic = NULL; - ret->cic = NULL; - tsk->io_context = ret; - } - - return ret; -} -EXPORT_SYMBOL(current_io_context); - -/* - * If the current task has no IO context then create one and initialise it. - * If it does have a context, take a ref on it. - * - * This is always called in the context of the task which submitted the I/O. - */ -struct io_context *get_io_context(gfp_t gfp_flags) -{ - struct io_context *ret; - ret = current_io_context(gfp_flags); - if (likely(ret)) - atomic_inc(&ret->refcount); - return ret; -} -EXPORT_SYMBOL(get_io_context); - -void copy_io_context(struct io_context **pdst, struct io_context **psrc) -{ - struct io_context *src = *psrc; - struct io_context *dst = *pdst; - - if (src) { - BUG_ON(atomic_read(&src->refcount) == 0); - atomic_inc(&src->refcount); - put_io_context(dst); - *pdst = src; - } -} -EXPORT_SYMBOL(copy_io_context); - -void swap_io_context(struct io_context **ioc1, struct io_context **ioc2) -{ - struct io_context *temp; - temp = *ioc1; - *ioc1 = *ioc2; - *ioc2 = temp; -} -EXPORT_SYMBOL(swap_io_context); - -/* - * sysfs parts below - */ -struct queue_sysfs_entry { - struct attribute attr; - ssize_t (*show)(struct request_queue *, char *); - ssize_t (*store)(struct request_queue *, const char *, size_t); -}; - -static ssize_t -queue_var_show(unsigned int var, char *page) -{ - return sprintf(page, "%d\n", var); -} - -static ssize_t -queue_var_store(unsigned long *var, const char *page, size_t count) -{ - char *p = (char *) page; - - *var = simple_strtoul(p, &p, 10); - return count; -} - -static ssize_t queue_requests_show(struct request_queue *q, char *page) -{ - return queue_var_show(q->nr_requests, (page)); -} - -static ssize_t -queue_requests_store(struct request_queue *q, const char *page, size_t count) -{ - struct request_list *rl = &q->rq; - - int ret = queue_var_store(&q->nr_requests, page, count); - if (q->nr_requests < BLKDEV_MIN_RQ) - q->nr_requests = BLKDEV_MIN_RQ; - blk_queue_congestion_threshold(q); - - if (rl->count[READ] >= queue_congestion_on_threshold(q)) - set_queue_congested(q, READ); - else if (rl->count[READ] < queue_congestion_off_threshold(q)) - clear_queue_congested(q, READ); - - if (rl->count[WRITE] >= queue_congestion_on_threshold(q)) - set_queue_congested(q, WRITE); - else if (rl->count[WRITE] < queue_congestion_off_threshold(q)) - clear_queue_congested(q, WRITE); - - if (rl->count[READ] >= q->nr_requests) { - blk_set_queue_full(q, READ); - } else if (rl->count[READ]+1 <= q->nr_requests) { - blk_clear_queue_full(q, READ); - wake_up(&rl->wait[READ]); - } - - if (rl->count[WRITE] >= q->nr_requests) { - blk_set_queue_full(q, WRITE); - } else if (rl->count[WRITE]+1 <= q->nr_requests) { - blk_clear_queue_full(q, WRITE); - wake_up(&rl->wait[WRITE]); - } - return ret; -} - -static ssize_t queue_ra_show(struct request_queue *q, char *page) -{ - int ra_kb = q->backing_dev_info.ra_pages << (PAGE_CACHE_SHIFT - 10); - - return queue_var_show(ra_kb, (page)); -} - -static ssize_t -queue_ra_store(struct request_queue *q, const char *page, size_t count) -{ - unsigned long ra_kb; - ssize_t ret = queue_var_store(&ra_kb, page, count); - - spin_lock_irq(q->queue_lock); - if (ra_kb > (q->max_sectors >> 1)) - ra_kb = (q->max_sectors >> 1); - - q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10); - spin_unlock_irq(q->queue_lock); - - return ret; -} - -static ssize_t queue_max_sectors_show(struct request_queue *q, char *page) -{ - int max_sectors_kb = q->max_sectors >> 1; - - return queue_var_show(max_sectors_kb, (page)); -} - -static ssize_t -queue_max_sectors_store(struct request_queue *q, const char *page, size_t count) -{ - unsigned long max_sectors_kb, - max_hw_sectors_kb = q->max_hw_sectors >> 1, - page_kb = 1 << (PAGE_CACHE_SHIFT - 10); - ssize_t ret = queue_var_store(&max_sectors_kb, page, count); - int ra_kb; - - if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb) - return -EINVAL; - /* - * Take the queue lock to update the readahead and max_sectors - * values synchronously: - */ - spin_lock_irq(q->queue_lock); - /* - * Trim readahead window as well, if necessary: - */ - ra_kb = q->backing_dev_info.ra_pages << (PAGE_CACHE_SHIFT - 10); - if (ra_kb > max_sectors_kb) - q->backing_dev_info.ra_pages = - max_sectors_kb >> (PAGE_CACHE_SHIFT - 10); - - q->max_sectors = max_sectors_kb << 1; - spin_unlock_irq(q->queue_lock); - - return ret; -} - -static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page) -{ - int max_hw_sectors_kb = q->max_hw_sectors >> 1; - - return queue_var_show(max_hw_sectors_kb, (page)); -} - - -static struct queue_sysfs_entry queue_requests_entry = { - .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR }, - .show = queue_requests_show, - .store = queue_requests_store, -}; - -static struct queue_sysfs_entry queue_ra_entry = { - .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR }, - .show = queue_ra_show, - .store = queue_ra_store, -}; - -static struct queue_sysfs_entry queue_max_sectors_entry = { - .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR }, - .show = queue_max_sectors_show, - .store = queue_max_sectors_store, -}; - -static struct queue_sysfs_entry queue_max_hw_sectors_entry = { - .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO }, - .show = queue_max_hw_sectors_show, -}; - -static struct queue_sysfs_entry queue_iosched_entry = { - .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR }, - .show = elv_iosched_show, - .store = elv_iosched_store, -}; - -static struct attribute *default_attrs[] = { - &queue_requests_entry.attr, - &queue_ra_entry.attr, - &queue_max_hw_sectors_entry.attr, - &queue_max_sectors_entry.attr, - &queue_iosched_entry.attr, - NULL, -}; - -#define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr) - -static ssize_t -queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page) -{ - struct queue_sysfs_entry *entry = to_queue(attr); - struct request_queue *q; - - q = container_of(kobj, struct request_queue, kobj); - if (!entry->show) - return -EIO; - - return entry->show(q, page); -} - -static ssize_t -queue_attr_store(struct kobject *kobj, struct attribute *attr, - const char *page, size_t length) -{ - struct queue_sysfs_entry *entry = to_queue(attr); - struct request_queue *q; - - q = container_of(kobj, struct request_queue, kobj); - if (!entry->store) - return -EIO; - - return entry->store(q, page, length); -} - -static struct sysfs_ops queue_sysfs_ops = { - .show = queue_attr_show, - .store = queue_attr_store, -}; - -static struct kobj_type queue_ktype = { - .sysfs_ops = &queue_sysfs_ops, - .default_attrs = default_attrs, -}; - -int blk_register_queue(struct gendisk *disk) -{ - int ret; - - request_queue_t *q = disk->queue; - - if (!q || !q->request_fn) - return -ENXIO; - - q->kobj.parent = kobject_get(&disk->kobj); - if (!q->kobj.parent) - return -EBUSY; - - snprintf(q->kobj.name, KOBJ_NAME_LEN, "%s", "queue"); - q->kobj.ktype = &queue_ktype; - - ret = kobject_register(&q->kobj); - if (ret < 0) - return ret; - - ret = elv_register_queue(q); - if (ret) { - kobject_unregister(&q->kobj); - return ret; - } - - return 0; -} - -void blk_unregister_queue(struct gendisk *disk) -{ - request_queue_t *q = disk->queue; - - if (q && q->request_fn) { - elv_unregister_queue(q); - - kobject_unregister(&q->kobj); - kobject_put(&disk->kobj); - } -} diff --git a/drivers/block/noop-iosched.c b/drivers/block/noop-iosched.c deleted file mode 100644 index e54f006..0000000 --- a/drivers/block/noop-iosched.c +++ /dev/null @@ -1,46 +0,0 @@ -/* - * elevator noop - */ -#include <linux/blkdev.h> -#include <linux/elevator.h> -#include <linux/bio.h> -#include <linux/module.h> -#include <linux/init.h> - -static void elevator_noop_add_request(request_queue_t *q, struct request *rq) -{ - rq->flags |= REQ_NOMERGE; - elv_dispatch_add_tail(q, rq); -} - -static int elevator_noop_dispatch(request_queue_t *q, int force) -{ - return 0; -} - -static struct elevator_type elevator_noop = { - .ops = { - .elevator_dispatch_fn = elevator_noop_dispatch, - .elevator_add_req_fn = elevator_noop_add_request, - }, - .elevator_name = "noop", - .elevator_owner = THIS_MODULE, -}; - -static int __init noop_init(void) -{ - return elv_register(&elevator_noop); -} - -static void __exit noop_exit(void) -{ - elv_unregister(&elevator_noop); -} - -module_init(noop_init); -module_exit(noop_exit); - - -MODULE_AUTHOR("Jens Axboe"); -MODULE_LICENSE("GPL"); -MODULE_DESCRIPTION("No-op IO scheduler"); diff --git a/drivers/block/scsi_ioctl.c b/drivers/block/scsi_ioctl.c deleted file mode 100644 index 382dea7..0000000 --- a/drivers/block/scsi_ioctl.c +++ /dev/null @@ -1,589 +0,0 @@ -/* - * Copyright (C) 2001 Jens Axboe <axboe@suse.de> - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License version 2 as - * published by the Free Software Foundation. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public Licens - * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111- - * - */ -#include <linux/kernel.h> -#include <linux/errno.h> -#include <linux/string.h> -#include <linux/module.h> -#include <linux/blkdev.h> -#include <linux/completion.h> -#include <linux/cdrom.h> -#include <linux/slab.h> -#include <linux/times.h> -#include <asm/uaccess.h> - -#include <scsi/scsi.h> -#include <scsi/scsi_ioctl.h> -#include <scsi/scsi_cmnd.h> - -/* Command group 3 is reserved and should never be used. */ -const unsigned char scsi_command_size[8] = -{ - 6, 10, 10, 12, - 16, 12, 10, 10 -}; - -EXPORT_SYMBOL(scsi_command_size); - -#define BLK_DEFAULT_TIMEOUT (60 * HZ) - -#include <scsi/sg.h> - -static int sg_get_version(int __user *p) -{ - static int sg_version_num = 30527; - return put_user(sg_version_num, p); -} - -static int scsi_get_idlun(request_queue_t *q, int __user *p) -{ - return put_user(0, p); -} - -static int scsi_get_bus(request_queue_t *q, int __user *p) -{ - return put_user(0, p); -} - -static int sg_get_timeout(request_queue_t *q) -{ - return q->sg_timeout / (HZ / USER_HZ); -} - -static int sg_set_timeout(request_queue_t *q, int __user *p) -{ - int timeout, err = get_user(timeout, p); - - if (!err) - q->sg_timeout = timeout * (HZ / USER_HZ); - - return err; -} - -static int sg_get_reserved_size(request_queue_t *q, int __user *p) -{ - return put_user(q->sg_reserved_size, p); -} - -static int sg_set_reserved_size(request_queue_t *q, int __user *p) -{ - int size, err = get_user(size, p); - - if (err) - return err; - - if (size < 0) - return -EINVAL; - if (size > (q->max_sectors << 9)) - size = q->max_sectors << 9; - - q->sg_reserved_size = size; - return 0; -} - -/* - * will always return that we are ATAPI even for a real SCSI drive, I'm not - * so sure this is worth doing anything about (why would you care??) - */ -static int sg_emulated_host(request_queue_t *q, int __user *p) -{ - return put_user(1, p); -} - -#define CMD_READ_SAFE 0x01 -#define CMD_WRITE_SAFE 0x02 -#define CMD_WARNED 0x04 -#define safe_for_read(cmd) [cmd] = CMD_READ_SAFE -#define safe_for_write(cmd) [cmd] = CMD_WRITE_SAFE - -static int verify_command(struct file *file, unsigned char *cmd) -{ - static unsigned char cmd_type[256] = { - - /* Basic read-only commands */ - safe_for_read(TEST_UNIT_READY), - safe_for_read(REQUEST_SENSE), - safe_for_read(READ_6), - safe_for_read(READ_10), - safe_for_read(READ_12), - safe_for_read(READ_16), - safe_for_read(READ_BUFFER), - safe_for_read(READ_DEFECT_DATA), - safe_for_read(READ_LONG), - safe_for_read(INQUIRY), - safe_for_read(MODE_SENSE), - safe_for_read(MODE_SENSE_10), - safe_for_read(LOG_SENSE), - safe_for_read(START_STOP), - safe_for_read(GPCMD_VERIFY_10), - safe_for_read(VERIFY_16), - - /* Audio CD commands */ - safe_for_read(GPCMD_PLAY_CD), - safe_for_read(GPCMD_PLAY_AUDIO_10), - safe_for_read(GPCMD_PLAY_AUDIO_MSF), - safe_for_read(GPCMD_PLAY_AUDIO_TI), - safe_for_read(GPCMD_PAUSE_RESUME), - - /* CD/DVD data reading */ - safe_for_read(GPCMD_READ_BUFFER_CAPACITY), - safe_for_read(GPCMD_READ_CD), - safe_for_read(GPCMD_READ_CD_MSF), - safe_for_read(GPCMD_READ_DISC_INFO), - safe_for_read(GPCMD_READ_CDVD_CAPACITY), - safe_for_read(GPCMD_READ_DVD_STRUCTURE), - safe_for_read(GPCMD_READ_HEADER), - safe_for_read(GPCMD_READ_TRACK_RZONE_INFO), - safe_for_read(GPCMD_READ_SUBCHANNEL), - safe_for_read(GPCMD_READ_TOC_PMA_ATIP), - safe_for_read(GPCMD_REPORT_KEY), - safe_for_read(GPCMD_SCAN), - safe_for_read(GPCMD_GET_CONFIGURATION), - safe_for_read(GPCMD_READ_FORMAT_CAPACITIES), - safe_for_read(GPCMD_GET_EVENT_STATUS_NOTIFICATION), - safe_for_read(GPCMD_GET_PERFORMANCE), - safe_for_read(GPCMD_SEEK), - safe_for_read(GPCMD_STOP_PLAY_SCAN), - - /* Basic writing commands */ - safe_for_write(WRITE_6), - safe_for_write(WRITE_10), - safe_for_write(WRITE_VERIFY), - safe_for_write(WRITE_12), - safe_for_write(WRITE_VERIFY_12), - safe_for_write(WRITE_16), - safe_for_write(WRITE_LONG), - safe_for_write(WRITE_LONG_2), - safe_for_write(ERASE), - safe_for_write(GPCMD_MODE_SELECT_10), - safe_for_write(MODE_SELECT), - safe_for_write(LOG_SELECT), - safe_for_write(GPCMD_BLANK), - safe_for_write(GPCMD_CLOSE_TRACK), - safe_for_write(GPCMD_FLUSH_CACHE), - safe_for_write(GPCMD_FORMAT_UNIT), - safe_for_write(GPCMD_REPAIR_RZONE_TRACK), - safe_for_write(GPCMD_RESERVE_RZONE_TRACK), - safe_for_write(GPCMD_SEND_DVD_STRUCTURE), - safe_for_write(GPCMD_SEND_EVENT), - safe_for_write(GPCMD_SEND_KEY), - safe_for_write(GPCMD_SEND_OPC), - safe_for_write(GPCMD_SEND_CUE_SHEET), - safe_for_write(GPCMD_SET_SPEED), - safe_for_write(GPCMD_PREVENT_ALLOW_MEDIUM_REMOVAL), - safe_for_write(GPCMD_LOAD_UNLOAD), - safe_for_write(GPCMD_SET_STREAMING), - }; - unsigned char type = cmd_type[cmd[0]]; - - /* Anybody who can open the device can do a read-safe command */ - if (type & CMD_READ_SAFE) - return 0; - - /* Write-safe commands just require a writable open.. */ - if (type & CMD_WRITE_SAFE) { - if (file->f_mode & FMODE_WRITE) - return 0; - } - - /* And root can do any command.. */ - if (capable(CAP_SYS_RAWIO)) - return 0; - - if (!type) { - cmd_type[cmd[0]] = CMD_WARNED; - printk(KERN_WARNING "scsi: unknown opcode 0x%02x\n", cmd[0]); - } - - /* Otherwise fail it with an "Operation not permitted" */ - return -EPERM; -} - -static int sg_io(struct file *file, request_queue_t *q, - struct gendisk *bd_disk, struct sg_io_hdr *hdr) -{ - unsigned long start_time; - int writing = 0, ret = 0; - struct request *rq; - struct bio *bio; - char sense[SCSI_SENSE_BUFFERSIZE]; - unsigned char cmd[BLK_MAX_CDB]; - - if (hdr->interface_id != 'S') - return -EINVAL; - if (hdr->cmd_len > BLK_MAX_CDB) - return -EINVAL; - if (copy_from_user(cmd, hdr->cmdp, hdr->cmd_len)) - return -EFAULT; - if (verify_command(file, cmd)) - return -EPERM; - - if (hdr->dxfer_len > (q->max_sectors << 9)) - return -EIO; - - if (hdr->dxfer_len) - switch (hdr->dxfer_direction) { - default: - return -EINVAL; - case SG_DXFER_TO_FROM_DEV: - case SG_DXFER_TO_DEV: - writing = 1; - break; - case SG_DXFER_FROM_DEV: - break; - } - - rq = blk_get_request(q, writing ? WRITE : READ, GFP_KERNEL); - if (!rq) - return -ENOMEM; - - if (hdr->iovec_count) { - const int size = sizeof(struct sg_iovec) * hdr->iovec_count; - struct sg_iovec *iov; - - iov = kmalloc(size, GFP_KERNEL); - if (!iov) { - ret = -ENOMEM; - goto out; - } - - if (copy_from_user(iov, hdr->dxferp, size)) { - kfree(iov); - ret = -EFAULT; - goto out; - } - - ret = blk_rq_map_user_iov(q, rq, iov, hdr->iovec_count); - kfree(iov); - } else if (hdr->dxfer_len) - ret = blk_rq_map_user(q, rq, hdr->dxferp, hdr->dxfer_len); - - if (ret) - goto out; - - /* - * fill in request structure - */ - rq->cmd_len = hdr->cmd_len; - memcpy(rq->cmd, cmd, hdr->cmd_len); - if (sizeof(rq->cmd) != hdr->cmd_len) - memset(rq->cmd + hdr->cmd_len, 0, sizeof(rq->cmd) - hdr->cmd_len); - - memset(sense, 0, sizeof(sense)); - rq->sense = sense; - rq->sense_len = 0; - - rq->flags |= REQ_BLOCK_PC; - bio = rq->bio; - - /* - * bounce this after holding a reference to the original bio, it's - * needed for proper unmapping - */ - if (rq->bio) - blk_queue_bounce(q, &rq->bio); - - rq->timeout = (hdr->timeout * HZ) / 1000; - if (!rq->timeout) - rq->timeout = q->sg_timeout; - if (!rq->timeout) - rq->timeout = BLK_DEFAULT_TIMEOUT; - - start_time = jiffies; - - /* ignore return value. All information is passed back to caller - * (if he doesn't check that is his problem). - * N.B. a non-zero SCSI status is _not_ necessarily an error. - */ - blk_execute_rq(q, bd_disk, rq, 0); - - /* write to all output members */ - hdr->status = 0xff & rq->errors; - hdr->masked_status = status_byte(rq->errors); - hdr->msg_status = msg_byte(rq->errors); - hdr->host_status = host_byte(rq->errors); - hdr->driver_status = driver_byte(rq->errors); - hdr->info = 0; - if (hdr->masked_status || hdr->host_status || hdr->driver_status) - hdr->info |= SG_INFO_CHECK; - hdr->resid = rq->data_len; - hdr->duration = ((jiffies - start_time) * 1000) / HZ; - hdr->sb_len_wr = 0; - - if (rq->sense_len && hdr->sbp) { - int len = min((unsigned int) hdr->mx_sb_len, rq->sense_len); - - if (!copy_to_user(hdr->sbp, rq->sense, len)) - hdr->sb_len_wr = len; - } - - if (blk_rq_unmap_user(bio, hdr->dxfer_len)) - ret = -EFAULT; - - /* may not have succeeded, but output values written to control - * structure (struct sg_io_hdr). */ -out: - blk_put_request(rq); - return ret; -} - -#define OMAX_SB_LEN 16 /* For backward compatibility */ - -static int sg_scsi_ioctl(struct file *file, request_queue_t *q, - struct gendisk *bd_disk, Scsi_Ioctl_Command __user *sic) -{ - struct request *rq; - int err; - unsigned int in_len, out_len, bytes, opcode, cmdlen; - char *buffer = NULL, sense[SCSI_SENSE_BUFFERSIZE]; - - /* - * get in an out lengths, verify they don't exceed a page worth of data - */ - if (get_user(in_len, &sic->inlen)) - return -EFAULT; - if (get_user(out_len, &sic->outlen)) - return -EFAULT; - if (in_len > PAGE_SIZE || out_len > PAGE_SIZE) - return -EINVAL; - if (get_user(opcode, sic->data)) - return -EFAULT; - - bytes = max(in_len, out_len); - if (bytes) { - buffer = kmalloc(bytes, q->bounce_gfp | GFP_USER| __GFP_NOWARN); - if (!buffer) - return -ENOMEM; - - memset(buffer, 0, bytes); - } - - rq = blk_get_request(q, in_len ? WRITE : READ, __GFP_WAIT); - - cmdlen = COMMAND_SIZE(opcode); - - /* - * get command and data to send to device, if any - */ - err = -EFAULT; - rq->cmd_len = cmdlen; - if (copy_from_user(rq->cmd, sic->data, cmdlen)) - goto error; - - if (copy_from_user(buffer, sic->data + cmdlen, in_len)) - goto error; - - err = verify_command(file, rq->cmd); - if (err) - goto error; - - switch (opcode) { - case SEND_DIAGNOSTIC: - case FORMAT_UNIT: - rq->timeout = FORMAT_UNIT_TIMEOUT; - break; - case START_STOP: - rq->timeout = START_STOP_TIMEOUT; - break; - case MOVE_MEDIUM: - rq->timeout = MOVE_MEDIUM_TIMEOUT; - break; - case READ_ELEMENT_STATUS: - rq->timeout = READ_ELEMENT_STATUS_TIMEOUT; - break; - case READ_DEFECT_DATA: - rq->timeout = READ_DEFECT_DATA_TIMEOUT; - break; - default: - rq->timeout = BLK_DEFAULT_TIMEOUT; - break; - } - - memset(sense, 0, sizeof(sense)); - rq->sense = sense; - rq->sense_len = 0; - - rq->data = buffer; - rq->data_len = bytes; - rq->flags |= REQ_BLOCK_PC; - - blk_execute_rq(q, bd_disk, rq, 0); - err = rq->errors & 0xff; /* only 8 bit SCSI status */ - if (err) { - if (rq->sense_len && rq->sense) { - bytes = (OMAX_SB_LEN > rq->sense_len) ? - rq->sense_len : OMAX_SB_LEN; - if (copy_to_user(sic->data, rq->sense, bytes)) - err = -EFAULT; - } - } else { - if (copy_to_user(sic->data, buffer, out_len)) - err = -EFAULT; - } - -error: - kfree(buffer); - blk_put_request(rq); - return err; -} - -int scsi_cmd_ioctl(struct file *file, struct gendisk *bd_disk, unsigned int cmd, void __user *arg) -{ - request_queue_t *q; - struct request *rq; - int close = 0, err; - - q = bd_disk->queue; - if (!q) - return -ENXIO; - - if (blk_get_queue(q)) - return -ENXIO; - - switch (cmd) { - /* - * new sgv3 interface - */ - case SG_GET_VERSION_NUM: - err = sg_get_version(arg); - break; - case SCSI_IOCTL_GET_IDLUN: - err = scsi_get_idlun(q, arg); - break; - case SCSI_IOCTL_GET_BUS_NUMBER: - err = scsi_get_bus(q, arg); - break; - case SG_SET_TIMEOUT: - err = sg_set_timeout(q, arg); - break; - case SG_GET_TIMEOUT: - err = sg_get_timeout(q); - break; - case SG_GET_RESERVED_SIZE: - err = sg_get_reserved_size(q, arg); - break; - case SG_SET_RESERVED_SIZE: - err = sg_set_reserved_size(q, arg); - break; - case SG_EMULATED_HOST: - err = sg_emulated_host(q, arg); - break; - case SG_IO: { - struct sg_io_hdr hdr; - - err = -EFAULT; - if (copy_from_user(&hdr, arg, sizeof(hdr))) - break; - err = sg_io(file, q, bd_disk, &hdr); - if (err == -EFAULT) - break; - - if (copy_to_user(arg, &hdr, sizeof(hdr))) - err = -EFAULT; - break; - } - case CDROM_SEND_PACKET: { - struct cdrom_generic_command cgc; - struct sg_io_hdr hdr; - - err = -EFAULT; - if (copy_from_user(&cgc, arg, sizeof(cgc))) - break; - cgc.timeout = clock_t_to_jiffies(cgc.timeout); - memset(&hdr, 0, sizeof(hdr)); - hdr.interface_id = 'S'; - hdr.cmd_len = sizeof(cgc.cmd); - hdr.dxfer_len = cgc.buflen; - err = 0; - switch (cgc.data_direction) { - case CGC_DATA_UNKNOWN: - hdr.dxfer_direction = SG_DXFER_UNKNOWN; - break; - case CGC_DATA_WRITE: - hdr.dxfer_direction = SG_DXFER_TO_DEV; - break; - case CGC_DATA_READ: - hdr.dxfer_direction = SG_DXFER_FROM_DEV; - break; - case CGC_DATA_NONE: - hdr.dxfer_direction = SG_DXFER_NONE; - break; - default: - err = -EINVAL; - } - if (err) - break; - - hdr.dxferp = cgc.buffer; - hdr.sbp = cgc.sense; - if (hdr.sbp) - hdr.mx_sb_len = sizeof(struct request_sense); - hdr.timeout = cgc.timeout; - hdr.cmdp = ((struct cdrom_generic_command __user*) arg)->cmd; - hdr.cmd_len = sizeof(cgc.cmd); - - err = sg_io(file, q, bd_disk, &hdr); - if (err == -EFAULT) - break; - - if (hdr.status) - err = -EIO; - - cgc.stat = err; - cgc.buflen = hdr.resid; - if (copy_to_user(arg, &cgc, sizeof(cgc))) - err = -EFAULT; - - break; - } - - /* - * old junk scsi send command ioctl - */ - case SCSI_IOCTL_SEND_COMMAND: - printk(KERN_WARNING "program %s is using a deprecated SCSI ioctl, please convert it to SG_IO\n", current->comm); - err = -EINVAL; - if (!arg) - break; - - err = sg_scsi_ioctl(file, q, bd_disk, arg); - break; - case CDROMCLOSETRAY: - close = 1; - case CDROMEJECT: - rq = blk_get_request(q, WRITE, __GFP_WAIT); - rq->flags |= REQ_BLOCK_PC; - rq->data = NULL; - rq->data_len = 0; - rq->timeout = BLK_DEFAULT_TIMEOUT; - memset(rq->cmd, 0, sizeof(rq->cmd)); - rq->cmd[0] = GPCMD_START_STOP_UNIT; - rq->cmd[4] = 0x02 + (close != 0); - rq->cmd_len = 6; - err = blk_execute_rq(q, bd_disk, rq, 0); - blk_put_request(rq); - break; - default: - err = -ENOTTY; - } - - blk_put_queue(q); - return err; -} - -EXPORT_SYMBOL(scsi_cmd_ioctl); |
