diff options
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-core.c | 20 | ||||
| -rw-r--r-- | block/blk-merge.c | 9 | ||||
| -rw-r--r-- | block/genhd.c | 218 | ||||
| -rw-r--r-- | block/ioctl.c | 26 |
4 files changed, 226 insertions, 47 deletions
diff --git a/block/blk-core.c b/block/blk-core.c index a0dc2e7..d6128d9a 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -60,7 +60,9 @@ static void drive_stat_acct(struct request *rq, int new_io) if (!blk_fs_request(rq) || !rq->rq_disk) return; - part = disk_map_sector(rq->rq_disk, rq->sector); + rcu_read_lock(); + + part = disk_map_sector_rcu(rq->rq_disk, rq->sector); if (!new_io) __all_stat_inc(rq->rq_disk, part, merges[rw], rq->sector); else { @@ -71,6 +73,8 @@ static void drive_stat_acct(struct request *rq, int new_io) part->in_flight++; } } + + rcu_read_unlock(); } void blk_queue_congestion_threshold(struct request_queue *q) @@ -1557,12 +1561,14 @@ static int __end_that_request_first(struct request *req, int error, } if (blk_fs_request(req) && req->rq_disk) { - struct hd_struct *part = - disk_map_sector(req->rq_disk, req->sector); const int rw = rq_data_dir(req); + struct hd_struct *part; + rcu_read_lock(); + part = disk_map_sector_rcu(req->rq_disk, req->sector); all_stat_add(req->rq_disk, part, sectors[rw], nr_bytes >> 9, req->sector); + rcu_read_unlock(); } total_bytes = bio_nbytes = 0; @@ -1746,7 +1752,11 @@ static void end_that_request_last(struct request *req, int error) if (disk && blk_fs_request(req) && req != &req->q->bar_rq) { unsigned long duration = jiffies - req->start_time; const int rw = rq_data_dir(req); - struct hd_struct *part = disk_map_sector(disk, req->sector); + struct hd_struct *part; + + rcu_read_lock(); + + part = disk_map_sector_rcu(disk, req->sector); __all_stat_inc(disk, part, ios[rw], req->sector); __all_stat_add(disk, part, ticks[rw], duration, req->sector); @@ -1756,6 +1766,8 @@ static void end_that_request_last(struct request *req, int error) part_round_stats(part); part->in_flight--; } + + rcu_read_unlock(); } if (req->end_io) diff --git a/block/blk-merge.c b/block/blk-merge.c index 9b17da6..eb2a3ca 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -387,14 +387,19 @@ static int attempt_merge(struct request_queue *q, struct request *req, elv_merge_requests(q, req, next); if (req->rq_disk) { - struct hd_struct *part = - disk_map_sector(req->rq_disk, req->sector); + struct hd_struct *part; + + rcu_read_lock(); + + part = disk_map_sector_rcu(req->rq_disk, req->sector); disk_round_stats(req->rq_disk); req->rq_disk->in_flight--; if (part) { part_round_stats(part); part->in_flight--; } + + rcu_read_unlock(); } req->ioprio = ioprio_best(req->ioprio, next->ioprio); diff --git a/block/genhd.c b/block/genhd.c index fa32d09..b431d65 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -26,6 +26,158 @@ struct kobject *block_depr; static struct device_type disk_type; +/** + * disk_get_part - get partition + * @disk: disk to look partition from + * @partno: partition number + * + * Look for partition @partno from @disk. If found, increment + * reference count and return it. + * + * CONTEXT: + * Don't care. + * + * RETURNS: + * Pointer to the found partition on success, NULL if not found. + */ +struct hd_struct *disk_get_part(struct gendisk *disk, int partno) +{ + struct hd_struct *part; + + if (unlikely(partno < 1 || partno > disk_max_parts(disk))) + return NULL; + rcu_read_lock(); + part = rcu_dereference(disk->__part[partno - 1]); + if (part) + get_device(&part->dev); + rcu_read_unlock(); + + return part; +} +EXPORT_SYMBOL_GPL(disk_get_part); + +/** + * disk_part_iter_init - initialize partition iterator + * @piter: iterator to initialize + * @disk: disk to iterate over + * @flags: DISK_PITER_* flags + * + * Initialize @piter so that it iterates over partitions of @disk. + * + * CONTEXT: + * Don't care. + */ +void disk_part_iter_init(struct disk_part_iter *piter, struct gendisk *disk, + unsigned int flags) +{ + piter->disk = disk; + piter->part = NULL; + + if (flags & DISK_PITER_REVERSE) + piter->idx = disk_max_parts(piter->disk) - 1; + else + piter->idx = 0; + + piter->flags = flags; +} +EXPORT_SYMBOL_GPL(disk_part_iter_init); + +/** + * disk_part_iter_next - proceed iterator to the next partition and return it + * @piter: iterator of interest + * + * Proceed @piter to the next partition and return it. + * + * CONTEXT: + * Don't care. + */ +struct hd_struct *disk_part_iter_next(struct disk_part_iter *piter) +{ + int inc, end; + + /* put the last partition */ + disk_put_part(piter->part); + piter->part = NULL; + + rcu_read_lock(); + + /* determine iteration parameters */ + if (piter->flags & DISK_PITER_REVERSE) { + inc = -1; + end = -1; + } else { + inc = 1; + end = disk_max_parts(piter->disk); + } + + /* iterate to the next partition */ + for (; piter->idx != end; piter->idx += inc) { + struct hd_struct *part; + + part = rcu_dereference(piter->disk->__part[piter->idx]); + if (!part) + continue; + if (!(piter->flags & DISK_PITER_INCL_EMPTY) && !part->nr_sects) + continue; + + get_device(&part->dev); + piter->part = part; + piter->idx += inc; + break; + } + + rcu_read_unlock(); + + return piter->part; +} +EXPORT_SYMBOL_GPL(disk_part_iter_next); + +/** + * disk_part_iter_exit - finish up partition iteration + * @piter: iter of interest + * + * Called when iteration is over. Cleans up @piter. + * + * CONTEXT: + * Don't care. + */ +void disk_part_iter_exit(struct disk_part_iter *piter) +{ + disk_put_part(piter->part); + piter->part = NULL; +} +EXPORT_SYMBOL_GPL(disk_part_iter_exit); + +/** + * disk_map_sector_rcu - map sector to partition + * @disk: gendisk of interest + * @sector: sector to map + * + * Find out which partition @sector maps to on @disk. This is + * primarily used for stats accounting. + * + * CONTEXT: + * RCU read locked. The returned partition pointer is valid only + * while preemption is disabled. + * + * RETURNS: + * Found partition on success, NULL if there's no matching partition. + */ +struct hd_struct *disk_map_sector_rcu(struct gendisk *disk, sector_t sector) +{ + int i; + + for (i = 0; i < disk_max_parts(disk); i++) { + struct hd_struct *part = rcu_dereference(disk->__part[i]); + + if (part && part->start_sect <= sector && + sector < part->start_sect + part->nr_sects) + return part; + } + return NULL; +} +EXPORT_SYMBOL_GPL(disk_map_sector_rcu); + /* * Can be deleted altogether. Later. * @@ -245,10 +397,12 @@ extern struct block_device *bdget_disk(struct gendisk *disk, int partno) if (partno == 0) devt = disk_devt(disk); else { - struct hd_struct *part = disk->part[partno - 1]; + struct hd_struct *part; + part = disk_get_part(disk, partno); if (part && part->nr_sects) devt = part_devt(part); + disk_put_part(part); } if (likely(devt != MKDEV(0, 0))) @@ -270,8 +424,9 @@ void __init printk_all_partitions(void) class_dev_iter_init(&iter, &block_class, NULL, &disk_type); while ((dev = class_dev_iter_next(&iter))) { struct gendisk *disk = dev_to_disk(dev); + struct disk_part_iter piter; + struct hd_struct *part; char buf[BDEVNAME_SIZE]; - int n; /* * Don't show empty devices or things that have been @@ -298,16 +453,13 @@ void __init printk_all_partitions(void) printk(" (driver?)\n"); /* now show the partitions */ - for (n = 0; n < disk_max_parts(disk); ++n) { - struct hd_struct *part = disk->part[n]; - - if (!part || !part->nr_sects) - continue; + disk_part_iter_init(&piter, disk, 0); + while ((part = disk_part_iter_next(&piter))) printk(" %02x%02x %10llu %s\n", MAJOR(part_devt(part)), MINOR(part_devt(part)), (unsigned long long)part->nr_sects >> 1, disk_name(disk, part->partno, buf)); - } + disk_part_iter_exit(&piter); } class_dev_iter_exit(&iter); } @@ -371,7 +523,8 @@ static void *show_partition_start(struct seq_file *seqf, loff_t *pos) static int show_partition(struct seq_file *seqf, void *v) { struct gendisk *sgp = v; - int n; + struct disk_part_iter piter; + struct hd_struct *part; char buf[BDEVNAME_SIZE]; /* Don't show non-partitionable removeable devices or empty devices */ @@ -386,17 +539,14 @@ static int show_partition(struct seq_file *seqf, void *v) MAJOR(disk_devt(sgp)), MINOR(disk_devt(sgp)), (unsigned long long)get_capacity(sgp) >> 1, disk_name(sgp, 0, buf)); - for (n = 0; n < disk_max_parts(sgp); n++) { - struct hd_struct *part = sgp->part[n]; - if (!part) - continue; - if (part->nr_sects == 0) - continue; + + disk_part_iter_init(&piter, sgp, 0); + while ((part = disk_part_iter_next(&piter))) seq_printf(seqf, "%4d %4d %10llu %s\n", MAJOR(part_devt(part)), MINOR(part_devt(part)), (unsigned long long)part->nr_sects >> 1, disk_name(sgp, part->partno, buf)); - } + disk_part_iter_exit(&piter); return 0; } @@ -571,7 +721,7 @@ static void disk_release(struct device *dev) struct gendisk *disk = dev_to_disk(dev); kfree(disk->random); - kfree(disk->part); + kfree(disk->__part); free_disk_stats(disk); kfree(disk); } @@ -596,8 +746,9 @@ static struct device_type disk_type = { static int diskstats_show(struct seq_file *seqf, void *v) { struct gendisk *gp = v; + struct disk_part_iter piter; + struct hd_struct *hd; char buf[BDEVNAME_SIZE]; - int n; /* if (&gp->dev.kobj.entry == block_class.devices.next) @@ -624,12 +775,8 @@ static int diskstats_show(struct seq_file *seqf, void *v) jiffies_to_msecs(disk_stat_read(gp, time_in_queue))); /* now show all non-0 size partitions of it */ - for (n = 0; n < disk_max_parts(gp); n++) { - struct hd_struct *hd = gp->part[n]; - - if (!hd || !hd->nr_sects) - continue; - + disk_part_iter_init(&piter, gp, 0); + while ((hd = disk_part_iter_next(&piter))) { preempt_disable(); part_round_stats(hd); preempt_enable(); @@ -650,6 +797,7 @@ static int diskstats_show(struct seq_file *seqf, void *v) jiffies_to_msecs(part_stat_read(hd, time_in_queue)) ); } + disk_part_iter_exit(&piter); return 0; } @@ -703,12 +851,16 @@ dev_t blk_lookup_devt(const char *name, int partno) if (partno == 0) devt = disk_devt(disk); else { - struct hd_struct *part = disk->part[partno - 1]; + struct hd_struct *part; - if (!part || !part->nr_sects) + part = disk_get_part(disk, partno); + if (!part || !part->nr_sects) { + disk_put_part(part); continue; + } devt = part_devt(part); + disk_put_part(part); } break; } @@ -735,9 +887,9 @@ struct gendisk *alloc_disk_node(int minors, int node_id) } if (minors > 1) { int size = (minors - 1) * sizeof(struct hd_struct *); - disk->part = kmalloc_node(size, + disk->__part = kmalloc_node(size, GFP_KERNEL | __GFP_ZERO, node_id); - if (!disk->part) { + if (!disk->__part) { free_disk_stats(disk); kfree(disk); return NULL; @@ -798,10 +950,14 @@ EXPORT_SYMBOL(set_device_ro); void set_disk_ro(struct gendisk *disk, int flag) { - int i; + struct disk_part_iter piter; + struct hd_struct *part; + disk->policy = flag; - for (i = 0; i < disk_max_parts(disk); i++) - if (disk->part[i]) disk->part[i]->policy = flag; + disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY); + while ((part = disk_part_iter_next(&piter))) + part->policy = flag; + disk_part_iter_exit(&piter); } EXPORT_SYMBOL(set_disk_ro); diff --git a/block/ioctl.c b/block/ioctl.c index 403f7d7e..a5f672a 100644 --- a/block/ioctl.c +++ b/block/ioctl.c @@ -12,11 +12,12 @@ static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user { struct block_device *bdevp; struct gendisk *disk; + struct hd_struct *part; struct blkpg_ioctl_arg a; struct blkpg_partition p; + struct disk_part_iter piter; long long start, length; int partno; - int i; int err; if (!capable(CAP_SYS_ADMIN)) @@ -47,28 +48,33 @@ static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user mutex_lock(&bdev->bd_mutex); /* overlap? */ - for (i = 0; i < disk_max_parts(disk); i++) { - struct hd_struct *s = disk->part[i]; - - if (!s) - continue; - if (!(start+length <= s->start_sect || - start >= s->start_sect + s->nr_sects)) { + disk_part_iter_init(&piter, disk, + DISK_PITER_INCL_EMPTY); + while ((part = disk_part_iter_next(&piter))) { + if (!(start + length <= part->start_sect || + start >= part->start_sect + part->nr_sects)) { + disk_part_iter_exit(&piter); mutex_unlock(&bdev->bd_mutex); return -EBUSY; } } + disk_part_iter_exit(&piter); + /* all seems OK */ err = add_partition(disk, partno, start, length, ADDPART_FLAG_NONE); mutex_unlock(&bdev->bd_mutex); return err; case BLKPG_DEL_PARTITION: - if (!disk->part[partno - 1]) + part = disk_get_part(disk, partno); + if (!part) return -ENXIO; - bdevp = bdget_disk(disk, partno); + + bdevp = bdget(part_devt(part)); + disk_put_part(part); if (!bdevp) return -ENOMEM; + mutex_lock(&bdevp->bd_mutex); if (bdevp->bd_openers) { mutex_unlock(&bdevp->bd_mutex); |
