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authorLinus Torvalds <torvalds@g5.osdl.org>2006-03-23 16:24:24 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-23 16:24:24 -0800
commitcec6062037783a762aa5606b06b8bc5c14d9657f (patch)
treec862659eb55e44314f6d524f5479204994b91901 /include/linux
parent88f07ffb63add018bfafd480ec6a294088277f06 (diff)
parent2056a782f8e7e65fd4bfd027506b4ce1c5e9ccd4 (diff)
downloadop-kernel-dev-cec6062037783a762aa5606b06b8bc5c14d9657f.zip
op-kernel-dev-cec6062037783a762aa5606b06b8bc5c14d9657f.tar.gz
Merge branch 'blktrace' of git://brick.kernel.dk/data/git/linux-2.6-block
* 'blktrace' of git://brick.kernel.dk/data/git/linux-2.6-block: [PATCH] Block queue IO tracing support (blktrace) as of 2006-03-23 [PATCH] relay: consolidate sendfile() and read() code [PATCH] relay: add sendfile() support [PATCH] relay: migrate from relayfs to a generic relay API
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/blkdev.h3
-rw-r--r--include/linux/blktrace_api.h277
-rw-r--r--include/linux/compat_ioctl.h4
-rw-r--r--include/linux/fs.h4
-rw-r--r--include/linux/relay.h281
-rw-r--r--include/linux/sched.h1
6 files changed, 570 insertions, 0 deletions
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 56bb6a4..c179966 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -22,6 +22,7 @@ typedef struct request_queue request_queue_t;
struct elevator_queue;
typedef struct elevator_queue elevator_t;
struct request_pm_state;
+struct blk_trace;
#define BLKDEV_MIN_RQ 4
#define BLKDEV_MAX_RQ 128 /* Default maximum */
@@ -416,6 +417,8 @@ struct request_queue
unsigned int sg_reserved_size;
int node;
+ struct blk_trace *blk_trace;
+
/*
* reserved for flush operations
*/
diff --git a/include/linux/blktrace_api.h b/include/linux/blktrace_api.h
new file mode 100644
index 0000000..b34d3e7
--- /dev/null
+++ b/include/linux/blktrace_api.h
@@ -0,0 +1,277 @@
+#ifndef BLKTRACE_H
+#define BLKTRACE_H
+
+#include <linux/config.h>
+#include <linux/blkdev.h>
+#include <linux/relay.h>
+
+/*
+ * Trace categories
+ */
+enum blktrace_cat {
+ BLK_TC_READ = 1 << 0, /* reads */
+ BLK_TC_WRITE = 1 << 1, /* writes */
+ BLK_TC_BARRIER = 1 << 2, /* barrier */
+ BLK_TC_SYNC = 1 << 3, /* barrier */
+ BLK_TC_QUEUE = 1 << 4, /* queueing/merging */
+ BLK_TC_REQUEUE = 1 << 5, /* requeueing */
+ BLK_TC_ISSUE = 1 << 6, /* issue */
+ BLK_TC_COMPLETE = 1 << 7, /* completions */
+ BLK_TC_FS = 1 << 8, /* fs requests */
+ BLK_TC_PC = 1 << 9, /* pc requests */
+ BLK_TC_NOTIFY = 1 << 10, /* special message */
+
+ BLK_TC_END = 1 << 15, /* only 16-bits, reminder */
+};
+
+#define BLK_TC_SHIFT (16)
+#define BLK_TC_ACT(act) ((act) << BLK_TC_SHIFT)
+
+/*
+ * Basic trace actions
+ */
+enum blktrace_act {
+ __BLK_TA_QUEUE = 1, /* queued */
+ __BLK_TA_BACKMERGE, /* back merged to existing rq */
+ __BLK_TA_FRONTMERGE, /* front merge to existing rq */
+ __BLK_TA_GETRQ, /* allocated new request */
+ __BLK_TA_SLEEPRQ, /* sleeping on rq allocation */
+ __BLK_TA_REQUEUE, /* request requeued */
+ __BLK_TA_ISSUE, /* sent to driver */
+ __BLK_TA_COMPLETE, /* completed by driver */
+ __BLK_TA_PLUG, /* queue was plugged */
+ __BLK_TA_UNPLUG_IO, /* queue was unplugged by io */
+ __BLK_TA_UNPLUG_TIMER, /* queue was unplugged by timer */
+ __BLK_TA_INSERT, /* insert request */
+ __BLK_TA_SPLIT, /* bio was split */
+ __BLK_TA_BOUNCE, /* bio was bounced */
+ __BLK_TA_REMAP, /* bio was remapped */
+};
+
+/*
+ * Trace actions in full. Additionally, read or write is masked
+ */
+#define BLK_TA_QUEUE (__BLK_TA_QUEUE | BLK_TC_ACT(BLK_TC_QUEUE))
+#define BLK_TA_BACKMERGE (__BLK_TA_BACKMERGE | BLK_TC_ACT(BLK_TC_QUEUE))
+#define BLK_TA_FRONTMERGE (__BLK_TA_FRONTMERGE | BLK_TC_ACT(BLK_TC_QUEUE))
+#define BLK_TA_GETRQ (__BLK_TA_GETRQ | BLK_TC_ACT(BLK_TC_QUEUE))
+#define BLK_TA_SLEEPRQ (__BLK_TA_SLEEPRQ | BLK_TC_ACT(BLK_TC_QUEUE))
+#define BLK_TA_REQUEUE (__BLK_TA_REQUEUE | BLK_TC_ACT(BLK_TC_REQUEUE))
+#define BLK_TA_ISSUE (__BLK_TA_ISSUE | BLK_TC_ACT(BLK_TC_ISSUE))
+#define BLK_TA_COMPLETE (__BLK_TA_COMPLETE| BLK_TC_ACT(BLK_TC_COMPLETE))
+#define BLK_TA_PLUG (__BLK_TA_PLUG | BLK_TC_ACT(BLK_TC_QUEUE))
+#define BLK_TA_UNPLUG_IO (__BLK_TA_UNPLUG_IO | BLK_TC_ACT(BLK_TC_QUEUE))
+#define BLK_TA_UNPLUG_TIMER (__BLK_TA_UNPLUG_TIMER | BLK_TC_ACT(BLK_TC_QUEUE))
+#define BLK_TA_INSERT (__BLK_TA_INSERT | BLK_TC_ACT(BLK_TC_QUEUE))
+#define BLK_TA_SPLIT (__BLK_TA_SPLIT)
+#define BLK_TA_BOUNCE (__BLK_TA_BOUNCE)
+#define BLK_TA_REMAP (__BLK_TA_REMAP | BLK_TC_ACT(BLK_TC_QUEUE))
+
+#define BLK_IO_TRACE_MAGIC 0x65617400
+#define BLK_IO_TRACE_VERSION 0x07
+
+/*
+ * The trace itself
+ */
+struct blk_io_trace {
+ u32 magic; /* MAGIC << 8 | version */
+ u32 sequence; /* event number */
+ u64 time; /* in microseconds */
+ u64 sector; /* disk offset */
+ u32 bytes; /* transfer length */
+ u32 action; /* what happened */
+ u32 pid; /* who did it */
+ u32 device; /* device number */
+ u32 cpu; /* on what cpu did it happen */
+ u16 error; /* completion error */
+ u16 pdu_len; /* length of data after this trace */
+};
+
+/*
+ * The remap event
+ */
+struct blk_io_trace_remap {
+ u32 device;
+ u32 __pad;
+ u64 sector;
+};
+
+enum {
+ Blktrace_setup = 1,
+ Blktrace_running,
+ Blktrace_stopped,
+};
+
+struct blk_trace {
+ int trace_state;
+ struct rchan *rchan;
+ unsigned long *sequence;
+ u16 act_mask;
+ u64 start_lba;
+ u64 end_lba;
+ u32 pid;
+ u32 dev;
+ struct dentry *dir;
+ struct dentry *dropped_file;
+ atomic_t dropped;
+};
+
+/*
+ * User setup structure passed with BLKTRACESTART
+ */
+struct blk_user_trace_setup {
+ char name[BDEVNAME_SIZE]; /* output */
+ u16 act_mask; /* input */
+ u32 buf_size; /* input */
+ u32 buf_nr; /* input */
+ u64 start_lba;
+ u64 end_lba;
+ u32 pid;
+};
+
+#if defined(CONFIG_BLK_DEV_IO_TRACE)
+extern int blk_trace_ioctl(struct block_device *, unsigned, char __user *);
+extern void blk_trace_shutdown(request_queue_t *);
+extern void __blk_add_trace(struct blk_trace *, sector_t, int, int, u32, int, int, void *);
+
+/**
+ * blk_add_trace_rq - Add a trace for a request oriented action
+ * @q: queue the io is for
+ * @rq: the source request
+ * @what: the action
+ *
+ * Description:
+ * Records an action against a request. Will log the bio offset + size.
+ *
+ **/
+static inline void blk_add_trace_rq(struct request_queue *q, struct request *rq,
+ u32 what)
+{
+ struct blk_trace *bt = q->blk_trace;
+ int rw = rq->flags & 0x07;
+
+ if (likely(!bt))
+ return;
+
+ if (blk_pc_request(rq)) {
+ what |= BLK_TC_ACT(BLK_TC_PC);
+ __blk_add_trace(bt, 0, rq->data_len, rw, what, rq->errors, sizeof(rq->cmd), rq->cmd);
+ } else {
+ what |= BLK_TC_ACT(BLK_TC_FS);
+ __blk_add_trace(bt, rq->hard_sector, rq->hard_nr_sectors << 9, rw, what, rq->errors, 0, NULL);
+ }
+}
+
+/**
+ * blk_add_trace_bio - Add a trace for a bio oriented action
+ * @q: queue the io is for
+ * @bio: the source bio
+ * @what: the action
+ *
+ * Description:
+ * Records an action against a bio. Will log the bio offset + size.
+ *
+ **/
+static inline void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
+ u32 what)
+{
+ struct blk_trace *bt = q->blk_trace;
+
+ if (likely(!bt))
+ return;
+
+ __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what, !bio_flagged(bio, BIO_UPTODATE), 0, NULL);
+}
+
+/**
+ * blk_add_trace_generic - Add a trace for a generic action
+ * @q: queue the io is for
+ * @bio: the source bio
+ * @rw: the data direction
+ * @what: the action
+ *
+ * Description:
+ * Records a simple trace
+ *
+ **/
+static inline void blk_add_trace_generic(struct request_queue *q,
+ struct bio *bio, int rw, u32 what)
+{
+ struct blk_trace *bt = q->blk_trace;
+
+ if (likely(!bt))
+ return;
+
+ if (bio)
+ blk_add_trace_bio(q, bio, what);
+ else
+ __blk_add_trace(bt, 0, 0, rw, what, 0, 0, NULL);
+}
+
+/**
+ * blk_add_trace_pdu_int - Add a trace for a bio with an integer payload
+ * @q: queue the io is for
+ * @what: the action
+ * @bio: the source bio
+ * @pdu: the integer payload
+ *
+ * Description:
+ * Adds a trace with some integer payload. This might be an unplug
+ * option given as the action, with the depth at unplug time given
+ * as the payload
+ *
+ **/
+static inline void blk_add_trace_pdu_int(struct request_queue *q, u32 what,
+ struct bio *bio, unsigned int pdu)
+{
+ struct blk_trace *bt = q->blk_trace;
+ u64 rpdu = cpu_to_be64(pdu);
+
+ if (likely(!bt))
+ return;
+
+ if (bio)
+ __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what, !bio_flagged(bio, BIO_UPTODATE), sizeof(rpdu), &rpdu);
+ else
+ __blk_add_trace(bt, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu);
+}
+
+/**
+ * blk_add_trace_remap - Add a trace for a remap operation
+ * @q: queue the io is for
+ * @bio: the source bio
+ * @dev: target device
+ * @from: source sector
+ * @to: target sector
+ *
+ * Description:
+ * Device mapper or raid target sometimes need to split a bio because
+ * it spans a stripe (or similar). Add a trace for that action.
+ *
+ **/
+static inline void blk_add_trace_remap(struct request_queue *q, struct bio *bio,
+ dev_t dev, sector_t from, sector_t to)
+{
+ struct blk_trace *bt = q->blk_trace;
+ struct blk_io_trace_remap r;
+
+ if (likely(!bt))
+ return;
+
+ r.device = cpu_to_be32(dev);
+ r.sector = cpu_to_be64(to);
+
+ __blk_add_trace(bt, from, bio->bi_size, bio->bi_rw, BLK_TA_REMAP, !bio_flagged(bio, BIO_UPTODATE), sizeof(r), &r);
+}
+
+#else /* !CONFIG_BLK_DEV_IO_TRACE */
+#define blk_trace_ioctl(bdev, cmd, arg) (-ENOTTY)
+#define blk_trace_shutdown(q) do { } while (0)
+#define blk_add_trace_rq(q, rq, what) do { } while (0)
+#define blk_add_trace_bio(q, rq, what) do { } while (0)
+#define blk_add_trace_generic(q, rq, rw, what) do { } while (0)
+#define blk_add_trace_pdu_int(q, what, bio, pdu) do { } while (0)
+#define blk_add_trace_remap(q, bio, dev, f, t) do {} while (0)
+#endif /* CONFIG_BLK_DEV_IO_TRACE */
+
+#endif
diff --git a/include/linux/compat_ioctl.h b/include/linux/compat_ioctl.h
index ae7dfb7..efb518f 100644
--- a/include/linux/compat_ioctl.h
+++ b/include/linux/compat_ioctl.h
@@ -97,6 +97,10 @@ COMPATIBLE_IOCTL(BLKRRPART)
COMPATIBLE_IOCTL(BLKFLSBUF)
COMPATIBLE_IOCTL(BLKSECTSET)
COMPATIBLE_IOCTL(BLKSSZGET)
+COMPATIBLE_IOCTL(BLKTRACESTART)
+COMPATIBLE_IOCTL(BLKTRACESTOP)
+COMPATIBLE_IOCTL(BLKTRACESETUP)
+COMPATIBLE_IOCTL(BLKTRACETEARDOWN)
ULONG_IOCTL(BLKRASET)
ULONG_IOCTL(BLKFRASET)
/* RAID */
diff --git a/include/linux/fs.h b/include/linux/fs.h
index f9c9dea..9b34a1b 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -197,6 +197,10 @@ extern int dir_notify_enable;
#define BLKBSZGET _IOR(0x12,112,size_t)
#define BLKBSZSET _IOW(0x12,113,size_t)
#define BLKGETSIZE64 _IOR(0x12,114,size_t) /* return device size in bytes (u64 *arg) */
+#define BLKTRACESETUP _IOWR(0x12,115,struct blk_user_trace_setup)
+#define BLKTRACESTART _IO(0x12,116)
+#define BLKTRACESTOP _IO(0x12,117)
+#define BLKTRACETEARDOWN _IO(0x12,118)
#define BMAP_IOCTL 1 /* obsolete - kept for compatibility */
#define FIBMAP _IO(0x00,1) /* bmap access */
diff --git a/include/linux/relay.h b/include/linux/relay.h
new file mode 100644
index 0000000..4bcc153
--- /dev/null
+++ b/include/linux/relay.h
@@ -0,0 +1,281 @@
+/*
+ * linux/include/linux/relay.h
+ *
+ * Copyright (C) 2002, 2003 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp
+ * Copyright (C) 1999, 2000, 2001, 2002 - Karim Yaghmour (karim@opersys.com)
+ *
+ * CONFIG_RELAY definitions and declarations
+ */
+
+#ifndef _LINUX_RELAY_H
+#define _LINUX_RELAY_H
+
+#include <linux/config.h>
+#include <linux/types.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
+#include <linux/list.h>
+#include <linux/fs.h>
+#include <linux/poll.h>
+#include <linux/kref.h>
+
+/* Needs a _much_ better name... */
+#define FIX_SIZE(x) ((((x) - 1) & PAGE_MASK) + PAGE_SIZE)
+
+/*
+ * Tracks changes to rchan/rchan_buf structs
+ */
+#define RELAYFS_CHANNEL_VERSION 6
+
+/*
+ * Per-cpu relay channel buffer
+ */
+struct rchan_buf
+{
+ void *start; /* start of channel buffer */
+ void *data; /* start of current sub-buffer */
+ size_t offset; /* current offset into sub-buffer */
+ size_t subbufs_produced; /* count of sub-buffers produced */
+ size_t subbufs_consumed; /* count of sub-buffers consumed */
+ struct rchan *chan; /* associated channel */
+ wait_queue_head_t read_wait; /* reader wait queue */
+ struct work_struct wake_readers; /* reader wake-up work struct */
+ struct dentry *dentry; /* channel file dentry */
+ struct kref kref; /* channel buffer refcount */
+ struct page **page_array; /* array of current buffer pages */
+ unsigned int page_count; /* number of current buffer pages */
+ unsigned int finalized; /* buffer has been finalized */
+ size_t *padding; /* padding counts per sub-buffer */
+ size_t prev_padding; /* temporary variable */
+ size_t bytes_consumed; /* bytes consumed in cur read subbuf */
+ unsigned int cpu; /* this buf's cpu */
+} ____cacheline_aligned;
+
+/*
+ * Relay channel data structure
+ */
+struct rchan
+{
+ u32 version; /* the version of this struct */
+ size_t subbuf_size; /* sub-buffer size */
+ size_t n_subbufs; /* number of sub-buffers per buffer */
+ size_t alloc_size; /* total buffer size allocated */
+ struct rchan_callbacks *cb; /* client callbacks */
+ struct kref kref; /* channel refcount */
+ void *private_data; /* for user-defined data */
+ size_t last_toobig; /* tried to log event > subbuf size */
+ struct rchan_buf *buf[NR_CPUS]; /* per-cpu channel buffers */
+};
+
+/*
+ * Relay channel client callbacks
+ */
+struct rchan_callbacks
+{
+ /*
+ * subbuf_start - called on buffer-switch to a new sub-buffer
+ * @buf: the channel buffer containing the new sub-buffer
+ * @subbuf: the start of the new sub-buffer
+ * @prev_subbuf: the start of the previous sub-buffer
+ * @prev_padding: unused space at the end of previous sub-buffer
+ *
+ * The client should return 1 to continue logging, 0 to stop
+ * logging.
+ *
+ * NOTE: subbuf_start will also be invoked when the buffer is
+ * created, so that the first sub-buffer can be initialized
+ * if necessary. In this case, prev_subbuf will be NULL.
+ *
+ * NOTE: the client can reserve bytes at the beginning of the new
+ * sub-buffer by calling subbuf_start_reserve() in this callback.
+ */
+ int (*subbuf_start) (struct rchan_buf *buf,
+ void *subbuf,
+ void *prev_subbuf,
+ size_t prev_padding);
+
+ /*
+ * buf_mapped - relay buffer mmap notification
+ * @buf: the channel buffer
+ * @filp: relay file pointer
+ *
+ * Called when a relay file is successfully mmapped
+ */
+ void (*buf_mapped)(struct rchan_buf *buf,
+ struct file *filp);
+
+ /*
+ * buf_unmapped - relay buffer unmap notification
+ * @buf: the channel buffer
+ * @filp: relay file pointer
+ *
+ * Called when a relay file is successfully unmapped
+ */
+ void (*buf_unmapped)(struct rchan_buf *buf,
+ struct file *filp);
+ /*
+ * create_buf_file - create file to represent a relay channel buffer
+ * @filename: the name of the file to create
+ * @parent: the parent of the file to create
+ * @mode: the mode of the file to create
+ * @buf: the channel buffer
+ * @is_global: outparam - set non-zero if the buffer should be global
+ *
+ * Called during relay_open(), once for each per-cpu buffer,
+ * to allow the client to create a file to be used to
+ * represent the corresponding channel buffer. If the file is
+ * created outside of relay, the parent must also exist in
+ * that filesystem.
+ *
+ * The callback should return the dentry of the file created
+ * to represent the relay buffer.
+ *
+ * Setting the is_global outparam to a non-zero value will
+ * cause relay_open() to create a single global buffer rather
+ * than the default set of per-cpu buffers.
+ *
+ * See Documentation/filesystems/relayfs.txt for more info.
+ */
+ struct dentry *(*create_buf_file)(const char *filename,
+ struct dentry *parent,
+ int mode,
+ struct rchan_buf *buf,
+ int *is_global);
+
+ /*
+ * remove_buf_file - remove file representing a relay channel buffer
+ * @dentry: the dentry of the file to remove
+ *
+ * Called during relay_close(), once for each per-cpu buffer,
+ * to allow the client to remove a file used to represent a
+ * channel buffer.
+ *
+ * The callback should return 0 if successful, negative if not.
+ */
+ int (*remove_buf_file)(struct dentry *dentry);
+};
+
+/*
+ * CONFIG_RELAY kernel API, kernel/relay.c
+ */
+
+struct rchan *relay_open(const char *base_filename,
+ struct dentry *parent,
+ size_t subbuf_size,
+ size_t n_subbufs,
+ struct rchan_callbacks *cb);
+extern void relay_close(struct rchan *chan);
+extern void relay_flush(struct rchan *chan);
+extern void relay_subbufs_consumed(struct rchan *chan,
+ unsigned int cpu,
+ size_t consumed);
+extern void relay_reset(struct rchan *chan);
+extern int relay_buf_full(struct rchan_buf *buf);
+
+extern size_t relay_switch_subbuf(struct rchan_buf *buf,
+ size_t length);
+
+/**
+ * relay_write - write data into the channel
+ * @chan: relay channel
+ * @data: data to be written
+ * @length: number of bytes to write
+ *
+ * Writes data into the current cpu's channel buffer.
+ *
+ * Protects the buffer by disabling interrupts. Use this
+ * if you might be logging from interrupt context. Try
+ * __relay_write() if you know you won't be logging from
+ * interrupt context.
+ */
+static inline void relay_write(struct rchan *chan,
+ const void *data,
+ size_t length)
+{
+ unsigned long flags;
+ struct rchan_buf *buf;
+
+ local_irq_save(flags);
+ buf = chan->buf[smp_processor_id()];
+ if (unlikely(buf->offset + length > chan->subbuf_size))
+ length = relay_switch_subbuf(buf, length);
+ memcpy(buf->data + buf->offset, data, length);
+ buf->offset += length;
+ local_irq_restore(flags);
+}
+
+/**
+ * __relay_write - write data into the channel
+ * @chan: relay channel
+ * @data: data to be written
+ * @length: number of bytes to write
+ *
+ * Writes data into the current cpu's channel buffer.
+ *
+ * Protects the buffer by disabling preemption. Use
+ * relay_write() if you might be logging from interrupt
+ * context.
+ */
+static inline void __relay_write(struct rchan *chan,
+ const void *data,
+ size_t length)
+{
+ struct rchan_buf *buf;
+
+ buf = chan->buf[get_cpu()];
+ if (unlikely(buf->offset + length > buf->chan->subbuf_size))
+ length = relay_switch_subbuf(buf, length);
+ memcpy(buf->data + buf->offset, data, length);
+ buf->offset += length;
+ put_cpu();
+}
+
+/**
+ * relay_reserve - reserve slot in channel buffer
+ * @chan: relay channel
+ * @length: number of bytes to reserve
+ *
+ * Returns pointer to reserved slot, NULL if full.
+ *
+ * Reserves a slot in the current cpu's channel buffer.
+ * Does not protect the buffer at all - caller must provide
+ * appropriate synchronization.
+ */
+static inline void *relay_reserve(struct rchan *chan, size_t length)
+{
+ void *reserved;
+ struct rchan_buf *buf = chan->buf[smp_processor_id()];
+
+ if (unlikely(buf->offset + length > buf->chan->subbuf_size)) {
+ length = relay_switch_subbuf(buf, length);
+ if (!length)
+ return NULL;
+ }
+ reserved = buf->data + buf->offset;
+ buf->offset += length;
+
+ return reserved;
+}
+
+/**
+ * subbuf_start_reserve - reserve bytes at the start of a sub-buffer
+ * @buf: relay channel buffer
+ * @length: number of bytes to reserve
+ *
+ * Helper function used to reserve bytes at the beginning of
+ * a sub-buffer in the subbuf_start() callback.
+ */
+static inline void subbuf_start_reserve(struct rchan_buf *buf,
+ size_t length)
+{
+ BUG_ON(length >= buf->chan->subbuf_size - 1);
+ buf->offset = length;
+}
+
+/*
+ * exported relay file operations, kernel/relay.c
+ */
+extern struct file_operations relay_file_operations;
+
+#endif /* _LINUX_RELAY_H */
+
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 62e6314..e60a91d 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -706,6 +706,7 @@ struct task_struct {
prio_array_t *array;
unsigned short ioprio;
+ unsigned int btrace_seq;
unsigned long sleep_avg;
unsigned long long timestamp, last_ran;
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