1 files changed, 206 insertions, 160 deletions

diff --git a/include/trace/events/block.h b/include/trace/events/block.h
index 00405b5f624a..d870a918559c 100644
--- a/include/trace/events/block.h
+++ b/include/trace/events/block.h
@@ -8,7 +8,7 @@
 #include <linux/blkdev.h>
 #include <linux/tracepoint.h>
 
-TRACE_EVENT(block_rq_abort,
+DECLARE_EVENT_CLASS(block_rq_with_error,
 
         TP_PROTO(struct request_queue *q, struct request *rq),
 
@@ -40,41 +40,58 @@ TRACE_EVENT(block_rq_abort,
                   __entry->nr_sector, __entry->errors)
 );
 
-TRACE_EVENT(block_rq_insert,
+/**
+ * block_rq_abort - abort block operation request
+ * @q: queue containing the block operation request
+ * @rq: block IO operation request
+ *
+ * Called immediately after pending block IO operation request @rq in
+ * queue @q is aborted. The fields in the operation request @rq
+ * can be examined to determine which device and sectors the pending
+ * operation would access.
+ */
+DEFINE_EVENT(block_rq_with_error, block_rq_abort,
 
         TP_PROTO(struct request_queue *q, struct request *rq),
 
-        TP_ARGS(q, rq),
+        TP_ARGS(q, rq)
+);
 
-        TP_STRUCT__entry(
-                __field(  dev_t,        dev                     )
-                __field(  sector_t,     sector                  )
-                __field(  unsigned int, nr_sector               )
-                __field(  unsigned int, bytes                   )
-                __array(  char,         rwbs,   6               )
-                __array(  char,         comm,   TASK_COMM_LEN   )
-                __dynamic_array( char,  cmd,    blk_cmd_buf_len(rq)     )
-        ),
+/**
+ * block_rq_requeue - place block IO request back on a queue
+ * @q: queue holding operation
+ * @rq: block IO operation request
+ *
+ * The block operation request @rq is being placed back into queue
+ * @q.  For some reason the request was not completed and needs to be
+ * put back in the queue.
+ */
+DEFINE_EVENT(block_rq_with_error, block_rq_requeue,
 
-        TP_fast_assign(
-                __entry->dev       = rq->rq_disk ? disk_devt(rq->rq_disk) : 0;
-                __entry->sector    = blk_pc_request(rq) ? 0 : blk_rq_pos(rq);
-                __entry->nr_sector = blk_pc_request(rq) ? 0 : blk_rq_sectors(rq);
-                __entry->bytes     = blk_pc_request(rq) ? blk_rq_bytes(rq) : 0;
+        TP_PROTO(struct request_queue *q, struct request *rq),
 
-                blk_fill_rwbs_rq(__entry->rwbs, rq);
-                blk_dump_cmd(__get_str(cmd), rq);
-                memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
-        ),
+        TP_ARGS(q, rq)
+);
 
-        TP_printk("%d,%d %s %u (%s) %llu + %u [%s]",
-                  MAJOR(__entry->dev), MINOR(__entry->dev),
-                  __entry->rwbs, __entry->bytes, __get_str(cmd),
-                  (unsigned long long)__entry->sector,
-                  __entry->nr_sector, __entry->comm)
+/**
+ * block_rq_complete - block IO operation completed by device driver
+ * @q: queue containing the block operation request
+ * @rq: block operations request
+ *
+ * The block_rq_complete tracepoint event indicates that some portion
+ * of operation request has been completed by the device driver.  If
+ * the @rq->bio is %NULL, then there is absolutely no additional work to
+ * do for the request. If @rq->bio is non-NULL then there is
+ * additional work required to complete the request.
+ */
+DEFINE_EVENT(block_rq_with_error, block_rq_complete,
+
+        TP_PROTO(struct request_queue *q, struct request *rq),
+
+        TP_ARGS(q, rq)
 );
 
-TRACE_EVENT(block_rq_issue,
+DECLARE_EVENT_CLASS(block_rq,
 
         TP_PROTO(struct request_queue *q, struct request *rq),
 
@@ -86,7 +103,7 @@ TRACE_EVENT(block_rq_issue,
                 __field(  unsigned int, nr_sector               )
                 __field(  unsigned int, bytes                   )
                 __array(  char,         rwbs,   6               )
-                __array(  char,         comm,   TASK_COMM_LEN   )
+                __array(  char,         comm,   TASK_COMM_LEN   )
                 __dynamic_array( char,  cmd,    blk_cmd_buf_len(rq)     )
         ),
 
@@ -108,70 +125,49 @@ TRACE_EVENT(block_rq_issue,
                   __entry->nr_sector, __entry->comm)
 );
 
-TRACE_EVENT(block_rq_requeue,
+/**
+ * block_rq_insert - insert block operation request into queue
+ * @q: target queue
+ * @rq: block IO operation request
+ *
+ * Called immediately before block operation request @rq is inserted
+ * into queue @q.  The fields in the operation request @rq struct can
+ * be examined to determine which device and sectors the pending
+ * operation would access.
+ */
+DEFINE_EVENT(block_rq, block_rq_insert,
 
         TP_PROTO(struct request_queue *q, struct request *rq),
 
-        TP_ARGS(q, rq),
-
-        TP_STRUCT__entry(
-                __field(  dev_t,        dev                     )
-                __field(  sector_t,     sector                  )
-                __field(  unsigned int, nr_sector               )
-                __field(  int,          errors                  )
-                __array(  char,         rwbs,   6               )
-                __dynamic_array( char,  cmd,    blk_cmd_buf_len(rq)     )
-        ),
-
-        TP_fast_assign(
-                __entry->dev       = rq->rq_disk ? disk_devt(rq->rq_disk) : 0;
-                __entry->sector    = blk_pc_request(rq) ? 0 : blk_rq_pos(rq);
-                __entry->nr_sector = blk_pc_request(rq) ? 0 : blk_rq_sectors(rq);
-                __entry->errors    = rq->errors;
-
-                blk_fill_rwbs_rq(__entry->rwbs, rq);
-                blk_dump_cmd(__get_str(cmd), rq);
-        ),
-
-        TP_printk("%d,%d %s (%s) %llu + %u [%d]",
-                  MAJOR(__entry->dev), MINOR(__entry->dev),
-                  __entry->rwbs, __get_str(cmd),
-                  (unsigned long long)__entry->sector,
-                  __entry->nr_sector, __entry->errors)
+        TP_ARGS(q, rq)
 );
 
-TRACE_EVENT(block_rq_complete,
+/**
+ * block_rq_issue - issue pending block IO request operation to device driver
+ * @q: queue holding operation
+ * @rq: block IO operation operation request
+ *
+ * Called when block operation request @rq from queue @q is sent to a
+ * device driver for processing.
+ */
+DEFINE_EVENT(block_rq, block_rq_issue,
 
         TP_PROTO(struct request_queue *q, struct request *rq),
 
-        TP_ARGS(q, rq),
-
-        TP_STRUCT__entry(
-                __field(  dev_t,        dev                     )
-                __field(  sector_t,     sector                  )
-                __field(  unsigned int, nr_sector               )
-                __field(  int,          errors                  )
-                __array(  char,         rwbs,   6               )
-                __dynamic_array( char,  cmd,    blk_cmd_buf_len(rq)     )
-        ),
-
-        TP_fast_assign(
-                __entry->dev       = rq->rq_disk ? disk_devt(rq->rq_disk) : 0;
-                __entry->sector    = blk_pc_request(rq) ? 0 : blk_rq_pos(rq);
-                __entry->nr_sector = blk_pc_request(rq) ? 0 : blk_rq_sectors(rq);
-                __entry->errors    = rq->errors;
-
-                blk_fill_rwbs_rq(__entry->rwbs, rq);
-                blk_dump_cmd(__get_str(cmd), rq);
-        ),
-
-        TP_printk("%d,%d %s (%s) %llu + %u [%d]",
-                  MAJOR(__entry->dev), MINOR(__entry->dev),
-                  __entry->rwbs, __get_str(cmd),
-                  (unsigned long long)__entry->sector,
-                  __entry->nr_sector, __entry->errors)
+        TP_ARGS(q, rq)
 );
 
+/**
+ * block_bio_bounce - used bounce buffer when processing block operation
+ * @q: queue holding the block operation
+ * @bio: block operation
+ *
+ * A bounce buffer was used to handle the block operation @bio in @q.
+ * This occurs when hardware limitations prevent a direct transfer of
+ * data between the @bio data memory area and the IO device.  Use of a
+ * bounce buffer requires extra copying of data and decreases
+ * performance.
+ */
 TRACE_EVENT(block_bio_bounce,
 
         TP_PROTO(struct request_queue *q, struct bio *bio),
@@ -201,6 +197,14 @@ TRACE_EVENT(block_bio_bounce,
                   __entry->nr_sector, __entry->comm)
 );
 
+/**
+ * block_bio_complete - completed all work on the block operation
+ * @q: queue holding the block operation
+ * @bio: block operation completed
+ *
+ * This tracepoint indicates there is no further work to do on this
+ * block IO operation @bio.
+ */
 TRACE_EVENT(block_bio_complete,
 
         TP_PROTO(struct request_queue *q, struct bio *bio),
@@ -228,7 +232,7 @@ TRACE_EVENT(block_bio_complete,
                   __entry->nr_sector, __entry->error)
 );
 
-TRACE_EVENT(block_bio_backmerge,
+DECLARE_EVENT_CLASS(block_bio,
 
         TP_PROTO(struct request_queue *q, struct bio *bio),
 
@@ -256,63 +260,51 @@ TRACE_EVENT(block_bio_backmerge,
                   __entry->nr_sector, __entry->comm)
 );
 
-TRACE_EVENT(block_bio_frontmerge,
+/**
+ * block_bio_backmerge - merging block operation to the end of an existing operation
+ * @q: queue holding operation
+ * @bio: new block operation to merge
+ *
+ * Merging block request @bio to the end of an existing block request
+ * in queue @q.
+ */
+DEFINE_EVENT(block_bio, block_bio_backmerge,
 
         TP_PROTO(struct request_queue *q, struct bio *bio),
 
-        TP_ARGS(q, bio),
-
-        TP_STRUCT__entry(
-                __field( dev_t,         dev                     )
-                __field( sector_t,      sector                  )
-                __field( unsigned,      nr_sector               )
-                __array( char,          rwbs,   6               )
-                __array( char,          comm,   TASK_COMM_LEN   )
-        ),
-
-        TP_fast_assign(
-                __entry->dev            = bio->bi_bdev->bd_dev;
-                __entry->sector         = bio->bi_sector;
-                __entry->nr_sector      = bio->bi_size >> 9;
-                blk_fill_rwbs(__entry->rwbs, bio->bi_rw, bio->bi_size);
-                memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
-        ),
-
-        TP_printk("%d,%d %s %llu + %u [%s]",
-                  MAJOR(__entry->dev), MINOR(__entry->dev), __entry->rwbs,
-                  (unsigned long long)__entry->sector,
-                  __entry->nr_sector, __entry->comm)
+        TP_ARGS(q, bio)
 );
 
-TRACE_EVENT(block_bio_queue,
+/**
+ * block_bio_frontmerge - merging block operation to the beginning of an existing operation
+ * @q: queue holding operation
+ * @bio: new block operation to merge
+ *
+ * Merging block IO operation @bio to the beginning of an existing block
+ * operation in queue @q.
+ */
+DEFINE_EVENT(block_bio, block_bio_frontmerge,
 
         TP_PROTO(struct request_queue *q, struct bio *bio),
 
-        TP_ARGS(q, bio),
+        TP_ARGS(q, bio)
+);
 
-        TP_STRUCT__entry(
-                __field( dev_t,         dev                     )
-                __field( sector_t,      sector                  )
-                __field( unsigned int,  nr_sector               )
-                __array( char,          rwbs,   6               )
-                __array( char,          comm,   TASK_COMM_LEN   )
-        ),
+/**
+ * block_bio_queue - putting new block IO operation in queue
+ * @q: queue holding operation
+ * @bio: new block operation
+ *
+ * About to place the block IO operation @bio into queue @q.
+ */
+DEFINE_EVENT(block_bio, block_bio_queue,
 
-        TP_fast_assign(
-                __entry->dev            = bio->bi_bdev->bd_dev;
-                __entry->sector         = bio->bi_sector;
-                __entry->nr_sector      = bio->bi_size >> 9;
-                blk_fill_rwbs(__entry->rwbs, bio->bi_rw, bio->bi_size);
-                memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
-        ),
+        TP_PROTO(struct request_queue *q, struct bio *bio),
 
-        TP_printk("%d,%d %s %llu + %u [%s]",
-                  MAJOR(__entry->dev), MINOR(__entry->dev), __entry->rwbs,
-                  (unsigned long long)__entry->sector,
-                  __entry->nr_sector, __entry->comm)
+        TP_ARGS(q, bio)
 );
 
-TRACE_EVENT(block_getrq,
+DECLARE_EVENT_CLASS(block_get_rq,
 
         TP_PROTO(struct request_queue *q, struct bio *bio, int rw),
 
@@ -341,35 +333,48 @@ TRACE_EVENT(block_getrq,
                   __entry->nr_sector, __entry->comm)
 );
 
-TRACE_EVENT(block_sleeprq,
+/**
+ * block_getrq - get a free request entry in queue for block IO operations
+ * @q: queue for operations
+ * @bio: pending block IO operation
+ * @rw: low bit indicates a read (%0) or a write (%1)
+ *
+ * A request struct for queue @q has been allocated to handle the
+ * block IO operation @bio.
+ */
+DEFINE_EVENT(block_get_rq, block_getrq,
 
         TP_PROTO(struct request_queue *q, struct bio *bio, int rw),
 
-        TP_ARGS(q, bio, rw),
+        TP_ARGS(q, bio, rw)
+);
 
-        TP_STRUCT__entry(
-                __field( dev_t,         dev                     )
-                __field( sector_t,      sector                  )
-                __field( unsigned int,  nr_sector               )
-                __array( char,          rwbs,   6               )
-                __array( char,          comm,   TASK_COMM_LEN   )
-        ),
+/**
+ * block_sleeprq - waiting to get a free request entry in queue for block IO operation
+ * @q: queue for operation
+ * @bio: pending block IO operation
+ * @rw: low bit indicates a read (%0) or a write (%1)
+ *
+ * In the case where a request struct cannot be provided for queue @q
+ * the process needs to wait for an request struct to become
+ * available.  This tracepoint event is generated each time the
+ * process goes to sleep waiting for request struct become available.
+ */
+DEFINE_EVENT(block_get_rq, block_sleeprq,
 
-        TP_fast_assign(
-                __entry->dev            = bio ? bio->bi_bdev->bd_dev : 0;
-                __entry->sector         = bio ? bio->bi_sector : 0;
-                __entry->nr_sector      = bio ? bio->bi_size >> 9 : 0;
-                blk_fill_rwbs(__entry->rwbs,
-                            bio ? bio->bi_rw : 0, __entry->nr_sector);
-                memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
-        ),
+        TP_PROTO(struct request_queue *q, struct bio *bio, int rw),
 
-        TP_printk("%d,%d %s %llu + %u [%s]",
-                  MAJOR(__entry->dev), MINOR(__entry->dev), __entry->rwbs,
-                  (unsigned long long)__entry->sector,
-                  __entry->nr_sector, __entry->comm)
+        TP_ARGS(q, bio, rw)
 );
 
+/**
+ * block_plug - keep operations requests in request queue
+ * @q: request queue to plug
+ *
+ * Plug the request queue @q.  Do not allow block operation requests
+ * to be sent to the device driver. Instead, accumulate requests in
+ * the queue to improve throughput performance of the block device.
+ */
 TRACE_EVENT(block_plug,
 
         TP_PROTO(struct request_queue *q),
@@ -387,7 +392,7 @@ TRACE_EVENT(block_plug,
         TP_printk("[%s]", __entry->comm)
 );
 
-TRACE_EVENT(block_unplug_timer,
+DECLARE_EVENT_CLASS(block_unplug,
 
         TP_PROTO(struct request_queue *q),
 
@@ -406,25 +411,45 @@ TRACE_EVENT(block_unplug_timer,
         TP_printk("[%s] %d", __entry->comm, __entry->nr_rq)
 );
 
-TRACE_EVENT(block_unplug_io,
+/**
+ * block_unplug_timer - timed release of operations requests in queue to device driver
+ * @q: request queue to unplug
+ *
+ * Unplug the request queue @q because a timer expired and allow block
+ * operation requests to be sent to the device driver.
+ */
+DEFINE_EVENT(block_unplug, block_unplug_timer,
 
         TP_PROTO(struct request_queue *q),
 
-        TP_ARGS(q),
+        TP_ARGS(q)
+);
 
-        TP_STRUCT__entry(
-                __field( int,           nr_rq                   )
-                __array( char,          comm,   TASK_COMM_LEN   )
-        ),
+/**
+ * block_unplug_io - release of operations requests in request queue
+ * @q: request queue to unplug
+ *
+ * Unplug request queue @q because device driver is scheduled to work
+ * on elements in the request queue.
+ */
+DEFINE_EVENT(block_unplug, block_unplug_io,
 
-        TP_fast_assign(
-                __entry->nr_rq  = q->rq.count[READ] + q->rq.count[WRITE];
-                memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
-        ),
+        TP_PROTO(struct request_queue *q),
 
-        TP_printk("[%s] %d", __entry->comm, __entry->nr_rq)
+        TP_ARGS(q)
 );
 
+/**
+ * block_split - split a single bio struct into two bio structs
+ * @q: queue containing the bio
+ * @bio: block operation being split
+ * @new_sector: The starting sector for the new bio
+ *
+ * The bio request @bio in request queue @q needs to be split into two
+ * bio requests. The newly created @bio request starts at
+ * @new_sector. This split may be required due to hardware limitation
+ * such as operation crossing device boundaries in a RAID system.
+ */
 TRACE_EVENT(block_split,
 
         TP_PROTO(struct request_queue *q, struct bio *bio,
@@ -455,6 +480,16 @@ TRACE_EVENT(block_split,
                   __entry->comm)
 );
 
+/**
+ * block_remap - map request for a partition to the raw device
+ * @q: queue holding the operation
+ * @bio: revised operation
+ * @dev: device for the operation
+ * @from: original sector for the operation
+ *
+ * An operation for a partition on a block device has been mapped to the
+ * raw block device.
+ */
 TRACE_EVENT(block_remap,
 
         TP_PROTO(struct request_queue *q, struct bio *bio, dev_t dev,
@@ -488,6 +523,17 @@ TRACE_EVENT(block_remap,
                   (unsigned long long)__entry->old_sector)
 );
 
+/**
+ * block_rq_remap - map request for a block operation request
+ * @q: queue holding the operation
+ * @rq: block IO operation request
+ * @dev: device for the operation
+ * @from: original sector for the operation
+ *
+ * The block operation request @rq in @q has been remapped.  The block
+ * operation request @rq holds the current information and @from hold
+ * the original sector.
+ */
 TRACE_EVENT(block_rq_remap,
 
         TP_PROTO(struct request_queue *q, struct request *rq, dev_t dev,