block: add @req to bio_{front|back}_merge tracepoints

bio_{front|back}_merge tracepoints report a bio merging into an
existing request but didn't specify which request the bio is being
merged into.  Add @req to it.  This makes it impossible to share the
event template with block_bio_queue - split it out.

@req isn't used or exported to userland at this point and there is no
userland visible behavior change.  Later changes will make use of the
extra parameter.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

3 files changed, 38 insertions, 13 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index 4f5aec708be6..66d31687cf6b 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1347,7 +1347,7 @@ static bool bio_attempt_back_merge(struct request_queue *q, struct request *req,
         if (!ll_back_merge_fn(q, req, bio))
                 return false;
 
-        trace_block_bio_backmerge(q, bio);
+        trace_block_bio_backmerge(q, req, bio);
 
         if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff)
                 blk_rq_set_mixed_merge(req);
@@ -1369,7 +1369,7 @@ static bool bio_attempt_front_merge(struct request_queue *q,
         if (!ll_front_merge_fn(q, req, bio))
                 return false;
 
-        trace_block_bio_frontmerge(q, bio);
+        trace_block_bio_frontmerge(q, req, bio);
 
         if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff)
                 blk_rq_set_mixed_merge(req);
diff --git a/include/trace/events/block.h b/include/trace/events/block.h
index 8a168db9a645..b408f518a819 100644
--- a/include/trace/events/block.h
+++ b/include/trace/events/block.h
@@ -241,11 +241,11 @@ TRACE_EVENT(block_bio_complete,
                   __entry->nr_sector, __entry->error)
 );
 
-DECLARE_EVENT_CLASS(block_bio,
+DECLARE_EVENT_CLASS(block_bio_merge,
 
-        TP_PROTO(struct request_queue *q, struct bio *bio),
+        TP_PROTO(struct request_queue *q, struct request *rq, struct bio *bio),
 
-        TP_ARGS(q, bio),
+        TP_ARGS(q, rq, bio),
 
         TP_STRUCT__entry(
                 __field( dev_t,         dev                     )
@@ -272,31 +272,33 @@ DECLARE_EVENT_CLASS(block_bio,
 /**
  * block_bio_backmerge - merging block operation to the end of an existing operation
  * @q: queue holding operation
+ * @rq: request bio is being merged into
  * @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,
+DEFINE_EVENT(block_bio_merge, block_bio_backmerge,
 
-        TP_PROTO(struct request_queue *q, struct bio *bio),
+        TP_PROTO(struct request_queue *q, struct request *rq, struct bio *bio),
 
-        TP_ARGS(q, bio)
+        TP_ARGS(q, rq, bio)
 );
 
 /**
  * block_bio_frontmerge - merging block operation to the beginning of an existing operation
  * @q: queue holding operation
+ * @rq: request bio is being merged into
  * @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,
+DEFINE_EVENT(block_bio_merge, block_bio_frontmerge,
 
-        TP_PROTO(struct request_queue *q, struct bio *bio),
+        TP_PROTO(struct request_queue *q, struct request *rq, struct bio *bio),
 
-        TP_ARGS(q, bio)
+        TP_ARGS(q, rq, bio)
 );
 
 /**
@@ -306,11 +308,32 @@ DEFINE_EVENT(block_bio, block_bio_frontmerge,
  *
  * About to place the block IO operation @bio into queue @q.
  */
-DEFINE_EVENT(block_bio, block_bio_queue,
+TRACE_EVENT(block_bio_queue,
 
         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,   RWBS_LEN        )
+                __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)
 );
 
 DECLARE_EVENT_CLASS(block_get_rq,
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 190d98fbed27..fb593f6a687e 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -803,6 +803,7 @@ static void blk_add_trace_bio_complete(void *ignore, struct bio *bio, int error)
 
 static void blk_add_trace_bio_backmerge(void *ignore,
                                         struct request_queue *q,
+                                        struct request *rq,
                                         struct bio *bio)
 {
         blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0);
@@ -810,6 +811,7 @@ static void blk_add_trace_bio_backmerge(void *ignore,
 
 static void blk_add_trace_bio_frontmerge(void *ignore,
                                          struct request_queue *q,
+                                         struct request *rq,
                                          struct bio *bio)
 {
         blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0);