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>
diff --git a/include/trace/events/block.h b/include/trace/events/block.h
index 8a168db..b408f51 100644
--- a/include/trace/events/block.h
+++ b/include/trace/events/block.h
@@ -241,11 +241,11 @@
 		  __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 @@
 /**
  * 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 @@
  *
  * 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,