[PATCH] block: add call to split trace point

[Mike Krinkin <krinkin.m.u@gmail.com>]

There is a split tracepoint that is supposed to be called when
bio is splitted, and it was called in bio_split function until
commit 4b1faf931650d4a35b2a ("block: Kill bio_pair_split()").
But now, no one reports splits, so this patch adds call to
trace_block_split back in blk_queue_split right after split.

Signed-off-by: Mike Krinkin <krinkin.m.u@gmail.com>
---
 block/blk-merge.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/block/blk-merge.c b/block/blk-merge.c
index de5716d8..3bb4537 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -7,6 +7,8 @@
 #include <linux/blkdev.h>
 #include <linux/scatterlist.h>
 
+#include <trace/events/block.h>
+
 #include "blk.h"
 
 static struct bio *blk_bio_discard_split(struct request_queue *q,
@@ -143,6 +145,7 @@ void blk_queue_split(struct request_queue *q, struct bio **bio,
 		split->bi_rw |= REQ_NOMERGE;
 
 		bio_chain(split, *bio);
+		trace_block_split(q, split, (*bio)->bi_iter.bi_sector);
 		generic_make_request(*bio);
 		*bio = split;
 	}
-- 
1.9.1