[PATCH v2 3/7] block: avoid to merge splitted bio

[Ming Lei]

The splitted bio has been already too fat to merge, so mark it
as NOMERGE.

Reviewed-by: Jeff Moyer <jmoyer@xxxxxxxxxx>
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxxxxx>
---
 block/blk-merge.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/block/blk-merge.c b/block/blk-merge.c
index 22293fd..de5716d8 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -139,6 +139,9 @@ void blk_queue_split(struct request_queue *q, struct bio **bio,
 	bio_set_flag(res, BIO_SEG_VALID);
 
 	if (split) {
+		/* there isn't chance to merge the splitted bio */
+		split->bi_rw |= REQ_NOMERGE;
+
 		bio_chain(split, *bio);
 		generic_make_request(*bio);
 		*bio = split;
-- 
1.9.1

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