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authorShaohua Li <shli@fb.com>2016-04-26 02:52:38 +0300
committerShaohua Li <shli@fb.com>2016-04-26 04:21:33 +0300
commit9c573de3283af007ea11c17bde1e4568d9417328 (patch)
tree65df34db491d33e1432691b5ec69d53388df6f4f /drivers/md
parentb297874a2d5c5fcaeb5242a8b4708e54c5477d90 (diff)
downloadlinux-9c573de3283af007ea11c17bde1e4568d9417328.tar.xz
MD: make bio mergeable
blk_queue_split marks bio unmergeable, which makes sense for normal bio. But if dispatching the bio to underlayer disk, the blk_queue_split checks are invalid, hence it's possible the bio becomes mergeable. In the reported bug, this bug causes trim against raid0 performance slash https://bugzilla.kernel.org/show_bug.cgi?id=117051 Reported-and-tested-by: Park Ju Hyung <qkrwngud825@gmail.com> Fixes: 6ac45aeb6bca(block: avoid to merge splitted bio) Cc: stable@vger.kernel.org (v4.3+) Cc: Ming Lei <ming.lei@canonical.com> Cc: Neil Brown <neilb@suse.de> Reviewed-by: Jens Axboe <axboe@fb.com> Signed-off-by: Shaohua Li <shli@fb.com>
Diffstat (limited to 'drivers/md')
-rw-r--r--drivers/md/md.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 194580fba7fd..14d3b37944df 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -284,6 +284,8 @@ static blk_qc_t md_make_request(struct request_queue *q, struct bio *bio)
* go away inside make_request
*/
sectors = bio_sectors(bio);
+ /* bio could be mergeable after passing to underlayer */
+ bio->bi_rw &= ~REQ_NOMERGE;
mddev->pers->make_request(mddev, bio);
cpu = part_stat_lock();