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| author | Shaohua Li <shli@fb.com> | 2016-04-25 16:52:38 -0700 |
|---|---|---|
| committer | Sasha Levin <sasha.levin@oracle.com> | 2016-05-17 14:32:05 -0400 |
| commit | 4c6a29348c5f7b692c23542c52bf26b471fee2ee (patch) | |
| tree | 9ec7b35a25329821228b7fd7a3d7ed86567043f0 | |
| parent | 44c1efb35ee387bbef4c052803ea196aaab0012e (diff) | |
| download | lwn-4c6a29348c5f7b692c23542c52bf26b471fee2ee.tar.gz lwn-4c6a29348c5f7b692c23542c52bf26b471fee2ee.zip | |
MD: make bio mergeable
[ Upstream commit 9c573de3283af007ea11c17bde1e4568d9417328 ]
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>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
| -rw-r--r-- | drivers/md/md.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c index 6c169f18aab8..3d2cc7453ec1 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -282,6 +282,8 @@ static void 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(); |