linux/drivers/md/md.c
Shaohua Li 4c6a29348c MD: make bio mergeable
[ Upstream commit 9c573de328 ]

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>
2016-05-17 14:32:05 -04:00

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