| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 22/67] MD: make bio mergeable | Date | Mon, 9 May 2016 09:18:27 +0200 |
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4.4-stable review patch. If anyone has any objections, please let me know.
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From: Shaohua Li <shli@fb.com>
commit 9c573de3283af007ea11c17bde1e4568d9417328 upstream.
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: 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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/md/md.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -293,6 +293,8 @@ static blk_qc_t md_make_request(struct r * 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();
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