diff options
author | Ming Lei <ming.lei@redhat.com> | 2021-06-28 05:33:12 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-07-14 17:53:19 +0300 |
commit | 05bc31902755f9a916f060257eb760d39cfd6ba7 (patch) | |
tree | bad3bde8c9abbca00abd01f93574854b97d48fc2 /block | |
parent | 8978dd2518985bf0cc14ab8b0a7883f9da58425e (diff) | |
download | linux-05bc31902755f9a916f060257eb760d39cfd6ba7.tar.xz |
block: fix discard request merge
[ Upstream commit 2705dfb2094777e405e065105e307074af8965c1 ]
ll_new_hw_segment() is reached only in case of single range discard
merge, and we don't have max discard segment size limit actually, so
it is wrong to run the following check:
if (req->nr_phys_segments + nr_phys_segs > blk_rq_get_max_segments(req))
it may be always false since req->nr_phys_segments is initialized as
one, and bio's segment count is still 1, blk_rq_get_max_segments(reg)
is 1 too.
Fix the issue by not doing the check and bypassing the calculation of
discard request's nr_phys_segments.
Based on analysis from Wang Shanker.
Cc: Christoph Hellwig <hch@lst.de>
Reported-by: Wang Shanker <shankerwangmiao@gmail.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20210628023312.1903255-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'block')
-rw-r--r-- | block/blk-merge.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/block/blk-merge.c b/block/blk-merge.c index 03959bfe961c..4b022f0c49d2 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -571,10 +571,14 @@ static inline unsigned int blk_rq_get_max_segments(struct request *rq) static inline int ll_new_hw_segment(struct request *req, struct bio *bio, unsigned int nr_phys_segs) { - if (req->nr_phys_segments + nr_phys_segs > blk_rq_get_max_segments(req)) + if (blk_integrity_merge_bio(req->q, req, bio) == false) goto no_merge; - if (blk_integrity_merge_bio(req->q, req, bio) == false) + /* discard request merge won't add new segment */ + if (req_op(req) == REQ_OP_DISCARD) + return 1; + + if (req->nr_phys_segments + nr_phys_segs > blk_rq_get_max_segments(req)) goto no_merge; /* |