diff options
| author | Ming Lei | 2021-06-28 10:33:12 +0800 |
|---|---|---|
| committer | Jens Axboe | 2021-06-29 07:41:08 -0600 |
| commit | 2705dfb2094777e405e065105e307074af8965c1 (patch) | |
| tree | 1fdc528a77f5be9455dcedf07b303dbceac04bd1 | |
| parent | c06bc5a3fb42304d815a2dc41e324b5a97c9f7da (diff) | |
block: fix discard request merge
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>
| -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 1398b52a24b4..a11b3b53717e 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -559,10 +559,14 @@ 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; /* |