From: Ming Lei <ming.lei@redhat.com> mainline inclusion from mainline-v5.9-rc3 commit 943b40c832beb71115e38a1c4d99b640b5342738 category: bugfix bugzilla: 41908 CVE: NA --------------------------- When queue_max_discard_segments(q) is 1, blk_discard_mergable() will return false for discard request, then normal request merge is applied. However, only queue_max_segments() is checked, so max discard segment limit isn't respected. Check max discard segment limit in the request merge code for fixing the issue. Discard request failure of virtio_blk is fixed. Fixes: 69840466086d ("block: fix the DISCARD request merge") Signed-off-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Stefano Garzarella <sgarzare@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Conflict: block/blk-merge.c Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Yufen Yu <yuyufen@huawei.com> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> Signed-off-by: Cheng Jian <cj.chengjian@huawei.com> --- block/blk-merge.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/block/blk-merge.c b/block/blk-merge.c index 044bff9afa5e..d24a6c9398ed 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -477,13 +477,20 @@ int blk_rq_map_sg(struct request_queue *q, struct request *rq, } EXPORT_SYMBOL(blk_rq_map_sg); +static inline unsigned int blk_rq_get_max_segments(struct request *rq) +{ + if (req_op(rq) == REQ_OP_DISCARD) + return queue_max_discard_segments(rq->q); + return queue_max_segments(rq->q); +} + static inline int ll_new_hw_segment(struct request_queue *q, struct request *req, struct bio *bio) { int nr_phys_segs = bio_phys_segments(q, bio); - if (req->nr_phys_segments + nr_phys_segs > queue_max_segments(q)) + if (req->nr_phys_segments + nr_phys_segs > blk_rq_get_max_segments(req)) goto no_merge; if (blk_integrity_merge_bio(q, req, bio) == false) @@ -606,7 +613,7 @@ static int ll_merge_requests_fn(struct request_queue *q, struct request *req, total_phys_segments--; } - if (total_phys_segments > queue_max_segments(q)) + if (total_phys_segments > blk_rq_get_max_segments(req)) return 0; if (blk_integrity_merge_rq(q, req, next) == false) -- 2.25.1