From: Ming Lei ming.lei@redhat.com
mainline inclusion from mainline-v5.9-rc3 commit 943b40c832beb71115e38a1c4d99b640b5342738 category: bugfix bugzilla: 41908 CVE: NA
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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 --- 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 044bff9afa5e7..d24a6c9398ed8 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)