From: Ming Lei ming.lei@redhat.com
[ Upstream commit 943b40c832beb71115e38a1c4d99b640b5342738 ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- 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 93cff719b0661..c874931bae6b5 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -553,10 +553,17 @@ 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 *req, struct bio *bio, unsigned int nr_phys_segs) { - if (req->nr_phys_segments + nr_phys_segs > queue_max_segments(req->q)) + if (req->nr_phys_segments + nr_phys_segs > blk_rq_get_max_segments(req)) goto no_merge;
if (blk_integrity_merge_bio(req->q, req, bio) == false) @@ -640,7 +647,7 @@ static int ll_merge_requests_fn(struct request_queue *q, struct request *req, return 0;
total_phys_segments = req->nr_phys_segments + next->nr_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)