block: respect queue limit of max discard segment (943b40c8) · Commits · 戴 / test

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: ("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>

block/blk-merge.c

+9 −2

Original line number	Diff line number	Diff line
		@@ -533,10 +533,17 @@ 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)
		@@ -624,7 +631,7 @@ 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)

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