block: force an unlimited segment size on queues with a virt boundary (09324d32) · Commits · 戴 / test

We currently fail to update the front/back segment size in the bio when deciding to allow an otherwise gappy segement to a device with a virt boundary. The reason why this did not cause problems is that devices with a virt boundary fundamentally don't use segments as we know it and thus don't care. Make that assumption formal by forcing an unlimited segement size in this case. Fixes: ("block: don't check if adjacent bvecs in one bio can be mergeable") Signed-off-by:

Christoph Hellwig <hch@lst.de> Reviewed-by:

Ming Lei <ming.lei@redhat.com> Reviewed-by:

Hannes Reinecke <hare@suse.com> Signed-off-by:

Jens Axboe <axboe@kernel.dk>

block/blk-settings.c

+11 −0

Original line number	Diff line number	Diff line
		@@ -310,6 +310,9 @@ void blk_queue_max_segment_size(struct request_queue *q, unsigned int max_size)
		__func__, max_size);
		}

		/* see blk_queue_virt_boundary() for the explanation */
		WARN_ON_ONCE(q->limits.virt_boundary_mask);

		q->limits.max_segment_size = max_size;
		}
		EXPORT_SYMBOL(blk_queue_max_segment_size);
		@@ -742,6 +745,14 @@ EXPORT_SYMBOL(blk_queue_segment_boundary);
		void blk_queue_virt_boundary(struct request_queue *q, unsigned long mask)
		{
		q->limits.virt_boundary_mask = mask;

		/*
		* Devices that require a virtual boundary do not support scatter/gather
		* I/O natively, but instead require a descriptor list entry for each
		* page (which might not be idential to the Linux PAGE_SIZE). Because
		* of that they are not limited by our notion of "segment size".
		*/
		q->limits.max_segment_size = UINT_MAX;
		}
		EXPORT_SYMBOL(blk_queue_virt_boundary);

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