Commit fe4c3862 authored by Jason Wang's avatar Jason Wang Committed by Michael S. Tsirkin
Browse files

virtio_ring: introduce virtqueue_desc_add_split() 



This patch introduces a helper for storing descriptor in the
descriptor table for split virtqueue.

Signed-off-by: default avatarJason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20210604055350.58753-6-jasowang@redhat.com


Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 44593865

drivers/virtio/virtio_ring.c

+24 −15
Original line number Diff line number Diff line
@@ -415,6 +415,20 @@ static struct vring_desc *alloc_indirect_split(struct virtqueue *_vq, 
	return desc;

}



static inline unsigned int virtqueue_add_desc_split(struct virtqueue *vq,

						    struct vring_desc *desc,

						    unsigned int i,

						    dma_addr_t addr,

						    unsigned int len,

						    u16 flags)

{

	desc[i].flags = cpu_to_virtio16(vq->vdev, flags);

	desc[i].addr = cpu_to_virtio64(vq->vdev, addr);

	desc[i].len = cpu_to_virtio32(vq->vdev, len);



	return virtio16_to_cpu(vq->vdev, desc[i].next);

}



static inline int virtqueue_add_split(struct virtqueue *_vq,

				      struct scatterlist *sgs[],

				      unsigned int total_sg,
@@ -487,11 +501,9 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, 
			if (vring_mapping_error(vq, addr))

				goto unmap_release;



			desc[i].flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_NEXT);

			desc[i].addr = cpu_to_virtio64(_vq->vdev, addr);

			desc[i].len = cpu_to_virtio32(_vq->vdev, sg->length);

			prev = i;

			i = virtio16_to_cpu(_vq->vdev, desc[i].next);

			i = virtqueue_add_desc_split(_vq, desc, i, addr, sg->length,

						     VRING_DESC_F_NEXT);

		}

	}

	for (; n < (out_sgs + in_sgs); n++) {
@@ -500,11 +512,11 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, 
			if (vring_mapping_error(vq, addr))

				goto unmap_release;



			desc[i].flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_NEXT | VRING_DESC_F_WRITE);

			desc[i].addr = cpu_to_virtio64(_vq->vdev, addr);

			desc[i].len = cpu_to_virtio32(_vq->vdev, sg->length);

			prev = i;

			i = virtio16_to_cpu(_vq->vdev, desc[i].next);

			i = virtqueue_add_desc_split(_vq, desc, i, addr,

						     sg->length,

						     VRING_DESC_F_NEXT |

						     VRING_DESC_F_WRITE);

		}

	}

	/* Last one doesn't continue. */
@@ -518,13 +530,10 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, 
		if (vring_mapping_error(vq, addr))

			goto unmap_release;



		vq->split.vring.desc[head].flags = cpu_to_virtio16(_vq->vdev,

		virtqueue_add_desc_split(_vq, vq->split.vring.desc,

					 head, addr,

					 total_sg * sizeof(struct vring_desc),

			                 VRING_DESC_F_INDIRECT);

		vq->split.vring.desc[head].addr = cpu_to_virtio64(_vq->vdev,

				addr);



		vq->split.vring.desc[head].len = cpu_to_virtio32(_vq->vdev,

				total_sg * sizeof(struct vring_desc));

	}



	/* We're using some buffers from the free list. */