diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index d0904ac0aa93..e55b26a03037 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -574,7 +574,7 @@ static inline int virtqueue_add_split(struct vring_virtqueue *vq, struct vring_desc_extra *extra; struct scatterlist *sg; struct vring_desc *desc; - unsigned int i, n, avail, descs_used, prev, err_idx; + unsigned int i, n, avail, descs_used, err_idx, sg_count = 0; int head; bool indirect; @@ -634,42 +634,40 @@ static inline int virtqueue_add_split(struct vring_virtqueue *vq, for (sg = sgs[n]; sg; sg = sg_next(sg)) { dma_addr_t addr; u32 len; + u16 flags = 0; + + if (++sg_count != total_sg) + flags |= VRING_DESC_F_NEXT; if (vring_map_one_sg(vq, sg, DMA_TO_DEVICE, &addr, &len, premapped)) goto unmap_release; - prev = i; /* Note that we trust indirect descriptor * table since it use stream DMA mapping. */ - i = virtqueue_add_desc_split(vq, desc, extra, i, addr, len, - VRING_DESC_F_NEXT, - premapped); + i = virtqueue_add_desc_split(vq, desc, extra, i, addr, + len, flags, premapped); } } for (; n < (out_sgs + in_sgs); n++) { for (sg = sgs[n]; sg; sg = sg_next(sg)) { dma_addr_t addr; u32 len; + u16 flags = VRING_DESC_F_WRITE; + + if (++sg_count != total_sg) + flags |= VRING_DESC_F_NEXT; if (vring_map_one_sg(vq, sg, DMA_FROM_DEVICE, &addr, &len, premapped)) goto unmap_release; - prev = i; /* Note that we trust indirect descriptor * table since it use stream DMA mapping. */ - i = virtqueue_add_desc_split(vq, desc, extra, i, addr, len, - VRING_DESC_F_NEXT | - VRING_DESC_F_WRITE, - premapped); + i = virtqueue_add_desc_split(vq, desc, extra, i, addr, + len, flags, premapped); } } - /* Last one doesn't continue. */ - desc[prev].flags &= cpu_to_virtio16(vq->vq.vdev, ~VRING_DESC_F_NEXT); - if (!indirect && vring_need_unmap_buffer(vq, &extra[prev])) - vq->split.desc_extra[prev & (vq->split.vring.num - 1)].flags &= - ~VRING_DESC_F_NEXT; if (indirect) { /* Now that the indirect table is filled in, map it. */