On Thu, Mar 2, 2023 at 7:59 PM Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> wrote:
>
> DMA-related logic is separated from the virtqueue_add_vring_packed() to
> prepare for subsequent support for premapped.
>
> DMA address will be saved as sg->dma_address, then
> virtqueue_add_vring_packed() will use it directly.
>
> If it is a premapped scene, the transmitted sgs should have saved DMA
> address in dma_address, and in virtio core, we need to pass
> virtqueue_map_sgs().
>
> Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
> ---
> drivers/virtio/virtio_ring.c | 59 ++++++++----------------------------
> 1 file changed, 12 insertions(+), 47 deletions(-)
>
> diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> index 6796cbee0207..81a9c0692fec 100644
> --- a/drivers/virtio/virtio_ring.c
> +++ b/drivers/virtio/virtio_ring.c
> @@ -1350,7 +1350,7 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
> struct vring_packed_desc *desc)
> {
> struct scatterlist *sg;
> - unsigned int i, n, err_idx;
> + unsigned int i, n;
> u16 head, id;
> dma_addr_t addr;
>
> @@ -1362,14 +1362,9 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
>
> for (n = 0; n < out_sgs + in_sgs; n++) {
> for (sg = sgs[n]; sg; sg = sg_next(sg)) {
> - addr = vring_map_one_sg(vq, sg, n < out_sgs ?
> - DMA_TO_DEVICE : DMA_FROM_DEVICE);
> - if (vring_mapping_error(vq, addr))
> - goto unmap_release;
> -
> desc[i].flags = cpu_to_le16(n < out_sgs ?
> 0 : VRING_DESC_F_WRITE);
> - desc[i].addr = cpu_to_le64(addr);
> + desc[i].addr = cpu_to_le64(sg->dma_address);
> desc[i].len = cpu_to_le32(sg->length);
> i++;
> }
> @@ -1380,7 +1375,7 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
> total_sg * sizeof(struct vring_packed_desc),
> DMA_TO_DEVICE);
> if (vring_mapping_error(vq, addr))
> - goto unmap_release;
> + return -ENOMEM;
>
> vq->packed.vring.desc[head].addr = cpu_to_le64(addr);
> vq->packed.vring.desc[head].len = cpu_to_le32(total_sg *
> @@ -1429,16 +1424,6 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
> pr_debug("Added buffer head %i to %p\n", head, vq);
>
> return 0;
> -
> -unmap_release:
> - err_idx = i;
> -
> - for (i = 0; i < err_idx; i++)
> - vring_unmap_desc_packed(vq, &desc[i]);
> -
> - kfree(desc);
> -
> - return -ENOMEM;
> }
>
> static inline struct vring_packed_desc *virtqueue_get_desc_packed(struct vring_virtqueue *vq,
> @@ -1498,15 +1483,14 @@ static inline int virtqueue_add_vring_packed(struct vring_virtqueue *vq,
> {
> struct vring_packed_desc *desc;
> struct scatterlist *sg;
> - unsigned int i, n, c, descs_used, err_idx;
> + unsigned int i, n, c, descs_used;
> __le16 head_flags, flags;
> - u16 head, id, prev, curr, avail_used_flags;
> + u16 head, id, prev, curr;
>
> desc = vq->packed.vring.desc;
> head = vq->packed.next_avail_idx;
> i = head;
> descs_used = total_sg;
> - avail_used_flags = vq->packed.avail_used_flags;
>
> id = vq->free_head;
> BUG_ON(id == vq->packed.vring.num);
> @@ -1515,11 +1499,6 @@ static inline int virtqueue_add_vring_packed(struct vring_virtqueue *vq,
> c = 0;
> for (n = 0; n < out_sgs + in_sgs; n++) {
> for (sg = sgs[n]; sg; sg = sg_next(sg)) {
> - dma_addr_t addr = vring_map_one_sg(vq, sg, n < out_sgs ?
> - DMA_TO_DEVICE : DMA_FROM_DEVICE);
> - if (vring_mapping_error(vq, addr))
> - goto unmap_release;
> -
> flags = cpu_to_le16(vq->packed.avail_used_flags |
> (++c == total_sg ? 0 : VRING_DESC_F_NEXT) |
> (n < out_sgs ? 0 : VRING_DESC_F_WRITE));
> @@ -1528,12 +1507,12 @@ static inline int virtqueue_add_vring_packed(struct vring_virtqueue *vq,
> else
> desc[i].flags = flags;
>
> - desc[i].addr = cpu_to_le64(addr);
> + desc[i].addr = cpu_to_le64(sg->dma_address);
> desc[i].len = cpu_to_le32(sg->length);
> desc[i].id = cpu_to_le16(id);
>
> if (unlikely(vq->use_dma_api)) {
> - vq->packed.desc_extra[curr].addr = addr;
> + vq->packed.desc_extra[curr].addr = sg->dma_address;
> vq->packed.desc_extra[curr].len = sg->length;
> vq->packed.desc_extra[curr].flags =
> le16_to_cpu(flags);
> @@ -1576,25 +1555,6 @@ static inline int virtqueue_add_vring_packed(struct vring_virtqueue *vq,
> pr_debug("Added buffer head %i to %p\n", head, vq);
>
> return 0;
> -
> -unmap_release:
> - err_idx = i;
> - i = head;
> - curr = vq->free_head;
> -
> - vq->packed.avail_used_flags = avail_used_flags;
> -
> - for (n = 0; n < total_sg; n++) {
> - if (i == err_idx)
> - break;
> - vring_unmap_extra_packed(vq, &vq->packed.desc_extra[curr]);
> - curr = vq->packed.desc_extra[curr].next;
> - i++;
> - if (i >= vq->packed.vring.num)
> - i = 0;
> - }
> -
> - return -EIO;
> }
>
> static inline int virtqueue_add_packed(struct virtqueue *_vq,
> @@ -1621,6 +1581,10 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq,
> goto end;
> }
>
> + err = virtqueue_map_sgs(vq, sgs, total_sg, out_sgs, in_sgs);
> + if (err)
> + goto err;
> +
> id = vq->free_head;
>
> if (desc) {
> @@ -1637,6 +1601,7 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq,
> goto end;
>
> err:
> + virtqueue_unmap_sgs(vq, sgs, total_sg, out_sgs, in_sgs);
Similar to the case of split, if possible let's move it to
virtqueue_add_vring_packed() assuming virtqueue_add_vring_packed() and
virtqueue_add_indirect_packed() could be unified.
Thanks
> kfree(desc);
>
> end:
> --
> 2.32.0.3.g01195cf9f
>
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