On Tue, Feb 14, 2023 at 3:27 PM Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> wrote:
>
> DMA-related logic is separated from virtqueue_add_packed to prepare for
> the subsequent support for premapped.
As stated in patch 1, I think it's better to split.
>
> Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
> ---
> drivers/virtio/virtio_ring.c | 150 ++++++++++++++++++-----------------
> 1 file changed, 78 insertions(+), 72 deletions(-)
>
> diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> index 42b1ff87518e..47b6f9152f9f 100644
> --- a/drivers/virtio/virtio_ring.c
> +++ b/drivers/virtio/virtio_ring.c
> @@ -1329,7 +1329,6 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
> unsigned int total_sg,
> unsigned int out_sgs,
> unsigned int in_sgs,
> - void *data,
> struct vring_packed_desc *desc)
> {
> struct scatterlist *sg;
> @@ -1345,14 +1344,9 @@ 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++;
> }
> @@ -1363,7 +1357,7 @@ 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 *
> @@ -1404,53 +1398,30 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
>
> /* Store token and indirect buffer state. */
> vq->packed.desc_state[id].num = 1;
> - vq->packed.desc_state[id].data = data;
> vq->packed.desc_state[id].indir_desc = desc;
> vq->packed.desc_state[id].last = id;
>
> vq->num_added += 1;
>
> pr_debug("Added buffer head %i to %p\n", head, vq);
> - END_USE(vq);
>
> return 0;
> -
> -unmap_release:
> - err_idx = i;
> -
> - for (i = 0; i < err_idx; i++)
> - vring_unmap_desc_packed(vq, &desc[i]);
> -
> - kfree(desc);
> -
> - END_USE(vq);
> - return -ENOMEM;
> }
>
> -static inline int virtqueue_add_packed(struct virtqueue *_vq,
> - struct scatterlist *sgs[],
> - unsigned int total_sg,
> - unsigned int out_sgs,
> - unsigned int in_sgs,
> - void *data,
> - void *ctx,
> - gfp_t gfp)
> +static inline int virtqueue_add_packed_prepare(struct vring_virtqueue *vq,
> + unsigned int total_sg,
> + void *data,
> + void *ctx,
> + struct vring_packed_desc **pdesc,
> + gfp_t gfp)
> {
> - struct vring_virtqueue *vq = to_vvq(_vq);
> struct vring_packed_desc *desc;
> - struct scatterlist *sg;
> - unsigned int i, n, c, descs_used, err_idx;
> - __le16 head_flags, flags;
> - u16 head, id, prev, curr, avail_used_flags;
> - int err;
> -
> - START_USE(vq);
> + unsigned int descs_used;
>
> BUG_ON(data == NULL);
> BUG_ON(ctx && vq->indirect);
>
> if (unlikely(vq->broken)) {
> - END_USE(vq);
> return -EIO;
> }
>
> @@ -1458,39 +1429,55 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq,
>
> BUG_ON(total_sg == 0);
>
> + desc = NULL;
> +
> if (virtqueue_use_indirect(vq, total_sg)) {
> desc = alloc_indirect_packed(total_sg, gfp);
> if (desc) {
> if (unlikely(vq->vq.num_free < 1)) {
> pr_debug("Can't add buf len 1 - avail = 0\n");
> kfree(desc);
> - END_USE(vq);
> return -ENOSPC;
> }
>
> - return virtqueue_add_indirect_packed(vq, sgs, total_sg, out_sgs,
> - in_sgs, data, desc);
> + return 0;
> }
>
> /* fall back on direct */
> }
>
> - head = vq->packed.next_avail_idx;
> - avail_used_flags = vq->packed.avail_used_flags;
> -
> WARN_ON_ONCE(total_sg > vq->packed.vring.num && !vq->indirect);
>
> - desc = vq->packed.vring.desc;
> - i = head;
> descs_used = total_sg;
>
> if (unlikely(vq->vq.num_free < descs_used)) {
> pr_debug("Can't add buf len %i - avail = %i\n",
> descs_used, vq->vq.num_free);
> - END_USE(vq);
> return -ENOSPC;
> }
>
> + *pdesc = desc;
> +
> + return 0;
> +}
> +
> +static void virtqueue_add_packed_vring(struct vring_virtqueue *vq,
> + struct scatterlist *sgs[],
> + unsigned int total_sg,
> + unsigned int out_sgs,
> + unsigned int in_sgs)
> +{
> + struct vring_packed_desc *desc;
> + struct scatterlist *sg;
> + unsigned int i, n, c, descs_used;
> + __le16 head_flags, flags;
> + u16 head, id, prev, curr;
> +
> + desc = vq->packed.vring.desc;
> + head = vq->packed.next_avail_idx;
> + i = head;
> + descs_used = total_sg;
> +
> id = vq->free_head;
> BUG_ON(id == vq->packed.vring.num);
>
> @@ -1498,11 +1485,6 @@ static inline int virtqueue_add_packed(struct 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));
> @@ -1511,12 +1493,12 @@ static inline int virtqueue_add_packed(struct 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);
> @@ -1545,8 +1527,6 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq,
>
> /* Store token. */
> vq->packed.desc_state[id].num = descs_used;
> - vq->packed.desc_state[id].data = data;
> - vq->packed.desc_state[id].indir_desc = ctx;
> vq->packed.desc_state[id].last = prev;
>
> /*
> @@ -1559,29 +1539,55 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq,
> vq->num_added += descs_used;
>
> pr_debug("Added buffer head %i to %p\n", head, vq);
> - END_USE(vq);
> +}
>
> - return 0;
> +static inline int virtqueue_add_packed(struct virtqueue *_vq,
> + struct scatterlist *sgs[],
> + unsigned int total_sg,
> + unsigned int out_sgs,
> + unsigned int in_sgs,
> + void *data,
> + void *ctx,
> + gfp_t gfp)
> +{
> + struct vring_virtqueue *vq = to_vvq(_vq);
> + struct vring_packed_desc *desc;
> + u16 id;
> + int err;
>
> -unmap_release:
> - err_idx = i;
> - i = head;
> - curr = vq->free_head;
> + START_USE(vq);
>
> - vq->packed.avail_used_flags = avail_used_flags;
> + /* check vq state and try to alloc desc for indirect. */
> + err = virtqueue_add_packed_prepare(vq, total_sg, data, ctx, &desc, gfp);
> + if (err)
> + goto end;
>
> - 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;
> + err = virtqueue_map_sgs(vq, sgs, total_sg, out_sgs, in_sgs);
> + if (err)
> + goto err;
> +
> + id = vq->free_head;
> +
> + if (desc) {
> + err = virtqueue_add_indirect_packed(vq, sgs, total_sg, out_sgs, in_sgs, desc);
> + if (err)
> + goto err;
> + } else {
> + virtqueue_add_packed_vring(vq, sgs, total_sg, out_sgs, in_sgs);
> + vq->packed.desc_state[id].indir_desc = ctx;
I think it's better to be consistent here, e.g split hides those into
virtqueue_add_split_vring().
Thanks
> }
>
> + vq->packed.desc_state[id].data = data;
> +
> + goto end;
> +
> +err:
> + virtqueue_unmap_sgs(vq, sgs, total_sg, out_sgs, in_sgs);
> + kfree(desc);
> +
> +end:
> END_USE(vq);
> - return -EIO;
> + return err;
> }
>
> static bool virtqueue_kick_prepare_packed(struct virtqueue *_vq)
> --
> 2.32.0.3.g01195cf9f
>
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