On Tue, 7 Mar 2023 14:43:39 +0800, Jason Wang <jasowang@xxxxxxxxxx> wrote:
> On Thu, Mar 2, 2023 at 7:59 PM Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> wrote:
> >
> > DMA-related logic is separated from the virtqueue_add_vring_split() to
> > prepare for subsequent support for premapped.
> >
> > DMA address will be saved as sg->dma_address, then
> > virtqueue_add_vring_split() 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 | 116 ++++++++++++++++++++++++-----------
> > 1 file changed, 80 insertions(+), 36 deletions(-)
> >
> > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> > index 3005893ecc61..17520f0d7649 100644
> > --- a/drivers/virtio/virtio_ring.c
> > +++ b/drivers/virtio/virtio_ring.c
> > @@ -520,6 +520,73 @@ static inline unsigned int virtqueue_add_desc_split(struct virtqueue *vq,
> > return next;
> > }
> >
> > +static int virtqueue_map_sgs(struct vring_virtqueue *vq,
> > + struct scatterlist *sgs[],
> > + unsigned int total_sg,
> > + unsigned int out_sgs,
> > + unsigned int in_sgs)
> > +{
> > + struct scatterlist *sg;
> > + unsigned int n;
> > +
> > + for (n = 0; n < out_sgs; n++) {
> > + for (sg = sgs[n]; sg; sg = sg_next(sg)) {
> > + dma_addr_t addr = vring_map_one_sg(vq, sg, DMA_TO_DEVICE);
> > +
> > + if (vring_mapping_error(vq, addr))
> > + return -ENOMEM;
> > +
> > + sg->dma_address = addr;
> > + }
> > + }
> > +
> > + for (; 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, DMA_FROM_DEVICE);
> > +
> > + if (vring_mapping_error(vq, addr))
> > + return -ENOMEM;
> > +
> > + sg->dma_address = addr;
> > + }
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static void virtqueue_unmap_sgs(struct vring_virtqueue *vq,
> > + struct scatterlist *sgs[],
> > + unsigned int total_sg,
> > + unsigned int out_sgs,
> > + unsigned int in_sgs)
> > +{
> > + struct scatterlist *sg;
> > + unsigned int n;
> > +
> > + if (!vq->use_dma_api)
> > + return;
> > +
> > + for (n = 0; n < out_sgs; n++) {
> > + for (sg = sgs[n]; sg; sg = sg_next(sg)) {
> > + if (!sg->dma_address)
> > + return;
> > +
> > + dma_unmap_page(vring_dma_dev(vq), sg->dma_address,
> > + sg->length, DMA_TO_DEVICE);
> > + }
> > + }
> > +
> > + for (; n < (out_sgs + in_sgs); n++) {
> > + for (sg = sgs[n]; sg; sg = sg_next(sg)) {
> > + if (!sg->dma_address)
> > + return;
> > +
> > + dma_unmap_page(vring_dma_dev(vq), sg->dma_address,
> > + sg->length, DMA_FROM_DEVICE);
> > + }
> > + }
> > +}
> > +
> > /* note: return NULL means no indirect that is valid. */
> > static struct vring_desc *virtqueue_get_desc_split(struct vring_virtqueue *vq,
> > unsigned int total_sg,
> > @@ -577,7 +644,7 @@ static inline int virtqueue_add_vring_split(struct vring_virtqueue *vq,
> > {
> > struct virtqueue *_vq = &vq->vq;
> > struct scatterlist *sg;
> > - unsigned int i, n, avail, descs_used, prev, err_idx;
> > + unsigned int i, n, avail, descs_used, prev;
> > int head;
> > bool indirect;
> >
> > @@ -598,30 +665,25 @@ static inline int virtqueue_add_vring_split(struct vring_virtqueue *vq,
> >
> > for (n = 0; n < out_sgs; n++) {
> > for (sg = sgs[n]; sg; sg = sg_next(sg)) {
> > - dma_addr_t addr = vring_map_one_sg(vq, sg, DMA_TO_DEVICE);
> > - if (vring_mapping_error(vq, addr))
> > - 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, i, addr, sg->length,
> > + i = virtqueue_add_desc_split(_vq, desc, i,
> > + sg->dma_address,
> > + sg->length,
> > VRING_DESC_F_NEXT,
> > indirect);
> > }
> > }
> > for (; 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, DMA_FROM_DEVICE);
> > - if (vring_mapping_error(vq, addr))
> > - 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, i, addr,
> > + i = virtqueue_add_desc_split(_vq, desc, i,
> > + sg->dma_address,
> > sg->length,
> > VRING_DESC_F_NEXT |
> > VRING_DESC_F_WRITE,
> > @@ -640,7 +702,7 @@ static inline int virtqueue_add_vring_split(struct vring_virtqueue *vq,
> > vq, desc, total_sg * sizeof(struct vring_desc),
> > DMA_TO_DEVICE);
> > if (vring_mapping_error(vq, addr))
> > - goto unmap_release;
> > + return -ENOMEM;
> >
> > virtqueue_add_desc_split(_vq, vq->split.vring.desc,
> > head, addr,
> > @@ -680,30 +742,6 @@ static inline int virtqueue_add_vring_split(struct vring_virtqueue *vq,
> > virtqueue_kick(_vq);
> >
> > return 0;
> > -
> > -unmap_release:
> > - err_idx = i;
> > -
> > - if (indirect)
> > - i = 0;
> > - else
> > - i = head;
> > -
> > - for (n = 0; n < total_sg; n++) {
> > - if (i == err_idx)
> > - break;
> > - if (indirect) {
> > - vring_unmap_one_split_indirect(vq, &desc[i]);
> > - i = virtio16_to_cpu(_vq->vdev, desc[i].next);
> > - } else
> > - i = vring_unmap_one_split(vq, i);
> > - }
> > -
> > - if (indirect)
> > - kfree(desc);
> > -
> > - END_USE(vq);
> > - return -ENOMEM;
> > }
> >
> > static inline int virtqueue_add_split(struct virtqueue *_vq,
> > @@ -729,6 +767,10 @@ static inline int virtqueue_add_split(struct virtqueue *_vq,
> > goto end;
> > }
> >
> > + err = virtqueue_map_sgs(vq, sgs, total_sg, out_sgs, in_sgs);
> > + if (err)
> > + goto err;
> > +
> > head = vq->free_head;
> > err = virtqueue_add_vring_split(vq, sgs, total_sg, out_sgs, in_sgs, desc);
>
> Any reason we don't do virtqueue_map_sgs()/virtqueue_unmap_sgs()
> inside virtqueue_add_vring_split()?
As the answer to #1.
Thanks.
>
> Thanks
>
>
> > if (err)
> > @@ -741,6 +783,8 @@ static inline int virtqueue_add_split(struct virtqueue *_vq,
> > goto end;
> >
> > err:
> > + virtqueue_unmap_sgs(vq, sgs, total_sg, out_sgs, in_sgs);
> > +
> > kfree(desc);
> >
> > end:
> > --
> > 2.32.0.3.g01195cf9f
> >
>
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