On Wed, 12 Jul 2023 16:31:35 +0800, Jason Wang <jasowang@xxxxxxxxxx> wrote:
> On Mon, Jul 10, 2023 at 11:42 AM Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> wrote:
> >
> > If the vq is the premapped mode, use the sg_dma_address() directly.
> >
> > Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
> > ---
> > drivers/virtio/virtio_ring.c | 19 +++++++++++++++++--
> > 1 file changed, 17 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> > index 5ace4539344c..d471dee3f4f7 100644
> > --- a/drivers/virtio/virtio_ring.c
> > +++ b/drivers/virtio/virtio_ring.c
> > @@ -361,6 +361,11 @@ static struct device *vring_dma_dev(const struct vring_virtqueue *vq)
> > static int vring_map_one_sg(const struct vring_virtqueue *vq, struct scatterlist *sg,
> > enum dma_data_direction direction, dma_addr_t *addr)
> > {
> > + if (vq->premapped) {
> > + *addr = sg_dma_address(sg);
> > + return 0;
> > + }
> > +
> > if (!vq->use_dma_api) {
> > /*
> > * If DMA is not used, KMSAN doesn't know that the scatterlist
> > @@ -639,8 +644,12 @@ static inline int virtqueue_add_split(struct virtqueue *_vq,
> > dma_addr_t addr = vring_map_single(
> > vq, desc, total_sg * sizeof(struct vring_desc),
> > DMA_TO_DEVICE);
> > - if (vring_mapping_error(vq, addr))
> > + if (vring_mapping_error(vq, addr)) {
> > + if (vq->premapped)
> > + goto free_indirect;
>
> Under which case could we hit this? A bug of the driver?
Here the map operate is for the indirect descs array.
So this is done inside the virtio core.
Thanks.
>
> Thanks
>
> > +
> > goto unmap_release;
> > + }
> >
> > virtqueue_add_desc_split(_vq, vq->split.vring.desc,
> > head, addr,
> > @@ -706,6 +715,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq,
> > i = vring_unmap_one_split(vq, i);
> > }
> >
> > +free_indirect:
> > if (indirect)
> > kfree(desc);
> >
> > @@ -1307,8 +1317,12 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
> > addr = vring_map_single(vq, desc,
> > total_sg * sizeof(struct vring_packed_desc),
> > DMA_TO_DEVICE);
> > - if (vring_mapping_error(vq, addr))
> > + if (vring_mapping_error(vq, addr)) {
> > + if (vq->premapped)
> > + goto free_desc;
> > +
> > goto unmap_release;
> > + }
> >
> > vq->packed.vring.desc[head].addr = cpu_to_le64(addr);
> > vq->packed.vring.desc[head].len = cpu_to_le32(total_sg *
> > @@ -1366,6 +1380,7 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
> > for (i = 0; i < err_idx; i++)
> > vring_unmap_desc_packed(vq, &desc[i]);
> >
> > +free_desc:
> > kfree(desc);
> >
> > END_USE(vq);
> > --
> > 2.32.0.3.g01195cf9f
> >
>
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