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?
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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