On Thu, 30 Nov 2023 04:45:58 -0500, "Michael S. Tsirkin" <mst@xxxxxxxxxx> wrote:
> On Thu, Aug 10, 2023 at 08:30:56PM +0800, Xuan Zhuo wrote:
> > These API has been introduced:
> >
> > * virtqueue_dma_need_sync
> > * virtqueue_dma_sync_single_range_for_cpu
> > * virtqueue_dma_sync_single_range_for_device
> >
> > These APIs can be used together with the premapped mechanism to sync the
> > DMA address.
> >
> > Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
> > ---
> > drivers/virtio/virtio_ring.c | 76 ++++++++++++++++++++++++++++++++++++
> > include/linux/virtio.h | 8 ++++
> > 2 files changed, 84 insertions(+)
> >
> > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> > index 916479c9c72c..81ecb29c88f1 100644
> > --- a/drivers/virtio/virtio_ring.c
> > +++ b/drivers/virtio/virtio_ring.c
> > @@ -3175,4 +3175,80 @@ int virtqueue_dma_mapping_error(struct virtqueue *_vq, dma_addr_t addr)
> > }
> > EXPORT_SYMBOL_GPL(virtqueue_dma_mapping_error);
> >
> > +/**
> > + * virtqueue_dma_need_sync - check a dma address needs sync
> > + * @_vq: the struct virtqueue we're talking about.
> > + * @addr: DMA address
> > + *
> > + * Check if the dma address mapped by the virtqueue_dma_map_* APIs needs to be
> > + * synchronized
> > + *
> > + * return bool
> > + */
> > +bool virtqueue_dma_need_sync(struct virtqueue *_vq, dma_addr_t addr)
> > +{
> > + struct vring_virtqueue *vq = to_vvq(_vq);
> > +
> > + if (!vq->use_dma_api)
> > + return false;
> > +
> > + return dma_need_sync(vring_dma_dev(vq), addr);
> > +}
> > +EXPORT_SYMBOL_GPL(virtqueue_dma_need_sync);
> > +
> > +/**
> > + * virtqueue_dma_sync_single_range_for_cpu - dma sync for cpu
> > + * @_vq: the struct virtqueue we're talking about.
> > + * @addr: DMA address
> > + * @offset: DMA address offset
> > + * @size: buf size for sync
> > + * @dir: DMA direction
> > + *
> > + * Before calling this function, use virtqueue_dma_need_sync() to confirm that
> > + * the DMA address really needs to be synchronized
> > + *
> > + */
> > +void virtqueue_dma_sync_single_range_for_cpu(struct virtqueue *_vq,
> > + dma_addr_t addr,
> > + unsigned long offset, size_t size,
> > + enum dma_data_direction dir)
> > +{
> > + struct vring_virtqueue *vq = to_vvq(_vq);
> > + struct device *dev = vring_dma_dev(vq);
> > +
> > + if (!vq->use_dma_api)
> > + return;
> > +
> > + dma_sync_single_range_for_cpu(dev, addr, offset, size,
> > + DMA_BIDIRECTIONAL);
> > +}
>
>
> Why did you use DMA_BIDIRECTIONAL here?
> Why is "dir" ignored?
This is a mistake.
I see Jason has a fix patch.
How can I help?
Thanks.
>
>
> > +EXPORT_SYMBOL_GPL(virtqueue_dma_sync_single_range_for_cpu);
> > +
> > +/**
> > + * virtqueue_dma_sync_single_range_for_device - dma sync for device
> > + * @_vq: the struct virtqueue we're talking about.
> > + * @addr: DMA address
> > + * @offset: DMA address offset
> > + * @size: buf size for sync
> > + * @dir: DMA direction
> > + *
> > + * Before calling this function, use virtqueue_dma_need_sync() to confirm that
> > + * the DMA address really needs to be synchronized
> > + */
> > +void virtqueue_dma_sync_single_range_for_device(struct virtqueue *_vq,
> > + dma_addr_t addr,
> > + unsigned long offset, size_t size,
> > + enum dma_data_direction dir)
> > +{
> > + struct vring_virtqueue *vq = to_vvq(_vq);
> > + struct device *dev = vring_dma_dev(vq);
> > +
> > + if (!vq->use_dma_api)
> > + return;
> > +
> > + dma_sync_single_range_for_device(dev, addr, offset, size,
> > + DMA_BIDIRECTIONAL);
> > +}
> > +EXPORT_SYMBOL_GPL(virtqueue_dma_sync_single_range_for_device);
> > +
> > MODULE_LICENSE("GPL");
>
> same question here.
>
> > diff --git a/include/linux/virtio.h b/include/linux/virtio.h
> > index 79e3c74391e0..1311a7fbe675 100644
> > --- a/include/linux/virtio.h
> > +++ b/include/linux/virtio.h
> > @@ -220,4 +220,12 @@ void virtqueue_dma_unmap_single_attrs(struct virtqueue *_vq, dma_addr_t addr,
> > size_t size, enum dma_data_direction dir,
> > unsigned long attrs);
> > int virtqueue_dma_mapping_error(struct virtqueue *_vq, dma_addr_t addr);
> > +
> > +bool virtqueue_dma_need_sync(struct virtqueue *_vq, dma_addr_t addr);
> > +void virtqueue_dma_sync_single_range_for_cpu(struct virtqueue *_vq, dma_addr_t addr,
> > + unsigned long offset, size_t size,
> > + enum dma_data_direction dir);
> > +void virtqueue_dma_sync_single_range_for_device(struct virtqueue *_vq, dma_addr_t addr,
> > + unsigned long offset, size_t size,
> > + enum dma_data_direction dir);
> > #endif /* _LINUX_VIRTIO_H */
> > --
> > 2.32.0.3.g01195cf9f
>
>
