On Mon, Feb 20, 2023 at 3:05 PM Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> wrote:
>
> On Mon, 20 Feb 2023 13:38:20 +0800, Jason Wang <jasowang@xxxxxxxxxx> wrote:
> > On Tue, Feb 14, 2023 at 3:27 PM Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> wrote:
> > >
> > > These API has been introduced:
> > >
> > > * virtio_dma_need_sync
> > > * virtio_dma_sync_single_range_for_cpu
> > > * virtio_dma_sync_single_range_for_device
> >
> > What's the advantages of exporting internal logic like
> > virtio_dma_need_sync() over hiding it in
> > virtio_dma_sync_single_range_for_cpu() and
> > virtio_dma_sync_single_range_for_device()?
>
> Sorry, I didn't understand it.
I meant:
virtio_dma_sync_single_range_for_cpu()
{
if (!virtio_dma_need_sync())
return;
......
}
Thanks
>
> Thanks.
>
> >
> > Thanks
> >
> >
> > >
> > > 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 | 70 ++++++++++++++++++++++++++++++++++++
> > > include/linux/virtio.h | 8 +++++
> > > 2 files changed, 78 insertions(+)
> > >
> > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> > > index 855338609c7f..84129b8c3e2a 100644
> > > --- a/drivers/virtio/virtio_ring.c
> > > +++ b/drivers/virtio/virtio_ring.c
> > > @@ -3264,4 +3264,74 @@ void virtio_dma_unmap(struct device *dev, dma_addr_t dma, unsigned int length,
> > > }
> > > EXPORT_SYMBOL_GPL(virtio_dma_unmap);
> > >
> > > +/**
> > > + * virtio_dma_need_sync - check a dma address needs sync
> > > + * @dev: virtio device
> > > + * @addr: DMA address
> > > + *
> > > + * This API is only for pre-mapped buffers, for non premapped buffers virtio
> > > + * core handles DMA API internally.
> > > + */
> > > +bool virtio_dma_need_sync(struct device *dev, dma_addr_t addr)
> > > +{
> > > + struct virtio_device *vdev = dev_to_virtio(dev);
> > > +
> > > + if (!vring_use_dma_api(vdev))
> > > + return 0;
> > > +
> > > + return dma_need_sync(vdev->dev.parent, addr);
> > > +}
> > > +EXPORT_SYMBOL_GPL(virtio_dma_need_sync);
> > > +
> > > +/**
> > > + * virtio_dma_sync_single_range_for_cpu - dma sync for cpu
> > > + * @dev: virtio device
> > > + * @addr: DMA address
> > > + * @offset: DMA address offset
> > > + * @size: mem size for sync
> > > + * @dir: DMA direction
> > > + *
> > > + * Before calling this function, use virtio_dma_need_sync() to confirm that the
> > > + * DMA address really needs to be synchronized
> > > + *
> > > + * This API is only for pre-mapped buffers, for non premapped buffers virtio
> > > + * core handles DMA API internally.
> > > + */
> > > +void virtio_dma_sync_single_range_for_cpu(struct device *dev, dma_addr_t addr,
> > > + unsigned long offset, size_t size,
> > > + enum dma_data_direction dir)
> > > +{
> > > + struct virtio_device *vdev = dev_to_virtio(dev);
> > > +
> > > + dma_sync_single_range_for_cpu(vdev->dev.parent, addr, offset,
> > > + size, DMA_BIDIRECTIONAL);
> > > +}
> > > +EXPORT_SYMBOL_GPL(virtio_dma_sync_single_range_for_cpu);
> > > +
> > > +/**
> > > + * virtio_dma_sync_single_range_for_device - dma sync for device
> > > + * @dev: virtio device
> > > + * @addr: DMA address
> > > + * @offset: DMA address offset
> > > + * @size: mem size for sync
> > > + * @dir: DMA direction
> > > + *
> > > + * Before calling this function, use virtio_dma_need_sync() to confirm that the
> > > + * DMA address really needs to be synchronized
> > > + *
> > > + * This API is only for pre-mapped buffers, for non premapped buffers virtio
> > > + * core handles DMA API internally.
> > > + */
> > > +void virtio_dma_sync_single_range_for_device(struct device *dev,
> > > + dma_addr_t addr,
> > > + unsigned long offset, size_t size,
> > > + enum dma_data_direction dir)
> > > +{
> > > + struct virtio_device *vdev = dev_to_virtio(dev);
> > > +
> > > + dma_sync_single_range_for_device(vdev->dev.parent, addr, offset,
> > > + size, DMA_BIDIRECTIONAL);
> > > +}
> > > +EXPORT_SYMBOL_GPL(virtio_dma_sync_single_range_for_device);
> > > +
> > > MODULE_LICENSE("GPL");
> > > diff --git a/include/linux/virtio.h b/include/linux/virtio.h
> > > index b5fa71476737..d0e707d744a0 100644
> > > --- a/include/linux/virtio.h
> > > +++ b/include/linux/virtio.h
> > > @@ -225,4 +225,12 @@ dma_addr_t virtio_dma_map(struct device *dev, void *addr, unsigned int length,
> > > int virtio_dma_mapping_error(struct device *dev, dma_addr_t addr);
> > > void virtio_dma_unmap(struct device *dev, dma_addr_t dma, unsigned int length,
> > > enum dma_data_direction dir);
> > > +bool virtio_dma_need_sync(struct device *dev, dma_addr_t addr);
> > > +void virtio_dma_sync_single_range_for_cpu(struct device *dev, dma_addr_t addr,
> > > + unsigned long offset, size_t size,
> > > + enum dma_data_direction dir);
> > > +void virtio_dma_sync_single_range_for_device(struct device *dev,
> > > + dma_addr_t addr,
> > > + unsigned long offset, size_t size,
> > > + enum dma_data_direction dir);
> > > #endif /* _LINUX_VIRTIO_H */
> > > --
> > > 2.32.0.3.g01195cf9f
> > >
> >
>
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