On Tue, 10 Sep 2019 16:19:33 +0800
Jason Wang <jasowang@xxxxxxxxxx> wrote:
> This patch introduces mdev_set_dma_ops() which allows parent to set
> per device DMA ops. This help for the kernel driver to setup a correct
> DMA mappings.
>
> Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
> ---
> drivers/vfio/mdev/mdev_core.c | 7 +++++++
> include/linux/mdev.h | 2 ++
> 2 files changed, 9 insertions(+)
>
> diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
> index b558d4cfd082..eb28552082d7 100644
> --- a/drivers/vfio/mdev/mdev_core.c
> +++ b/drivers/vfio/mdev/mdev_core.c
> @@ -13,6 +13,7 @@
> #include <linux/uuid.h>
> #include <linux/sysfs.h>
> #include <linux/mdev.h>
> +#include <linux/dma-mapping.h>
>
> #include "mdev_private.h"
>
> @@ -27,6 +28,12 @@ static struct class_compat *mdev_bus_compat_class;
> static LIST_HEAD(mdev_list);
> static DEFINE_MUTEX(mdev_list_lock);
>
> +void mdev_set_dma_ops(struct mdev_device *mdev, struct dma_map_ops *ops)
> +{
> + set_dma_ops(&mdev->dev, ops);
> +}
> +EXPORT_SYMBOL(mdev_set_dma_ops);
> +
Why does mdev need to be involved here? Your sample driver in 4/4 calls
this from its create callback, where it could just as easily call:
set_dma_ops(mdev_dev(mdev), ops);
Thanks,
Alex
> struct device *mdev_parent_dev(struct mdev_device *mdev)
> {
> return mdev->parent->dev;
> diff --git a/include/linux/mdev.h b/include/linux/mdev.h
> index 0ce30ca78db0..7195f40bf8bf 100644
> --- a/include/linux/mdev.h
> +++ b/include/linux/mdev.h
> @@ -145,4 +145,6 @@ struct device *mdev_parent_dev(struct mdev_device *mdev);
> struct device *mdev_dev(struct mdev_device *mdev);
> struct mdev_device *mdev_from_dev(struct device *dev);
>
> +void mdev_set_dma_ops(struct mdev_device *mdev, struct dma_map_ops *ops);
> +
> #endif /* MDEV_H */
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