> From: Liu, Yi L <yi.l.liu@xxxxxxxxx>
> Sent: Monday, July 24, 2023 7:00 PM
>
> @@ -252,11 +258,20 @@ struct iommu_iotlb_gather {
> * @remove_dev_pasid: Remove any translation configurations of a specific
> * pasid, so that any DMA transactions with this pasid
> * will be blocked by the hardware.
> + * @hw_info_type: One of enum iommu_hw_info_type defined in
> + * include/uapi/linux/iommufd.h. It is used to tag the type
> + * of data returned by .hw_info callback. The drivers that
> + * support .hw_info callback should define a unique type
> + * in include/uapi/linux/iommufd.h. For the drivers that do
> + * not implement .hw_info callback, this field is
> + * IOMMU_HW_INFO_TYPE_NONE which is 0. Hence, such drivers
> + * do not need to care this field.
every time looking at this field the same question came out why it is required
(and looks I forgot your previous response).
e.g. why cannot the type be returned in @hw_info():
void *(*hw_info)(struct device *dev, u32 *length, int *type);
NULL callback implies IOMMU_HW_INFO_TYPE_NONE.
otherwise if there is a reason could you update the commit msg to reflect
it so I don't need to ask again next time? 😊
