Re: [PATCH 01/11] iommu: Add device dma ownership set/release interfaces

[Lu Baolu]

Hi Christoph,

On 11/15/21 9:14 PM, Christoph Hellwig wrote:
> On Mon, Nov 15, 2021 at 10:05:42AM +0800, Lu Baolu wrote:
> > +enum iommu_dma_owner {
> > +	DMA_OWNER_NONE,
> > +	DMA_OWNER_KERNEL,
> > +	DMA_OWNER_USER,
> > +};
> > +
>
> > +	enum iommu_dma_owner dma_owner;
> > +	refcount_t owner_cnt;
> > +	struct file *owner_user_file;
>
> I'd just overload the ownership into owner_user_file,
>
>   NULL			-> no owner
>   (struct file *)1UL)	-> kernel
>   real pointer		-> user
>
> Which could simplify a lot of the code dealing with the owner.

Yeah! Sounds reasonable. I will make this in the next version.

Best regards,
baolu