Re: [PATCH v6 01/11] iommu: Add dma ownership management interfaces

[Robin Murphy]

On 2022-02-23 18:02, Jason Gunthorpe via iommu wrote:
> On Wed, Feb 23, 2022 at 06:00:06PM +0000, Robin Murphy wrote:
>
> > ...and equivalently just set owner_cnt directly to 0 here. I don't see a
> > realistic use-case for any driver to claim the same group more than once,
> > and allowing it in the API just feels like opening up various potential
> > corners for things to get out of sync.
>
> I am Ok if we toss it out to get this merged, as there is no in-kernel
> user right now.
>
> Something will have to come back for iommufd, but we can look at what
> is best suited then.

If iommufd plans to be too dumb to keep track of whether it already owns 
a given group or not, I can't see it dealing with attaching that group 
to a single domain no more than once, either ;)

Robin.