Re: [PATCH 5/5] iommu: Retire group->domain

[Jason Gunthorpe <jgg@nvidia.com>]

On Thu, Feb 20, 2025 at 12:01:56PM +0800, Yi Liu wrote:
> On 2025/2/19 21:10, Jason Gunthorpe wrote:
> > On Wed, Feb 19, 2025 at 08:31:52PM +0800, Yi Liu wrote:
> > > > > And then iommu_get_domain_for_dev() which explains it is an older
> > > > > function that depends on the caller somehow ensuring that the attached
> > > > > domain cannot change. Ideally we would someday try to remove calls to
> > > > > iommu_get_domain_for_dev()..
> > > 
> > > currently, the paths hold group->mutex are mostly in the iommu drivers.
> > > So what we may do is updating the iommu drivers to use a version that
> > > has lockdep. While other callers keep using the iommu_get_domain_for_dev().
> > 
> > Honestly I would prefer to pass the old domain in as a function argument to
> > attach and remove the calls entirely.
> 
> hmmm. I may drop the retire group->domain from this series to avoid
> blocking the iommufd pasid series.

Ok

> yes. Since group->domain is set/clear under group->mutex as well. So I'm
> wondering if it is ok to add kdoc to iommu_get_domain_for_dev() to note
> it, and just add the xa_load && entry_decode stuffs without lockdep?

Yes, kdoc is the way to go here

Jason