Re: [PATCH v2 4/7] iommu: Let iommu.strict override ops->def_domain_type

Jason Gunthorpe
2022-12-07T14:30:50Z

On Wed, Dec 07, 2022 at 02:18:36PM +0000, Robin Murphy wrote:
> On 2022-12-07 13:23, Jason Gunthorpe wrote:
> > On Wed, Dec 07, 2022 at 09:18:19PM +0800, Baolu Lu wrote:
> >
> > > > - /* Check if the device in the group still has a driver bound to it */
> > > > - device_lock(dev);
> > >
> > > With device_lock() removed, this probably races with the
> > > iommu_release_device() path? group->mutex seems insufficient to avoid
> > > the race. Perhaps I missed anything.
> >
> > This path only deals with group, so there is no 'dev' and no race with
> > removal.
>
> If we can now use the ownership mechanism to enforce the required
> constraints for change_dev_def_domain, that would be worthwhile (and a lot
> clearer) as a separate patch in its own right.

Oh for sure, this is just a brain dump to share

I have a few other patches streamlining things in this file, just need time...

Jason