Re: [PATCH 07/10] iommu/ipmmu-vmsa: Convert to generic_single_device_group()

[Jason Gunthorpe <jgg@nvidia.com>]

On Fri, Jul 21, 2023 at 07:20:21AM +0000, Tian, Kevin wrote:
> > From: Jason Gunthorpe <jgg@nvidia.com>
> > Sent: Wednesday, July 19, 2023 3:06 AM
> > 
> > -static struct iommu_group *ipmmu_find_group(struct device *dev)
> > -{
> > -	struct ipmmu_vmsa_device *mmu = to_ipmmu(dev);
> > -	struct iommu_group *group;
> > -
> > -	if (mmu->group)
> > -		return iommu_group_ref_get(mmu->group);
> > -
> > -	group = iommu_group_alloc();
> > -	if (!IS_ERR(group))
> > -		mmu->group = group;
> > -
> > -	return group;
> > -}
> 
> Looks existing code has a leak w/o freeing the group in ipmmu_remove().

IIRC many of the drivers had this, or other bugs here.
 
> While at it could you add a patch to fix it allowing backport and then this
> patch to convert to the generic helper?

It isn't worth it, these drivers are never removed, so it is a bug
that nobody will ever hit.

Jason