Re: [PATCH v4 4/7] iommufd: Destroy vdevice on idevice destroy

[Nicolin Chen <nicolinc@nvidia.com>]

On Mon, Jul 14, 2025 at 01:53:46PM -0300, Jason Gunthorpe wrote:
> On Tue, Jul 15, 2025 at 12:40:40AM +0800, Xu Yilun wrote:
> > diff --git a/drivers/iommu/iommufd/viommu.c b/drivers/iommu/iommufd/viommu.c
> > index 702ae248df17..bdd5a5227cbf 100644
> > --- a/drivers/iommu/iommufd/viommu.c
> > +++ b/drivers/iommu/iommufd/viommu.c
> > @@ -128,7 +128,8 @@ void iommufd_vdevice_destroy(struct iommufd_object *obj)
> >         mutex_lock(&idev->igroup->lock);
> >         iommufd_vdevice_abort(obj);
> >         mutex_unlock(&idev->igroup->lock);
> > -       iommufd_put_object(idev->ictx, &idev->obj);
> > +       refcount_dec(&idev->obj.shortterm_users);
> > +       wake_up_interruptible_all(&vdev->viommu->ictx->destroy_wait);
> >  }
> 
> I think the main point of keeping both refcounts is to keep the above
> hidden in the main functions and out of the object functions.

I see. Maybe we can just update the comments that we are keeping
both refcounts but using shortterm_users only to do the trick.

Otherwise, we'd need an iommufd_lock_obj_shortterm..

Thanks
Nicolin