[PATCH v3 03/16] iommufd/viommu: Add IOMMU_VDEVICE_ALLOC ioctl

[Jason Gunthorpe]

On Sat, Oct 19, 2024 at 06:42:30PM -0700, Nicolin Chen wrote:
> > But be mindful of this abort, it doesn't want to be inside the lock if
> > it also gets the lock.. fail_nth should be updated to cover these new
> > ioctls to look for tricky things like that
> 
> I added an abort() beside destroy():
> 
> +void iommufd_vdevice_abort(struct iommufd_object *obj)
> +{
> +       struct iommufd_vdevice *old, *vdev =
> +               container_of(obj, struct iommufd_vdevice, obj);
> +       struct iommufd_viommu *viommu = vdev->viommu;
> +       struct iommufd_device *idev = vdev->idev;
> +
> +       lockdep_assert_not_held(&idev->igroup->lock);

???

> +
> +       if (viommu->ops && viommu->ops->vdevice_free)
> +               viommu->ops->vdevice_free(vdev);
> +
> +       old = xa_cmpxchg(&viommu->vdevs, vdev->id, vdev, NULL, GFP_KERNEL);
> +       if (old)
> +               WARN_ON(old != vdev);
> +
> +       refcount_dec(&viommu->obj.users);
> +       refcount_dec(&idev->obj.users);
> +       idev->vdev = NULL;
> +}
> +
> +void iommufd_vdevice_destroy(struct iommufd_object *obj)
> +{
> +       struct iommufd_vdevice *vdev =
> +               container_of(obj, struct iommufd_vdevice, obj);
> +
> +       mutex_lock(&vdev->idev->igroup->lock);
> +       iommufd_vdevice_abort(obj);

When we get it here??

Jason