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

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