On Thu, Mar 16, 2023 at 12:17:11AM +0000, Tian, Kevin wrote: > > > > > > > > @@ -449,33 +450,18 @@ iommufd_access_create(struct > > > > iommufd_ctx > > > > > > > > refcount_inc(&access->obj.users); > > > > > > > > + mutex_init(&access->ioas_lock); > > > > > > > > access->ictx = ictx; > > > > > > > > iommufd_ctx_get(ictx); > > > > > > > > > > > > > > this refcnt get should be moved to the start given next patch > > > > > > > removes the reference in the caller side. > > > > This change is ok but seems not necessary. > > > > Yes, vfio_iommufd_emulated_bind() will not have reference on the > > ictx after the next patch. However, it gets reference only because it > > wants to store it in vfio_device. Now, it does not store it. So no get. > > I think the caller of vfio_iommufd_emulated_bind() should ensure > > the ictx is valid. Also check the physical device bind. So maybe not > > necessary to get ictx before calling iommufd_access_create(). This is > > the same with the vfio_iommufd_physical_bind() which calls > > iommufd_device_bind() without ictx get, and iommufd_device_bind() > > also gets ictx in the end. > > > > You are right. I overlooked the fact that ictx is already held by the > caller of bind. I am dropping it then :) Nic