On 4/25/22 06:53, Jean-Philippe Brucker wrote: > On Sat, Apr 23, 2022 at 07:13:39PM +0800, zhangfei....@foxmail.com wrote: >>>> On 5.17 >>>> fops_release is called automatically, as well as iommu_sva_unbind_device. >>>> On 5.18-rc1. >>>> fops_release is not called, have to manually call close(fd) >>> Right that's weird >> Looks it is caused by the fix patch, via mmget, which may add refcount of >> fd. > Yes indirectly I think: when the process mmaps the queue, mmap_region() > takes a reference to the uacce fd. That reference is released either by > explicit close() or munmap(), or by exit_mmap() (which is triggered by > mmput()). Since there is an mm->fd dependency, we cannot add a fd->mm > dependency, so no mmget()/mmput() in bind()/unbind(). > > I guess we should go back to refcounted PASIDs instead, to avoid freeing > them until unbind().
Yeah, this is a bit gnarly for -rc4. Let's just make sure there's nothing else simple we can do. How does the IOMMU hardware know that all activity to a given PASID is finished? That activity should, today, be independent of an mm or a fd's lifetime. _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
