On Mon, Mar 30, 2026 at 01:11:08PM +0300, Mike Rapoport wrote: > First, there is no fundamental reason to limit userfaultfd support only to > the core memory types and userfaults can be handled similarly to regular > page faults provided a VMA owner implements appropriate callbacks. > > Second, historically various code paths were conditioned on > vma_is_anonymous(), vma_is_shmem() and is_vm_hugetlb_page() and some of > these conditions can be expressed as operations implemented by a > particular memory type. > > Introduce vm_uffd_ops extension to vm_operations_struct that will delegate > memory type specific operations to a VMA owner.
But the VMA owner already gets control of the page fault. We don't need the vm_uffd_ops to be accessible from the vm_operations_struct. The page faullt handler can pass a vm_uffd_ops into the uffd functions that it calls.
