On 11/30/25 12:18, Mike Rapoport wrote:
From: "Mike Rapoport (Microsoft)" <[email protected]>
When a VMA is registered with userfaulfd in minor mode, its ->fault()
method should check if a folio exists in the page cache and if yes
->fault() should call handle_userfault(VM_UFFD_MINOR).
Instead of calling handle_userfault() directly from a specific ->fault()
implementation introduce new fault reason VM_FAULT_UFFD_MINOR that will
notify the core page fault handler that it should call
handle_userfaultfd(VM_UFFD_MINOR) to complete a page fault.
Replace a call to handle_userfault(VM_UFFD_MINOR) in shmem and use the
new VM_FAULT_UFFD_MINOR there instead.
For configurations that don't enable CONFIG_USERFAULTFD,
VM_FAULT_UFFD_MINOR is set to 0.
Suggested-by: David Hildenbrand (Red Hat) <[email protected]>
Signed-off-by: Mike Rapoport (Microsoft) <[email protected]>
---
LGTM and does not look too invasive for me.
Acked-by: David Hildenbrand (Red Hat) <[email protected]>
--
Cheers
David
