On Tue, 27 Apr 2021, Axel Rasmussen wrote:

This patch allows shmem-backed VMAs to be registered for minor faults.
Minor faults are appropriately relayed to userspace in the fault path,
for VMAs with the relevant flag.

This commit doesn't hook up the UFFDIO_CONTINUE ioctl for shmem-backed
minor faults, though, so userspace doesn't yet have a way to resolve
such faults.

Because of this, we also don't yet advertise this as a supported
feature. That will be done in a separate commit when the feature is
fully implemented.

Acked-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Axel Rasmussen <axelrasmussen@google.com>

Acked-by: Hugh Dickins <hughd@google.com>

---
 fs/userfaultfd.c |  3 +--
 mm/memory.c      |  8 +++++---
 mm/shmem.c       | 12 +++++++++++-
 3 files changed, 17 insertions(+), 6 deletions(-)