On Tue, Jan 24, 2023 at 01:43:21PM +0500, Muhammad Usama Anjum wrote:

Split mwriteprotect_range() to create a unlocked version. This
will be used in the next patch to write protect a memory area.
Add a helper function, wp_range_async() as well.

Signed-off-by: Muhammad Usama Anjum <redacted>

IIUC this patch is not needed.  You have a stable vma, so I think you can
directly use uffd_wp_range(), while most of the mwriteprotect_range() is
not needed.

There's one trivial detail of ignoring userfaultfd_ctx->mmap_changing when
it's set to true, but I don't think it applies here either because it was
used to resolve a problem in uffd non-cooperative mode on the predictable
behavior of events, here I don't think it matters a lot either.

-- 
Peter Xu