Re: [PATCH] userfaultfd: fix remap event with MREMAP_DONTUNMAP.

[Brian Geffon]

> > -       mremap_userfaultfd_complete(&uf, addr, new_addr, old_len);
> > +       mremap_userfaultfd_complete(&uf, addr, ret, old_len);
>
> Not super familiar with this code, but thought I'd ask, does ret
> to be checked for -ENOMEM before calling mremap_userfaultfd_complete?
> Sorry if I missed something.

No, mremap_userfaultfd_complete will do a check similar to
offset_in_page() by checking the page mask.
It does (to & ~PAGE_MASK) to check for a non-aligned "to" value, so we're good.

Additionally, earlier in the process then ctx will be null because we
will have never called mremap_userfaultfd_prep,
and mremap_userfaultfd_complete will check if there is a context
before proceeding.

Brian