When doing UFFDIO_COPY, it is necessary to find the correct destination
vma and make sure fault range is in it.

Since there are two places need to do the same task, just wrap those
common check into an inlined function.

Link: http://lkml.kernel.org/r/20190927070032.2129-3-richardw.yang@linux.intel.comSigned-off-by: Wei Yang <richardw.yang@linux.intel.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>