mm/mempolicy: use vma_lookup() in __access_remote_vm()

vma_lookup() finds the vma of a specific address with a cleaner interface
and is more readable.

Link: https://lkml.kernel.org/r/20210521174745.2219620-23-Liam.Howlett@Oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/mempolicy.c

@@ -975,7 +975,7 @@ static long do_get_mempolicy(int *policy, nodemask_t *nmask,
 		 * want to return MPOL_DEFAULT in this case.
 		 */
 		mmap_read_lock(mm);
-		vma = find_vma_intersection(mm, addr, addr+1);
+		vma = vma_lookup(mm, addr);
 		if (!vma) {
 			mmap_read_unlock(mm);
 			return -EFAULT;