mm/madvise: use vma_find() instead of vma linked list

madvise_walk_vmas() no longer uses linked list.

Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Alexandre Frade <kernel@xanmod.org>

mm/madvise.c

@@ -1241,7 +1241,7 @@ int madvise_walk_vmas(struct mm_struct *mm, unsigned long start,
 		if (start >= end)
 			break;
 		if (prev)
-			vma = prev->vm_next;
+			vma = find_vma(mm, prev->vm_end);
 		else	/* madvise_remove dropped mmap_lock */
 			vma = find_vma(mm, start);
 	}