diff --git a/mm/filemap.c b/mm/filemap.c
index 182b218..0169033 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -213,7 +213,7 @@
 			 * some other bad page check should catch it later.
 			 */
 			page_mapcount_reset(page);
-			atomic_sub(mapcount, &page->_count);
+			page_ref_sub(page, mapcount);
 		}
 	}