diff --git a/mm/readahead.c b/mm/readahead.c
index 7b05082c89ea2..b44f13ce59358 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -270,7 +270,7 @@ void page_cache_ra_unbounded(struct readahead_control *ractl,
 			 */
 			read_pages(ractl);
 			ractl->_index += min_nrpages;
-			i = ractl->_index + ractl->_nr_pages - index;
+			i = ractl->_index - index;
 			continue;
 		}
 
@@ -286,7 +286,7 @@ void page_cache_ra_unbounded(struct readahead_control *ractl,
 				break;
 			read_pages(ractl);
 			ractl->_index += min_nrpages;
-			i = ractl->_index + ractl->_nr_pages - index;
+			i = ractl->_index - index;
 			continue;
 		}
 		if (i == mark)