1 files changed, 16 insertions, 2 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index cb476e70cf19..a29318147365 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -863,9 +863,13 @@ repeat:
                 page = radix_tree_deref_slot((void **)pages[i]);
                 if (unlikely(!page))
                         continue;
+
+                /*
+                 * This can only trigger when the entry at index 0 moves out
+                 * of or back to the root: none yet gotten, safe to restart.
+                 */
                 if (radix_tree_deref_retry(page)) {
-                        if (ret)
-                                start = pages[ret-1]->index;
+                        WARN_ON(start | i);
                         goto restart;
                 }
 
@@ -915,6 +919,11 @@ repeat:
                 page = radix_tree_deref_slot((void **)pages[i]);
                 if (unlikely(!page))
                         continue;
+
+                /*
+                 * This can only trigger when the entry at index 0 moves out
+                 * of or back to the root: none yet gotten, safe to restart.
+                 */
                 if (radix_tree_deref_retry(page))
                         goto restart;
 
@@ -975,6 +984,11 @@ repeat:
                 page = radix_tree_deref_slot((void **)pages[i]);
                 if (unlikely(!page))
                         continue;
+
+                /*
+                 * This can only trigger when the entry at index 0 moves out
+                 * of or back to the root: none yet gotten, safe to restart.
+                 */
                 if (radix_tree_deref_retry(page))
                         goto restart;