diff --git a/mm/filemap.c b/mm/filemap.c
index 96778fa..645a080 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -700,10 +700,14 @@
 		if (unlikely(!page))
 			goto out;
 		if (radix_tree_exception(page)) {
-			if (radix_tree_exceptional_entry(page))
-				goto out;
-			/* radix_tree_deref_retry(page) */
-			goto repeat;
+			if (radix_tree_deref_retry(page))
+				goto repeat;
+			/*
+			 * Otherwise, shmem/tmpfs must be storing a swap entry
+			 * here as an exceptional entry: so return it without
+			 * attempting to raise page count.
+			 */
+			goto out;
 		}
 		if (!page_cache_get_speculative(page))
 			goto repeat;
@@ -838,15 +842,21 @@
 			continue;
 
 		if (radix_tree_exception(page)) {
-			if (radix_tree_exceptional_entry(page))
-				continue;
+			if (radix_tree_deref_retry(page)) {
+				/*
+				 * Transient condition which can only trigger
+				 * when entry at index 0 moves out of or back
+				 * to root: none yet gotten, safe to restart.
+				 */
+				WARN_ON(start | i);
+				goto restart;
+			}
 			/*
-			 * radix_tree_deref_retry(page):
-			 * can only trigger when entry at index 0 moves out of
-			 * or back to root: none yet gotten, safe to restart.
+			 * Otherwise, shmem/tmpfs must be storing a swap entry
+			 * here as an exceptional entry: so skip over it -
+			 * we only reach this from invalidate_mapping_pages().
 			 */
-			WARN_ON(start | i);
-			goto restart;
+			continue;
 		}
 
 		if (!page_cache_get_speculative(page))
@@ -904,14 +914,20 @@
 			continue;
 
 		if (radix_tree_exception(page)) {
-			if (radix_tree_exceptional_entry(page))
-				break;
+			if (radix_tree_deref_retry(page)) {
+				/*
+				 * Transient condition which can only trigger
+				 * when entry at index 0 moves out of or back
+				 * to root: none yet gotten, safe to restart.
+				 */
+				goto restart;
+			}
 			/*
-			 * radix_tree_deref_retry(page):
-			 * can only trigger when entry at index 0 moves out of
-			 * or back to root: none yet gotten, safe to restart.
+			 * Otherwise, shmem/tmpfs must be storing a swap entry
+			 * here as an exceptional entry: so stop looking for
+			 * contiguous pages.
 			 */
-			goto restart;
+			break;
 		}
 
 		if (!page_cache_get_speculative(page))
@@ -973,13 +989,19 @@
 			continue;
 
 		if (radix_tree_exception(page)) {
-			BUG_ON(radix_tree_exceptional_entry(page));
+			if (radix_tree_deref_retry(page)) {
+				/*
+				 * Transient condition which can only trigger
+				 * when entry at index 0 moves out of or back
+				 * to root: none yet gotten, safe to restart.
+				 */
+				goto restart;
+			}
 			/*
-			 * radix_tree_deref_retry(page):
-			 * can only trigger when entry at index 0 moves out of
-			 * or back to root: none yet gotten, safe to restart.
+			 * This function is never used on a shmem/tmpfs
+			 * mapping, so a swap entry won't be found here.
 			 */
-			goto restart;
+			BUG();
 		}
 
 		if (!page_cache_get_speculative(page))
diff --git a/mm/mincore.c b/mm/mincore.c
index 733f182..636a868 100644
--- a/mm/mincore.c
+++ b/mm/mincore.c
@@ -72,6 +72,7 @@
 	 */
 	page = find_get_page(mapping, pgoff);
 #ifdef CONFIG_SWAP
+	/* shmem/tmpfs may return swap: account for swapcache page too. */
 	if (radix_tree_exceptional_entry(page)) {
 		swp_entry_t swap = radix_to_swp_entry(page);
 		page = find_get_page(&swapper_space, swap.val);
diff --git a/mm/shmem.c b/mm/shmem.c
index 1c702f6..32f6763 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -332,10 +332,14 @@
 		if (unlikely(!page))
 			continue;
 		if (radix_tree_exception(page)) {
-			if (radix_tree_exceptional_entry(page))
-				goto export;
-			/* radix_tree_deref_retry(page) */
-			goto restart;
+			if (radix_tree_deref_retry(page))
+				goto restart;
+			/*
+			 * Otherwise, we must be storing a swap entry
+			 * here as an exceptional entry: so return it
+			 * without attempting to raise page count.
+			 */
+			goto export;
 		}
 		if (!page_cache_get_speculative(page))
 			goto repeat;