diff --git a/mm/swapfile.c b/mm/swapfile.c
index d1bd8d1e17bd..2b3a2d85e350 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -3335,7 +3335,8 @@ static int __swap_duplicate(swp_entry_t entry, unsigned char usage)
 	} else
 		err = -ENOENT;			/* unused swap entry */
 
-	WRITE_ONCE(p->swap_map[offset], count | has_cache);
+	if (!err)
+		WRITE_ONCE(p->swap_map[offset], count | has_cache);
 
 unlock_out:
 	unlock_cluster_or_swap_info(p, ci);