diff --git a/[refs] b/[refs]
index 9a9175ff8973..37edbdbcea48 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: c08c6e1f54c85fc299cf9f88cf330d6dd28a9a1d
+refs/heads/master: 08259d58e4fa12ceaece82193c5816152f638cca
diff --git a/trunk/mm/swapfile.c b/trunk/mm/swapfile.c
index 4a986127f15e..84374d8cf814 100644
--- a/trunk/mm/swapfile.c
+++ b/trunk/mm/swapfile.c
@@ -2161,7 +2161,11 @@ void swap_shmem_alloc(swp_entry_t entry)
 }
 
 /*
- * increase reference count of swap entry by 1.
+ * Increase reference count of swap entry by 1.
+ * Returns 0 for success, or -ENOMEM if a swap_count_continuation is required
+ * but could not be atomically allocated.  Returns 0, just as if it succeeded,
+ * if __swap_duplicate() fails for another reason (-EINVAL or -ENOENT), which
+ * might occur if a page table entry has got corrupted.
  */
 int swap_duplicate(swp_entry_t entry)
 {