1 files changed, 10 insertions, 4 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index c11418dd94e8..88611928e71f 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -54,9 +54,8 @@
  *
  *  ->i_mmap_lock               (vmtruncate)
  *    ->private_lock            (__free_pte->__set_page_dirty_buffers)
- *      ->swap_list_lock
- *        ->swap_device_lock    (exclusive_swap_page, others)
- *          ->mapping->tree_lock
+ *      ->swap_lock             (exclusive_swap_page, others)
+ *        ->mapping->tree_lock
  *
  *  ->i_sem
  *    ->i_mmap_lock             (truncate->unmap_mapping_range)
@@ -86,7 +85,7 @@
  *    ->page_table_lock         (anon_vma_prepare and various)
  *
  *  ->page_table_lock
- *    ->swap_device_lock        (try_to_unmap_one)
+ *    ->swap_lock               (try_to_unmap_one)
  *    ->private_lock            (try_to_unmap_one)
  *    ->tree_lock               (try_to_unmap_one)
  *    ->zone.lru_lock           (follow_page->mark_page_accessed)
@@ -1505,8 +1504,12 @@ repeat:
                 return -EINVAL;
 
         page = filemap_getpage(file, pgoff, nonblock);
+
+        /* XXX: This is wrong, a filesystem I/O error may have happened. Fix that as
+         * done in shmem_populate calling shmem_getpage */
         if (!page && !nonblock)
                 return -ENOMEM;
+
         if (page) {
                 err = install_page(mm, vma, addr, page, prot);
                 if (err) {
@@ -1514,6 +1517,9 @@ repeat:
                         return err;
                 }
         } else {
+                /* No page was found just because we can't read it in now (being
+                 * here implies nonblock != 0), but the page may exist, so set
+                 * the PTE to fault it in later. */
                 err = install_file_pte(mm, vma, addr, pgoff, prot);
                 if (err)
                         return err;