Clean up __page_set_anon_rmap

Linus asked for a cleanup of __page_set_anon_rmap to make
it look more like the cleaner huge pages version.

Factor out the duplicated PageAnon check into a single check
at the beginning of the function.

Remove obsolete comments and rewrite them into standard English.

No functional changes.

Signed-off-by: Andi Kleen <ak@linux.intel.com>

diff --git a/mm/rmap.c b/mm/rmap.c
index 92e6757f196ed4e3b3598c1f8b7214616a4cbe39..8adc6e3b09b3d03130b86fb6a5f7a3bb7741d524 100644 (file)
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -780,10 +780,10 @@ void page_move_anon_rmap(struct page *page,
 }
 
 /**
- * __page_set_anon_rmap - setup new anonymous rmap
- * @page:      the page to add the mapping to
- * @vma:       the vm area in which the mapping is added
- * @address:   the user virtual address mapped
+ * __page_set_anon_rmap - set up new anonymous rmap
+ * @page:      Page to add to rmap     
+ * @vma:       VM area to add page to.
+ * @address:   User virtual address of the mapping     
  * @exclusive: the page is exclusively owned by the current process
  */
 static void __page_set_anon_rmap(struct page *page,
@@ -793,25 +793,16 @@ static void __page_set_anon_rmap(struct page *page,
 
        BUG_ON(!anon_vma);
 
+       if (PageAnon(page))
+               return;
+
        /*
         * If the page isn't exclusively mapped into this vma,
         * we must use the _oldest_ possible anon_vma for the
         * page mapping!
         */
-       if (!exclusive) {
-               if (PageAnon(page))
-                       return;
+       if (!exclusive)
                anon_vma = anon_vma->root;
-       } else {
-               /*
-                * In this case, swapped-out-but-not-discarded swap-cache
-                * is remapped. So, no need to update page->mapping here.
-                * We convice anon_vma poitned by page->mapping is not obsolete
-                * because vma->anon_vma is necessary to be a family of it.
-                */
-               if (PageAnon(page))
-                       return;
-       }
 
        anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON;
        page->mapping = (struct address_space *) anon_vma;