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>

1 files changed, 8 insertions, 17 deletions

diff --git a/mm/rmap.c b/mm/rmap.c
index 92e6757f196e..8adc6e3b09b3 100644
--- 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;