1 files changed, 30 insertions, 48 deletions

diff --git a/mm/rmap.c b/mm/rmap.c
index 0895b5c7cbff..720fc03a7bc4 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -710,27 +710,6 @@ void page_add_file_rmap(struct page *page)
         }
 }
 
-#ifdef CONFIG_DEBUG_VM
-/**
- * page_dup_rmap - duplicate pte mapping to a page
- * @page:       the page to add the mapping to
- * @vma:        the vm area being duplicated
- * @address:    the user virtual address mapped
- *
- * For copy_page_range only: minimal extract from page_add_file_rmap /
- * page_add_anon_rmap, avoiding unnecessary tests (already checked) so it's
- * quicker.
- *
- * The caller needs to hold the pte lock.
- */
-void page_dup_rmap(struct page *page, struct vm_area_struct *vma, unsigned long address)
-{
-        if (PageAnon(page))
-                __page_check_anon_rmap(page, vma, address);
-        atomic_inc(&page->_mapcount);
-}
-#endif
-
 /**
  * page_remove_rmap - take down pte mapping from a page
  * @page: page to remove mapping from
@@ -739,34 +718,37 @@ void page_dup_rmap(struct page *page, struct vm_area_struct *vma, unsigned long
  */
 void page_remove_rmap(struct page *page)
 {
-        if (atomic_add_negative(-1, &page->_mapcount)) {
-                /*
-                 * Now that the last pte has gone, s390 must transfer dirty
-                 * flag from storage key to struct page.  We can usually skip
-                 * this if the page is anon, so about to be freed; but perhaps
-                 * not if it's in swapcache - there might be another pte slot
-                 * containing the swap entry, but page not yet written to swap.
-                 */
-                if ((!PageAnon(page) || PageSwapCache(page)) &&
-                    page_test_dirty(page)) {
-                        page_clear_dirty(page);
-                        set_page_dirty(page);
-                }
-                if (PageAnon(page))
-                        mem_cgroup_uncharge_page(page);
-                __dec_zone_page_state(page,
-                        PageAnon(page) ? NR_ANON_PAGES : NR_FILE_MAPPED);
-                mem_cgroup_update_mapped_file_stat(page, -1);
-                /*
-                 * It would be tidy to reset the PageAnon mapping here,
-                 * but that might overwrite a racing page_add_anon_rmap
-                 * which increments mapcount after us but sets mapping
-                 * before us: so leave the reset to free_hot_cold_page,
-                 * and remember that it's only reliable while mapped.
-                 * Leaving it set also helps swapoff to reinstate ptes
-                 * faster for those pages still in swapcache.
-                 */
+        /* page still mapped by someone else? */
+        if (!atomic_add_negative(-1, &page->_mapcount))
+                return;
+
+        /*
+         * Now that the last pte has gone, s390 must transfer dirty
+         * flag from storage key to struct page.  We can usually skip
+         * this if the page is anon, so about to be freed; but perhaps
+         * not if it's in swapcache - there might be another pte slot
+         * containing the swap entry, but page not yet written to swap.
+         */
+        if ((!PageAnon(page) || PageSwapCache(page)) && page_test_dirty(page)) {
+                page_clear_dirty(page);
+                set_page_dirty(page);
         }
+        if (PageAnon(page)) {
+                mem_cgroup_uncharge_page(page);
+                __dec_zone_page_state(page, NR_ANON_PAGES);
+        } else {
+                __dec_zone_page_state(page, NR_FILE_MAPPED);
+        }
+        mem_cgroup_update_mapped_file_stat(page, -1);
+        /*
+         * It would be tidy to reset the PageAnon mapping here,
+         * but that might overwrite a racing page_add_anon_rmap
+         * which increments mapcount after us but sets mapping
+         * before us: so leave the reset to free_hot_cold_page,
+         * and remember that it's only reliable while mapped.
+         * Leaving it set also helps swapoff to reinstate ptes
+         * faster for those pages still in swapcache.
+         */
 }
 
 /*