+ /*
+ * Make sure try_to_free_swap or reuse_swap_page or swapoff did not
+ * release the swapcache from under us. The page pin, and pte_same
+ * test below, are not enough to exclude that. Even if it is still
+ * swapcache, we need to check that the page's swap has not changed.
+ */
+ if (unlikely(!PageSwapCache(page) || page_private(page) != entry.val))
+ goto out_page;
+
+ if (ksm_might_need_to_copy(page, vma, address)) {
+ swapcache = page;
+ page = ksm_does_need_to_copy(page, vma, address);
+
+ if (unlikely(!page)) {
+ ret = VM_FAULT_OOM;
+ page = swapcache;
+ swapcache = NULL;
+ goto out_page;
+ }