1 files changed, 26 insertions, 0 deletions

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 71373d03fcee..f89af5ba2eb2 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -33,6 +33,7 @@
 #include <linux/oom.h>
 #include <linux/frontswap.h>
 #include <linux/swapfile.h>
+#include <linux/export.h>
 
 #include <asm/pgtable.h>
 #include <asm/tlbflush.h>
@@ -2285,6 +2286,31 @@ int swapcache_prepare(swp_entry_t entry)
         return __swap_duplicate(entry, SWAP_HAS_CACHE);
 }
 
+struct swap_info_struct *page_swap_info(struct page *page)
+{
+        swp_entry_t swap = { .val = page_private(page) };
+        BUG_ON(!PageSwapCache(page));
+        return swap_info[swp_type(swap)];
+}
+
+/*
+ * out-of-line __page_file_ methods to avoid include hell.
+ */
+struct address_space *__page_file_mapping(struct page *page)
+{
+        VM_BUG_ON(!PageSwapCache(page));
+        return page_swap_info(page)->swap_file->f_mapping;
+}
+EXPORT_SYMBOL_GPL(__page_file_mapping);
+
+pgoff_t __page_file_index(struct page *page)
+{
+        swp_entry_t swap = { .val = page_private(page) };
+        VM_BUG_ON(!PageSwapCache(page));
+        return swp_offset(swap);
+}
+EXPORT_SYMBOL_GPL(__page_file_index);
+
 /*
  * add_swap_count_continuation - called when a swap count is duplicated
  * beyond SWAP_MAP_MAX, it allocates a new page and links that to the entry's