diff --git a/include/linux/swap.h b/include/linux/swap.h
index 667935c0dbd4c..fbc6805358da0 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -484,6 +484,7 @@ struct backing_dev_info;
 extern int init_swap_address_space(unsigned int type, unsigned long nr_pages);
 extern void exit_swap_address_space(unsigned int type);
 extern struct swap_info_struct *get_swap_device(swp_entry_t entry);
+sector_t swap_page_sector(struct page *page);
 
 static inline void put_swap_device(struct swap_info_struct *si)
 {
diff --git a/mm/page_io.c b/mm/page_io.c
index 433df12633495..96479817ffae3 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -273,11 +273,6 @@ int swap_writepage(struct page *page, struct writeback_control *wbc)
 	return ret;
 }
 
-static sector_t swap_page_sector(struct page *page)
-{
-	return (sector_t)__page_file_index(page) << (PAGE_SHIFT - 9);
-}
-
 static inline void count_swpout_vm_event(struct page *page)
 {
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 16db9d1ebcbf3..5256c10049b0f 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -220,6 +220,19 @@ offset_to_swap_extent(struct swap_info_struct *sis, unsigned long offset)
 	BUG();
 }
 
+sector_t swap_page_sector(struct page *page)
+{
+	struct swap_info_struct *sis = page_swap_info(page);
+	struct swap_extent *se;
+	sector_t sector;
+	pgoff_t offset;
+
+	offset = __page_file_index(page);
+	se = offset_to_swap_extent(sis, offset);
+	sector = se->start_block + (offset - se->start_page);
+	return sector << (PAGE_SHIFT - 9);
+}
+
 /*
  * swap allocation tell device that a cluster of swap can now be discarded,
  * to allow the swap device to optimize its wear-levelling.