diff --git a/include/linux/mm.h b/include/linux/mm.h
index fa42ef44c466..4935f58c249e 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -234,6 +234,9 @@ int __add_to_page_cache_locked(struct page *page, struct address_space *mapping,
 /* to align the pointer to the (next) page boundary */
 #define PAGE_ALIGN(addr) ALIGN(addr, PAGE_SIZE)
 
+/* to align the pointer to the (prev) page boundary */
+#define PAGE_ALIGN_DOWN(addr) ALIGN_DOWN(addr, PAGE_SIZE)
+
 /* test whether an address (unsigned long or pointer) is aligned to PAGE_SIZE */
 #define PAGE_ALIGNED(addr)	IS_ALIGNED((unsigned long)(addr), PAGE_SIZE)