1 files changed, 3 insertions, 1 deletions

diff --git a/include/asm-x86_64/page.h b/include/asm-x86_64/page.h
index 135ffaa0393b..e5ab4d231f2c 100644
--- a/include/asm-x86_64/page.h
+++ b/include/asm-x86_64/page.h
@@ -32,6 +32,8 @@
 #ifdef __KERNEL__
 #ifndef __ASSEMBLY__
 
+extern unsigned long end_pfn;
+
 void clear_page(void *);
 void copy_page(void *, void *);
 
@@ -111,7 +113,7 @@ typedef struct { unsigned long pgprot; } pgprot_t;
 #ifdef CONFIG_FLATMEM
 #define pfn_to_page(pfn)        (mem_map + (pfn))
 #define page_to_pfn(page)       ((unsigned long)((page) - mem_map))
-#define pfn_valid(pfn)          ((pfn) < max_mapnr)
+#define pfn_valid(pfn)          ((pfn) < end_pfn)
 #endif
 
 #define virt_to_page(kaddr)     pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)