diff --git a/include/linux/bootmem.h b/include/linux/bootmem.h
index 500f451..82bd884 100644
--- a/include/linux/bootmem.h
+++ b/include/linux/bootmem.h
@@ -22,6 +22,10 @@
  */
 extern unsigned long max_pfn;
 
+#ifdef CONFIG_CRASH_DUMP
+extern unsigned long saved_max_pfn;
+#endif
+
 /*
  * node_bootmem_map is a map pointer - the bits represent all physical 
  * memory pages (including holes) on the node.