diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index d294b57a4016ff0e0ba63cfa68e1c6ab828afe5a..ee9f7b74e613978a764c194d07fec1a6cd1be42f 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -435,7 +435,6 @@ extern struct pglist_data contig_page_data;
 #define NODE_DATA(nid)		(&contig_page_data)
 #define NODE_MEM_MAP(nid)	mem_map
 #define MAX_NODES_SHIFT		1
-#define pfn_to_nid(pfn)		(0)
 
 #else /* CONFIG_NEED_MULTIPLE_NODES */
 
@@ -470,6 +469,10 @@ extern struct pglist_data contig_page_data;
 #define early_pfn_to_nid(nid)  (0UL)
 #endif
 
+#ifdef CONFIG_FLATMEM
+#define pfn_to_nid(pfn)		(0)
+#endif
+
 #define pfn_to_section_nr(pfn) ((pfn) >> PFN_SECTION_SHIFT)
 #define section_nr_to_pfn(sec) ((sec) << PFN_SECTION_SHIFT)
 
@@ -594,6 +597,8 @@ static inline int pfn_valid(unsigned long pfn)
  */
 #ifdef CONFIG_NUMA
 #define pfn_to_nid		early_pfn_to_nid
+#else
+#define pfn_to_nid(pfn)		(0)
 #endif
 
 #define early_pfn_valid(pfn)	pfn_valid(pfn)