mmzone: add pgdat_{end_pfn,is_empty}() helpers & consolidate.

Add pgdat_end_pfn() and pgdat_is_empty() helpers which match the similar
zone_*() functions.

Change node_end_pfn() to be a wrapper of pgdat_end_pfn().

Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Cc: David Hansen <dave@linux.vnet.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/mmzone.h

@@ -756,11 +756,17 @@ typedef struct pglist_data {
 #define nid_page_nr(nid, pagenr) 	pgdat_page_nr(NODE_DATA(nid),(pagenr))
 
 #define node_start_pfn(nid)	(NODE_DATA(nid)->node_start_pfn)
+#define node_end_pfn(nid) pgdat_end_pfn(NODE_DATA(nid))
 
-#define node_end_pfn(nid) ({\
-	pg_data_t *__pgdat = NODE_DATA(nid);\
-	__pgdat->node_start_pfn + __pgdat->node_spanned_pages;\
-})
+static inline unsigned long pgdat_end_pfn(pg_data_t *pgdat)
+{
+	return pgdat->node_start_pfn + pgdat->node_spanned_pages;
+}
+
+static inline bool pgdat_is_empty(pg_data_t *pgdat)
+{
+	return !pgdat->node_start_pfn && !pgdat->node_spanned_pages;
+}
 
 #include <linux/memory_hotplug.h>