[PATCH] for_each_online_pgdat: remove pgdat_list

By using for_each_online_pgdat(), pgdat_list is not necessary now.  This patch
removes it.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

include/linux/mmzone.h

@@ -307,7 +307,6 @@ typedef struct pglist_data {
 	unsigned long node_spanned_pages; /* total size of physical page
 					     range, including holes */
 	int node_id;
-	struct pglist_data *pgdat_next;
 	wait_queue_head_t kswapd_wait;
 	struct task_struct *kswapd;
 	int kswapd_max_order;
@@ -324,8 +323,6 @@ typedef struct pglist_data {
 
 #include <linux/memory_hotplug.h>
 
-extern struct pglist_data *pgdat_list;
-
 void __get_zone_counts(unsigned long *active, unsigned long *inactive,
 			unsigned long *free, struct pglist_data *pgdat);
 void get_zone_counts(unsigned long *active, unsigned long *inactive,

mm/page_alloc.c

@@ -49,7 +49,6 @@ nodemask_t node_online_map __read_mostly = { { [0] = 1UL } };
 EXPORT_SYMBOL(node_online_map);
 nodemask_t node_possible_map __read_mostly = NODE_MASK_ALL;
 EXPORT_SYMBOL(node_possible_map);
-struct pglist_data *pgdat_list __read_mostly;
 unsigned long totalram_pages __read_mostly;
 unsigned long totalhigh_pages __read_mostly;
 long nr_swap_pages;
@@ -2169,8 +2168,9 @@ static void *frag_start(struct seq_file *m, loff_t *pos)
 {
 	pg_data_t *pgdat;
 	loff_t node = *pos;
-
-	for (pgdat = pgdat_list; pgdat && node; pgdat = pgdat->pgdat_next)
+	for (pgdat = first_online_pgdat();
+	     pgdat && node;
+	     pgdat = next_online_pgdat(pgdat))
 		--node;
 
 	return pgdat;
@@ -2181,7 +2181,7 @@ static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
 	pg_data_t *pgdat = (pg_data_t *)arg;
 
 	(*pos)++;
-	return pgdat->pgdat_next;
+	return next_online_pgdat(pgdat);
 }
 
 static void frag_stop(struct seq_file *m, void *arg)