1/*
2 * linux/mm/mmzone.c
3 *
4 * management codes for pgdats and zones.
5 */
6
7
8#include <linux/stddef.h>
9#include <linux/mm.h>
10#include <linux/mmzone.h>
11#include <linux/module.h>
12
13struct pglist_data *first_online_pgdat(void)
14{
15	return NODE_DATA(first_online_node);
16}
17
18struct pglist_data *next_online_pgdat(struct pglist_data *pgdat)
19{
20	int nid = next_online_node(pgdat->node_id);
21
22	if (nid == MAX_NUMNODES)
23		return NULL;
24	return NODE_DATA(nid);
25}
26
27/*
28 * next_zone - helper magic for for_each_zone()
29 */
30struct zone *next_zone(struct zone *zone)
31{
32	pg_data_t *pgdat = zone->zone_pgdat;
33
34	if (zone < pgdat->node_zones + MAX_NR_ZONES - 1)
35		zone++;
36	else {
37		pgdat = next_online_pgdat(pgdat);
38		if (pgdat)
39			zone = pgdat->node_zones;
40		else
41			zone = NULL;
42	}
43	return zone;
44}
45
46static inline int zref_in_nodemask(struct zoneref *zref, nodemask_t *nodes)
47{
48#ifdef CONFIG_NUMA
49	return node_isset(zonelist_node_idx(zref), *nodes);
50#else
51	return 1;
52#endif /* CONFIG_NUMA */
53}
54
55/* Returns the next zone at or below highest_zoneidx in a zonelist */
56struct zoneref *next_zones_zonelist(struct zoneref *z,
57					enum zone_type highest_zoneidx,
58					nodemask_t *nodes,
59					struct zone **zone)
60{
61	/*
62	 * Find the next suitable zone to use for the allocation.
63	 * Only filter based on nodemask if it's set
64	 */
65	if (likely(nodes == NULL))
66		while (zonelist_zone_idx(z) > highest_zoneidx)
67			z++;
68	else
69		while (zonelist_zone_idx(z) > highest_zoneidx ||
70				(z->zone && !zref_in_nodemask(z, nodes)))
71			z++;
72
73	*zone = zonelist_zone(z);
74	return z;
75}
76
77#ifdef CONFIG_ARCH_HAS_HOLES_MEMORYMODEL
78int memmap_valid_within(unsigned long pfn,
79					struct page *page, struct zone *zone)
80{
81	if (page_to_pfn(page) != pfn)
82		return 0;
83
84	if (page_zone(page) != zone)
85		return 0;
86
87	return 1;
88}
89#endif /* CONFIG_ARCH_HAS_HOLES_MEMORYMODEL */
90