[PATCH] remove zone_mem_map

This patch removes zone_mem_map.

pfn_to_page uses pgdat, page_to_pfn uses zone.  page_to_pfn can use pgdat
instead of zone, which is only one user of zone_mem_map.  By modifing it,
we can remove zone_mem_map.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Christoph Lameter <christoph@lameter.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 2 insertions, 4 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 349b328763b7..8dc8f2735d22 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2042,7 +2042,6 @@ static __meminit void init_currently_empty_zone(struct zone *zone,
         zone_wait_table_init(zone, size);
         pgdat->nr_zones = zone_idx(zone) + 1;
 
-        zone->zone_mem_map = pfn_to_page(zone_start_pfn);
         zone->zone_start_pfn = zone_start_pfn;
 
         memmap_init(size, pgdat->node_id, zone_idx(zone), zone_start_pfn);
@@ -2768,9 +2767,8 @@ struct page *pfn_to_page(unsigned long pfn)
 }
 unsigned long page_to_pfn(struct page *page)
 {
-        struct zone *zone = page_zone(page);
-        return (page - zone->zone_mem_map) + zone->zone_start_pfn;
-
+        struct pglist_data *pgdat = NODE_DATA(page_to_nid(page));
+        return (page - pgdat->node_mem_map) + pgdat->node_start_pfn;
 }
 #elif defined(CONFIG_SPARSEMEM)
 struct page *pfn_to_page(unsigned long pfn)