x86: extend e820 early_res support 32bit -fix #4

reserve_early pgdata for 32bit numa
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/mm/discontig_32.c

@@ -159,8 +159,13 @@ static void __init allocate_pgdat(int nid)
 	if (nid && node_has_online_mem(nid))
 		NODE_DATA(nid) = (pg_data_t *)node_remap_start_vaddr[nid];
 	else {
-		NODE_DATA(nid) = (pg_data_t *)(pfn_to_kaddr(min_low_pfn));
-		min_low_pfn += PFN_UP(sizeof(pg_data_t));
+		unsigned long pgdat_phys;
+		pgdat_phys = find_e820_area(min_low_pfn<<PAGE_SHIFT,
+				 max_low_pfn<<PAGE_SHIFT, sizeof(pg_data_t),
+				 PAGE_SIZE);
+		NODE_DATA(nid) = (pg_data_t *)(pfn_to_kaddr(pgdat_phys>>PAGE_SHIFT));
+		reserve_early(pgdat_phys, pgdat_phys + sizeof(pg_data_t),
+			      "NODE_DATA");
 	}
 }