[PATCH] memory hotplug: fix compile error for i386 with NUMA config

Fix compile error when config memory hotplug with numa on i386.

The cause of compile error was missing of arch_add_memory(),
remove_memory(), and memory_add_physaddr_to_nid().
Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Acked-by: David Rientjes <rientjes@cs.washington.edu>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/i386/mm/discontig.c

@@ -405,3 +405,31 @@ void __init set_highmem_pages_init(int bad_ppro)
 	totalram_pages += totalhigh_pages;
 #endif
 }
+
+#ifdef CONFIG_MEMORY_HOTPLUG
+int paddr_to_nid(u64 addr)
+{
+	int nid;
+	unsigned long pfn = PFN_DOWN(addr);
+
+	for_each_node(nid)
+		if (node_start_pfn[nid] <= pfn &&
+		    pfn < node_end_pfn[nid])
+			return nid;
+
+	return -1;
+}
+
+/*
+ * This function is used to ask node id BEFORE memmap and mem_section's
+ * initialization (pfn_to_nid() can't be used yet).
+ * If _PXM is not defined on ACPI's DSDT, node id must be found by this.
+ */
+int memory_add_physaddr_to_nid(u64 addr)
+{
+	int nid = paddr_to_nid(addr);
+	return (nid >= 0) ? nid : 0;
+}
+
+EXPORT_SYMBOL_GPL(memory_add_physaddr_to_nid);
+#endif

arch/i386/mm/init.c

@@ -673,16 +673,10 @@ void __init mem_init(void)
 #endif
 }
 
-/*
- * this is for the non-NUMA, single node SMP system case.
- * Specifically, in the case of x86, we will always add
- * memory to the highmem for now.
- */
 #ifdef CONFIG_MEMORY_HOTPLUG
-#ifndef CONFIG_NEED_MULTIPLE_NODES
 int arch_add_memory(int nid, u64 start, u64 size)
 {
-	struct pglist_data *pgdata = &contig_page_data;
+	struct pglist_data *pgdata = NODE_DATA(nid);
 	struct zone *zone = pgdata->node_zones + ZONE_HIGHMEM;
 	unsigned long start_pfn = start >> PAGE_SHIFT;
 	unsigned long nr_pages = size >> PAGE_SHIFT;
@@ -694,7 +688,7 @@ int remove_memory(u64 start, u64 size)
 {
 	return -EINVAL;
 }
-#endif
+EXPORT_SYMBOL_GPL(remove_memory);
 #endif
 
 struct kmem_cache *pgd_cache;