+
+static pg_data_t *hotadd_new_pgdat(int nid, u64 start)
+{
+ struct pglist_data *pgdat;
+ unsigned long zones_size[MAX_NR_ZONES] = {0};
+ unsigned long zholes_size[MAX_NR_ZONES] = {0};
+ unsigned long start_pfn = start >> PAGE_SHIFT;
+
+ pgdat = arch_alloc_nodedata(nid);
+ if (!pgdat)
+ return NULL;
+
+ arch_refresh_nodedata(nid, pgdat);
+
+ /* we can use NODE_DATA(nid) from here */
+
+ /* init node's zones as empty zones, we don't have any present pages.*/
+ free_area_init_node(nid, pgdat, zones_size, start_pfn, zholes_size);
+
+ return pgdat;
+}
+
+static void rollback_node_hotadd(int nid, pg_data_t *pgdat)
+{
+ arch_refresh_nodedata(nid, NULL);
+ arch_free_nodedata(pgdat);
+ return;
+}
+
+/* add this memory to iomem resource */
+static struct resource *register_memory_resource(u64 start, u64 size)
+{
+ struct resource *res;
+ res = kzalloc(sizeof(struct resource), GFP_KERNEL);
+ BUG_ON(!res);
+
+ res->name = "System RAM";
+ res->start = start;
+ res->end = start + size - 1;
+ res->flags = IORESOURCE_MEM;
+ if (request_resource(&iomem_resource, res) < 0) {
+ printk("System RAM resource %llx - %llx cannot be added\n",
+ (unsigned long long)res->start, (unsigned long long)res->end);
+ kfree(res);
+ res = NULL;
+ }
+ return res;
+}
+
+static void release_memory_resource(struct resource *res)
+{
+ if (!res)
+ return;
+ release_resource(res);
+ kfree(res);
+ return;
+}
+
+
+
+int add_memory(int nid, u64 start, u64 size)
+{
+ pg_data_t *pgdat = NULL;
+ int new_pgdat = 0;
+ struct resource *res;
+ int ret;
+
+ res = register_memory_resource(start, size);
+ if (!res)
+ return -EEXIST;
+
+ if (!node_online(nid)) {
+ pgdat = hotadd_new_pgdat(nid, start);
+ if (!pgdat)
+ return -ENOMEM;
+ new_pgdat = 1;
+ ret = kswapd_run(nid);
+ if (ret)
+ goto error;
+ }
+
+ /* call arch's memory hotadd */
+ ret = arch_add_memory(nid, start, size);
+
+ if (ret < 0)
+ goto error;
+
+ /* we online node here. we can't roll back from here. */
+ node_set_online(nid);
+
+ if (new_pgdat) {
+ ret = register_one_node(nid);
+ /*
+ * If sysfs file of new node can't create, cpu on the node
+ * can't be hot-added. There is no rollback way now.
+ * So, check by BUG_ON() to catch it reluctantly..
+ */
+ BUG_ON(ret);
+ }
+
+ return ret;
+error:
+ /* rollback pgdat allocation and others */
+ if (new_pgdat)
+ rollback_node_hotadd(nid, pgdat);
+ if (res)
+ release_memory_resource(res);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(add_memory);