1 files changed, 23 insertions, 0 deletions

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index be211a582930..85eb4d342ac5 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -482,6 +482,29 @@ static void rollback_node_hotadd(int nid, pg_data_t *pgdat)
 }
 
 
+/*
+ * called by cpu_up() to online a node without onlined memory.
+ */
+int mem_online_node(int nid)
+{
+        pg_data_t       *pgdat;
+        int     ret;
+
+        lock_system_sleep();
+        pgdat = hotadd_new_pgdat(nid, 0);
+        if (pgdat) {
+                ret = -ENOMEM;
+                goto out;
+        }
+        node_set_online(nid);
+        ret = register_one_node(nid);
+        BUG_ON(ret);
+
+out:
+        unlock_system_sleep();
+        return ret;
+}
+
 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
 int __ref add_memory(int nid, u64 start, u64 size)
 {