1 files changed, 23 insertions, 2 deletions
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index d8c7f3ee6e19..3d48fc887ef4 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -25,6 +25,15 @@ EXPORT_SYMBOL_GPL(cpu_subsys);
 static DEFINE_PER_CPU(struct device *, cpu_sys_devices);
 #ifdef CONFIG_HOTPLUG_CPU
+static void change_cpu_under_node(struct cpu *cpu,
+                        unsigned int from_nid, unsigned int to_nid)
+{
+        int cpuid = cpu->dev.id;
+        unregister_cpu_under_node(cpuid, from_nid);
+        register_cpu_under_node(cpuid, to_nid);
+        cpu->node_id = to_nid;
+}
 static ssize_t show_online(struct device *dev,
                           struct device_attribute *attr,
                           char *buf)
@@ -39,17 +48,29 @@ static ssize_t __ref store_online(struct device *dev,
                                  const char *buf, size_t count)
 {
        struct cpu *cpu = container_of(dev, struct cpu, dev);
+        int cpuid = cpu->dev.id;
+        int from_nid, to_nid;
        ssize_t ret;
        cpu_hotplug_driver_lock();
        switch (buf[0]) {
        case '0':
-                ret = cpu_down(cpu->dev.id);
+                ret = cpu_down(cpuid);
                if (!ret)
                        kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
                break;
        case '1':
-                ret = cpu_up(cpu->dev.id);
+                from_nid = cpu_to_node(cpuid);
+                ret = cpu_up(cpuid);
+                /*
+                 * When hot adding memory to memoryless node and enabling a cpu
+                 * on the node, node number of the cpu may internally change.
+                 */
+                to_nid = cpu_to_node(cpuid);
+                if (from_nid != to_nid)
+                        change_cpu_under_node(cpu, from_nid, to_nid);
                if (!ret)
                        kobject_uevent(&dev->kobj, KOBJ_ONLINE);
                break;