From: Shaohui Zheng on
hotplug emulator: Abstract cpu register functions

Abstract function arch_register_cpu and register_cpu, move the implementation
details to a sub function with prefix "__".

each of the sub function has an extra parameter nid, it can be used to register
CPU under a fake NUMA node, it is a reserved interface for cpu hotplug emulation
(CPU PROBE/RELEASE) in x86.

Signed-off-by: Shaohui Zheng <shaohui.zheng(a)intel.com>
Signed-off-by: Haicheng Li <haicheng.li(a)intel.com>
---
diff --git a/arch/x86/kernel/topology.c b/arch/x86/kernel/topology.c
index 7e45159..f716cd9 100644
--- a/arch/x86/kernel/topology.c
+++ b/arch/x86/kernel/topology.c
@@ -34,7 +34,11 @@
static DEFINE_PER_CPU(struct x86_cpu, cpu_devices);

#ifdef CONFIG_HOTPLUG_CPU
-int __ref arch_register_cpu(int num)
+/*
+ * Add nid(NUMA node id) as parameter for cpu hotplug emulation. It supports
+ * to register a CPU to any nodes.
+ */
+static int __ref __arch_register_cpu(int num, int nid)
{
/*
* CPU0 cannot be offlined due to several
@@ -50,6 +54,11 @@ int __ref arch_register_cpu(int num)

return register_cpu(&per_cpu(cpu_devices, num).cpu, num);
}
+
+int __ref arch_register_cpu(int num)
+{
+ return __arch_register_cpu(num, NUMA_NO_NODE);
+}
EXPORT_SYMBOL(arch_register_cpu);

void arch_unregister_cpu(int num)
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index f35719a..4aca9e3 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -208,17 +208,20 @@ static ssize_t print_cpus_offline(struct sysdev_class *class,
static SYSDEV_CLASS_ATTR(offline, 0444, print_cpus_offline, NULL);

/*
- * register_cpu - Setup a sysfs device for a CPU.
+ * __register_cpu -Initialize and register the CPU device.
+ *
* @cpu - cpu->hotpluggable field set to 1 will generate a control file in
* sysfs for this CPU.
* @num - CPU number to use when creating the device.
+ * @nid - numa node id
*
- * Initialize and register the CPU device.
+ * We do not calculate nid by funciton cpu_to_node(), and change it as a
+ * parameter, it is an reserved interface for CPU hotplug emulation.
*/
-int __cpuinit register_cpu(struct cpu *cpu, int num)
+static int __cpuinit __register_cpu(struct cpu *cpu, int num, int nid)
{
int error;
- cpu->node_id = cpu_to_node(num);
+ cpu->node_id = nid;
cpu->sysdev.id = num;
cpu->sysdev.cls = &cpu_sysdev_class;

@@ -229,7 +232,7 @@ int __cpuinit register_cpu(struct cpu *cpu, int num)
if (!error)
per_cpu(cpu_sys_devices, num) = &cpu->sysdev;
if (!error)
- register_cpu_under_node(num, cpu_to_node(num));
+ register_cpu_under_node(num, nid);

#ifdef CONFIG_KEXEC
if (!error)
@@ -238,6 +241,15 @@ int __cpuinit register_cpu(struct cpu *cpu, int num)
return error;
}

+/*
+ * register_cpu - Setup a sysfs device for a CPU.
+ * Initialize and register the CPU device.
+ */
+int __cpuinit register_cpu(struct cpu *cpu, int num)
+{
+ return __register_cpu(cpu, num, cpu_to_node(num));
+}
+
struct sys_device *get_cpu_sysdev(unsigned cpu)
{
if (cpu < nr_cpu_ids && cpu_possible(cpu))
--
Thanks & Regards,
Shaohui