Driver core: Use generic offline/online for CPU offline/online
Rework the CPU hotplug code in drivers/base/cpu.c to use the
generic offline/online support introduced previously instead of
its own CPU-specific code.
For this purpose, modify cpu_subsys to provide offline and online
callbacks for CONFIG_HOTPLUG_CPU set and remove the code handling
the CPU-specific 'online' sysfs attribute.
This modification is not supposed to change the user-observable
behavior of the kernel (i.e. the 'online' attribute will be present
in exactly the same place in sysfs and should trigger exactly the
same actions as before).
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Toshi Kani <toshi.kani@hp.com>
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index 3d48fc8..25c8768 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -16,12 +16,6 @@
#include "base.h"
-struct bus_type cpu_subsys = {
- .name = "cpu",
- .dev_name = "cpu",
-};
-EXPORT_SYMBOL_GPL(cpu_subsys);
-
static DEFINE_PER_CPU(struct device *, cpu_sys_devices);
#ifdef CONFIG_HOTPLUG_CPU
@@ -34,69 +28,45 @@
cpu->node_id = to_nid;
}
-static ssize_t show_online(struct device *dev,
- struct device_attribute *attr,
- char *buf)
+static int __ref cpu_subsys_online(struct device *dev)
{
struct cpu *cpu = container_of(dev, struct cpu, dev);
-
- return sprintf(buf, "%u\n", !!cpu_online(cpu->dev.id));
-}
-
-static ssize_t __ref store_online(struct device *dev,
- struct device_attribute *attr,
- const char *buf, size_t count)
-{
- struct cpu *cpu = container_of(dev, struct cpu, dev);
- int cpuid = cpu->dev.id;
+ int cpuid = dev->id;
int from_nid, to_nid;
- ssize_t ret;
+ int ret;
cpu_hotplug_driver_lock();
- switch (buf[0]) {
- case '0':
- ret = cpu_down(cpuid);
- if (!ret)
- kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
- break;
- case '1':
- 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);
+ 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;
- default:
- ret = -EINVAL;
- }
cpu_hotplug_driver_unlock();
-
- if (ret >= 0)
- ret = count;
return ret;
}
-static DEVICE_ATTR(online, 0644, show_online, store_online);
-static void __cpuinit register_cpu_control(struct cpu *cpu)
+static int cpu_subsys_offline(struct device *dev)
{
- device_create_file(&cpu->dev, &dev_attr_online);
+ int ret;
+
+ cpu_hotplug_driver_lock();
+ ret = cpu_down(dev->id);
+ cpu_hotplug_driver_unlock();
+ return ret;
}
+
void unregister_cpu(struct cpu *cpu)
{
int logical_cpu = cpu->dev.id;
unregister_cpu_under_node(logical_cpu, cpu_to_node(logical_cpu));
- device_remove_file(&cpu->dev, &dev_attr_online);
-
device_unregister(&cpu->dev);
per_cpu(cpu_sys_devices, logical_cpu) = NULL;
return;
@@ -123,12 +93,18 @@
static DEVICE_ATTR(release, S_IWUSR, NULL, cpu_release_store);
#endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
-#else /* ... !CONFIG_HOTPLUG_CPU */
-static inline void register_cpu_control(struct cpu *cpu)
-{
-}
#endif /* CONFIG_HOTPLUG_CPU */
+struct bus_type cpu_subsys = {
+ .name = "cpu",
+ .dev_name = "cpu",
+#ifdef CONFIG_HOTPLUG_CPU
+ .online = cpu_subsys_online,
+ .offline = cpu_subsys_offline,
+#endif
+};
+EXPORT_SYMBOL_GPL(cpu_subsys);
+
#ifdef CONFIG_KEXEC
#include <linux/kexec.h>
@@ -277,12 +253,11 @@
cpu->dev.id = num;
cpu->dev.bus = &cpu_subsys;
cpu->dev.release = cpu_device_release;
+ cpu->dev.offline_disabled = !cpu->hotpluggable;
#ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE
cpu->dev.bus->uevent = arch_cpu_uevent;
#endif
error = device_register(&cpu->dev);
- if (!error && cpu->hotpluggable)
- register_cpu_control(cpu);
if (!error)
per_cpu(cpu_sys_devices, num) = &cpu->dev;
if (!error)