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Driver core: Use generic offline/online for CPU offline/online

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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>
This commit is contained in:
Rafael J. Wysocki 2013-05-03 00:25:49 +02:00
commit 0902a9044f
1 changed files with 31 additions and 56 deletions
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87
drivers/base/cpu.c
View file

@ -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 @@ static void change_cpu_under_node(struct cpu *cpu,
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(probe, S_IWUSR, NULL, cpu_probe_store);
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 @@ int __cpuinit register_cpu(struct cpu *cpu, int num)
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)