On Mon, 2013-04-29 at 14:28 +0200, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
>
> 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@xxxxxxxxx>
> ---
> drivers/base/cpu.c | 62 ++++++++++++-----------------------------------------
> 1 file changed, 15 insertions(+), 47 deletions(-)
>
> Index: linux-pm/drivers/base/cpu.c
> ===================================================================
> --- linux-pm.orig/drivers/base/cpu.c
> +++ linux-pm/drivers/base/cpu.c
> @@ -16,66 +16,25 @@
>
> #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
> -static ssize_t show_online(struct device *dev,
> - struct device_attribute *attr,
> - char *buf)
> +static int 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));
> + return cpu_up(dev->id);
> }
>
> -static ssize_t __ref store_online(struct device *dev,
> - struct device_attribute *attr,
> - const char *buf, size_t count)
> +static int cpu_subsys_offline(struct device *dev)
> {
> - struct cpu *cpu = container_of(dev, struct cpu, dev);
> - ssize_t ret;
> -
> - cpu_hotplug_driver_lock();
By replacing cpu_hotplug_driver_lock() with lock_device_offline() in
patch 1/3, it no longer protects from other places that still use
cpu_hotplug_device_lock(), such as save_mc_for_early().
Thanks,
-Toshi
> - switch (buf[0]) {
> - case '0':
> - ret = cpu_down(cpu->dev.id);
> - if (!ret)
> - kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
> - break;
> - case '1':
> - ret = cpu_up(cpu->dev.id);
> - if (!ret)
> - kobject_uevent(&dev->kobj, KOBJ_ONLINE);
> - break;
> - default:
> - ret = -EINVAL;
> - }
> - cpu_hotplug_driver_unlock();
> -
> - if (ret >= 0)
> - ret = count;
> - return ret;
> + return cpu_down(dev->id);
> }
> -static DEVICE_ATTR(online, 0644, show_online, store_online);
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