On Thu, Jan 31, 2013 at 12:11:15PM -0000, Thomas Gleixner wrote:
> Split out into separate functions, so we can convert it to a state machine.
>
> Signed-off-by: Thomas Gleixner <t...@linutronix.de>
Reviewed-by: Paul E. McKenney <paul...@linux.vnet.ibm.com>
> ---
> kernel/cpu.c | 69
> ++++++++++++++++++++++++++++++++++++++++-------------------
> 1 file changed, 47 insertions(+), 22 deletions(-)
>
> Index: linux-2.6/kernel/cpu.c
> ===================================================================
> --- linux-2.6.orig/kernel/cpu.c
> +++ linux-2.6/kernel/cpu.c
> @@ -168,6 +168,43 @@ static int cpu_notify(unsigned long val,
> return __cpu_notify(val, cpu, -1, NULL);
> }
>
> +/* Notifier wrappers for transitioning to state machine */
> +static int notify_prepare(unsigned int cpu)
> +{
> + int nr_calls = 0;
> + int ret;
> +
> + ret = __cpu_notify(CPU_UP_PREPARE, cpu, -1, &nr_calls);
> + if (ret) {
> + nr_calls--;
> + printk(KERN_WARNING "%s: attempt to bring up CPU %u failed\n",
> + __func__, cpu);
> + __cpu_notify(CPU_UP_CANCELED, cpu, nr_calls, NULL);
> + }
> + return ret;
> +}
> +
> +static int notify_online(unsigned int cpu)
> +{
> + cpu_notify(CPU_ONLINE, cpu);
> + return 0;
> +}
> +
> +static int bringup_cpu(unsigned int cpu)
> +{
> + struct task_struct *idle = idle_thread_get(cpu);
> + int ret;
> +
> + /* Arch-specific enabling code. */
> + ret = __cpu_up(cpu, idle);
> + if (ret) {
> + cpu_notify(CPU_UP_CANCELED, cpu);
> + return ret;
> + }
> + BUG_ON(!cpu_online(cpu));
> + return 0;
> +}
> +
> #ifdef CONFIG_HOTPLUG_CPU
>
> static void cpu_notify_nofail(unsigned long val, unsigned int cpu)
> @@ -340,7 +377,7 @@ EXPORT_SYMBOL(cpu_down);
> static int __cpuinit _cpu_up(unsigned int cpu, int tasks_frozen)
> {
> struct task_struct *idle;
> - int ret, nr_calls = 0;
> + int ret;
>
> cpu_hotplug_begin();
>
> @@ -355,35 +392,23 @@ static int __cpuinit _cpu_up(unsigned in
> goto out;
> }
>
> + cpuhp_tasks_frozen = tasks_frozen;
> +
> ret = smpboot_create_threads(cpu);
> if (ret)
> goto out;
>
> - cpuhp_tasks_frozen = tasks_frozen;
> -
> - ret = __cpu_notify(CPU_UP_PREPARE, cpu, -1, &nr_calls);
> - if (ret) {
> - nr_calls--;
> - printk(KERN_WARNING "%s: attempt to bring up CPU %u failed\n",
> - __func__, cpu);
> - goto out_notify;
> - }
> + ret = notify_prepare(cpu);
> + if (ret)
> + goto out;
>
> - /* Arch-specific enabling code. */
> - ret = __cpu_up(cpu, idle);
> - if (ret != 0)
> - goto out_notify;
> - BUG_ON(!cpu_online(cpu));
> + ret = bringup_cpu(cpu);
> + if (ret)
> + goto out;
>
> /* Wake the per cpu threads */
> smpboot_unpark_threads(cpu);
> -
> - /* Now call notifier in preparation. */
> - cpu_notify(CPU_ONLINE, cpu);
> -
> -out_notify:
> - if (ret != 0)
> - __cpu_notify(CPU_UP_CANCELED, cpu, nr_calls, NULL);
> + notify_online(cpu);
> out:
> cpu_hotplug_done();
>
>
>
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