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Commit ba997462 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

cpu/hotplug: Restructure cpu_up code 



Split out into separate functions, so we can convert it to a state machine.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: Rik van Riel <riel@redhat.com>
Cc: Rafael Wysocki <rafael.j.wysocki@intel.com>
Cc: "Srivatsa S. Bhat" <srivatsa@mit.edu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Turner <pjt@google.com>
Link: http://lkml.kernel.org/r/20160226182340.429389195@linutronix.de


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 090e77c3

kernel/cpu.c

+47 −22
Original line number Diff line number Diff line
@@ -228,6 +228,43 @@ static int cpu_notify(unsigned long val, unsigned int cpu) 
	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)
@@ -481,7 +518,7 @@ void smpboot_thread_init(void) 
static int _cpu_up(unsigned int cpu, int tasks_frozen)

{

	struct task_struct *idle;

	int ret, nr_calls = 0;

	int ret;



	cpu_hotplug_begin();
@@ -496,33 +533,21 @@ static int _cpu_up(unsigned int cpu, int tasks_frozen) 
		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--;

		pr_warn("%s: attempt to bring up CPU %u failed\n",

			__func__, cpu);

		goto out_notify;

	}



	/* Arch-specific enabling code. */

	ret = __cpu_up(cpu, idle);



	if (ret != 0)

		goto out_notify;

	BUG_ON(!cpu_online(cpu));

	ret = notify_prepare(cpu);

	if (ret)

		goto out;



	/* Now call notifier in preparation. */

	cpu_notify(CPU_ONLINE, cpu);

	ret = bringup_cpu(cpu);

	if (ret)

		goto out;



out_notify:

	if (ret != 0)

		__cpu_notify(CPU_UP_CANCELED, cpu, nr_calls, NULL);

	notify_online(cpu);

out:

	cpu_hotplug_done();