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Commit 2e1a3483 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

cpu/hotplug: Split out the state walk into functions 



We need that for running callbacks on the AP and the BP.

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/20160226182341.374946234@linutronix.de


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 931ef163

kernel/cpu.c

+68 −43
Original line number Diff line number Diff line
@@ -329,10 +329,74 @@ static int bringup_cpu(unsigned int cpu) 
	return 0;

}



/*

 * Hotplug state machine related functions

 */

static void undo_cpu_down(unsigned int cpu, struct cpuhp_cpu_state *st,

			  struct cpuhp_step *steps)

{

	for (st->state++; st->state < st->target; st->state++) {

		struct cpuhp_step *step = steps + st->state;



		if (!step->skip_onerr)

			cpuhp_invoke_callback(cpu, st->state, step->startup);

	}

}



static int cpuhp_down_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st,

				struct cpuhp_step *steps, enum cpuhp_state target)

{

	enum cpuhp_state prev_state = st->state;

	int ret = 0;



	for (; st->state > target; st->state--) {

		struct cpuhp_step *step = steps + st->state;



		ret = cpuhp_invoke_callback(cpu, st->state, step->teardown);

		if (ret) {

			st->target = prev_state;

			undo_cpu_down(cpu, st, steps);

			break;

		}

	}

	return ret;

}



static void undo_cpu_up(unsigned int cpu, struct cpuhp_cpu_state *st,

			struct cpuhp_step *steps)

{

	for (st->state--; st->state > st->target; st->state--) {

		struct cpuhp_step *step = steps + st->state;



		if (!step->skip_onerr)

			cpuhp_invoke_callback(cpu, st->state, step->teardown);

	}

}



static int cpuhp_up_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st,

			      struct cpuhp_step *steps, enum cpuhp_state target)

{

	enum cpuhp_state prev_state = st->state;

	int ret = 0;



	while (st->state < target) {

		struct cpuhp_step *step;



		st->state++;

		step = steps + st->state;

		ret = cpuhp_invoke_callback(cpu, st->state, step->startup);

		if (ret) {

			st->target = prev_state;

			undo_cpu_up(cpu, st, steps);

			break;

		}

	}

	return ret;

}



#ifdef CONFIG_HOTPLUG_CPU

EXPORT_SYMBOL(register_cpu_notifier);

EXPORT_SYMBOL(__register_cpu_notifier);



void unregister_cpu_notifier(struct notifier_block *nb)

{

	cpu_maps_update_begin();
@@ -537,15 +601,6 @@ static int notify_dead(unsigned int cpu) 
#endif



#ifdef CONFIG_HOTPLUG_CPU

static void undo_cpu_down(unsigned int cpu, struct cpuhp_cpu_state *st)

{

	for (st->state++; st->state < st->target; st->state++) {

		struct cpuhp_step *step = cpuhp_bp_states + st->state;



		if (!step->skip_onerr)

			cpuhp_invoke_callback(cpu, st->state, step->startup);

	}

}



/* Requires cpu_add_remove_lock to be held */

static int __ref _cpu_down(unsigned int cpu, int tasks_frozen,
@@ -567,16 +622,8 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen, 


	prev_state = st->state;

	st->target = target;

	for (; st->state > st->target; st->state--) {

		struct cpuhp_step *step = cpuhp_bp_states + st->state;

	ret = cpuhp_down_callbacks(cpu, st, cpuhp_bp_states, target);



		ret = cpuhp_invoke_callback(cpu, st->state, step->teardown);

		if (ret) {

			st->target = prev_state;

			undo_cpu_down(cpu, st);

			break;

		}

	}

	hasdied = prev_state != st->state && st->state == CPUHP_OFFLINE;



	cpu_hotplug_done();
@@ -645,22 +692,12 @@ static int cpuhp_set_cpu_active(unsigned int cpu) 
	return 0;

}



static void undo_cpu_up(unsigned int cpu, struct cpuhp_cpu_state *st)

{

	for (st->state--; st->state > st->target; st->state--) {

		struct cpuhp_step *step = cpuhp_bp_states + st->state;



		if (!step->skip_onerr)

			cpuhp_invoke_callback(cpu, st->state, step->teardown);

	}

}



/* Requires cpu_add_remove_lock to be held */

static int _cpu_up(unsigned int cpu, int tasks_frozen, enum cpuhp_state target)

{

	struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);

	struct task_struct *idle;

	int prev_state, ret = 0;

	int ret = 0;



	cpu_hotplug_begin();
@@ -687,20 +724,8 @@ static int _cpu_up(unsigned int cpu, int tasks_frozen, enum cpuhp_state target) 


	cpuhp_tasks_frozen = tasks_frozen;



	prev_state = st->state;

	st->target = target;

	while (st->state < st->target) {

		struct cpuhp_step *step;



		st->state++;

		step = cpuhp_bp_states + st->state;

		ret = cpuhp_invoke_callback(cpu, st->state, step->startup);

		if (ret) {

			st->target = prev_state;

			undo_cpu_up(cpu, st);

			break;

		}

	}

	ret = cpuhp_up_callbacks(cpu, st, cpuhp_bp_states, target);

out:

	cpu_hotplug_done();

	return ret;