Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit f3ca4164 authored by Lan Tianyu's avatar Lan Tianyu Committed by Rafael J. Wysocki
Browse files

ACPI / processor: Rework processor throttling with work_on_cpu() 



acpi_processor_set_throttling() uses set_cpus_allowed_ptr() to make
sure that the (struct acpi_processor)->acpi_processor_set_throttling()
callback will run on the right CPU.  However, the function may be
called from a worker thread already bound to a different CPU in which
case that won't work.

Make acpi_processor_set_throttling() use work_on_cpu() as appropriate
instead of abusing set_cpus_allowed_ptr().

Reported-and-tested-by: default avatarJiri Olsa <jolsa@redhat.com>
Signed-off-by: default avatarLan Tianyu <tianyu.lan@intel.com>
Cc: All applicable <stable@vger.kernel.org>
[rjw: Changelog]
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent cfbf8d48

drivers/acpi/processor_throttling.c

+32 −37
Original line number Diff line number Diff line
@@ -56,6 +56,12 @@ struct throttling_tstate { 
	int target_state;		/* target T-state */

};



struct acpi_processor_throttling_arg {

	struct acpi_processor *pr;

	int target_state;

	bool force;

};



#define THROTTLING_PRECHANGE       (1)

#define THROTTLING_POSTCHANGE      (2)
@@ -1060,16 +1066,24 @@ static int acpi_processor_set_throttling_ptc(struct acpi_processor *pr, 
	return 0;

}



static long acpi_processor_throttling_fn(void *data)

{

	struct acpi_processor_throttling_arg *arg = data;

	struct acpi_processor *pr = arg->pr;



	return pr->throttling.acpi_processor_set_throttling(pr,

			arg->target_state, arg->force);

}



int acpi_processor_set_throttling(struct acpi_processor *pr,

						int state, bool force)

{

	cpumask_var_t saved_mask;

	int ret = 0;

	unsigned int i;

	struct acpi_processor *match_pr;

	struct acpi_processor_throttling *p_throttling;

	struct acpi_processor_throttling_arg arg;

	struct throttling_tstate t_state;

	cpumask_var_t online_throttling_cpus;



	if (!pr)

		return -EINVAL;
@@ -1080,14 +1094,6 @@ int acpi_processor_set_throttling(struct acpi_processor *pr, 
	if ((state < 0) || (state > (pr->throttling.state_count - 1)))

		return -EINVAL;



	if (!alloc_cpumask_var(&saved_mask, GFP_KERNEL))

		return -ENOMEM;



	if (!alloc_cpumask_var(&online_throttling_cpus, GFP_KERNEL)) {

		free_cpumask_var(saved_mask);

		return -ENOMEM;

	}



	if (cpu_is_offline(pr->id)) {

		/*

		 * the cpu pointed by pr->id is offline. Unnecessary to change
@@ -1096,17 +1102,15 @@ int acpi_processor_set_throttling(struct acpi_processor *pr, 
		return -ENODEV;

	}



	cpumask_copy(saved_mask, &current->cpus_allowed);

	t_state.target_state = state;

	p_throttling = &(pr->throttling);

	cpumask_and(online_throttling_cpus, cpu_online_mask,

		    p_throttling->shared_cpu_map);



	/*

	 * The throttling notifier will be called for every

	 * affected cpu in order to get one proper T-state.

	 * The notifier event is THROTTLING_PRECHANGE.

	 */

	for_each_cpu(i, online_throttling_cpus) {

	for_each_cpu_and(i, cpu_online_mask, p_throttling->shared_cpu_map) {

		t_state.cpu = i;

		acpi_processor_throttling_notifier(THROTTLING_PRECHANGE,

							&t_state);
@@ -1118,21 +1122,18 @@ int acpi_processor_set_throttling(struct acpi_processor *pr, 
	 * it can be called only for the cpu pointed by pr.

	 */

	if (p_throttling->shared_type == DOMAIN_COORD_TYPE_SW_ANY) {

		/* FIXME: use work_on_cpu() */

		if (set_cpus_allowed_ptr(current, cpumask_of(pr->id))) {

			/* Can't migrate to the pr->id CPU. Exit */

			ret = -ENODEV;

			goto exit;

		}

		ret = p_throttling->acpi_processor_set_throttling(pr,

						t_state.target_state, force);

		arg.pr = pr;

		arg.target_state = state;

		arg.force = force;

		ret = work_on_cpu(pr->id, acpi_processor_throttling_fn, &arg);

	} else {

		/*

		 * When the T-state coordination is SW_ALL or HW_ALL,

		 * it is necessary to set T-state for every affected

		 * cpus.

		 */

		for_each_cpu(i, online_throttling_cpus) {

		for_each_cpu_and(i, cpu_online_mask,

		    p_throttling->shared_cpu_map) {

			match_pr = per_cpu(processors, i);

			/*

			 * If the pointer is invalid, we will report the
@@ -1153,13 +1154,12 @@ int acpi_processor_set_throttling(struct acpi_processor *pr, 
					"on CPU %d\n", i));

				continue;

			}

			t_state.cpu = i;

			/* FIXME: use work_on_cpu() */

			if (set_cpus_allowed_ptr(current, cpumask_of(i)))

				continue;

			ret = match_pr->throttling.

				acpi_processor_set_throttling(

				match_pr, t_state.target_state, force);



			arg.pr = match_pr;

			arg.target_state = state;

			arg.force = force;

			ret = work_on_cpu(pr->id, acpi_processor_throttling_fn,

				&arg);

		}

	}

	/*
@@ -1168,17 +1168,12 @@ int acpi_processor_set_throttling(struct acpi_processor *pr, 
	 * affected cpu to update the T-states.

	 * The notifier event is THROTTLING_POSTCHANGE

	 */

	for_each_cpu(i, online_throttling_cpus) {

	for_each_cpu_and(i, cpu_online_mask, p_throttling->shared_cpu_map) {

		t_state.cpu = i;

		acpi_processor_throttling_notifier(THROTTLING_POSTCHANGE,

							&t_state);

	}

	/* restore the previous state */

	/* FIXME: use work_on_cpu() */

	set_cpus_allowed_ptr(current, saved_mask);

exit:

	free_cpumask_var(online_throttling_cpus);

	free_cpumask_var(saved_mask);



	return ret;

}