Commit 69cee714 authored by Viresh Kumar's avatar Viresh Kumar Committed by Rafael J. Wysocki
Browse files

cpufreq: Merge cpufreq_offline_prepare/finish routines 



Commit 1aee40ac (cpufreq: Invoke __cpufreq_remove_dev_finish()
after releasing cpu_hotplug.lock) split the cpufreq's CPU offline
routine in two pieces, one of them to be run with CPU offline/online
locked and the other to be called later.  The reason for that split
was a possible deadlock scenario involving cpufreq sysfs attributes
and CPU offline.

However, the handling of CPU offline in cpufreq has changed since
then.  Policy sysfs attributes are never removed during CPU offline,
so there's no need to worry about accessing them during CPU offline,
because that can't lead to any deadlocks now.  Governor sysfs
attributes are still removed in __cpufreq_governor(_EXIT), but
there is a new kobject type for them now and its show/store
callbacks don't lock CPU offline/online (they don't need to do
that).

This means that the CPU offline code in cpufreq doesn't need to
be split any more, so combine cpufreq_offline_prepare() with
cpufreq_offline_finish().

Signed-off-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
[ rjw: Changelog ]
Tested-by: default avatarJuri Lelli <juri.lelli@arm.com>
Tested-by: default avatarShilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent c54df071

drivers/cpufreq/cpufreq.c

+10 −26
Original line number Diff line number Diff line
@@ -1362,9 +1362,10 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) 
	return ret;

}



static void cpufreq_offline_prepare(unsigned int cpu)

static void cpufreq_offline(unsigned int cpu)

{

	struct cpufreq_policy *policy;

	int ret;



	pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
@@ -1375,7 +1376,7 @@ static void cpufreq_offline_prepare(unsigned int cpu) 
	}



	if (has_target()) {

		int ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);

		ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);

		if (ret)

			pr_err("%s: Failed to stop governor\n", __func__);

	}
@@ -1398,34 +1399,23 @@ static void cpufreq_offline_prepare(unsigned int cpu) 
	/* Start governor again for active policy */

	if (!policy_is_inactive(policy)) {

		if (has_target()) {

			int ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);

			ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);

			if (!ret)

				ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);



			if (ret)

				pr_err("%s: Failed to start governor\n", __func__);

		}

	} else if (cpufreq_driver->stop_cpu) {

		cpufreq_driver->stop_cpu(policy);

	}

}



static void cpufreq_offline_finish(unsigned int cpu)

{

	struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);



	if (!policy) {

		pr_debug("%s: No cpu_data found\n", __func__);

		return;

	}



	/* Only proceed for inactive policies */

	if (!policy_is_inactive(policy))

		return;

	if (cpufreq_driver->stop_cpu)

		cpufreq_driver->stop_cpu(policy);



	/* If cpu is last user of policy, free policy */

	if (has_target()) {

		int ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);

		ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);

		if (ret)

			pr_err("%s: Failed to exit governor\n", __func__);

	}
@@ -1454,10 +1444,8 @@ static void cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif) 
	if (!policy)

		return;



	if (cpu_online(cpu)) {

		cpufreq_offline_prepare(cpu);

		cpufreq_offline_finish(cpu);

	}

	if (cpu_online(cpu))

		cpufreq_offline(cpu);



	cpumask_clear_cpu(cpu, policy->real_cpus);

	remove_cpu_dev_symlink(policy, cpu);
@@ -2305,11 +2293,7 @@ static int cpufreq_cpu_callback(struct notifier_block *nfb, 
		break;



	case CPU_DOWN_PREPARE:

		cpufreq_offline_prepare(cpu);

		break;



	case CPU_POST_DEAD:

		cpufreq_offline_finish(cpu);

		cpufreq_offline(cpu);

		break;



	case CPU_DOWN_FAILED:

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