Commit 9ef0ad49 authored by Liao Chang's avatar Liao Chang Committed by Rafael J. Wysocki
Browse files

cpufreq: userspace: Move is_managed indicator into per-policy structure 



The userspace governor uses the 'cpu' field of cpufreq_policy structure
to track if it is allowed to set the speed of the policy.

However, there is a window where the 'cpu' field is equal to the value
of nr_cpus_id when all affected CPUs of policy are offline, which is an
illegal value to get the per-CPU variable.

To avoid this issue, modify the governor to use a per-policy indicator
to track if the policy is managed.

Signed-off-by: default avatarLiao Chang <liaochang1@huawei.com>
Acked-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
[ rjw: Changelog edits ]
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 285189c5

drivers/cpufreq/cpufreq_userspace.c

+4 −5
Original line number Diff line number Diff line
@@ -15,9 +15,8 @@ 
#include <linux/mutex.h>

#include <linux/slab.h>



static DEFINE_PER_CPU(unsigned int, cpu_is_managed);



struct userspace_policy {

	unsigned int is_managed;

	unsigned int setspeed;

	struct mutex mutex;

};
@@ -37,7 +36,7 @@ static int cpufreq_set(struct cpufreq_policy *policy, unsigned int freq) 
	pr_debug("cpufreq_set for cpu %u, freq %u kHz\n", policy->cpu, freq);



	mutex_lock(&userspace->mutex);

	if (!per_cpu(cpu_is_managed, policy->cpu))

	if (!userspace->is_managed)

		goto err;



	userspace->setspeed = freq;
@@ -85,7 +84,7 @@ static int cpufreq_userspace_policy_start(struct cpufreq_policy *policy) 
	pr_debug("started managing cpu %u\n", policy->cpu);



	mutex_lock(&userspace->mutex);

	per_cpu(cpu_is_managed, policy->cpu) = 1;

	userspace->is_managed = 1;

	userspace->setspeed = policy->cur;

	mutex_unlock(&userspace->mutex);

	return 0;
@@ -98,7 +97,7 @@ static void cpufreq_userspace_policy_stop(struct cpufreq_policy *policy) 
	pr_debug("managing cpu %u stopped\n", policy->cpu);



	mutex_lock(&userspace->mutex);

	per_cpu(cpu_is_managed, policy->cpu) = 0;

	userspace->is_managed = 0;

	userspace->setspeed = 0;

	mutex_unlock(&userspace->mutex);

}