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cpufreq: Don't clear cpufreq_cpu_data and policy list for inactive po…
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Now that we can check policy->cpus to find if policy is active or not,
we don't need to clean cpufreq_cpu_data and delete policy from the list
on light weight tear down of policies (like in suspend).

To make it consistent and clean, set cpufreq_cpu_data for all related
CPUs when the policy is first created and clean it only while it is
freed.

Also update cpufreq_cpu_get_raw() to check if cpu is part of
policy->cpus mask, so that we don't end up getting policies for offline
CPUs.

In order to make sure that no users of 'policy' are using an inactive
policy, use cpufreq_cpu_get_raw() instead of directly accessing
cpufreq_cpu_data.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Viresh Kumar authored and Rafael J. Wysocki committed May 15, 2015
1 parent f963735 commit 988bed0
Showing 1 changed file with 34 additions and 45 deletions.
79 changes: 34 additions & 45 deletions drivers/cpufreq/cpufreq.c
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Original file line number Diff line number Diff line change
Expand Up @@ -239,10 +239,18 @@ int cpufreq_generic_init(struct cpufreq_policy *policy,
}
EXPORT_SYMBOL_GPL(cpufreq_generic_init);

unsigned int cpufreq_generic_get(unsigned int cpu)
/* Only for cpufreq core internal use */
struct cpufreq_policy *cpufreq_cpu_get_raw(unsigned int cpu)
{
struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);

return policy && cpumask_test_cpu(cpu, policy->cpus) ? policy : NULL;
}

unsigned int cpufreq_generic_get(unsigned int cpu)
{
struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);

if (!policy || IS_ERR(policy->clk)) {
pr_err("%s: No %s associated to cpu: %d\n",
__func__, policy ? "clk" : "policy", cpu);
Expand All @@ -253,12 +261,6 @@ unsigned int cpufreq_generic_get(unsigned int cpu)
}
EXPORT_SYMBOL_GPL(cpufreq_generic_get);

/* Only for cpufreq core internal use */
struct cpufreq_policy *cpufreq_cpu_get_raw(unsigned int cpu)
{
return per_cpu(cpufreq_cpu_data, cpu);
}

/**
* cpufreq_cpu_get: returns policy for a cpu and marks it busy.
*
Expand Down Expand Up @@ -292,7 +294,7 @@ struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)

if (cpufreq_driver) {
/* get the CPU */
policy = per_cpu(cpufreq_cpu_data, cpu);
policy = cpufreq_cpu_get_raw(cpu);
if (policy)
kobject_get(&policy->kobj);
}
Expand Down Expand Up @@ -1042,7 +1044,6 @@ static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy,
unsigned int cpu, struct device *dev)
{
int ret = 0;
unsigned long flags;

/* Has this CPU been taken care of already? */
if (cpumask_test_cpu(cpu, policy->cpus))
Expand All @@ -1057,13 +1058,7 @@ static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy,
}

down_write(&policy->rwsem);

write_lock_irqsave(&cpufreq_driver_lock, flags);

cpumask_set_cpu(cpu, policy->cpus);
per_cpu(cpufreq_cpu_data, cpu) = policy;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);

up_write(&policy->rwsem);

if (has_target()) {
Expand Down Expand Up @@ -1154,6 +1149,17 @@ static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy)

static void cpufreq_policy_free(struct cpufreq_policy *policy)
{
unsigned long flags;
int cpu;

/* Remove policy from list */
write_lock_irqsave(&cpufreq_driver_lock, flags);
list_del(&policy->policy_list);

for_each_cpu(cpu, policy->related_cpus)
per_cpu(cpufreq_cpu_data, cpu) = NULL;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);

free_cpumask_var(policy->related_cpus);
free_cpumask_var(policy->cpus);
kfree(policy);
Expand Down Expand Up @@ -1275,12 +1281,12 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
__func__, ret);
goto err_init_policy_kobj;
}
}

write_lock_irqsave(&cpufreq_driver_lock, flags);
for_each_cpu(j, policy->cpus)
per_cpu(cpufreq_cpu_data, j) = policy;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
write_lock_irqsave(&cpufreq_driver_lock, flags);
for_each_cpu(j, policy->related_cpus)
per_cpu(cpufreq_cpu_data, j) = policy;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
}

if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
policy->cur = cpufreq_driver->get(policy->cpu);
Expand Down Expand Up @@ -1339,11 +1345,11 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
goto err_out_unregister;
blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
CPUFREQ_CREATE_POLICY, policy);
}

write_lock_irqsave(&cpufreq_driver_lock, flags);
list_add(&policy->policy_list, &cpufreq_policy_list);
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
write_lock_irqsave(&cpufreq_driver_lock, flags);
list_add(&policy->policy_list, &cpufreq_policy_list);
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
}

cpufreq_init_policy(policy);

Expand All @@ -1367,11 +1373,6 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)

err_out_unregister:
err_get_freq:
write_lock_irqsave(&cpufreq_driver_lock, flags);
for_each_cpu(j, policy->cpus)
per_cpu(cpufreq_cpu_data, j) = NULL;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);

if (!recover_policy) {
kobject_put(&policy->kobj);
wait_for_completion(&policy->kobj_unregister);
Expand Down Expand Up @@ -1407,7 +1408,7 @@ static int __cpufreq_remove_dev_prepare(struct device *dev,

write_lock_irqsave(&cpufreq_driver_lock, flags);

policy = per_cpu(cpufreq_cpu_data, cpu);
policy = cpufreq_cpu_get_raw(cpu);

/* Save the policy somewhere when doing a light-weight tear-down */
if (cpufreq_suspended)
Expand Down Expand Up @@ -1465,28 +1466,21 @@ static int __cpufreq_remove_dev_prepare(struct device *dev,
static int __cpufreq_remove_dev_finish(struct device *dev,
struct subsys_interface *sif)
{
unsigned int cpu = dev->id, cpus;
unsigned int cpu = dev->id;
int ret;
unsigned long flags;
struct cpufreq_policy *policy;

write_lock_irqsave(&cpufreq_driver_lock, flags);
policy = per_cpu(cpufreq_cpu_data, cpu);
per_cpu(cpufreq_cpu_data, cpu) = NULL;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);

if (!policy) {
pr_debug("%s: No cpu_data found\n", __func__);
return -EINVAL;
}

down_write(&policy->rwsem);
cpus = cpumask_weight(policy->cpus);
cpumask_clear_cpu(cpu, policy->cpus);
up_write(&policy->rwsem);

/* If cpu is last user of policy, free policy */
if (cpus == 1) {
if (policy_is_inactive(policy)) {
if (has_target()) {
ret = __cpufreq_governor(policy,
CPUFREQ_GOV_POLICY_EXIT);
Expand All @@ -1508,11 +1502,6 @@ static int __cpufreq_remove_dev_finish(struct device *dev,
if (cpufreq_driver->exit)
cpufreq_driver->exit(policy);

/* Remove policy from list of active policies */
write_lock_irqsave(&cpufreq_driver_lock, flags);
list_del(&policy->policy_list);
write_unlock_irqrestore(&cpufreq_driver_lock, flags);

if (!cpufreq_suspended)
cpufreq_policy_free(policy);
} else if (has_target()) {
Expand Down

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