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Diffstat (limited to 'drivers/cpufreq')
-rw-r--r--drivers/cpufreq/cpufreq.c110
1 files changed, 31 insertions, 79 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 87ed83a6c894..6c9cbb9ebd1f 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -53,47 +53,6 @@ static inline bool has_target(void)
}
/*
- * cpu_policy_rwsem is a per CPU reader-writer semaphore designed to cure
- * all cpufreq/hotplug/workqueue/etc related lock issues.
- *
- * The rules for this semaphore:
- * - Any routine that wants to read from the policy structure will
- * do a down_read on this semaphore.
- * - Any routine that will write to the policy structure and/or may take away
- * the policy altogether (eg. CPU hotplug), will hold this lock in write
- * mode before doing so.
- *
- * Additional rules:
- * - Governor routines that can be called in cpufreq hotplug path should not
- * take this sem as top level hotplug notifier handler takes this.
- * - Lock should not be held across
- * __cpufreq_governor(data, CPUFREQ_GOV_STOP);
- */
-static DEFINE_PER_CPU(struct rw_semaphore, cpu_policy_rwsem);
-
-#define lock_policy_rwsem(mode, cpu) \
-static void lock_policy_rwsem_##mode(int cpu) \
-{ \
- struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu); \
- BUG_ON(!policy); \
- down_##mode(&per_cpu(cpu_policy_rwsem, policy->cpu)); \
-}
-
-lock_policy_rwsem(read, cpu);
-lock_policy_rwsem(write, cpu);
-
-#define unlock_policy_rwsem(mode, cpu) \
-static void unlock_policy_rwsem_##mode(int cpu) \
-{ \
- struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu); \
- BUG_ON(!policy); \
- up_##mode(&per_cpu(cpu_policy_rwsem, policy->cpu)); \
-}
-
-unlock_policy_rwsem(read, cpu);
-unlock_policy_rwsem(write, cpu);
-
-/*
* rwsem to guarantee that cpufreq driver module doesn't unload during critical
* sections
*/
@@ -688,14 +647,14 @@ static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
if (!down_read_trylock(&cpufreq_rwsem))
return -EINVAL;
- lock_policy_rwsem_read(policy->cpu);
+ down_read(&policy->rwsem);
if (fattr->show)
ret = fattr->show(policy, buf);
else
ret = -EIO;
- unlock_policy_rwsem_read(policy->cpu);
+ up_read(&policy->rwsem);
up_read(&cpufreq_rwsem);
return ret;
@@ -716,14 +675,14 @@ static ssize_t store(struct kobject *kobj, struct attribute *attr,
if (!down_read_trylock(&cpufreq_rwsem))
goto unlock;
- lock_policy_rwsem_write(policy->cpu);
+ down_write(&policy->rwsem);
if (fattr->store)
ret = fattr->store(policy, buf, count);
else
ret = -EIO;
- unlock_policy_rwsem_write(policy->cpu);
+ up_write(&policy->rwsem);
up_read(&cpufreq_rwsem);
unlock:
@@ -900,7 +859,7 @@ static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy,
}
}
- lock_policy_rwsem_write(policy->cpu);
+ down_write(&policy->rwsem);
write_lock_irqsave(&cpufreq_driver_lock, flags);
@@ -908,7 +867,7 @@ static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy,
per_cpu(cpufreq_cpu_data, cpu) = policy;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
- unlock_policy_rwsem_write(policy->cpu);
+ up_write(&policy->rwsem);
if (has_target()) {
if ((ret = __cpufreq_governor(policy, CPUFREQ_GOV_START)) ||
@@ -955,6 +914,8 @@ static struct cpufreq_policy *cpufreq_policy_alloc(void)
goto err_free_cpumask;
INIT_LIST_HEAD(&policy->policy_list);
+ init_rwsem(&policy->rwsem);
+
return policy;
err_free_cpumask:
@@ -977,19 +938,12 @@ static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
if (WARN_ON(cpu == policy->cpu))
return;
- /*
- * Take direct locks as lock_policy_rwsem_write wouldn't work here.
- * Also lock for last cpu is enough here as contention will happen only
- * after policy->cpu is changed and after it is changed, other threads
- * will try to acquire lock for new cpu. And policy is already updated
- * by then.
- */
- down_write(&per_cpu(cpu_policy_rwsem, policy->cpu));
+ down_write(&policy->rwsem);
policy->last_cpu = policy->cpu;
policy->cpu = cpu;
- up_write(&per_cpu(cpu_policy_rwsem, policy->last_cpu));
+ up_write(&policy->rwsem);
cpufreq_frequency_table_update_policy_cpu(policy);
blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
@@ -1181,9 +1135,9 @@ static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *policy,
if (ret) {
pr_err("%s: Failed to move kobj: %d", __func__, ret);
- lock_policy_rwsem_write(old_cpu);
+ down_write(&policy->rwsem);
cpumask_set_cpu(old_cpu, policy->cpus);
- unlock_policy_rwsem_write(old_cpu);
+ up_write(&policy->rwsem);
ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj,
"cpufreq");
@@ -1234,9 +1188,9 @@ static int __cpufreq_remove_dev_prepare(struct device *dev,
policy->governor->name, CPUFREQ_NAME_LEN);
#endif
- lock_policy_rwsem_read(cpu);
+ down_read(&policy->rwsem);
cpus = cpumask_weight(policy->cpus);
- unlock_policy_rwsem_read(cpu);
+ up_read(&policy->rwsem);
if (cpu != policy->cpu) {
if (!frozen)
@@ -1276,12 +1230,12 @@ static int __cpufreq_remove_dev_finish(struct device *dev,
return -EINVAL;
}
- lock_policy_rwsem_write(cpu);
+ down_write(&policy->rwsem);
cpus = cpumask_weight(policy->cpus);
if (cpus > 1)
cpumask_clear_cpu(cpu, policy->cpus);
- unlock_policy_rwsem_write(cpu);
+ up_write(&policy->rwsem);
/* If cpu is last user of policy, free policy */
if (cpus == 1) {
@@ -1296,10 +1250,10 @@ static int __cpufreq_remove_dev_finish(struct device *dev,
}
if (!frozen) {
- lock_policy_rwsem_read(cpu);
+ down_read(&policy->rwsem);
kobj = &policy->kobj;
cmp = &policy->kobj_unregister;
- unlock_policy_rwsem_read(cpu);
+ up_read(&policy->rwsem);
kobject_put(kobj);
/*
@@ -1479,19 +1433,22 @@ static unsigned int __cpufreq_get(unsigned int cpu)
*/
unsigned int cpufreq_get(unsigned int cpu)
{
+ struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
unsigned int ret_freq = 0;
if (cpufreq_disabled() || !cpufreq_driver)
return -ENOENT;
+ BUG_ON(!policy);
+
if (!down_read_trylock(&cpufreq_rwsem))
return 0;
- lock_policy_rwsem_read(cpu);
+ down_read(&policy->rwsem);
ret_freq = __cpufreq_get(cpu);
- unlock_policy_rwsem_read(cpu);
+ up_read(&policy->rwsem);
up_read(&cpufreq_rwsem);
return ret_freq;
@@ -1744,11 +1701,11 @@ int cpufreq_driver_target(struct cpufreq_policy *policy,
{
int ret = -EINVAL;
- lock_policy_rwsem_write(policy->cpu);
+ down_write(&policy->rwsem);
ret = __cpufreq_driver_target(policy, target_freq, relation);
- unlock_policy_rwsem_write(policy->cpu);
+ up_write(&policy->rwsem);
return ret;
}
@@ -1979,10 +1936,10 @@ static int cpufreq_set_policy(struct cpufreq_policy *policy,
/* end old governor */
if (policy->governor) {
__cpufreq_governor(policy, CPUFREQ_GOV_STOP);
- unlock_policy_rwsem_write(new_policy->cpu);
+ up_write(&policy->rwsem);
__cpufreq_governor(policy,
CPUFREQ_GOV_POLICY_EXIT);
- lock_policy_rwsem_write(new_policy->cpu);
+ down_write(&policy->rwsem);
}
/* start new governor */
@@ -1991,10 +1948,10 @@ static int cpufreq_set_policy(struct cpufreq_policy *policy,
if (!__cpufreq_governor(policy, CPUFREQ_GOV_START)) {
failed = 0;
} else {
- unlock_policy_rwsem_write(new_policy->cpu);
+ up_write(&policy->rwsem);
__cpufreq_governor(policy,
CPUFREQ_GOV_POLICY_EXIT);
- lock_policy_rwsem_write(new_policy->cpu);
+ down_write(&policy->rwsem);
}
}
@@ -2040,7 +1997,7 @@ int cpufreq_update_policy(unsigned int cpu)
goto no_policy;
}
- lock_policy_rwsem_write(cpu);
+ down_write(&policy->rwsem);
pr_debug("updating policy for CPU %u\n", cpu);
memcpy(&new_policy, policy, sizeof(*policy));
@@ -2067,7 +2024,7 @@ int cpufreq_update_policy(unsigned int cpu)
ret = cpufreq_set_policy(policy, &new_policy);
- unlock_policy_rwsem_write(cpu);
+ up_write(&policy->rwsem);
cpufreq_cpu_put(policy);
no_policy:
@@ -2225,14 +2182,9 @@ EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
static int __init cpufreq_core_init(void)
{
- int cpu;
-
if (cpufreq_disabled())
return -ENODEV;
- for_each_possible_cpu(cpu)
- init_rwsem(&per_cpu(cpu_policy_rwsem, cpu));
-
cpufreq_global_kobject = kobject_create();
BUG_ON(!cpufreq_global_kobject);
register_syscore_ops(&cpufreq_syscore_ops);
generated by cgit v1.2.3 (git 2.0.4) at 2024-11-15 06:57:18 +0000