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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2015-07-28 17:21:32 +0200
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2015-07-28 17:21:32 +0200
commitc6e53c69ef463ba2749ba9ee9b3d9d7f97dab94a (patch)
treeb6d4a3baadec8d95dc98edf70ee49d7b44f4cc7a /drivers/cpufreq/cpufreq.c
parent559ed40752dc63e68f9b9ad301b20e6a3fe5cf21 (diff)
parent454d3a2500a4eb33be85dde3bfba9e5f6b5efadc (diff)
Merge back earlier cpufreq material for v4.3.
Diffstat (limited to 'drivers/cpufreq/cpufreq.c')
-rw-r--r--drivers/cpufreq/cpufreq.c107
1 files changed, 45 insertions, 62 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 7a3c30c4336f..46251e8d30f2 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -112,12 +112,6 @@ static inline bool has_target(void)
return cpufreq_driver->target_index || cpufreq_driver->target;
}
-/*
- * rwsem to guarantee that cpufreq driver module doesn't unload during critical
- * sections
- */
-static DECLARE_RWSEM(cpufreq_rwsem);
-
/* internal prototypes */
static int __cpufreq_governor(struct cpufreq_policy *policy,
unsigned int event);
@@ -277,10 +271,6 @@ EXPORT_SYMBOL_GPL(cpufreq_generic_get);
* If corresponding call cpufreq_cpu_put() isn't made, the policy wouldn't be
* freed as that depends on the kobj count.
*
- * It also takes a read-lock of 'cpufreq_rwsem' and doesn't put it back if a
- * valid policy is found. This is done to make sure the driver doesn't get
- * unregistered while the policy is being used.
- *
* Return: A valid policy on success, otherwise NULL on failure.
*/
struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
@@ -291,9 +281,6 @@ struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
if (WARN_ON(cpu >= nr_cpu_ids))
return NULL;
- if (!down_read_trylock(&cpufreq_rwsem))
- return NULL;
-
/* get the cpufreq driver */
read_lock_irqsave(&cpufreq_driver_lock, flags);
@@ -306,9 +293,6 @@ struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
read_unlock_irqrestore(&cpufreq_driver_lock, flags);
- if (!policy)
- up_read(&cpufreq_rwsem);
-
return policy;
}
EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
@@ -320,13 +304,10 @@ EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
*
* This decrements the kobject reference count incremented earlier by calling
* cpufreq_cpu_get().
- *
- * It also drops the read-lock of 'cpufreq_rwsem' taken at cpufreq_cpu_get().
*/
void cpufreq_cpu_put(struct cpufreq_policy *policy)
{
kobject_put(&policy->kobj);
- up_read(&cpufreq_rwsem);
}
EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
@@ -851,9 +832,6 @@ static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
struct freq_attr *fattr = to_attr(attr);
ssize_t ret;
- if (!down_read_trylock(&cpufreq_rwsem))
- return -EINVAL;
-
down_read(&policy->rwsem);
if (fattr->show)
@@ -862,7 +840,6 @@ static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
ret = -EIO;
up_read(&policy->rwsem);
- up_read(&cpufreq_rwsem);
return ret;
}
@@ -879,9 +856,6 @@ static ssize_t store(struct kobject *kobj, struct attribute *attr,
if (!cpu_online(policy->cpu))
goto unlock;
- if (!down_read_trylock(&cpufreq_rwsem))
- goto unlock;
-
down_write(&policy->rwsem);
/* Updating inactive policies is invalid, so avoid doing that. */
@@ -897,8 +871,6 @@ static ssize_t store(struct kobject *kobj, struct attribute *attr,
unlock_policy_rwsem:
up_write(&policy->rwsem);
-
- up_read(&cpufreq_rwsem);
unlock:
put_online_cpus();
@@ -1060,11 +1032,10 @@ static int cpufreq_add_dev_interface(struct cpufreq_policy *policy,
return cpufreq_add_dev_symlink(policy);
}
-static void cpufreq_init_policy(struct cpufreq_policy *policy)
+static int cpufreq_init_policy(struct cpufreq_policy *policy)
{
struct cpufreq_governor *gov = NULL;
struct cpufreq_policy new_policy;
- int ret = 0;
memcpy(&new_policy, policy, sizeof(*policy));
@@ -1083,12 +1054,7 @@ static void cpufreq_init_policy(struct cpufreq_policy *policy)
cpufreq_parse_governor(gov->name, &new_policy.policy, NULL);
/* set default policy */
- ret = cpufreq_set_policy(policy, &new_policy);
- if (ret) {
- pr_debug("setting policy failed\n");
- if (cpufreq_driver->exit)
- cpufreq_driver->exit(policy);
- }
+ return cpufreq_set_policy(policy, &new_policy);
}
static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy,
@@ -1276,15 +1242,11 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
? add_cpu_dev_symlink(policy, cpu) : 0;
}
- if (!down_read_trylock(&cpufreq_rwsem))
- return 0;
-
/* Check if this CPU already has a policy to manage it */
policy = per_cpu(cpufreq_cpu_data, cpu);
if (policy && !policy_is_inactive(policy)) {
WARN_ON(!cpumask_test_cpu(cpu, policy->related_cpus));
ret = cpufreq_add_policy_cpu(policy, cpu, dev);
- up_read(&cpufreq_rwsem);
return ret;
}
@@ -1297,7 +1259,7 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
recover_policy = false;
policy = cpufreq_policy_alloc(dev);
if (!policy)
- goto nomem_out;
+ goto out_release_rwsem;
}
cpumask_copy(policy->cpus, cpumask_of(cpu));
@@ -1308,7 +1270,7 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
ret = cpufreq_driver->init(policy);
if (ret) {
pr_debug("initialization failed\n");
- goto err_set_policy_cpu;
+ goto out_free_policy;
}
down_write(&policy->rwsem);
@@ -1340,7 +1302,7 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
policy->cur = cpufreq_driver->get(policy->cpu);
if (!policy->cur) {
pr_err("%s: ->get() failed\n", __func__);
- goto err_get_freq;
+ goto out_exit_policy;
}
}
@@ -1390,7 +1352,7 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
if (!recover_policy) {
ret = cpufreq_add_dev_interface(policy, dev);
if (ret)
- goto err_out_unregister;
+ goto out_exit_policy;
blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
CPUFREQ_CREATE_POLICY, policy);
@@ -1399,7 +1361,12 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
}
- cpufreq_init_policy(policy);
+ ret = cpufreq_init_policy(policy);
+ if (ret) {
+ pr_err("%s: Failed to initialize policy for cpu: %d (%d)\n",
+ __func__, cpu, ret);
+ goto out_remove_policy_notify;
+ }
if (!recover_policy) {
policy->user_policy.policy = policy->policy;
@@ -1409,8 +1376,6 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
kobject_uevent(&policy->kobj, KOBJ_ADD);
- up_read(&cpufreq_rwsem);
-
/* Callback for handling stuff after policy is ready */
if (cpufreq_driver->ready)
cpufreq_driver->ready(policy);
@@ -1419,17 +1384,17 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
return 0;
-err_out_unregister:
-err_get_freq:
+out_remove_policy_notify:
+ /* cpufreq_policy_free() will notify based on this */
+ recover_policy = true;
+out_exit_policy:
up_write(&policy->rwsem);
if (cpufreq_driver->exit)
cpufreq_driver->exit(policy);
-err_set_policy_cpu:
+out_free_policy:
cpufreq_policy_free(policy, recover_policy);
-nomem_out:
- up_read(&cpufreq_rwsem);
-
+out_release_rwsem:
return ret;
}
@@ -2296,16 +2261,31 @@ static int cpufreq_set_policy(struct cpufreq_policy *policy,
old_gov = policy->governor;
/* end old governor */
if (old_gov) {
- __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
+ ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
+ if (ret) {
+ /* This can happen due to race with other operations */
+ pr_debug("%s: Failed to Stop Governor: %s (%d)\n",
+ __func__, old_gov->name, ret);
+ return ret;
+ }
+
up_write(&policy->rwsem);
- __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
+ ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
down_write(&policy->rwsem);
+
+ if (ret) {
+ pr_err("%s: Failed to Exit Governor: %s (%d)\n",
+ __func__, old_gov->name, ret);
+ return ret;
+ }
}
/* start new governor */
policy->governor = new_policy->governor;
- if (!__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT)) {
- if (!__cpufreq_governor(policy, CPUFREQ_GOV_START))
+ ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT);
+ if (!ret) {
+ ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
+ if (!ret)
goto out;
up_write(&policy->rwsem);
@@ -2317,11 +2297,13 @@ static int cpufreq_set_policy(struct cpufreq_policy *policy,
pr_debug("starting governor %s failed\n", policy->governor->name);
if (old_gov) {
policy->governor = old_gov;
- __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT);
- __cpufreq_governor(policy, CPUFREQ_GOV_START);
+ if (__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT))
+ policy->governor = NULL;
+ else
+ __cpufreq_governor(policy, CPUFREQ_GOV_START);
}
- return -EINVAL;
+ return ret;
out:
pr_debug("governor: change or update limits\n");
@@ -2588,19 +2570,20 @@ int cpufreq_unregister_driver(struct cpufreq_driver *driver)
pr_debug("unregistering driver %s\n", driver->name);
+ /* Protect against concurrent cpu hotplug */
+ get_online_cpus();
subsys_interface_unregister(&cpufreq_interface);
if (cpufreq_boost_supported())
cpufreq_sysfs_remove_file(&boost.attr);
unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
- down_write(&cpufreq_rwsem);
write_lock_irqsave(&cpufreq_driver_lock, flags);
cpufreq_driver = NULL;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
- up_write(&cpufreq_rwsem);
+ put_online_cpus();
return 0;
}