diff options
| -rw-r--r-- | drivers/cpufreq/cpufreq.c | 41 |
1 files changed, 3 insertions, 38 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index a3e8fb61cbcc..febda462681c 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(); @@ -1261,15 +1233,11 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) if (cpu_is_offline(cpu)) return add_cpu_dev_symlink(per_cpu(cpufreq_cpu_data, cpu), cpu); - 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; } @@ -1395,8 +1363,6 @@ 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); @@ -1416,8 +1382,6 @@ out_exit_policy: out_free_policy: cpufreq_policy_free(policy, recover_policy); out_release_rwsem: - up_read(&cpufreq_rwsem); - return ret; } @@ -2604,19 +2568,20 @@ 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; } |