diff options
| -rw-r--r-- | drivers/cpufreq/cpufreq.c | 72 |
1 files changed, 38 insertions, 34 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 7cbf1d53804..e000f369166 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -59,8 +59,6 @@ static DEFINE_SPINLOCK(cpufreq_driver_lock); * mode before doing so. * * Additional rules: - * - All holders of the lock should check to make sure that the CPU they - * are concerned with are online after they get the lock. * - 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 @@ -257,6 +255,7 @@ static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci) void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state) { struct cpufreq_policy *policy; + unsigned long flags; BUG_ON(irqs_disabled()); @@ -267,7 +266,10 @@ void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state) pr_debug("notification %u of frequency transition to %u kHz\n", state, freqs->new); + spin_lock_irqsave(&cpufreq_driver_lock, flags); policy = per_cpu(cpufreq_cpu_data, freqs->cpu); + spin_unlock_irqrestore(&cpufreq_driver_lock, flags); + switch (state) { case CPUFREQ_PRECHANGE: @@ -808,22 +810,22 @@ static int cpufreq_add_policy_cpu(unsigned int cpu, unsigned int sibling, policy = cpufreq_cpu_get(sibling); WARN_ON(!policy); - per_cpu(cpufreq_policy_cpu, cpu) = policy->cpu; - - lock_policy_rwsem_write(cpu); - __cpufreq_governor(policy, CPUFREQ_GOV_STOP); + lock_policy_rwsem_write(sibling); + spin_lock_irqsave(&cpufreq_driver_lock, flags); + cpumask_set_cpu(cpu, policy->cpus); + per_cpu(cpufreq_policy_cpu, cpu) = policy->cpu; per_cpu(cpufreq_cpu_data, cpu) = policy; spin_unlock_irqrestore(&cpufreq_driver_lock, flags); + unlock_policy_rwsem_write(sibling); + __cpufreq_governor(policy, CPUFREQ_GOV_START); __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); - unlock_policy_rwsem_write(cpu); - ret = sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq"); if (ret) { cpufreq_cpu_put(policy); @@ -870,11 +872,15 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) #ifdef CONFIG_HOTPLUG_CPU /* Check if this cpu was hot-unplugged earlier and has siblings */ + spin_lock_irqsave(&cpufreq_driver_lock, flags); for_each_online_cpu(sibling) { struct cpufreq_policy *cp = per_cpu(cpufreq_cpu_data, sibling); - if (cp && cpumask_test_cpu(cpu, cp->related_cpus)) + if (cp && cpumask_test_cpu(cpu, cp->related_cpus)) { + spin_unlock_irqrestore(&cpufreq_driver_lock, flags); return cpufreq_add_policy_cpu(cpu, sibling, dev); + } } + spin_unlock_irqrestore(&cpufreq_driver_lock, flags); #endif #endif @@ -899,8 +905,6 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) /* Initially set CPU itself as the policy_cpu */ per_cpu(cpufreq_policy_cpu, cpu) = cpu; - ret = (lock_policy_rwsem_write(cpu) < 0); - WARN_ON(ret); init_completion(&policy->kobj_unregister); INIT_WORK(&policy->update, handle_update); @@ -911,7 +915,7 @@ 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_unlock_policy; + goto err_set_policy_cpu; } /* related cpus should atleast have policy->cpus */ @@ -942,8 +946,6 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) if (ret) goto err_out_unregister; - unlock_policy_rwsem_write(cpu); - kobject_uevent(&policy->kobj, KOBJ_ADD); module_put(cpufreq_driver->owner); pr_debug("initialization complete\n"); @@ -959,8 +961,8 @@ err_out_unregister: kobject_put(&policy->kobj); wait_for_completion(&policy->kobj_unregister); -err_unlock_policy: - unlock_policy_rwsem_write(cpu); +err_set_policy_cpu: + per_cpu(cpufreq_policy_cpu, cpu) = -1; free_cpumask_var(policy->related_cpus); err_free_cpumask: free_cpumask_var(policy->cpus); @@ -1008,12 +1010,14 @@ static int __cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif pr_debug("%s: unregistering CPU %u\n", __func__, cpu); spin_lock_irqsave(&cpufreq_driver_lock, flags); + data = per_cpu(cpufreq_cpu_data, cpu); + per_cpu(cpufreq_cpu_data, cpu) = NULL; + + spin_unlock_irqrestore(&cpufreq_driver_lock, flags); if (!data) { pr_debug("%s: No cpu_data found\n", __func__); - spin_unlock_irqrestore(&cpufreq_driver_lock, flags); - unlock_policy_rwsem_write(cpu); return -EINVAL; } @@ -1025,9 +1029,10 @@ static int __cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif CPUFREQ_NAME_LEN); #endif - per_cpu(cpufreq_cpu_data, cpu) = NULL; + WARN_ON(lock_policy_rwsem_write(cpu)); cpus = cpumask_weight(data->cpus); cpumask_clear_cpu(cpu, data->cpus); + unlock_policy_rwsem_write(cpu); if (cpu != data->cpu) { sysfs_remove_link(&dev->kobj, "cpufreq"); @@ -1038,31 +1043,37 @@ static int __cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif ret = kobject_move(&data->kobj, &cpu_dev->kobj); if (ret) { pr_err("%s: Failed to move kobj: %d", __func__, ret); + + WARN_ON(lock_policy_rwsem_write(cpu)); cpumask_set_cpu(cpu, data->cpus); - ret = sysfs_create_link(&cpu_dev->kobj, &data->kobj, - "cpufreq"); + + spin_lock_irqsave(&cpufreq_driver_lock, flags); + per_cpu(cpufreq_cpu_data, cpu) = data; spin_unlock_irqrestore(&cpufreq_driver_lock, flags); + unlock_policy_rwsem_write(cpu); + + ret = sysfs_create_link(&cpu_dev->kobj, &data->kobj, + "cpufreq"); return -EINVAL; } + WARN_ON(lock_policy_rwsem_write(cpu)); update_policy_cpu(data, cpu_dev->id); + unlock_policy_rwsem_write(cpu); pr_debug("%s: policy Kobject moved to cpu: %d from: %d\n", __func__, cpu_dev->id, cpu); } - spin_unlock_irqrestore(&cpufreq_driver_lock, flags); - pr_debug("%s: removing link, cpu: %d\n", __func__, cpu); cpufreq_cpu_put(data); - unlock_policy_rwsem_write(cpu); /* If cpu is last user of policy, free policy */ if (cpus == 1) { - lock_policy_rwsem_write(cpu); + lock_policy_rwsem_read(cpu); kobj = &data->kobj; cmp = &data->kobj_unregister; - unlock_policy_rwsem_write(cpu); + unlock_policy_rwsem_read(cpu); kobject_put(kobj); /* we need to make sure that the underlying kobj is actually @@ -1073,10 +1084,8 @@ static int __cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif wait_for_completion(cmp); pr_debug("wait complete\n"); - lock_policy_rwsem_write(cpu); if (cpufreq_driver->exit) cpufreq_driver->exit(data); - unlock_policy_rwsem_write(cpu); free_cpumask_var(data->related_cpus); free_cpumask_var(data->cpus); @@ -1086,6 +1095,7 @@ static int __cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif __cpufreq_governor(data, CPUFREQ_GOV_LIMITS); } + per_cpu(cpufreq_policy_cpu, cpu) = -1; return 0; } @@ -1098,9 +1108,6 @@ static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif) if (cpu_is_offline(cpu)) return 0; - if (unlikely(lock_policy_rwsem_write(cpu))) - BUG(); - retval = __cpufreq_remove_dev(dev, sif); return retval; } @@ -1791,9 +1798,6 @@ static int __cpuinit cpufreq_cpu_callback(struct notifier_block *nfb, break; case CPU_DOWN_PREPARE: case CPU_DOWN_PREPARE_FROZEN: - if (unlikely(lock_policy_rwsem_write(cpu))) - BUG(); - __cpufreq_remove_dev(dev, NULL); break; case CPU_DOWN_FAILED: |