1 files changed, 187 insertions, 118 deletions

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 2968ed6a9c49..3938c7817095 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -61,6 +61,8 @@ static DEFINE_SPINLOCK(cpufreq_driver_lock);
  *   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
+ *     __cpufreq_governor(data, CPUFREQ_GOV_STOP);
  */
 static DEFINE_PER_CPU(int, policy_cpu);
 static DEFINE_PER_CPU(struct rw_semaphore, cpu_policy_rwsem);
@@ -686,6 +688,9 @@ static struct attribute *default_attrs[] = {
         NULL
 };
 
+struct kobject *cpufreq_global_kobject;
+EXPORT_SYMBOL(cpufreq_global_kobject);
+
 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
 #define to_attr(a) container_of(a, struct freq_attr, attr)
 
@@ -756,92 +761,20 @@ static struct kobj_type ktype_cpufreq = {
         .release        = cpufreq_sysfs_release,
 };
 
-
-/**
- * cpufreq_add_dev - add a CPU device
- *
- * Adds the cpufreq interface for a CPU device.
- *
- * The Oracle says: try running cpufreq registration/unregistration concurrently
- * with with cpu hotplugging and all hell will break loose. Tried to clean this
- * mess up, but more thorough testing is needed. - Mathieu
+/*
+ * Returns:
+ *   Negative: Failure
+ *   0:        Success
+ *   Positive: When we have a managed CPU and the sysfs got symlinked
  */
-static int cpufreq_add_dev(struct sys_device *sys_dev)
+int cpufreq_add_dev_policy(unsigned int cpu, struct cpufreq_policy *policy,
+                struct sys_device *sys_dev)
 {
-        unsigned int cpu = sys_dev->id;
         int ret = 0;
-        struct cpufreq_policy new_policy;
-        struct cpufreq_policy *policy;
-        struct freq_attr **drv_attr;
-        struct sys_device *cpu_sys_dev;
+#ifdef CONFIG_SMP
         unsigned long flags;
         unsigned int j;
 
-        if (cpu_is_offline(cpu))
-                return 0;
-
-        cpufreq_debug_disable_ratelimit();
-        dprintk("adding CPU %u\n", cpu);
-
-#ifdef CONFIG_SMP
-        /* check whether a different CPU already registered this
-         * CPU because it is in the same boat. */
-        policy = cpufreq_cpu_get(cpu);
-        if (unlikely(policy)) {
-                cpufreq_cpu_put(policy);
-                cpufreq_debug_enable_ratelimit();
-                return 0;
-        }
-#endif
-
-        if (!try_module_get(cpufreq_driver->owner)) {
-                ret = -EINVAL;
-                goto module_out;
-        }
-
-        policy = kzalloc(sizeof(struct cpufreq_policy), GFP_KERNEL);
-        if (!policy) {
-                ret = -ENOMEM;
-                goto nomem_out;
-        }
-        if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL)) {
-                ret = -ENOMEM;
-                goto err_free_policy;
-        }
-        if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL)) {
-                ret = -ENOMEM;
-                goto err_free_cpumask;
-        }
-
-        policy->cpu = cpu;
-        cpumask_copy(policy->cpus, cpumask_of(cpu));
-
-        /* Initially set CPU itself as the policy_cpu */
-        per_cpu(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);
-
-        /* Set governor before ->init, so that driver could check it */
-        policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
-        /* call driver. From then on the cpufreq must be able
-         * to accept all calls to ->verify and ->setpolicy for this CPU
-         */
-        ret = cpufreq_driver->init(policy);
-        if (ret) {
-                dprintk("initialization failed\n");
-                goto err_unlock_policy;
-        }
-        policy->user_policy.min = policy->min;
-        policy->user_policy.max = policy->max;
-
-        blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
-                                     CPUFREQ_START, policy);
-
-#ifdef CONFIG_SMP
-
 #ifdef CONFIG_HOTPLUG_CPU
         if (per_cpu(cpufreq_cpu_governor, cpu)) {
                 policy->governor = per_cpu(cpufreq_cpu_governor, cpu);
@@ -872,9 +805,8 @@ static int cpufreq_add_dev(struct sys_device *sys_dev)
                                 /* Should not go through policy unlock path */
                                 if (cpufreq_driver->exit)
                                         cpufreq_driver->exit(policy);
-                                ret = -EBUSY;
                                 cpufreq_cpu_put(managed_policy);
-                                goto err_free_cpumask;
+                                return -EBUSY;
                         }
 
                         spin_lock_irqsave(&cpufreq_driver_lock, flags);
@@ -893,17 +825,62 @@ static int cpufreq_add_dev(struct sys_device *sys_dev)
                          * Call driver->exit() because only the cpu parent of
                          * the kobj needed to call init().
                          */
-                        goto out_driver_exit; /* call driver->exit() */
+                        if (cpufreq_driver->exit)
+                                cpufreq_driver->exit(policy);
+
+                        if (!ret)
+                                return 1;
+                        else
+                                return ret;
                 }
         }
 #endif
-        memcpy(&new_policy, policy, sizeof(struct cpufreq_policy));
+        return ret;
+}
+
+
+/* symlink affected CPUs */
+int cpufreq_add_dev_symlink(unsigned int cpu, struct cpufreq_policy *policy)
+{
+        unsigned int j;
+        int ret = 0;
+
+        for_each_cpu(j, policy->cpus) {
+                struct cpufreq_policy *managed_policy;
+                struct sys_device *cpu_sys_dev;
+
+                if (j == cpu)
+                        continue;
+                if (!cpu_online(j))
+                        continue;
+
+                dprintk("CPU %u already managed, adding link\n", j);
+                managed_policy = cpufreq_cpu_get(cpu);
+                cpu_sys_dev = get_cpu_sysdev(j);
+                ret = sysfs_create_link(&cpu_sys_dev->kobj, &policy->kobj,
+                                        "cpufreq");
+                if (ret) {
+                        cpufreq_cpu_put(managed_policy);
+                        return ret;
+                }
+        }
+        return ret;
+}
+
+int cpufreq_add_dev_interface(unsigned int cpu, struct cpufreq_policy *policy,
+                struct sys_device *sys_dev)
+{
+        struct cpufreq_policy new_policy;
+        struct freq_attr **drv_attr;
+        unsigned long flags;
+        int ret = 0;
+        unsigned int j;
 
         /* prepare interface data */
-        ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq, &sys_dev->kobj,
-                                   "cpufreq");
+        ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
+                                   &sys_dev->kobj, "cpufreq");
         if (ret)
-                goto out_driver_exit;
+                return ret;
 
         /* set up files for this cpu device */
         drv_attr = cpufreq_driver->attr;
@@ -926,35 +903,20 @@ static int cpufreq_add_dev(struct sys_device *sys_dev)
 
         spin_lock_irqsave(&cpufreq_driver_lock, flags);
         for_each_cpu(j, policy->cpus) {
-                if (!cpu_online(j))
-                        continue;
+        if (!cpu_online(j))
+                continue;
                 per_cpu(cpufreq_cpu_data, j) = policy;
                 per_cpu(policy_cpu, j) = policy->cpu;
         }
         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 
-        /* symlink affected CPUs */
-        for_each_cpu(j, policy->cpus) {
-                struct cpufreq_policy *managed_policy;
-
-                if (j == cpu)
-                        continue;
-                if (!cpu_online(j))
-                        continue;
-
-                dprintk("CPU %u already managed, adding link\n", j);
-                managed_policy = cpufreq_cpu_get(cpu);
-                cpu_sys_dev = get_cpu_sysdev(j);
-                ret = sysfs_create_link(&cpu_sys_dev->kobj, &policy->kobj,
-                                        "cpufreq");
-                if (ret) {
-                        cpufreq_cpu_put(managed_policy);
-                        goto err_out_unregister;
-                }
-        }
+        ret = cpufreq_add_dev_symlink(cpu, policy);
+        if (ret)
+                goto err_out_kobj_put;
 
-        policy->governor = NULL; /* to assure that the starting sequence is
-                                  * run in cpufreq_set_policy */
+        memcpy(&new_policy, policy, sizeof(struct cpufreq_policy));
+        /* assure that the starting sequence is run in __cpufreq_set_policy */
+        policy->governor = NULL;
 
         /* set default policy */
         ret = __cpufreq_set_policy(policy, &new_policy);
@@ -963,8 +925,107 @@ static int cpufreq_add_dev(struct sys_device *sys_dev)
 
         if (ret) {
                 dprintk("setting policy failed\n");
-                goto err_out_unregister;
+                if (cpufreq_driver->exit)
+                        cpufreq_driver->exit(policy);
+        }
+        return ret;
+
+err_out_kobj_put:
+        kobject_put(&policy->kobj);
+        wait_for_completion(&policy->kobj_unregister);
+        return ret;
+}
+
+
+/**
+ * cpufreq_add_dev - add a CPU device
+ *
+ * Adds the cpufreq interface for a CPU device.
+ *
+ * The Oracle says: try running cpufreq registration/unregistration concurrently
+ * with with cpu hotplugging and all hell will break loose. Tried to clean this
+ * mess up, but more thorough testing is needed. - Mathieu
+ */
+static int cpufreq_add_dev(struct sys_device *sys_dev)
+{
+        unsigned int cpu = sys_dev->id;
+        int ret = 0;
+        struct cpufreq_policy *policy;
+        unsigned long flags;
+        unsigned int j;
+
+        if (cpu_is_offline(cpu))
+                return 0;
+
+        cpufreq_debug_disable_ratelimit();
+        dprintk("adding CPU %u\n", cpu);
+
+#ifdef CONFIG_SMP
+        /* check whether a different CPU already registered this
+         * CPU because it is in the same boat. */
+        policy = cpufreq_cpu_get(cpu);
+        if (unlikely(policy)) {
+                cpufreq_cpu_put(policy);
+                cpufreq_debug_enable_ratelimit();
+                return 0;
+        }
+#endif
+
+        if (!try_module_get(cpufreq_driver->owner)) {
+                ret = -EINVAL;
+                goto module_out;
+        }
+
+        ret = -ENOMEM;
+        policy = kzalloc(sizeof(struct cpufreq_policy), GFP_KERNEL);
+        if (!policy)
+                goto nomem_out;
+
+        if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
+                goto err_free_policy;
+
+        if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
+                goto err_free_cpumask;
+
+        policy->cpu = cpu;
+        cpumask_copy(policy->cpus, cpumask_of(cpu));
+
+        /* Initially set CPU itself as the policy_cpu */
+        per_cpu(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);
+
+        /* Set governor before ->init, so that driver could check it */
+        policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
+        /* call driver. From then on the cpufreq must be able
+         * to accept all calls to ->verify and ->setpolicy for this CPU
+         */
+        ret = cpufreq_driver->init(policy);
+        if (ret) {
+                dprintk("initialization failed\n");
+                goto err_unlock_policy;
         }
+        policy->user_policy.min = policy->min;
+        policy->user_policy.max = policy->max;
+
+        blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
+                                     CPUFREQ_START, policy);
+
+        ret = cpufreq_add_dev_policy(cpu, policy, sys_dev);
+        if (ret) {
+                if (ret > 0)
+                        /* This is a managed cpu, symlink created,
+                           exit with 0 */
+                        ret = 0;
+                goto err_unlock_policy;
+        }
+
+        ret = cpufreq_add_dev_interface(cpu, policy, sys_dev);
+        if (ret)
+                goto err_out_unregister;
 
         unlock_policy_rwsem_write(cpu);
 
@@ -982,14 +1043,9 @@ err_out_unregister:
                 per_cpu(cpufreq_cpu_data, j) = NULL;
         spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 
-err_out_kobj_put:
         kobject_put(&policy->kobj);
         wait_for_completion(&policy->kobj_unregister);
 
-out_driver_exit:
-        if (cpufreq_driver->exit)
-                cpufreq_driver->exit(policy);
-
 err_unlock_policy:
         unlock_policy_rwsem_write(cpu);
 err_free_cpumask:
@@ -1653,8 +1709,17 @@ static int __cpufreq_set_policy(struct cpufreq_policy *data,
                         dprintk("governor switch\n");
 
                         /* end old governor */
-                        if (data->governor)
+                        if (data->governor) {
+                                /*
+                                 * Need to release the rwsem around governor
+                                 * stop due to lock dependency between
+                                 * cancel_delayed_work_sync and the read lock
+                                 * taken in the delayed work handler.
+                                 */
+                                unlock_policy_rwsem_write(data->cpu);
                                 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
+                                lock_policy_rwsem_write(data->cpu);
+                        }
 
                         /* start new governor */
                         data->governor = policy->governor;
@@ -1884,7 +1949,11 @@ static int __init cpufreq_core_init(void)
                 per_cpu(policy_cpu, cpu) = -1;
                 init_rwsem(&per_cpu(cpu_policy_rwsem, cpu));
         }
+
+        cpufreq_global_kobject = kobject_create_and_add("cpufreq",
+                                                &cpu_sysdev_class.kset.kobj);
+        BUG_ON(!cpufreq_global_kobject);
+
         return 0;
 }
-
 core_initcall(cpufreq_core_init);