1 files changed, 213 insertions, 131 deletions

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 9a9d8ee9fae..e34bd94e12b 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -44,6 +44,7 @@
  */
 static struct cpufreq_driver *cpufreq_driver;
 static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data);
+static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data_fallback);
 static DEFINE_RWLOCK(cpufreq_driver_lock);
 static DEFINE_MUTEX(cpufreq_governor_lock);
 
@@ -805,41 +806,32 @@ void cpufreq_sysfs_remove_file(const struct attribute *attr)
 EXPORT_SYMBOL(cpufreq_sysfs_remove_file);
 
 /* symlink affected CPUs */
-static int cpufreq_add_dev_symlink(unsigned int cpu,
-				   struct cpufreq_policy *policy)
+static int cpufreq_add_dev_symlink(struct cpufreq_policy *policy)
 {
 	unsigned int j;
 	int ret = 0;
 
 	for_each_cpu(j, policy->cpus) {
-		struct cpufreq_policy *managed_policy;
 		struct device *cpu_dev;
 
-		if (j == cpu)
+		if (j == policy->cpu)
 			continue;
 
-		pr_debug("CPU %u already managed, adding link\n", j);
-		managed_policy = cpufreq_cpu_get(cpu);
+		pr_debug("Adding link for CPU: %u\n", j);
 		cpu_dev = get_cpu_device(j);
 		ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj,
 					"cpufreq");
-		if (ret) {
-			cpufreq_cpu_put(managed_policy);
-			return ret;
-		}
+		if (ret)
+			break;
 	}
 	return ret;
 }
 
-static int cpufreq_add_dev_interface(unsigned int cpu,
-				     struct cpufreq_policy *policy,
+static int cpufreq_add_dev_interface(struct cpufreq_policy *policy,
 				     struct device *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,
@@ -871,17 +863,23 @@ static int cpufreq_add_dev_interface(unsigned int cpu,
 			goto err_out_kobj_put;
 	}
 
-	write_lock_irqsave(&cpufreq_driver_lock, flags);
-	for_each_cpu(j, policy->cpus) {
-		per_cpu(cpufreq_cpu_data, j) = policy;
-		per_cpu(cpufreq_policy_cpu, j) = policy->cpu;
-	}
-	write_unlock_irqrestore(&cpufreq_driver_lock, flags);
-
-	ret = cpufreq_add_dev_symlink(cpu, policy);
+	ret = cpufreq_add_dev_symlink(policy);
 	if (ret)
 		goto err_out_kobj_put;
 
+	return ret;
+
+err_out_kobj_put:
+	kobject_put(&policy->kobj);
+	wait_for_completion(&policy->kobj_unregister);
+	return ret;
+}
+
+static void cpufreq_init_policy(struct cpufreq_policy *policy)
+{
+	struct cpufreq_policy new_policy;
+	int ret = 0;
+
 	memcpy(&new_policy, policy, sizeof(struct cpufreq_policy));
 	/* assure that the starting sequence is run in __cpufreq_set_policy */
 	policy->governor = NULL;
@@ -896,29 +894,20 @@ static int cpufreq_add_dev_interface(unsigned int cpu,
 		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;
 }
 
 #ifdef CONFIG_HOTPLUG_CPU
-static int cpufreq_add_policy_cpu(unsigned int cpu, unsigned int sibling,
-				  struct device *dev)
+static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy,
+				  unsigned int cpu, struct device *dev,
+				  bool frozen)
 {
-	struct cpufreq_policy *policy;
 	int ret = 0, has_target = !!cpufreq_driver->target;
 	unsigned long flags;
 
-	policy = cpufreq_cpu_get(sibling);
-	WARN_ON(!policy);
-
 	if (has_target)
 		__cpufreq_governor(policy, CPUFREQ_GOV_STOP);
 
-	lock_policy_rwsem_write(sibling);
+	lock_policy_rwsem_write(policy->cpu);
 
 	write_lock_irqsave(&cpufreq_driver_lock, flags);
 
@@ -927,33 +916,68 @@ static int cpufreq_add_policy_cpu(unsigned int cpu, unsigned int sibling,
 	per_cpu(cpufreq_cpu_data, cpu) = policy;
 	write_unlock_irqrestore(&cpufreq_driver_lock, flags);
 
-	unlock_policy_rwsem_write(sibling);
+	unlock_policy_rwsem_write(policy->cpu);
 
 	if (has_target) {
 		__cpufreq_governor(policy, CPUFREQ_GOV_START);
 		__cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
 	}
 
-	ret = sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq");
-	if (ret) {
-		cpufreq_cpu_put(policy);
-		return ret;
-	}
+	/* Don't touch sysfs links during light-weight init */
+	if (!frozen)
+		ret = sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq");
 
-	return 0;
+	return ret;
 }
 #endif
 
-/**
- * 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 device *dev, struct subsys_interface *sif)
+static struct cpufreq_policy *cpufreq_policy_restore(unsigned int cpu)
+{
+	struct cpufreq_policy *policy;
+	unsigned long flags;
+
+	write_lock_irqsave(&cpufreq_driver_lock, flags);
+
+	policy = per_cpu(cpufreq_cpu_data_fallback, cpu);
+
+	write_unlock_irqrestore(&cpufreq_driver_lock, flags);
+
+	return policy;
+}
+
+static struct cpufreq_policy *cpufreq_policy_alloc(void)
+{
+	struct cpufreq_policy *policy;
+
+	policy = kzalloc(sizeof(*policy), GFP_KERNEL);
+	if (!policy)
+		return NULL;
+
+	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;
+
+	return policy;
+
+err_free_cpumask:
+	free_cpumask_var(policy->cpus);
+err_free_policy:
+	kfree(policy);
+
+	return NULL;
+}
+
+static void cpufreq_policy_free(struct cpufreq_policy *policy)
+{
+	free_cpumask_var(policy->related_cpus);
+	free_cpumask_var(policy->cpus);
+	kfree(policy);
+}
+
+static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif,
+			     bool frozen)
 {
 	unsigned int j, cpu = dev->id;
 	int ret = -ENOMEM;
@@ -985,7 +1009,7 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
 		struct cpufreq_policy *cp = per_cpu(cpufreq_cpu_data, sibling);
 		if (cp && cpumask_test_cpu(cpu, cp->related_cpus)) {
 			read_unlock_irqrestore(&cpufreq_driver_lock, flags);
-			return cpufreq_add_policy_cpu(cpu, sibling, dev);
+			return cpufreq_add_policy_cpu(cp, cpu, dev, frozen);
 		}
 	}
 	read_unlock_irqrestore(&cpufreq_driver_lock, flags);
@@ -997,16 +1021,15 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
 		goto module_out;
 	}
 
-	policy = kzalloc(sizeof(struct cpufreq_policy), GFP_KERNEL);
+	if (frozen)
+		/* Restore the saved policy when doing light-weight init */
+		policy = cpufreq_policy_restore(cpu);
+	else
+		policy = cpufreq_policy_alloc();
+
 	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;
 	policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
 	cpumask_copy(policy->cpus, cpumask_of(cpu));
@@ -1050,9 +1073,20 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
 	}
 #endif
 
-	ret = cpufreq_add_dev_interface(cpu, policy, dev);
-	if (ret)
-		goto err_out_unregister;
+	write_lock_irqsave(&cpufreq_driver_lock, flags);
+	for_each_cpu(j, policy->cpus) {
+		per_cpu(cpufreq_cpu_data, j) = policy;
+		per_cpu(cpufreq_policy_cpu, j) = policy->cpu;
+	}
+	write_unlock_irqrestore(&cpufreq_driver_lock, flags);
+
+	if (!frozen) {
+		ret = cpufreq_add_dev_interface(policy, dev);
+		if (ret)
+			goto err_out_unregister;
+	}
+
+	cpufreq_init_policy(policy);
 
 	kobject_uevent(&policy->kobj, KOBJ_ADD);
 	module_put(cpufreq_driver->owner);
@@ -1062,26 +1096,36 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
 
 err_out_unregister:
 	write_lock_irqsave(&cpufreq_driver_lock, flags);
-	for_each_cpu(j, policy->cpus)
+	for_each_cpu(j, policy->cpus) {
 		per_cpu(cpufreq_cpu_data, j) = NULL;
+		if (j != cpu)
+			per_cpu(cpufreq_policy_cpu, j) = -1;
+	}
 	write_unlock_irqrestore(&cpufreq_driver_lock, flags);
 
-	kobject_put(&policy->kobj);
-	wait_for_completion(&policy->kobj_unregister);
-
 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);
-err_free_policy:
-	kfree(policy);
+	cpufreq_policy_free(policy);
 nomem_out:
 	module_put(cpufreq_driver->owner);
 module_out:
 	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 device *dev, struct subsys_interface *sif)
+{
+	return __cpufreq_add_dev(dev, sif, false);
+}
+
 static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
 {
 	int j;
@@ -1099,6 +1143,43 @@ static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
 			CPUFREQ_UPDATE_POLICY_CPU, policy);
 }
 
+static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *data,
+					   unsigned int old_cpu, bool frozen)
+{
+	struct device *cpu_dev;
+	unsigned long flags;
+	int ret;
+
+	/* first sibling now owns the new sysfs dir */
+	cpu_dev = get_cpu_device(cpumask_first(data->cpus));
+
+	/* Don't touch sysfs files during light-weight tear-down */
+	if (frozen)
+		return cpu_dev->id;
+
+	sysfs_remove_link(&cpu_dev->kobj, "cpufreq");
+	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(old_cpu));
+		cpumask_set_cpu(old_cpu, data->cpus);
+
+		write_lock_irqsave(&cpufreq_driver_lock, flags);
+		per_cpu(cpufreq_cpu_data, old_cpu) = data;
+		write_unlock_irqrestore(&cpufreq_driver_lock, flags);
+
+		unlock_policy_rwsem_write(old_cpu);
+
+		ret = sysfs_create_link(&cpu_dev->kobj, &data->kobj,
+					"cpufreq");
+
+		return -EINVAL;
+	}
+
+	return cpu_dev->id;
+}
+
 /**
  * __cpufreq_remove_dev - remove a CPU device
  *
@@ -1107,14 +1188,14 @@ static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
  * This routine frees the rwsem before returning.
  */
 static int __cpufreq_remove_dev(struct device *dev,
-		struct subsys_interface *sif)
+				struct subsys_interface *sif, bool frozen)
 {
-	unsigned int cpu = dev->id, ret, cpus;
+	unsigned int cpu = dev->id, cpus;
+	int new_cpu;
 	unsigned long flags;
 	struct cpufreq_policy *data;
 	struct kobject *kobj;
 	struct completion *cmp;
-	struct device *cpu_dev;
 
 	pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
 
@@ -1123,6 +1204,10 @@ static int __cpufreq_remove_dev(struct device *dev,
 	data = per_cpu(cpufreq_cpu_data, cpu);
 	per_cpu(cpufreq_cpu_data, cpu) = NULL;
 
+	/* Save the policy somewhere when doing a light-weight tear-down */
+	if (frozen)
+		per_cpu(cpufreq_cpu_data_fallback, cpu) = data;
+
 	write_unlock_irqrestore(&cpufreq_driver_lock, flags);
 
 	if (!data) {
@@ -1146,68 +1231,60 @@ static int __cpufreq_remove_dev(struct device *dev,
 		cpumask_clear_cpu(cpu, data->cpus);
 	unlock_policy_rwsem_write(cpu);
 
-	if (cpu != data->cpu) {
+	if (cpu != data->cpu && !frozen) {
 		sysfs_remove_link(&dev->kobj, "cpufreq");
 	} else if (cpus > 1) {
-		/* first sibling now owns the new sysfs dir */
-		cpu_dev = get_cpu_device(cpumask_first(data->cpus));
-		sysfs_remove_link(&cpu_dev->kobj, "cpufreq");
-		ret = kobject_move(&data->kobj, &cpu_dev->kobj);
-		if (ret) {
-			pr_err("%s: Failed to move kobj: %d", __func__, ret);
 
+		new_cpu = cpufreq_nominate_new_policy_cpu(data, cpu, frozen);
+		if (new_cpu >= 0) {
 			WARN_ON(lock_policy_rwsem_write(cpu));
-			cpumask_set_cpu(cpu, data->cpus);
-
-			write_lock_irqsave(&cpufreq_driver_lock, flags);
-			per_cpu(cpufreq_cpu_data, cpu) = data;
-			write_unlock_irqrestore(&cpufreq_driver_lock, flags);
-
+			update_policy_cpu(data, new_cpu);
 			unlock_policy_rwsem_write(cpu);
 
-			ret = sysfs_create_link(&cpu_dev->kobj, &data->kobj,
-					"cpufreq");
-			return -EINVAL;
+			if (!frozen) {
+				pr_debug("%s: policy Kobject moved to cpu: %d "
+					 "from: %d\n",__func__, new_cpu, cpu);
+			}
 		}
-
-		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);
 	}
 
-	if ((cpus == 1) && (cpufreq_driver->target))
-		__cpufreq_governor(data, CPUFREQ_GOV_POLICY_EXIT);
-
-	pr_debug("%s: removing link, cpu: %d\n", __func__, cpu);
-	cpufreq_cpu_put(data);
-
 	/* If cpu is last user of policy, free policy */
 	if (cpus == 1) {
-		lock_policy_rwsem_read(cpu);
-		kobj = &data->kobj;
-		cmp = &data->kobj_unregister;
-		unlock_policy_rwsem_read(cpu);
-		kobject_put(kobj);
-
-		/* we need to make sure that the underlying kobj is actually
-		 * not referenced anymore by anybody before we proceed with
-		 * unloading.
-		 */
-		pr_debug("waiting for dropping of refcount\n");
-		wait_for_completion(cmp);
-		pr_debug("wait complete\n");
+		if (cpufreq_driver->target)
+			__cpufreq_governor(data, CPUFREQ_GOV_POLICY_EXIT);
+
+		if (!frozen) {
+			lock_policy_rwsem_read(cpu);
+			kobj = &data->kobj;
+			cmp = &data->kobj_unregister;
+			unlock_policy_rwsem_read(cpu);
+			kobject_put(kobj);
+
+			/*
+			 * We need to make sure that the underlying kobj is
+			 * actually not referenced anymore by anybody before we
+			 * proceed with unloading.
+			 */
+			pr_debug("waiting for dropping of refcount\n");
+			wait_for_completion(cmp);
+			pr_debug("wait complete\n");
+		}
 
+		/*
+		 * Perform the ->exit() even during light-weight tear-down,
+		 * since this is a core component, and is essential for the
+		 * subsequent light-weight ->init() to succeed.
+		 */
 		if (cpufreq_driver->exit)
 			cpufreq_driver->exit(data);
 
-		free_cpumask_var(data->related_cpus);
-		free_cpumask_var(data->cpus);
-		kfree(data);
-	} else if (cpufreq_driver->target) {
-		__cpufreq_governor(data, CPUFREQ_GOV_START);
-		__cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
+		if (!frozen)
+			cpufreq_policy_free(data);
+	} else {
+		if (cpufreq_driver->target) {
+			__cpufreq_governor(data, CPUFREQ_GOV_START);
+			__cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
+		}
 	}
 
 	per_cpu(cpufreq_policy_cpu, cpu) = -1;
@@ -1222,7 +1299,7 @@ static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
 	if (cpu_is_offline(cpu))
 		return 0;
 
-	retval = __cpufreq_remove_dev(dev, sif);
+	retval = __cpufreq_remove_dev(dev, sif, false);
 	return retval;
 }
 
@@ -1925,21 +2002,26 @@ static int cpufreq_cpu_callback(struct notifier_block *nfb,
 {
 	unsigned int cpu = (unsigned long)hcpu;
 	struct device *dev;
+	bool frozen = false;
 
 	dev = get_cpu_device(cpu);
 	if (dev) {
-		switch (action) {
+
+		if (action & CPU_TASKS_FROZEN)
+			frozen = true;
+
+		switch (action & ~CPU_TASKS_FROZEN) {
 		case CPU_ONLINE:
-		case CPU_ONLINE_FROZEN:
-			cpufreq_add_dev(dev, NULL);
+			__cpufreq_add_dev(dev, NULL, frozen);
+			cpufreq_update_policy(cpu);
 			break;
+
 		case CPU_DOWN_PREPARE:
-		case CPU_DOWN_PREPARE_FROZEN:
-			__cpufreq_remove_dev(dev, NULL);
+			__cpufreq_remove_dev(dev, NULL, frozen);
 			break;
+
 		case CPU_DOWN_FAILED:
-		case CPU_DOWN_FAILED_FROZEN:
-			cpufreq_add_dev(dev, NULL);
+			__cpufreq_add_dev(dev, NULL, frozen);
 			break;
 		}
 	}