These changes are the raw update to linux-4.4.6-rt14. Kernel sources

are taken from kernel.org, and rt patch from the rt wiki download page.

During the rebasing, the following patch collided:

Force tick interrupt and get rid of softirq magic(I70131fb85).

Collisions have been removed because its logic was found on the
source already.

Change-Id: I7f57a4081d9deaa0d9ccfc41a6c8daccdee3b769
Signed-off-by: José Pekkarinen <jose.pekkarinen@nokia.com>

1 files changed, 300 insertions, 175 deletions

diff --git a/kernel/drivers/cpufreq/cpufreq_governor.c b/kernel/drivers/cpufreq/cpufreq_governor.c
index 1b44496b2..d994b0f65 100644
--- a/kernel/drivers/cpufreq/cpufreq_governor.c
+++ b/kernel/drivers/cpufreq/cpufreq_governor.c
@@ -32,10 +32,10 @@ static struct attribute_group *get_sysfs_attr(struct dbs_data *dbs_data)
 
 void dbs_check_cpu(struct dbs_data *dbs_data, int cpu)
 {
-	struct cpu_dbs_common_info *cdbs = dbs_data->cdata->get_cpu_cdbs(cpu);
+	struct cpu_dbs_info *cdbs = dbs_data->cdata->get_cpu_cdbs(cpu);
 	struct od_dbs_tuners *od_tuners = dbs_data->tuners;
 	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
-	struct cpufreq_policy *policy;
+	struct cpufreq_policy *policy = cdbs->shared->policy;
 	unsigned int sampling_rate;
 	unsigned int max_load = 0;
 	unsigned int ignore_nice;
@@ -60,11 +60,9 @@ void dbs_check_cpu(struct dbs_data *dbs_data, int cpu)
 		ignore_nice = cs_tuners->ignore_nice_load;
 	}
 
-	policy = cdbs->cur_policy;
-
 	/* Get Absolute Load */
 	for_each_cpu(j, policy->cpus) {
-		struct cpu_dbs_common_info *j_cdbs;
+		struct cpu_dbs_info *j_cdbs;
 		u64 cur_wall_time, cur_idle_time;
 		unsigned int idle_time, wall_time;
 		unsigned int load;
@@ -163,9 +161,9 @@ EXPORT_SYMBOL_GPL(dbs_check_cpu);
 static inline void __gov_queue_work(int cpu, struct dbs_data *dbs_data,
 		unsigned int delay)
 {
-	struct cpu_dbs_common_info *cdbs = dbs_data->cdata->get_cpu_cdbs(cpu);
+	struct cpu_dbs_info *cdbs = dbs_data->cdata->get_cpu_cdbs(cpu);
 
-	mod_delayed_work_on(cpu, system_wq, &cdbs->work, delay);
+	mod_delayed_work_on(cpu, system_wq, &cdbs->dwork, delay);
 }
 
 void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy,
@@ -173,10 +171,6 @@ void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy,
 {
 	int i;
 
-	mutex_lock(&cpufreq_governor_lock);
-	if (!policy->governor_enabled)
-		goto out_unlock;
-
 	if (!all_cpus) {
 		/*
 		 * Use raw_smp_processor_id() to avoid preemptible warnings.
@@ -190,42 +184,81 @@ void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy,
 		for_each_cpu(i, policy->cpus)
 			__gov_queue_work(i, dbs_data, delay);
 	}
-
-out_unlock:
-	mutex_unlock(&cpufreq_governor_lock);
 }
 EXPORT_SYMBOL_GPL(gov_queue_work);
 
 static inline void gov_cancel_work(struct dbs_data *dbs_data,
 		struct cpufreq_policy *policy)
 {
-	struct cpu_dbs_common_info *cdbs;
+	struct cpu_dbs_info *cdbs;
 	int i;
 
 	for_each_cpu(i, policy->cpus) {
 		cdbs = dbs_data->cdata->get_cpu_cdbs(i);
-		cancel_delayed_work_sync(&cdbs->work);
+		cancel_delayed_work_sync(&cdbs->dwork);
 	}
 }
 
 /* Will return if we need to evaluate cpu load again or not */
-bool need_load_eval(struct cpu_dbs_common_info *cdbs,
-		unsigned int sampling_rate)
+static bool need_load_eval(struct cpu_common_dbs_info *shared,
+			   unsigned int sampling_rate)
 {
-	if (policy_is_shared(cdbs->cur_policy)) {
+	if (policy_is_shared(shared->policy)) {
 		ktime_t time_now = ktime_get();
-		s64 delta_us = ktime_us_delta(time_now, cdbs->time_stamp);
+		s64 delta_us = ktime_us_delta(time_now, shared->time_stamp);
 
 		/* Do nothing if we recently have sampled */
 		if (delta_us < (s64)(sampling_rate / 2))
 			return false;
 		else
-			cdbs->time_stamp = time_now;
+			shared->time_stamp = time_now;
 	}
 
 	return true;
 }
-EXPORT_SYMBOL_GPL(need_load_eval);
+
+static void dbs_timer(struct work_struct *work)
+{
+	struct cpu_dbs_info *cdbs = container_of(work, struct cpu_dbs_info,
+						 dwork.work);
+	struct cpu_common_dbs_info *shared = cdbs->shared;
+	struct cpufreq_policy *policy;
+	struct dbs_data *dbs_data;
+	unsigned int sampling_rate, delay;
+	bool modify_all = true;
+
+	mutex_lock(&shared->timer_mutex);
+
+	policy = shared->policy;
+
+	/*
+	 * Governor might already be disabled and there is no point continuing
+	 * with the work-handler.
+	 */
+	if (!policy)
+		goto unlock;
+
+	dbs_data = policy->governor_data;
+
+	if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
+		struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
+
+		sampling_rate = cs_tuners->sampling_rate;
+	} else {
+		struct od_dbs_tuners *od_tuners = dbs_data->tuners;
+
+		sampling_rate = od_tuners->sampling_rate;
+	}
+
+	if (!need_load_eval(cdbs->shared, sampling_rate))
+		modify_all = false;
+
+	delay = dbs_data->cdata->gov_dbs_timer(cdbs, dbs_data, modify_all);
+	gov_queue_work(dbs_data, policy, delay, modify_all);
+
+unlock:
+	mutex_unlock(&shared->timer_mutex);
+}
 
 static void set_sampling_rate(struct dbs_data *dbs_data,
 		unsigned int sampling_rate)
@@ -239,211 +272,303 @@ static void set_sampling_rate(struct dbs_data *dbs_data,
 	}
 }
 
-int cpufreq_governor_dbs(struct cpufreq_policy *policy,
-		struct common_dbs_data *cdata, unsigned int event)
+static int alloc_common_dbs_info(struct cpufreq_policy *policy,
+				 struct common_dbs_data *cdata)
 {
-	struct dbs_data *dbs_data;
-	struct od_cpu_dbs_info_s *od_dbs_info = NULL;
-	struct cs_cpu_dbs_info_s *cs_dbs_info = NULL;
-	struct od_ops *od_ops = NULL;
-	struct od_dbs_tuners *od_tuners = NULL;
-	struct cs_dbs_tuners *cs_tuners = NULL;
-	struct cpu_dbs_common_info *cpu_cdbs;
-	unsigned int sampling_rate, latency, ignore_nice, j, cpu = policy->cpu;
-	int io_busy = 0;
-	int rc;
+	struct cpu_common_dbs_info *shared;
+	int j;
 
-	if (have_governor_per_policy())
-		dbs_data = policy->governor_data;
-	else
-		dbs_data = cdata->gdbs_data;
+	/* Allocate memory for the common information for policy->cpus */
+	shared = kzalloc(sizeof(*shared), GFP_KERNEL);
+	if (!shared)
+		return -ENOMEM;
 
-	WARN_ON(!dbs_data && (event != CPUFREQ_GOV_POLICY_INIT));
+	/* Set shared for all CPUs, online+offline */
+	for_each_cpu(j, policy->related_cpus)
+		cdata->get_cpu_cdbs(j)->shared = shared;
 
-	switch (event) {
-	case CPUFREQ_GOV_POLICY_INIT:
-		if (have_governor_per_policy()) {
-			WARN_ON(dbs_data);
-		} else if (dbs_data) {
-			dbs_data->usage_count++;
-			policy->governor_data = dbs_data;
-			return 0;
-		}
+	return 0;
+}
 
-		dbs_data = kzalloc(sizeof(*dbs_data), GFP_KERNEL);
-		if (!dbs_data) {
-			pr_err("%s: POLICY_INIT: kzalloc failed\n", __func__);
-			return -ENOMEM;
-		}
+static void free_common_dbs_info(struct cpufreq_policy *policy,
+				 struct common_dbs_data *cdata)
+{
+	struct cpu_dbs_info *cdbs = cdata->get_cpu_cdbs(policy->cpu);
+	struct cpu_common_dbs_info *shared = cdbs->shared;
+	int j;
 
-		dbs_data->cdata = cdata;
-		dbs_data->usage_count = 1;
-		rc = cdata->init(dbs_data);
-		if (rc) {
-			pr_err("%s: POLICY_INIT: init() failed\n", __func__);
-			kfree(dbs_data);
-			return rc;
-		}
+	for_each_cpu(j, policy->cpus)
+		cdata->get_cpu_cdbs(j)->shared = NULL;
 
-		if (!have_governor_per_policy())
-			WARN_ON(cpufreq_get_global_kobject());
-
-		rc = sysfs_create_group(get_governor_parent_kobj(policy),
-				get_sysfs_attr(dbs_data));
-		if (rc) {
-			cdata->exit(dbs_data);
-			kfree(dbs_data);
-			return rc;
-		}
+	kfree(shared);
+}
+
+static int cpufreq_governor_init(struct cpufreq_policy *policy,
+				 struct dbs_data *dbs_data,
+				 struct common_dbs_data *cdata)
+{
+	unsigned int latency;
+	int ret;
+
+	/* State should be equivalent to EXIT */
+	if (policy->governor_data)
+		return -EBUSY;
+
+	if (dbs_data) {
+		if (WARN_ON(have_governor_per_policy()))
+			return -EINVAL;
+
+		ret = alloc_common_dbs_info(policy, cdata);
+		if (ret)
+			return ret;
 
+		dbs_data->usage_count++;
 		policy->governor_data = dbs_data;
+		return 0;
+	}
+
+	dbs_data = kzalloc(sizeof(*dbs_data), GFP_KERNEL);
+	if (!dbs_data)
+		return -ENOMEM;
+
+	ret = alloc_common_dbs_info(policy, cdata);
+	if (ret)
+		goto free_dbs_data;
+
+	dbs_data->cdata = cdata;
+	dbs_data->usage_count = 1;
+
+	ret = cdata->init(dbs_data, !policy->governor->initialized);
+	if (ret)
+		goto free_common_dbs_info;
 
-		/* policy latency is in ns. Convert it to us first */
-		latency = policy->cpuinfo.transition_latency / 1000;
-		if (latency == 0)
-			latency = 1;
+	/* policy latency is in ns. Convert it to us first */
+	latency = policy->cpuinfo.transition_latency / 1000;
+	if (latency == 0)
+		latency = 1;
 
-		/* Bring kernel and HW constraints together */
-		dbs_data->min_sampling_rate = max(dbs_data->min_sampling_rate,
-				MIN_LATENCY_MULTIPLIER * latency);
-		set_sampling_rate(dbs_data, max(dbs_data->min_sampling_rate,
+	/* Bring kernel and HW constraints together */
+	dbs_data->min_sampling_rate = max(dbs_data->min_sampling_rate,
+					  MIN_LATENCY_MULTIPLIER * latency);
+	set_sampling_rate(dbs_data, max(dbs_data->min_sampling_rate,
 					latency * LATENCY_MULTIPLIER));
 
-		if ((cdata->governor == GOV_CONSERVATIVE) &&
-				(!policy->governor->initialized)) {
-			struct cs_ops *cs_ops = dbs_data->cdata->gov_ops;
+	if (!have_governor_per_policy())
+		cdata->gdbs_data = dbs_data;
 
-			cpufreq_register_notifier(cs_ops->notifier_block,
-					CPUFREQ_TRANSITION_NOTIFIER);
-		}
+	policy->governor_data = dbs_data;
 
-		if (!have_governor_per_policy())
-			cdata->gdbs_data = dbs_data;
+	ret = sysfs_create_group(get_governor_parent_kobj(policy),
+				 get_sysfs_attr(dbs_data));
+	if (ret)
+		goto reset_gdbs_data;
 
-		return 0;
-	case CPUFREQ_GOV_POLICY_EXIT:
-		if (!--dbs_data->usage_count) {
-			sysfs_remove_group(get_governor_parent_kobj(policy),
-					get_sysfs_attr(dbs_data));
+	return 0;
+
+reset_gdbs_data:
+	policy->governor_data = NULL;
+
+	if (!have_governor_per_policy())
+		cdata->gdbs_data = NULL;
+	cdata->exit(dbs_data, !policy->governor->initialized);
+free_common_dbs_info:
+	free_common_dbs_info(policy, cdata);
+free_dbs_data:
+	kfree(dbs_data);
+	return ret;
+}
+
+static int cpufreq_governor_exit(struct cpufreq_policy *policy,
+				 struct dbs_data *dbs_data)
+{
+	struct common_dbs_data *cdata = dbs_data->cdata;
+	struct cpu_dbs_info *cdbs = cdata->get_cpu_cdbs(policy->cpu);
 
-			if (!have_governor_per_policy())
-				cpufreq_put_global_kobject();
+	/* State should be equivalent to INIT */
+	if (!cdbs->shared || cdbs->shared->policy)
+		return -EBUSY;
 
-			if ((dbs_data->cdata->governor == GOV_CONSERVATIVE) &&
-				(policy->governor->initialized == 1)) {
-				struct cs_ops *cs_ops = dbs_data->cdata->gov_ops;
+	if (!--dbs_data->usage_count) {
+		sysfs_remove_group(get_governor_parent_kobj(policy),
+				   get_sysfs_attr(dbs_data));
 
-				cpufreq_unregister_notifier(cs_ops->notifier_block,
-						CPUFREQ_TRANSITION_NOTIFIER);
-			}
+		policy->governor_data = NULL;
 
-			cdata->exit(dbs_data);
-			kfree(dbs_data);
+		if (!have_governor_per_policy())
 			cdata->gdbs_data = NULL;
-		}
 
+		cdata->exit(dbs_data, policy->governor->initialized == 1);
+		kfree(dbs_data);
+	} else {
 		policy->governor_data = NULL;
-		return 0;
 	}
 
-	cpu_cdbs = dbs_data->cdata->get_cpu_cdbs(cpu);
+	free_common_dbs_info(policy, cdata);
+	return 0;
+}
+
+static int cpufreq_governor_start(struct cpufreq_policy *policy,
+				  struct dbs_data *dbs_data)
+{
+	struct common_dbs_data *cdata = dbs_data->cdata;
+	unsigned int sampling_rate, ignore_nice, j, cpu = policy->cpu;
+	struct cpu_dbs_info *cdbs = cdata->get_cpu_cdbs(cpu);
+	struct cpu_common_dbs_info *shared = cdbs->shared;
+	int io_busy = 0;
+
+	if (!policy->cur)
+		return -EINVAL;
+
+	/* State should be equivalent to INIT */
+	if (!shared || shared->policy)
+		return -EBUSY;
+
+	if (cdata->governor == GOV_CONSERVATIVE) {
+		struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
 
-	if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
-		cs_tuners = dbs_data->tuners;
-		cs_dbs_info = dbs_data->cdata->get_cpu_dbs_info_s(cpu);
 		sampling_rate = cs_tuners->sampling_rate;
 		ignore_nice = cs_tuners->ignore_nice_load;
 	} else {
-		od_tuners = dbs_data->tuners;
-		od_dbs_info = dbs_data->cdata->get_cpu_dbs_info_s(cpu);
+		struct od_dbs_tuners *od_tuners = dbs_data->tuners;
+
 		sampling_rate = od_tuners->sampling_rate;
 		ignore_nice = od_tuners->ignore_nice_load;
-		od_ops = dbs_data->cdata->gov_ops;
 		io_busy = od_tuners->io_is_busy;
 	}
 
-	switch (event) {
-	case CPUFREQ_GOV_START:
-		if (!policy->cur)
-			return -EINVAL;
+	shared->policy = policy;
+	shared->time_stamp = ktime_get();
+	mutex_init(&shared->timer_mutex);
 
-		mutex_lock(&dbs_data->mutex);
+	for_each_cpu(j, policy->cpus) {
+		struct cpu_dbs_info *j_cdbs = cdata->get_cpu_cdbs(j);
+		unsigned int prev_load;
 
-		for_each_cpu(j, policy->cpus) {
-			struct cpu_dbs_common_info *j_cdbs =
-				dbs_data->cdata->get_cpu_cdbs(j);
-			unsigned int prev_load;
+		j_cdbs->prev_cpu_idle =
+			get_cpu_idle_time(j, &j_cdbs->prev_cpu_wall, io_busy);
 
-			j_cdbs->cpu = j;
-			j_cdbs->cur_policy = policy;
-			j_cdbs->prev_cpu_idle = get_cpu_idle_time(j,
-					       &j_cdbs->prev_cpu_wall, io_busy);
+		prev_load = (unsigned int)(j_cdbs->prev_cpu_wall -
+					    j_cdbs->prev_cpu_idle);
+		j_cdbs->prev_load = 100 * prev_load /
+				    (unsigned int)j_cdbs->prev_cpu_wall;
 
-			prev_load = (unsigned int)
-				(j_cdbs->prev_cpu_wall - j_cdbs->prev_cpu_idle);
-			j_cdbs->prev_load = 100 * prev_load /
-					(unsigned int) j_cdbs->prev_cpu_wall;
+		if (ignore_nice)
+			j_cdbs->prev_cpu_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE];
 
-			if (ignore_nice)
-				j_cdbs->prev_cpu_nice =
-					kcpustat_cpu(j).cpustat[CPUTIME_NICE];
+		INIT_DEFERRABLE_WORK(&j_cdbs->dwork, dbs_timer);
+	}
 
-			mutex_init(&j_cdbs->timer_mutex);
-			INIT_DEFERRABLE_WORK(&j_cdbs->work,
-					     dbs_data->cdata->gov_dbs_timer);
-		}
+	if (cdata->governor == GOV_CONSERVATIVE) {
+		struct cs_cpu_dbs_info_s *cs_dbs_info =
+			cdata->get_cpu_dbs_info_s(cpu);
 
-		if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
-			cs_dbs_info->down_skip = 0;
-			cs_dbs_info->enable = 1;
-			cs_dbs_info->requested_freq = policy->cur;
-		} else {
-			od_dbs_info->rate_mult = 1;
-			od_dbs_info->sample_type = OD_NORMAL_SAMPLE;
-			od_ops->powersave_bias_init_cpu(cpu);
-		}
+		cs_dbs_info->down_skip = 0;
+		cs_dbs_info->requested_freq = policy->cur;
+	} else {
+		struct od_ops *od_ops = cdata->gov_ops;
+		struct od_cpu_dbs_info_s *od_dbs_info = cdata->get_cpu_dbs_info_s(cpu);
 
-		mutex_unlock(&dbs_data->mutex);
+		od_dbs_info->rate_mult = 1;
+		od_dbs_info->sample_type = OD_NORMAL_SAMPLE;
+		od_ops->powersave_bias_init_cpu(cpu);
+	}
 
-		/* Initiate timer time stamp */
-		cpu_cdbs->time_stamp = ktime_get();
+	gov_queue_work(dbs_data, policy, delay_for_sampling_rate(sampling_rate),
+		       true);
+	return 0;
+}
 
-		gov_queue_work(dbs_data, policy,
-				delay_for_sampling_rate(sampling_rate), true);
-		break;
+static int cpufreq_governor_stop(struct cpufreq_policy *policy,
+				 struct dbs_data *dbs_data)
+{
+	struct cpu_dbs_info *cdbs = dbs_data->cdata->get_cpu_cdbs(policy->cpu);
+	struct cpu_common_dbs_info *shared = cdbs->shared;
 
-	case CPUFREQ_GOV_STOP:
-		if (dbs_data->cdata->governor == GOV_CONSERVATIVE)
-			cs_dbs_info->enable = 0;
+	/* State should be equivalent to START */
+	if (!shared || !shared->policy)
+		return -EBUSY;
 
-		gov_cancel_work(dbs_data, policy);
+	/*
+	 * Work-handler must see this updated, as it should not proceed any
+	 * further after governor is disabled. And so timer_mutex is taken while
+	 * updating this value.
+	 */
+	mutex_lock(&shared->timer_mutex);
+	shared->policy = NULL;
+	mutex_unlock(&shared->timer_mutex);
 
-		mutex_lock(&dbs_data->mutex);
-		mutex_destroy(&cpu_cdbs->timer_mutex);
-		cpu_cdbs->cur_policy = NULL;
+	gov_cancel_work(dbs_data, policy);
 
-		mutex_unlock(&dbs_data->mutex);
+	mutex_destroy(&shared->timer_mutex);
+	return 0;
+}
 
-		break;
+static int cpufreq_governor_limits(struct cpufreq_policy *policy,
+				   struct dbs_data *dbs_data)
+{
+	struct common_dbs_data *cdata = dbs_data->cdata;
+	unsigned int cpu = policy->cpu;
+	struct cpu_dbs_info *cdbs = cdata->get_cpu_cdbs(cpu);
+
+	/* State should be equivalent to START */
+	if (!cdbs->shared || !cdbs->shared->policy)
+		return -EBUSY;
+
+	mutex_lock(&cdbs->shared->timer_mutex);
+	if (policy->max < cdbs->shared->policy->cur)
+		__cpufreq_driver_target(cdbs->shared->policy, policy->max,
+					CPUFREQ_RELATION_H);
+	else if (policy->min > cdbs->shared->policy->cur)
+		__cpufreq_driver_target(cdbs->shared->policy, policy->min,
+					CPUFREQ_RELATION_L);
+	dbs_check_cpu(dbs_data, cpu);
+	mutex_unlock(&cdbs->shared->timer_mutex);
+
+	return 0;
+}
+
+int cpufreq_governor_dbs(struct cpufreq_policy *policy,
+			 struct common_dbs_data *cdata, unsigned int event)
+{
+	struct dbs_data *dbs_data;
+	int ret;
+
+	/* Lock governor to block concurrent initialization of governor */
+	mutex_lock(&cdata->mutex);
+
+	if (have_governor_per_policy())
+		dbs_data = policy->governor_data;
+	else
+		dbs_data = cdata->gdbs_data;
+
+	if (!dbs_data && (event != CPUFREQ_GOV_POLICY_INIT)) {
+		ret = -EINVAL;
+		goto unlock;
+	}
 
+	switch (event) {
+	case CPUFREQ_GOV_POLICY_INIT:
+		ret = cpufreq_governor_init(policy, dbs_data, cdata);
+		break;
+	case CPUFREQ_GOV_POLICY_EXIT:
+		ret = cpufreq_governor_exit(policy, dbs_data);
+		break;
+	case CPUFREQ_GOV_START:
+		ret = cpufreq_governor_start(policy, dbs_data);
+		break;
+	case CPUFREQ_GOV_STOP:
+		ret = cpufreq_governor_stop(policy, dbs_data);
+		break;
 	case CPUFREQ_GOV_LIMITS:
-		mutex_lock(&dbs_data->mutex);
-		if (!cpu_cdbs->cur_policy) {
-			mutex_unlock(&dbs_data->mutex);
-			break;
-		}
-		mutex_lock(&cpu_cdbs->timer_mutex);
-		if (policy->max < cpu_cdbs->cur_policy->cur)
-			__cpufreq_driver_target(cpu_cdbs->cur_policy,
-					policy->max, CPUFREQ_RELATION_H);
-		else if (policy->min > cpu_cdbs->cur_policy->cur)
-			__cpufreq_driver_target(cpu_cdbs->cur_policy,
-					policy->min, CPUFREQ_RELATION_L);
-		dbs_check_cpu(dbs_data, cpu);
-		mutex_unlock(&cpu_cdbs->timer_mutex);
-		mutex_unlock(&dbs_data->mutex);
+		ret = cpufreq_governor_limits(policy, dbs_data);
 		break;
+	default:
+		ret = -EINVAL;
 	}
-	return 0;
+
+unlock:
+	mutex_unlock(&cdata->mutex);
+
+	return ret;
 }
 EXPORT_SYMBOL_GPL(cpufreq_governor_dbs);