cpufreq: governor: Serialize governor callbacks

[firefly-linux-kernel-4.4.55.git] / drivers / cpufreq / cpufreq_governor.c

diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c
index ccf6ce7e598398824072f26130f6a042efec56db..57a39f8a92b7fd41689ac3083decf3a5db4943d9 100644 (file)
--- a/drivers/cpufreq/cpufreq_governor.c
+++ b/drivers/cpufreq/cpufreq_governor.c
@@ -349,8 +349,6 @@ static int cpufreq_governor_start(struct cpufreq_policy *policy,
                io_busy = od_tuners->io_is_busy;
        }
 
-       mutex_lock(&dbs_data->mutex);
-
        for_each_cpu(j, policy->cpus) {
                struct cpu_dbs_common_info *j_cdbs = cdata->get_cpu_cdbs(j);
                unsigned int prev_load;
@@ -388,8 +386,6 @@ static int cpufreq_governor_start(struct cpufreq_policy *policy,
                od_ops->powersave_bias_init_cpu(cpu);
        }
 
-       mutex_unlock(&dbs_data->mutex);
-
        /* Initiate timer time stamp */
        cpu_cdbs->time_stamp = ktime_get();
 
@@ -414,10 +410,8 @@ static void cpufreq_governor_stop(struct cpufreq_policy *policy,
 
        gov_cancel_work(dbs_data, policy);
 
-       mutex_lock(&dbs_data->mutex);
        mutex_destroy(&cpu_cdbs->timer_mutex);
        cpu_cdbs->cur_policy = NULL;
-       mutex_unlock(&dbs_data->mutex);
 }
 
 static void cpufreq_governor_limits(struct cpufreq_policy *policy,
@@ -427,11 +421,8 @@ static void cpufreq_governor_limits(struct cpufreq_policy *policy,
        unsigned int cpu = policy->cpu;
        struct cpu_dbs_common_info *cpu_cdbs = cdata->get_cpu_cdbs(cpu);
 
-       mutex_lock(&dbs_data->mutex);
-       if (!cpu_cdbs->cur_policy) {
-               mutex_unlock(&dbs_data->mutex);
+       if (!cpu_cdbs->cur_policy)
                return;
-       }
 
        mutex_lock(&cpu_cdbs->timer_mutex);
        if (policy->max < cpu_cdbs->cur_policy->cur)
@@ -442,8 +433,6 @@ static void cpufreq_governor_limits(struct cpufreq_policy *policy,
                                        CPUFREQ_RELATION_L);
        dbs_check_cpu(dbs_data, cpu);
        mutex_unlock(&cpu_cdbs->timer_mutex);
-
-       mutex_unlock(&dbs_data->mutex);
 }
 
 int cpufreq_governor_dbs(struct cpufreq_policy *policy,
@@ -452,12 +441,18 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,
        struct dbs_data *dbs_data;
        int ret = 0;
 
+       /* 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;
 
-       WARN_ON(!dbs_data && (event != CPUFREQ_GOV_POLICY_INIT));
+       if (WARN_ON(!dbs_data && (event != CPUFREQ_GOV_POLICY_INIT))) {
+               ret = -EINVAL;
+               goto unlock;
+       }
 
        switch (event) {
        case CPUFREQ_GOV_POLICY_INIT:
@@ -477,6 +472,9 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,
                break;
        }
 
+unlock:
+       mutex_unlock(&cdata->mutex);
+
        return ret;
 }
 EXPORT_SYMBOL_GPL(cpufreq_governor_dbs);