cpufreq: governors: Fix WARN_ON() for multi-policy platforms

On multi-policy systems there is a single instance of governor for both the
policies (if same governor is chosen for both policies). With the code update
from following patches:

8eeed09 cpufreq: governors: Get rid of dbs_data->enable field
b394058 cpufreq: governors: Reset tunables only for cpufreq_unregister_governor()

We are creating/removing sysfs directory of governor for for every call to
GOV_START and STOP. This would fail for multi-policy system as there is a
per-policy call to START/STOP.

This patch reuses the governor->initialized variable to detect total users of
governor.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 0dc9933069c510c0a47ae50501e883a344762a92..cd7644554a628485f2e2fffdd3dd9a5b97d74172 100644 (file)
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1552,8 +1552,10 @@ static int __cpufreq_governor(struct cpufreq_policy *policy,
                                                policy->cpu, event);
        ret = policy->governor->governor(policy, event);
 
-       if (!policy->governor->initialized && (event == CPUFREQ_GOV_START))
-               policy->governor->initialized = 1;
+       if (event == CPUFREQ_GOV_START)
+               policy->governor->initialized++;
+       else if (event == CPUFREQ_GOV_STOP)
+               policy->governor->initialized--;
 
        /* we keep one module reference alive for
                        each CPU governed by this CPU */

diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c
index e4a306c8ff1b8c93bc13db35a9cc11c12af343ee..5a76086ff09becd77fff867d05b6f2782da50f0f 100644 (file)
--- a/drivers/cpufreq/cpufreq_governor.c
+++ b/drivers/cpufreq/cpufreq_governor.c
@@ -247,11 +247,13 @@ int cpufreq_governor_dbs(struct dbs_data *dbs_data,
                                             dbs_data->gov_dbs_timer);
                }
 
-               rc = sysfs_create_group(cpufreq_global_kobject,
-                               dbs_data->attr_group);
-               if (rc) {
-                       mutex_unlock(&dbs_data->mutex);
-                       return rc;
+               if (!policy->governor->initialized) {
+                       rc = sysfs_create_group(cpufreq_global_kobject,
+                                       dbs_data->attr_group);
+                       if (rc) {
+                               mutex_unlock(&dbs_data->mutex);
+                               return rc;
+                       }
                }
 
                /*
@@ -262,13 +264,15 @@ int cpufreq_governor_dbs(struct dbs_data *dbs_data,
                        cs_dbs_info->down_skip = 0;
                        cs_dbs_info->enable = 1;
                        cs_dbs_info->requested_freq = policy->cur;
-                       cpufreq_register_notifier(cs_ops->notifier_block,
-                                       CPUFREQ_TRANSITION_NOTIFIER);
 
-                       if (!policy->governor->initialized)
+                       if (!policy->governor->initialized) {
+                               cpufreq_register_notifier(cs_ops->notifier_block,
+                                               CPUFREQ_TRANSITION_NOTIFIER);
+
                                dbs_data->min_sampling_rate =
                                        MIN_SAMPLING_RATE_RATIO *
                                        jiffies_to_usecs(10);
+                       }
                } else {
                        od_dbs_info->rate_mult = 1;
                        od_dbs_info->sample_type = OD_NORMAL_SAMPLE;
@@ -311,11 +315,13 @@ unlock:
                mutex_lock(&dbs_data->mutex);
                mutex_destroy(&cpu_cdbs->timer_mutex);
 
-               sysfs_remove_group(cpufreq_global_kobject,
-                               dbs_data->attr_group);
-               if (dbs_data->governor == GOV_CONSERVATIVE)
-                       cpufreq_unregister_notifier(cs_ops->notifier_block,
-                                       CPUFREQ_TRANSITION_NOTIFIER);
+               if (policy->governor->initialized == 1) {
+                       sysfs_remove_group(cpufreq_global_kobject,
+                                       dbs_data->attr_group);
+                       if (dbs_data->governor == GOV_CONSERVATIVE)
+                               cpufreq_unregister_notifier(cs_ops->notifier_block,
+                                               CPUFREQ_TRANSITION_NOTIFIER);
+               }
                mutex_unlock(&dbs_data->mutex);
 
                break;