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>

1 files changed, 19 insertions, 13 deletions

diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c
index e4a306c8ff1b..5a76086ff09b 100644
--- 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;