cpufreq: governors: Fix CPUFREQ_GOV_POLICY_{INIT|EXIT} notifiers

There are two types of INIT/EXIT activities that we need to do for
governors:
 - Done only once per governor (doesn't depend how many instances of
   the governor there are). eg: cpufreq_register_notifier() for
   conservative governor.
 - Done per governor instance, eg: sysfs_{create|remove}_group().

There were some corner cases where current code isn't able to handle
them separately and so failing for some test cases.

We use two separate variables now for keeping track of above two
requirements.
 - governor->initialized for first one
 - dbs_data->usage_count for per governor instance

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

drivers/cpufreq/cpufreq_governor.c

@@ -255,6 +255,7 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 		if (have_governor_per_policy()) {
 			WARN_ON(dbs_data);
 		} else if (dbs_data) {
+			dbs_data->usage_count++;
 			policy->governor_data = dbs_data;
 			return 0;
 		}
@@ -266,6 +267,7 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 		}
 
 		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__);
@@ -294,7 +296,8 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 		set_sampling_rate(dbs_data, max(dbs_data->min_sampling_rate,
 					latency * LATENCY_MULTIPLIER));
 
-		if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
+		if ((cdata->governor == GOV_CONSERVATIVE) &&
+				(!policy->governor->initialized)) {
 			struct cs_ops *cs_ops = dbs_data->cdata->gov_ops;
 
 			cpufreq_register_notifier(cs_ops->notifier_block,
@@ -306,12 +309,12 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 
 		return 0;
 	case CPUFREQ_GOV_POLICY_EXIT:
-		if ((policy->governor->initialized == 1) ||
-				have_governor_per_policy()) {
+		if (!--dbs_data->usage_count) {
 			sysfs_remove_group(get_governor_parent_kobj(policy),
 					get_sysfs_attr(dbs_data));
 
-			if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
+			if ((dbs_data->cdata->governor == GOV_CONSERVATIVE) &&
+				(policy->governor->initialized == 1)) {
 				struct cs_ops *cs_ops = dbs_data->cdata->gov_ops;
 
 				cpufreq_unregister_notifier(cs_ops->notifier_block,

drivers/cpufreq/cpufreq_governor.h

@@ -211,6 +211,7 @@ struct common_dbs_data {
 struct dbs_data {
 	struct common_dbs_data *cdata;
 	unsigned int min_sampling_rate;
+	int usage_count;
 	void *tuners;
 
 	/* dbs_mutex protects dbs_enable in governor start/stop */