PM / devfreq: Fix cpufreq passive unregister erroring on PROBE_DEFER

With the passive governor, the cpu based scaling can PROBE_DEFER due to
the fact that CPU policy are not ready.
The cpufreq passive unregister notifier is called both from the
GOV_START errors and for the GOV_STOP and assume the notifier is
successfully registred every time. With GOV_START failing it's wrong to
loop over each possible CPU since the register path has failed for
some CPU policy not ready. Change the logic and unregister the notifer
based on the current allocated parent_cpu_data list to correctly handle
errors and the governor unregister path.

Fixes: a03dacb ("PM / devfreq: Add cpu based scaling support to passive governor")
Signed-off-by: Christian 'Ansuel' Marangi <[email protected]>
Signed-off-by: Chanwoo Choi <[email protected]>

Author: Ansuel

drivers/devfreq/governor_passive.c

@@ -34,6 +34,20 @@ get_parent_cpu_data(struct devfreq_passive_data *p_data,
 	return NULL;
 }
 
+static void delete_parent_cpu_data(struct devfreq_passive_data *p_data)
+{
+	struct devfreq_cpu_data *parent_cpu_data, *tmp;
+
+	list_for_each_entry_safe(parent_cpu_data, tmp, &p_data->cpu_data_list, node) {
+		list_del(&parent_cpu_data->node);
+
+		if (parent_cpu_data->opp_table)
+			dev_pm_opp_put_opp_table(parent_cpu_data->opp_table);
+
+		kfree(parent_cpu_data);
+	}
+}
+
 static unsigned long get_target_freq_by_required_opp(struct device *p_dev,
 						struct opp_table *p_opp_table,
 						struct opp_table *opp_table,
@@ -222,8 +236,7 @@ static int cpufreq_passive_unregister_notifier(struct devfreq *devfreq)
 {
 	struct devfreq_passive_data *p_data
 			= (struct devfreq_passive_data *)devfreq->data;
-	struct devfreq_cpu_data *parent_cpu_data;
-	int cpu, ret = 0;
+	int ret;
 
 	if (p_data->nb.notifier_call) {
 		ret = cpufreq_unregister_notifier(&p_data->nb,
@@ -232,27 +245,9 @@ static int cpufreq_passive_unregister_notifier(struct devfreq *devfreq)
 			return ret;
 	}
 
-	for_each_possible_cpu(cpu) {
-		struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
-		if (!policy) {
-			ret = -EINVAL;
-			continue;
-		}
-
-		parent_cpu_data = get_parent_cpu_data(p_data, policy);
-		if (!parent_cpu_data) {
-			cpufreq_cpu_put(policy);
-			continue;
-		}
-
-		list_del(&parent_cpu_data->node);
-		if (parent_cpu_data->opp_table)
-			dev_pm_opp_put_opp_table(parent_cpu_data->opp_table);
-		kfree(parent_cpu_data);
-		cpufreq_cpu_put(policy);
-	}
+	delete_parent_cpu_data(p_data);
 
-	return ret;
+	return 0;
 }
 
 static int cpufreq_passive_register_notifier(struct devfreq *devfreq)