cpufreq: Don't find governor for setpolicy drivers in cpufreq_init_policy()

In cpufreq_init_policy() we will check if there's last_governor for target
and setpolicy type. However last_governor is set only if has_target() is
true in cpufreq_offline(). That means find last_governor for setpolicy
type is pointless. Also new_policy.governor will not be used if ->setpolicy
callback is set in cpufreq_set_policy().

Moreover, there's duplicate ->setpolicy check in using default policy path.
Let's add a new helper function to avoid it. Also update comments.

Signed-off-by: Yue Hu <huyue2@yulong.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpufreq/cpufreq.c

@@ -619,23 +619,26 @@ static struct cpufreq_governor *find_governor(const char *str_governor)
 	return NULL;
 }
 
-/**
- * cpufreq_parse_governor - parse a governor string
- */
-static int cpufreq_parse_governor(char *str_governor,
+static int cpufreq_parse_policy(char *str_governor,
 				struct cpufreq_policy *policy)
 {
-	if (cpufreq_driver->setpolicy) {
 	if (!strncasecmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
 		policy->policy = CPUFREQ_POLICY_PERFORMANCE;
 		return 0;
 	}
-
 	if (!strncasecmp(str_governor, "powersave", CPUFREQ_NAME_LEN)) {
 		policy->policy = CPUFREQ_POLICY_POWERSAVE;
 		return 0;
 	}
-	} else {
+	return -EINVAL;
+}
+
+/**
+ * cpufreq_parse_governor - parse a governor string only for !setpolicy
+ */
+static int cpufreq_parse_governor(char *str_governor,
+				  struct cpufreq_policy *policy)
+{
 	struct cpufreq_governor *t;
 
 	mutex_lock(&cpufreq_governor_mutex);
@@ -663,7 +666,6 @@ static int cpufreq_parse_governor(char *str_governor,
 		policy->governor = t;
 		return 0;
 	}
-	}
 
 	return -EINVAL;
 }
@@ -784,8 +786,13 @@ static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
 	if (ret != 1)
 		return -EINVAL;
 
+	if (cpufreq_driver->setpolicy) {
+		if (cpufreq_parse_policy(str_governor, &new_policy))
+			return -EINVAL;
+	} else {
 		if (cpufreq_parse_governor(str_governor, &new_policy))
 			return -EINVAL;
+	}
 
 	ret = cpufreq_set_policy(policy, &new_policy);
 
@@ -1051,32 +1058,39 @@ __weak struct cpufreq_governor *cpufreq_default_governor(void)
 
 static int cpufreq_init_policy(struct cpufreq_policy *policy)
 {
-	struct cpufreq_governor *gov = NULL;
+	struct cpufreq_governor *gov = NULL, *def_gov = NULL;
 	struct cpufreq_policy new_policy;
 
 	memcpy(&new_policy, policy, sizeof(*policy));
 
-	/* Update governor of new_policy to the governor used before hotplug */
+	def_gov = cpufreq_default_governor();
+
+	if (has_target()) {
+		/*
+		 * Update governor of new_policy to the governor used before
+		 * hotplug
+		 */
 		gov = find_governor(policy->last_governor);
 		if (gov) {
 			pr_debug("Restoring governor %s for cpu %d\n",
 				policy->governor->name, policy->cpu);
 		} else {
-		gov = cpufreq_default_governor();
-		if (!gov)
+			if (!def_gov)
 				return -ENODATA;
+			gov = def_gov;
 		}
-
 		new_policy.governor = gov;
-
+	} else {
 		/* Use the default policy if there is no last_policy. */
-	if (cpufreq_driver->setpolicy) {
-		if (policy->last_policy)
+		if (policy->last_policy) {
 			new_policy.policy = policy->last_policy;
-		else
-			cpufreq_parse_governor(gov->name, &new_policy);
+		} else {
+			if (!def_gov)
+				return -ENODATA;
+			cpufreq_parse_policy(def_gov->name, &new_policy);
 		}
-	/* set default policy */
+	}
+
 	return cpufreq_set_policy(policy, &new_policy);
 }