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>

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 57a3853a55fb58193ff3a519e754c36ab3511236..f941efd9b8365f01b7bcedcaab134bdfdc2cba42 100644 (file)
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -619,50 +619,52 @@ static struct cpufreq_governor *find_governor(const char *str_governor)
        return NULL;
 }
 
+static int cpufreq_parse_policy(char *str_governor,
+                               struct cpufreq_policy *policy)
+{
+       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;
+       }
+       return -EINVAL;
+}
+
 /**
- * cpufreq_parse_governor - parse a governor string
+ * cpufreq_parse_governor - parse a governor string only for !setpolicy
  */
 static int cpufreq_parse_governor(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 {
-               struct cpufreq_governor *t;
+       struct cpufreq_governor *t;
 
-               mutex_lock(&cpufreq_governor_mutex);
+       mutex_lock(&cpufreq_governor_mutex);
 
-               t = find_governor(str_governor);
-               if (!t) {
-                       int ret;
+       t = find_governor(str_governor);
+       if (!t) {
+               int ret;
 
-                       mutex_unlock(&cpufreq_governor_mutex);
+               mutex_unlock(&cpufreq_governor_mutex);
 
-                       ret = request_module("cpufreq_%s", str_governor);
-                       if (ret)
-                               return -EINVAL;
+               ret = request_module("cpufreq_%s", str_governor);
+               if (ret)
+                       return -EINVAL;
 
-                       mutex_lock(&cpufreq_governor_mutex);
+               mutex_lock(&cpufreq_governor_mutex);
 
-                       t = find_governor(str_governor);
-               }
-               if (t && !try_module_get(t->owner))
-                       t = NULL;
+               t = find_governor(str_governor);
+       }
+       if (t && !try_module_get(t->owner))
+               t = NULL;
 
-               mutex_unlock(&cpufreq_governor_mutex);
+       mutex_unlock(&cpufreq_governor_mutex);
 
-               if (t) {
-                       policy->governor = t;
-                       return 0;
-               }
+       if (t) {
+               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_parse_governor(str_governor, &new_policy))
-               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 */
-       gov = find_governor(policy->last_governor);
-       if (gov) {
-               pr_debug("Restoring governor %s for cpu %d\n",
+       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 {
+                       if (!def_gov)
+                               return -ENODATA;
+                       gov = def_gov;
+               }
+               new_policy.governor = gov;
        } else {
-               gov = cpufreq_default_governor();
-               if (!gov)
-                       return -ENODATA;
-       }
-
-       new_policy.governor = gov;
-
-       /* Use the default policy if there is no last_policy. */
-       if (cpufreq_driver->setpolicy) {
-               if (policy->last_policy)
+               /* Use the default policy if there is no 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);
 }