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>

1 files changed, 65 insertions, 51 deletions

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 57a3853a55fb..f941efd9b836 100644
--- 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);
 }