cpufreq: Exit governor when failed to start old governor

Detect the result of starting old governor in cpufreq_set_policy(). If it
fails, exit the governor and clear policy->governor.

Signed-off-by: Lifeng Zheng <zhenglifeng1@huawei.com>
Link: https://patch.msgid.link/20250709104145.2348017-5-zhenglifeng1@huawei.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Author: Lifeng Zheng

drivers/cpufreq/cpufreq.c

@@ -2711,10 +2711,12 @@ static int cpufreq_set_policy(struct cpufreq_policy *policy,
 	pr_debug("starting governor %s failed\n", policy->governor->name);
 	if (old_gov) {
 		policy->governor = old_gov;
-		if (cpufreq_init_governor(policy))
+		if (cpufreq_init_governor(policy)) {
 			policy->governor = NULL;
-		else
-			cpufreq_start_governor(policy);
+		} else if (cpufreq_start_governor(policy)) {
+			cpufreq_exit_governor(policy);
+			policy->governor = NULL;
+		}
 	}
 
 	return ret;