cpufreq: Fix up cpufreq_boost_set_sw()

After commit 18c4992 ("cpufreq: Add QoS requests for userspace
constraints") the return value of freq_qos_update_request(), that can
be 1, passed by cpufreq_boost_set_sw() to its caller sometimes
confuses the latter, which only expects to see 0 or negative error
codes, so notice that cpufreq_boost_set_sw() can return an error code
(which should not be -EINVAL for that matter) as soon as the first
policy without a frequency table is found (because either all policies
have a frequency table or none of them have it) and rework it to meet
its caller's expectations.

Fixes: 18c4992 ("cpufreq: Add QoS requests for userspace constraints")
Reported-by: Serge Semin <[email protected]>
Reported-by: Xiongfeng Wang <[email protected]>
Acked-by: Viresh Kumar <[email protected]>
Cc: 5.3+ <[email protected]> # 5.3+
Signed-off-by: Rafael J. Wysocki <[email protected]>

Author: rafaeljw

drivers/cpufreq/cpufreq.c

@@ -2535,26 +2535,27 @@ EXPORT_SYMBOL_GPL(cpufreq_update_limits);
 static int cpufreq_boost_set_sw(int state)
 {
 	struct cpufreq_policy *policy;
-	int ret = -EINVAL;
 
 	for_each_active_policy(policy) {
+		int ret;
+
 		if (!policy->freq_table)
-			continue;
+			return -ENXIO;
 
 		ret = cpufreq_frequency_table_cpuinfo(policy,
 						      policy->freq_table);
 		if (ret) {
 			pr_err("%s: Policy frequency update failed\n",
 			       __func__);
-			break;
+			return ret;
 		}
 
 		ret = freq_qos_update_request(policy->max_freq_req, policy->max);
 		if (ret < 0)
-			break;
+			return ret;
 	}
 
-	return ret;
+	return 0;
 }
 
 int cpufreq_boost_trigger_state(int state)