linux-kernel - [PATCH 5.6 120/161] cpufreq: Fix up cpufreq_boost_set

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Date:   Tue, 16 Jun 2020 17:35:10 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Serge Semin <Sergey.Semin@...kalelectronics.ru>,
        Xiongfeng Wang <wangxiongfeng2@...wei.com>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>
Subject: [PATCH 5.6 120/161] cpufreq: Fix up cpufreq_boost_set_sw()

From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

commit 552abb884e97d26589964e5a8c7e736f852f95f0 upstream.

After commit 18c49926c4bf ("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: 18c49926c4bf ("cpufreq: Add QoS requests for userspace constraints")
Reported-by: Serge Semin <Sergey.Semin@...kalelectronics.ru>
Reported-by: Xiongfeng Wang <wangxiongfeng2@...wei.com>
Acked-by: Viresh Kumar <viresh.kumar@...aro.org>
Cc: 5.3+ <stable@...r.kernel.org> # 5.3+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/cpufreq/cpufreq.c |   11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -2515,26 +2515,27 @@ 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)