linux-kernel - [PATCH 08/10] cpufreq: Fix broken usage of governor->owner's refcount

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Date:	Sat,  3 Aug 2013 17:19:26 +0530
From:	Viresh Kumar <viresh.kumar@...aro.org>
To:	rjw@...k.pl
Cc:	linaro-kernel@...ts.linaro.org, patches@...aro.org,
	cpufreq@...r.kernel.org, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org, srivatsa.bhat@...ux.vnet.ibm.com,
	l.majewski@...sung.com, Viresh Kumar <viresh.kumar@...aro.org>
Subject: [PATCH 08/10] cpufreq: Fix broken usage of governor->owner's refcount

Governor's owner refcount usage was broken. We should increment refcount only
when CPUFREQ_GOV_POLICY_INIT event has come and should decrement only if
CPUFREQ_GOV_POLICY_EXIT has come.

Lets fix it.

Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
---
 drivers/cpufreq/cpufreq.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index e9b969f..74d4969 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1707,8 +1707,9 @@ static int __cpufreq_governor(struct cpufreq_policy *policy,
 		}
 	}
 
-	if (!try_module_get(policy->governor->owner))
-		return -EINVAL;
+	if (event == CPUFREQ_GOV_POLICY_INIT)
+		if (!try_module_get(policy->governor->owner))
+			return -EINVAL;
 
 	pr_debug("__cpufreq_governor for CPU %u, event %u\n",
 						policy->cpu, event);
@@ -1717,6 +1718,8 @@ static int __cpufreq_governor(struct cpufreq_policy *policy,
 	if ((!policy->governor_enabled && (event == CPUFREQ_GOV_STOP)) ||
 	    (policy->governor_enabled && (event == CPUFREQ_GOV_START))) {
 		mutex_unlock(&cpufreq_governor_lock);
+		if (event == CPUFREQ_GOV_POLICY_INIT)
+			module_put(policy->governor->owner);
 		return -EBUSY;
 	}
 
@@ -1744,11 +1747,8 @@ static int __cpufreq_governor(struct cpufreq_policy *policy,
 		mutex_unlock(&cpufreq_governor_lock);
 	}
 
-	/* we keep one module reference alive for
-			each CPU governed by this CPU */
-	if ((event != CPUFREQ_GOV_START) || ret)
-		module_put(policy->governor->owner);
-	if ((event == CPUFREQ_GOV_STOP) && !ret)
+	if (((event == CPUFREQ_GOV_POLICY_INIT) && ret) ||
+			((event == CPUFREQ_GOV_POLICY_EXIT) && !ret))
 		module_put(policy->governor->owner);
 
 	return ret;
-- 
1.7.12.rc2.18.g61b472e

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