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From: Viresh Kumar <viresh.kumar@linaro.org>
To: rjw@sisk.pl
Cc: linaro-kernel@lists.linaro.org, patches@linaro.org,
	cpufreq@vger.kernel.org, linux-pm@vger.kernel.org,
	linux-kernel@vger.kernel.org, srivatsa.bhat@linux.vnet.ibm.com,
	l.majewski@samsung.com, Viresh Kumar <viresh.kumar@linaro.org>
Subject: [PATCH 08/10] cpufreq: Fix broken usage of governor->owner's refcount
Date: Sat,  3 Aug 2013 17:19:26 +0530	[thread overview]
Message-ID: <46faea4c060f91f7102d9d33c816693acc25a917.1375530162.git.viresh.kumar@linaro.org> (raw)
In-Reply-To: <cover.1375530162.git.viresh.kumar@linaro.org>
In-Reply-To: <cover.1375530162.git.viresh.kumar@linaro.org>

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@linaro.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

  parent reply	other threads:[~2013-08-03 11:49 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-08-03 11:49 [PATCH 00/10] CPUFreq: Fixes & Cleanups for 3.12 Viresh Kumar
2013-08-03 11:49 ` [PATCH 01/10] cpufreq: Cleanup header files included in core Viresh Kumar
2013-08-03 17:15   ` Viresh Kumar
2013-08-03 21:42     ` Rafael J. Wysocki
2013-08-03 11:49 ` [PATCH 02/10] cpufreq: Re-arrange declarations in cpufreq.h Viresh Kumar
2013-08-03 17:13   ` Viresh Kumar
2013-08-03 21:43     ` Rafael J. Wysocki
2013-08-03 11:49 ` [PATCH 03/10] cpufreq: Give consistent names for struct cpufreq_policy * Viresh Kumar
2013-08-06 13:38   ` Viresh Kumar
2013-08-06 14:02     ` Rafael J. Wysocki
2013-08-03 11:49 ` [PATCH 04/10] cpufreq: Use sizeof(*ptr) form for finding size of a struct Viresh Kumar
2013-08-03 11:49 ` [PATCH 05/10] cpufreq: Pass policy to cpufreq_add_policy_cpu() Viresh Kumar
2013-08-03 11:49 ` [PATCH 06/10] cpufreq: Store cpufreq policies in a list Viresh Kumar
2013-08-03 11:49 ` [PATCH 07/10] cpufreq: Use cpufreq_policy_list for iterating over policies Viresh Kumar
2013-08-03 11:49 ` Viresh Kumar [this message]
2013-08-03 12:08   ` [PATCH 08/10] cpufreq: Fix broken usage of governor->owner's refcount Rafael J. Wysocki
2013-08-03 13:27     ` Viresh Kumar
2013-08-03 22:06       ` Rafael J. Wysocki
2013-08-03 11:49 ` [PATCH 09/10] cpufreq: Don't use cpufreq_driver->owner's refcount to protect critical sections Viresh Kumar
2013-08-03 11:49 ` [PATCH 10/10] cpufreq: Remove struct cpufreq_driver's owner field Viresh Kumar
2013-08-03 12:07 ` [PATCH 00/10] CPUFreq: Fixes & Cleanups for 3.12 Rafael J. Wysocki
2013-08-03 13:28   ` Viresh Kumar
2013-08-03 22:02     ` Rafael J. Wysocki

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