linux-kernel - [PATCH 4/5] cpufreq: Remove temporary fix for race between CPU hotplug and sysfs-writes

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Date:	Sat, 07 Sep 2013 01:23:55 +0530
From:	"Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com>
To:	rjw@...k.pl, sboyd@...eaurora.org, viresh.kumar@...aro.org
Cc:	"Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com>,
	cpufreq@...r.kernel.org, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH 4/5] cpufreq: Remove temporary fix for race between CPU
 hotplug and sysfs-writes

Commit "cpufreq: serialize calls to __cpufreq_governor()" had been a temporary
and partial solution to the race condition between writing to a cpufreq sysfs
file and taking a CPU offline. Now that we have a proper and complete solution
to that problem, remove the temporary fix.

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@...ux.vnet.ibm.com>
---

 drivers/cpufreq/cpufreq.c |    7 +------
 include/linux/cpufreq.h   |    1 -
 2 files changed, 1 insertion(+), 7 deletions(-)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index c2eb413..9909789 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1783,15 +1783,13 @@ static int __cpufreq_governor(struct cpufreq_policy *policy,
 						policy->cpu, event);
 
 	mutex_lock(&cpufreq_governor_lock);
-	if (policy->governor_busy
-	    || (policy->governor_enabled && event == CPUFREQ_GOV_START)
+	if ((policy->governor_enabled && event == CPUFREQ_GOV_START)
 	    || (!policy->governor_enabled
 	    && (event == CPUFREQ_GOV_LIMITS || event == CPUFREQ_GOV_STOP))) {
 		mutex_unlock(&cpufreq_governor_lock);
 		return -EBUSY;
 	}
 
-	policy->governor_busy = true;
 	if (event == CPUFREQ_GOV_STOP)
 		policy->governor_enabled = false;
 	else if (event == CPUFREQ_GOV_START)
@@ -1820,9 +1818,6 @@ static int __cpufreq_governor(struct cpufreq_policy *policy,
 			((event == CPUFREQ_GOV_POLICY_EXIT) && !ret))
 		module_put(policy->governor->owner);
 
-	mutex_lock(&cpufreq_governor_lock);
-	policy->governor_busy = false;
-	mutex_unlock(&cpufreq_governor_lock);
 	return ret;
 }
 
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index cca885d..d568f39 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -76,7 +76,6 @@ struct cpufreq_policy {
 	struct cpufreq_governor	*governor; /* see below */
 	void			*governor_data;
 	bool			governor_enabled; /* governor start/stop flag */
-	bool			governor_busy;
 
 	struct work_struct	update; /* if update_policy() needs to be
 					 * called, but you're in IRQ context */

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