linux-kernel - [PATCH 07/15] thermal: sysfs: lock tz while on policy properties

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Message-Id: <1464676296-5610-8-git-send-email-edubezval@gmail.com>
Date:	Mon, 30 May 2016 23:31:28 -0700
From:	Eduardo Valentin <edubezval@...il.com>
To:	Rui Zhang <rui.zhang@...el.com>
Cc:	Linux PM <linux-pm@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Eduardo Valentin <edubezval@...il.com>
Subject: [PATCH 07/15] thermal: sysfs: lock tz while on policy properties

Serialized calls to tz.ops in user facing
sysfs handler policy_show().
policy_store() is already locked by
the thermal core.

Cc: Zhang Rui <rui.zhang@...el.com>
Cc: linux-pm@...r.kernel.org
Cc: linux-kernel@...r.kernel.org
Signed-off-by: Eduardo Valentin <edubezval@...il.com>
---
 drivers/thermal/thermal_sysfs.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/thermal/thermal_sysfs.c b/drivers/thermal/thermal_sysfs.c
index dcaeb17..234eb18 100644
--- a/drivers/thermal/thermal_sysfs.c
+++ b/drivers/thermal/thermal_sysfs.c
@@ -311,8 +311,14 @@ static ssize_t
 policy_show(struct device *dev, struct device_attribute *devattr, char *buf)
 {
 	struct thermal_zone_device *tz = to_thermal_zone(dev);
+	char *name;
 
-	return sprintf(buf, "%s\n", tz->governor->name);
+	/* locking the zone because governor->name does not change */
+	mutex_lock(&tz->lock);
+	name = tz->governor->name;
+	mutex_unlock(&tz->lock);
+
+	return sprintf(buf, "%s\n", name);
 }
 
 static ssize_t
-- 
2.1.4