From: Thara Gopinath <thara.gopinath@linaro.org>
Date: Tue, 27 Nov 2018 22:43:11 +0000 (-0500)
Subject: thermal: Fix locking in cooling device sysfs update cur_state
X-Git-Tag: v4.19.21~229
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=9c74cd4afbd3b5b6d90366b7dcb2a7befa8a37f2;p=platform%2Fkernel%2Flinux-rpi.git

thermal: Fix locking in cooling device sysfs update cur_state

[ Upstream commit 68000a0d983f539c95ebe5dccd4f29535c7ac0af ]

Sysfs interface to update cooling device cur_state does not
currently holding cooling device lock sometimes leading to
stale values in cur_state if getting updated simultanelously
from user space and thermal framework. Adding the proper locking
code fixes this issue.

Signed-off-by: Thara Gopinath <thara.gopinath@linaro.org>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/drivers/thermal/thermal_sysfs.c b/drivers/thermal/thermal_sysfs.c
index 2241cea..aa99edb 100644
--- a/drivers/thermal/thermal_sysfs.c
+++ b/drivers/thermal/thermal_sysfs.c
@@ -712,11 +712,14 @@ cur_state_store(struct device *dev, struct device_attribute *attr,
 	if ((long)state < 0)
 		return -EINVAL;
 
+	mutex_lock(&cdev->lock);
+
 	result = cdev->ops->set_cur_state(cdev, state);
-	if (result)
-		return result;
-	thermal_cooling_device_stats_update(cdev, state);
-	return count;
+	if (!result)
+		thermal_cooling_device_stats_update(cdev, state);
+
+	mutex_unlock(&cdev->lock);
+	return result ? result : count;
 }
 
 static struct device_attribute