thermal: Fix locking in cooling device sysfs update cur_state

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>

1 files changed, 7 insertions, 4 deletions

diff --git a/drivers/thermal/thermal_sysfs.c b/drivers/thermal/thermal_sysfs.c
index 2241ceae7d7f..aa99edb4dff7 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