thermal/core: Move the mutex inside the thermal_zone_device_update() function

All the different calls inside the thermal_zone_device_update()
function take the mutex.

The previous changes move the mutex out of the different functions,
like the throttling ops. Now that the mutexes are all at the same
level in the call stack for the thermal_zone_device_update() function,
they can be moved inside this one.

That has the benefit of:

1. Simplify the code by not having a plethora of places where the lock is taken

2. Probably closes more race windows because releasing the lock from
one line to another can give the opportunity to the thermal zone to change
its state in the meantime. For example, the thermal zone can be
enabled right after checking it is disabled.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20220805153834.2510142-5-daniel.lezcano@linaro.org

1 files changed, 5 insertions, 1 deletions

diff --git a/drivers/thermal/thermal_sysfs.c b/drivers/thermal/thermal_sysfs.c
index 0f8201060c38..78c5841bdfae 100644
--- a/drivers/thermal/thermal_sysfs.c
+++ b/drivers/thermal/thermal_sysfs.c
@@ -49,7 +49,11 @@ static ssize_t
 mode_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
 	struct thermal_zone_device *tz = to_thermal_zone(dev);
-	int enabled = thermal_zone_device_is_enabled(tz);
+	int enabled;
+
+	mutex_lock(&tz->lock);
+	enabled = thermal_zone_device_is_enabled(tz);
+	mutex_unlock(&tz->lock);
 
 	return sprintf(buf, "%s\n", enabled ? "enabled" : "disabled");
 }