thermal/core: Move parameter validation from __thermal_zone_get_temp to thermal_zone_...

All callers of __thermal_zone_get_temp() already validated the
thermal zone parameters. Move validation to thermal_zone_get_temp()
where it is actually needed. Also add kernel documentation for
__thermal_zone_get_temp(), listing the requirement that the
function must be called with validated parameters and with thermal
device mutex held.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/thermal/thermal_helpers.c b/drivers/thermal/thermal_helpers.c
index fca0b23..321f802 100644 (file)
--- a/drivers/thermal/thermal_helpers.c
+++ b/drivers/thermal/thermal_helpers.c
@@ -64,6 +64,20 @@ get_thermal_instance(struct thermal_zone_device *tz,
 }
 EXPORT_SYMBOL(get_thermal_instance);
 
+/**
+ * __thermal_zone_get_temp() - returns the temperature of a thermal zone
+ * @tz: a valid pointer to a struct thermal_zone_device
+ * @temp: a valid pointer to where to store the resulting temperature.
+ *
+ * When a valid thermal zone reference is passed, it will fetch its
+ * temperature and fill @temp.
+ *
+ * Both tz and tz->ops must be valid pointers when calling this function,
+ * and the tz->ops->get_temp callback must be provided.
+ * The function must be called under tz->lock.
+ *
+ * Return: On success returns 0, an error code otherwise
+ */
 int __thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp)
 {
        int ret = -EINVAL;
@@ -73,9 +87,6 @@ int __thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp)
 
        lockdep_assert_held(&tz->lock);
 
-       if (!tz || IS_ERR(tz) || !tz->ops->get_temp)
-               return -EINVAL;
-
        ret = tz->ops->get_temp(tz, temp);
 
        if (IS_ENABLED(CONFIG_THERMAL_EMULATION) && tz->emul_temperature) {
@@ -114,13 +125,22 @@ int thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp)
 {
        int ret;
 
+       if (IS_ERR_OR_NULL(tz))
+               return -EINVAL;
+
        mutex_lock(&tz->lock);
 
+       if (!tz->ops->get_temp) {
+               ret = -EINVAL;
+               goto unlock;
+       }
+
        if (device_is_registered(&tz->device))
                ret = __thermal_zone_get_temp(tz, temp);
        else
                ret = -ENODEV;
 
+unlock:
        mutex_unlock(&tz->lock);
 
        return ret;