Thermal: Introduce locking for cdev.thermal_instances list.

we need to go over all the thermal_instance list of a cooling device
to decide which cooling state to put the cooling device to.

But at this time, as a cooling device may be referenced in multiple
thermal zones, we need to lock the list first in case
another thermal zone is updating this cooling device.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Reviewed-by: Rafael J. Wysocki <rjw@sisk.pl>
Reviewed-by: Eduardo Valentin <eduardo.valentin@ti.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/thermal.h b/include/linux/thermal.h
index 76d0fe88eb1c..91b34812cd84 100644
--- a/include/linux/thermal.h
+++ b/include/linux/thermal.h
@@ -95,6 +95,7 @@ struct thermal_cooling_device {
         void *devdata;
         const struct thermal_cooling_device_ops *ops;
         bool updated; /* true if the cooling device does not need update */
+        struct mutex lock; /* protect thermal_instances list */
         struct list_head thermal_instances;
         struct list_head node;
 };