[PATCH v2 1/2] thermal: core: Allow orderly_poweroff to be called only once

[Keerthy]

thermal_zone_device_check --> thermal_zone_device_update -->
handle_thermal_trip --> handle_critical_trips --> orderly_poweroff

The above sequence happens every 250/500 mS based on the configuration.
The orderly_poweroff function is getting called every 250/500 mS.
With a full fledged file system it takes at least 5-10 Seconds to
power off gracefully.

In that period due to the thermal_zone_device_check triggering
periodically the thermal work queues bombard with
orderly_poweroff calls multiple times eventually leading to
failures in gracefully powering off the system.

Make sure that orderly_poweroff is called only once.

Reported-by: Nishanth Menon <n...@ti.com>
Signed-off-by: Keerthy <j-keer...@ti.com>
---

Changes in v2:

  * Added a global mutex to serialize poweroff code sequence.

 drivers/thermal/thermal_core.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index 11f0675..7462ae5 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -45,6 +45,7 @@
 
 static DEFINE_MUTEX(thermal_list_lock);
 static DEFINE_MUTEX(thermal_governor_lock);
+static DEFINE_MUTEX(poweroff_lock);
 
 static atomic_t in_suspend;
 
@@ -326,6 +327,7 @@ static void handle_critical_trips(struct 
thermal_zone_device *tz,
                                  int trip, enum thermal_trip_type trip_type)
 {
        int trip_temp;
+       static bool power_off_triggered;
 
        tz->ops->get_trip_temp(tz, trip, &trip_temp);
 
@@ -338,11 +340,14 @@ static void handle_critical_trips(struct 
thermal_zone_device *tz,
        if (tz->ops->notify)
                tz->ops->notify(tz, trip, trip_type);
 
-       if (trip_type == THERMAL_TRIP_CRITICAL) {
+       if (trip_type == THERMAL_TRIP_CRITICAL && !power_off_triggered) {
                dev_emerg(&tz->device,
                          "critical temperature reached(%d C),shutting down\n",
                          tz->temperature / 1000);
+               mutex_lock(&poweroff_lock);
                orderly_poweroff(true);
+               power_off_triggered = true;
+               mutex_unlock(&poweroff_lock);
        }
 }
 
@@ -1463,6 +1468,7 @@ static int __init thermal_init(void)
 {
        int result;
 
+       mutex_init(&poweroff_lock);
        result = thermal_register_governors();
        if (result)
                goto error;
@@ -1497,6 +1503,7 @@ static int __init thermal_init(void)
        ida_destroy(&thermal_cdev_ida);
        mutex_destroy(&thermal_list_lock);
        mutex_destroy(&thermal_governor_lock);
+       mutex_destroy(&poweroff_lock);
        return result;
 }
 
-- 
1.9.1