[PATCH v5 1/2] thermal: core: Allow orderly_poweroff to be called only once

From: Keerthy
Date: Fri Apr 14 2017 - 23:09:05 EST


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.

Signed-off-by: Keerthy <j-keerthy@xxxxxx>
Acked-by: Eduardo Valentin <edubezval@xxxxxxxxx>
---

Changes in v5:

* Added Eduardo's Ack.

Changes in v4:

* power_off_triggered declaration together with mutex definition.

Changes in v3:

* Changed the place where mutex was locked and unlocked.

Changes in v2:

* Added a global mutex to serialize poweroff code sequence.

drivers/thermal/thermal_core.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index 11f0675..8337c27 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -45,8 +45,10 @@

static DEFINE_MUTEX(thermal_list_lock);
static DEFINE_MUTEX(thermal_governor_lock);
+static DEFINE_MUTEX(poweroff_lock);

static atomic_t in_suspend;
+static bool power_off_triggered;

static struct thermal_governor *def_governor;

@@ -342,7 +344,12 @@ static void handle_critical_trips(struct thermal_zone_device *tz,
dev_emerg(&tz->device,
"critical temperature reached(%d C),shutting down\n",
tz->temperature / 1000);
- orderly_poweroff(true);
+ mutex_lock(&poweroff_lock);
+ if (!power_off_triggered) {
+ orderly_poweroff(true);
+ power_off_triggered = true;
+ }
+ mutex_unlock(&poweroff_lock);
}
}

@@ -1463,6 +1470,7 @@ static int __init thermal_init(void)
{
int result;

+ mutex_init(&poweroff_lock);
result = thermal_register_governors();
if (result)
goto error;
@@ -1497,6 +1505,7 @@ 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