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Commit 4a86c2f3 authored by Ram Chandrasekar's avatar Ram Chandrasekar
Browse files

drivers: thermal: Exit sysfs notify kthread when sensor unregisters 



When a thermal zone unregisters, it initiates a blocking call
kthread_stop for the sysfs notify kthread to exit. But the sysfs notify
kthread is blocked on a completion event, which may not be triggered after
the sensor driver initiates a thermal zone unregister call. So, the
kthread_stop will be blocked forever.

As a part of thermal zone unregister, set a thermal zone unregister flag
and send a completion event before calling kthread_stop. Make the sysfs
notify kthread to be aware of thermal zone unregister flag and exit
after the completion event is triggered.

Change-Id: Icf045e0ad6e28135cd3a54c15d9923f095a286ff
Signed-off-by: default avatarRam Chandrasekar <rkumbako@codeaurora.org>
parent 487ff740

drivers/thermal/thermal_core.c

+9 −4
Original line number Diff line number Diff line
@@ -4,7 +4,7 @@ 
 *  Copyright (C) 2008 Intel Corp

 *  Copyright (C) 2008 Zhang Rui <rui.zhang@intel.com>

 *  Copyright (C) 2008 Sujith Thomas <sujith.thomas@intel.com>

 *  Copyright (c) 2013-2014, The Linux Foundation. All rights reserved.

 *  Copyright (c) 2013-2017, The Linux Foundation. All rights reserved.

 *

 *  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 *
@@ -382,9 +382,11 @@ static __ref int sensor_sysfs_notify(void *data) 
	struct sensor_info *sensor = (struct sensor_info *)data;



	while (!kthread_should_stop()) {

		while (wait_for_completion_interruptible(

		if (wait_for_completion_interruptible(

			&sensor->sysfs_notify_complete) != 0)

			;

			continue;

		if (sensor->deregister_active)

			return ret;

		reinit_completion(&sensor->sysfs_notify_complete);

		sysfs_notify(&sensor->tz->device.kobj, NULL,

					THERMAL_UEVENT_DATA);
@@ -580,6 +582,7 @@ int sensor_init(struct thermal_zone_device *tz) 
	sensor->threshold_max = INT_MAX;

	sensor->max_idx = -1;

	sensor->min_idx = -1;

	sensor->deregister_active = false;

	mutex_init(&sensor->lock);

	INIT_LIST_HEAD_RCU(&sensor->sensor_list);

	INIT_LIST_HEAD_RCU(&sensor->threshold_list);
@@ -2471,6 +2474,8 @@ void thermal_zone_device_unregister(struct thermal_zone_device *tz) 


	thermal_remove_hwmon_sysfs(tz);

	flush_work(&tz->sensor.work);

	tz->sensor.deregister_active = true;

	complete(&tz->sensor.sysfs_notify_complete);

	kthread_stop(tz->sensor.sysfs_notify_thread);

	mutex_lock(&thermal_list_lock);

	list_del_rcu(&tz->sensor.sensor_list);

include/linux/thermal.h

+1 −0
Original line number Diff line number Diff line
@@ -178,6 +178,7 @@ struct sensor_info { 
	struct work_struct work;

	struct task_struct *sysfs_notify_thread;

	struct completion sysfs_notify_complete;

	bool deregister_active;

};



/**