Commit e8905914 authored Jun 28, 2018 by Uwe Kleine-König Committed by Greg Kroah-Hartman Jul 07, 2018

siox: don't create a thread without starting it



When a siox master device is registered a kthread is created that is
only started when triggered by userspace. So this thread might be in
TASK_UNINTERRUPTIBLE state for long and trigger a warning

	[  241.130465] INFO: task siox-0:626 blocked for more than 120 seconds.

with the respective debug settings enabled. It might be right to put an
unstarted thread to TASK_IDLE (in kernel/kthread.c:kthread()) instead,
but independant of this discussion it is cleaner for
siox_master_register() to start the thread immediately. The effect is
that it enters its own waiting state and then stays in state TASK_IDLE
which doesn't trigger the above warning.

As siox_poll_thread() uses some variables of the device the
initialisation of these is moved before thread creation.

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Gavin Schenk <g.schenk@eckelmann.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 7e6f7d24

drivers/siox/siox-core.c

+5 −5

Original line number	Diff line number	Diff line
		@@ -715,17 +715,17 @@ int siox_master_register(struct siox_master *smaster)

		dev_set_name(&smaster->dev, "siox-%d", smaster->busno);

		mutex_init(&smaster->lock);
		INIT_LIST_HEAD(&smaster->devices);

		smaster->last_poll = jiffies;
		smaster->poll_thread = kthread_create(siox_poll_thread, smaster,
		smaster->poll_thread = kthread_run(siox_poll_thread, smaster,
		"siox-%d", smaster->busno);
		if (IS_ERR(smaster->poll_thread)) {
		smaster->active = 0;
		return PTR_ERR(smaster->poll_thread);
		}

		mutex_init(&smaster->lock);
		INIT_LIST_HEAD(&smaster->devices);

		ret = device_add(&smaster->dev);
		if (ret)
		kthread_stop(smaster->poll_thread);

Admin message