thread.c

/**
 * kthread_stop - stop a thread created by kthread_create().
 * @k: thread created by kthread_create().
 *
 * Sets kthread_should_stop() for @k to return true, wakes it, and
 * waits for it to exit. This can also be called after kthread_create()
 * instead of calling wake_up_process(): the thread will exit without
 * calling threadfn().
 *
 * If threadfn() may call do_exit() itself, the caller must ensure
 * task_struct can't go away.
 *
 * Returns the result of threadfn(), or %-EINTR if wake_up_process()
 * was never called.
 */
int kthread_stop(struct task_struct *k)
{
	struct kthread *kthread;
	int ret;

	trace_sched_kthread_stop(k);
	get_task_struct(k);

	kthread = to_kthread(k);
	barrier(); /* it might have exited */
	if (k->vfork_done != NULL) {
		kthread->should_stop = 1;
		wake_up_process(k);
		wait_for_completion(&kthread->exited);
	}
	ret = k->exit_code;

	put_task_struct(k);
	trace_sched_kthread_stop_ret(ret);

	return ret;
}