kthread: use buffer from the stack space

{

	DECLARE_COMPLETION_ONSTACK(done);

	struct task_struct *task;

	struct kthread_create_info *create = kmalloc(sizeof(*create),

						     GFP_KERNEL);

	struct kthread_create_info create;

	if (!create)

		return ERR_PTR(-ENOMEM);

	create->threadfn = threadfn;

	create->data = data;

	create->node = node;

	create->done = &done;

	create.threadfn = threadfn;

	create.data = data;

	create.node = node;

	create.done = &done;

	spin_lock(&kthread_create_lock);

	list_add_tail(&create->list, &kthread_create_list);

	list_add_tail(&create.list, &kthread_create_list);

	spin_unlock(&kthread_create_lock);

	wake_up_process(kthreadd_task);

		 * calls complete(), leave the cleanup of this structure to

		 * that thread.

		 */

		if (xchg(&create->done, NULL))

		if (xchg(&create.done, NULL))

			return ERR_PTR(-EINTR);

		/*

		 * kthreadd (or new kernel thread) will call complete()

		 */

		wait_for_completion(&done);

	}

	task = create->result;

	task = create.result;

	if (!IS_ERR(task)) {

		static const struct sched_param param = { .sched_priority = 0 };

		char name[TASK_COMM_LEN];

		sched_setscheduler_nocheck(task, SCHED_NORMAL, &param);

		set_cpus_allowed_ptr(task, cpu_all_mask);

	}

	kfree(create);

	return task;

}