static struct intel_timeline *get_timeline(struct i915_request *rq)
{
	struct intel_timeline *tl;

	/*
	 * Even though we are holding the engine->active.lock here, there
	 * is no control over the submission queue per-se and we are
	 * inspecting the active state at a random point in time, with an
	 * unknown queue. Play safe and make sure the timeline remains valid.
	 * (Only being used for pretty printing, one extra kref shouldn't
	 * cause a camel stampede!)
	 */
	rcu_read_lock();
	tl = rcu_dereference(rq->timeline);
	if (!kref_get_unless_zero(&tl->kref))
		tl = NULL;
	rcu_read_unlock();

	return tl;
}
static struct intel_timeline *get_timeline(struct i915_request *rq)
{
	struct intel_timeline *tl;

	 
	rcu_read_lock();
	tl = rcu_dereference(rq->timeline);
	if (!kref_get_unless_zero(&tl->kref))
		tl = NULL;
	rcu_read_unlock();

	return tl;
}