+ trace_i915_gem_request_add(request);
+
+ request->head = request_start;
+
+ /* Whilst this request exists, batch_obj will be on the
+ * active_list, and so will hold the active reference. Only when this
+ * request is retired will the the batch_obj be moved onto the
+ * inactive_list and lose its active reference. Hence we do not need
+ * to explicitly hold another reference here.
+ */
+ request->batch_obj = obj;
+
+ /* Seal the request and mark it as pending execution. Note that
+ * we may inspect this state, without holding any locks, during
+ * hangcheck. Hence we apply the barrier to ensure that we do not
+ * see a more recent value in the hws than we are tracking.
+ */
+ request->emitted_jiffies = jiffies;
+ request->previous_seqno = engine->last_submitted_seqno;
+ smp_store_mb(engine->last_submitted_seqno, request->seqno);
+ list_add_tail(&request->list, &engine->request_list);
+