drm/etnaviv: move submit free out of critical section

There is no need to hold the GPU lock while freeing the submit
object. Only move the retired submits from the GPU active list to
a temporary retire list under the GPU lock.
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>

drivers/gpu/drm/etnaviv/etnaviv_gpu.c

@@ -1201,20 +1201,22 @@ static void retire_worker(struct work_struct *work)
 					       retire_work);
 	u32 fence = gpu->completed_fence;
 	struct etnaviv_gem_submit *submit, *tmp;
+	LIST_HEAD(retire_list);
 
 	mutex_lock(&gpu->lock);
 	list_for_each_entry_safe(submit, tmp, &gpu->active_submit_list, node) {
 		if (!dma_fence_is_signaled(submit->out_fence))
 			break;
 
-		list_del(&submit->node);
-
-		etnaviv_submit_put(submit);
+		list_move(&submit->node, &retire_list);
 	}
 
 	gpu->retired_fence = fence;
 
 	mutex_unlock(&gpu->lock);
+
+	list_for_each_entry_safe(submit, tmp, &retire_list, node)
+		etnaviv_submit_put(submit);
 }
 
 int etnaviv_gpu_wait_fence_interruptible(struct etnaviv_gpu *gpu,