[V1] Simplify GPUModelRunner._update_states check (vllm-project#13265)

Author: njhill

vllm/v1/worker/gpu_model_runner.py

@@ -347,6 +347,8 @@ def _update_states(self, scheduler_output: "SchedulerOutput") -> bool:
             self.input_batch.block_table.append_row(req_index, start_index,
                                                     req_data.new_block_ids)
 
+        batch_changed = len(removed_req_indices) > 0 or len(req_ids_to_add) > 0
+
         # Add the new or resumed requests to the persistent batch.
         # The smaller empty indices are filled first.
         removed_req_indices = sorted(removed_req_indices, reverse=True)
@@ -363,8 +365,8 @@ def _update_states(self, scheduler_output: "SchedulerOutput") -> bool:
         # Condense the batched states if there are empty indices.
         if removed_req_indices:
             self.input_batch.condense(removed_req_indices)
-        return (len(unscheduled_req_ids) > 0 or len(req_ids_to_add) > 0
-                or len(scheduler_output.finished_req_ids) > 0)
+
+        return batch_changed
 
     def _prepare_inputs(self, scheduler_output: "SchedulerOutput"):
         total_num_scheduled_tokens = scheduler_output.total_num_scheduled_tokens