[Bugfix] Fix GPUModelRunner has no attribute lora_manager (#24762)

Signed-off-by: Jee Jee Li <pandaleefree@gmail.com>

vllm/v1/worker/lora_model_runner_mixin.py

@@ -63,8 +63,7 @@ class LoRAModelRunnerMixin:
     def _set_active_loras(self, prompt_lora_mapping: tuple[int, ...],
                           token_lora_mapping: tuple[int, ...],
                           lora_requests: set[LoRARequest]) -> None:
-        if not self.lora_manager:
-            raise RuntimeError("LoRA is not enabled.")
+        self._ensure_lora_enabled()
 
         # Set is_prefill to True, so we always use the SGMV kernels on
         # non-cuda platforms.
@@ -75,6 +74,11 @@ class LoRAModelRunnerMixin:
                                    is_prefill=True)
         self.lora_manager.set_active_adapters(lora_requests, lora_mapping)
 
+    def _ensure_lora_enabled(self) -> None:
+        if not hasattr(self, "lora_manager"):
+            raise RuntimeError(
+                "LoRA is not enabled. Use --enable-lora to enable LoRA.")
+
     def set_active_loras(self, input_batch: InputBatch,
                          num_scheduled_tokens: np.ndarray) -> None:
 
@@ -172,21 +176,17 @@ class LoRAModelRunnerMixin:
         self.lora_manager.remove_all_adapters()
 
     def add_lora(self, lora_request: LoRARequest) -> bool:
-        if not self.lora_manager:
-            raise RuntimeError("LoRA is not enabled.")
+        self._ensure_lora_enabled()
         return self.lora_manager.add_adapter(lora_request)
 
     def remove_lora(self, lora_id: int) -> bool:
-        if not self.lora_manager:
-            raise RuntimeError("LoRA is not enabled.")
+        self._ensure_lora_enabled()
         return self.lora_manager.remove_adapter(lora_id)
 
     def pin_lora(self, lora_id: int) -> bool:
-        if not self.lora_manager:
-            raise RuntimeError("LoRA is not enabled.")
+        self._ensure_lora_enabled()
         return self.lora_manager.pin_adapter(lora_id)
 
     def list_loras(self) -> set[int]:
-        if not self.lora_manager:
-            raise RuntimeError("LoRA is not enabled.")
+        self._ensure_lora_enabled()
         return self.lora_manager.list_adapters()