[Misc] Adjust max_position_embeddings for LoRA compatibility (vllm-project#8957)

Signed-off-by: LeiWang1999 <leiwang1999@outlook.com>

Author: jeejeelee

vllm/worker/model_runner.py

@@ -1037,9 +1037,17 @@ def load_model(self) -> None:
             assert supports_lora(
                 self.model
             ), f"{self.model.__class__.__name__} does not support LoRA yet."
+
             if supports_multimodal(self.model):
                 logger.warning("Regarding multimodal models, vLLM currently "
                                "only supports adding LoRA to language model.")
+            # It's necessary to distinguish between the max_position_embeddings
+            # of VLMs and LLMs.
+            if hasattr(self.model.config, "max_position_embeddings"):
+                max_pos_embeddings = self.model.config.max_position_embeddings
+            else:
+                max_pos_embeddings = (
+                    self.model.config.text_config.max_position_embeddings)
 
             self.lora_manager = LRUCacheWorkerLoRAManager(
                 self.scheduler_config.max_num_seqs,
@@ -1049,8 +1057,7 @@ def load_model(self) -> None:
                 self.device,
                 self.model.embedding_modules,
                 self.model.embedding_padding_modules,
-                max_position_embeddings=self.model.config.
-                max_position_embeddings,
+                max_position_embeddings=max_pos_embeddings,
             )
             self.model = self.lora_manager.create_lora_manager(self.model)