Clean up imports (#5467)

python/sglang/srt/layers/moe/topk.py

@@ -13,7 +13,6 @@
 # ==============================================================================
 
 import math
-import os
 from typing import Callable, Optional
 
 import torch
@@ -29,6 +28,10 @@ _is_hip = is_hip()
 if _is_cuda:
     from sgl_kernel import moe_fused_gate
 
+if _is_cuda or _is_hip:
+    from sgl_kernel import topk_softmax
+
+
 expert_distribution_recorder = ExpertDistributionRecorder()
 
 
@@ -59,11 +62,6 @@ def fused_topk(
     topk: int,
     renormalize: bool,
 ):
-    if _is_cuda or _is_hip:
-        from sgl_kernel import topk_softmax
-    else:
-        from vllm import _custom_ops as vllm_ops
-
     assert hidden_states.shape[0] == gating_output.shape[0], "Number of tokens mismatch"
 
     M, _ = hidden_states.shape
@@ -76,20 +74,12 @@ def fused_topk(
         M, topk, dtype=torch.int32, device=hidden_states.device
     )
 
-    if _is_cuda or _is_hip:
-        topk_softmax(
-            topk_weights,
-            topk_ids,
-            token_expert_indicies,
-            gating_output.float(),
-        )
-    else:
-        vllm_ops.topk_softmax(
-            topk_weights,
-            topk_ids,
-            token_expert_indicies,
-            gating_output.float(),
-        )
+    topk_softmax(
+        topk_weights,
+        topk_ids,
+        token_expert_indicies,
+        gating_output.float(),
+    )
     del token_expert_indicies
 
     if renormalize: