remove redundant lock

Author: LindaSummer

Misc/NEWS.d/next/Core_and_Builtins/2025-11-15-23-58-23.gh-issue-139103.9cVYJ0.rst

@@ -1 +1 @@
-Make ``type_setattro`` use defer refcount in free-threading for functions without defer refcount.
+Improve multithreaded scaling of dataclasses on the free-threaded build.

Objects/typeobject.c

@@ -6547,14 +6547,10 @@ type_setattro(PyObject *self, PyObject *name, PyObject *value)
     assert(!_PyType_HasFeature(metatype, Py_TPFLAGS_MANAGED_DICT));
 
 #ifdef Py_GIL_DISABLED
-    if (value != NULL && PyFunction_Check(value)) {
-        if (!_PyObject_HasDeferredRefcount(value)) {
-            BEGIN_TYPE_LOCK();
-            if (!_PyObject_HasDeferredRefcount(value)) {
-                PyUnstable_Object_EnableDeferredRefcount(value);
-            }
-            END_TYPE_LOCK();
-        }
+    if (value != NULL &&
+        PyFunction_Check(value) &&
+        !_PyObject_HasDeferredRefcount(value)) {
+            PyUnstable_Object_EnableDeferredRefcount(value);
     }
 #endif
 
@@ -6585,7 +6581,6 @@ type_setattro(PyObject *self, PyObject *name, PyObject *value)
         }
     }
 
-
     BEGIN_TYPE_DICT_LOCK(dict);
     res = type_update_dict(type, (PyDictObject *)dict, name, value, &old_value);
     assert(_PyType_CheckConsistency(type));