Index: Modules/zlibmodule.c
===================================================================
--- Modules/zlibmodule.c	(Revision 67923)
+++ Modules/zlibmodule.c	(Arbeitskopie)
@@ -17,24 +17,15 @@
    about re-entering zlib functions.
 
    N.B.
-
-   Since ENTER_ZLIB and LEAVE_ZLIB only need to be called on functions
-   that modify the components of preexisting de/compress objects, it
-   could prove to be a performance gain on multiprocessor machines if
-   there was an de/compress object-specific lock.  However, for the
-   moment the ENTER_ZLIB and LEAVE_ZLIB calls are global for ALL
-   de/compress objects.
  */
 
-static PyThread_type_lock zlib_lock = NULL; /* initialized on module load */
-
 #define ENTER_ZLIB \
 	Py_BEGIN_ALLOW_THREADS \
-	PyThread_acquire_lock(zlib_lock, 1); \
+	PyThread_acquire_lock(self->lock, 1); \
 	Py_END_ALLOW_THREADS
 
 #define LEAVE_ZLIB \
-	PyThread_release_lock(zlib_lock);
+	PyThread_release_lock(self->lock);
 
 #else
 
@@ -67,6 +58,9 @@
     PyObject *unused_data;
     PyObject *unconsumed_tail;
     int is_initialised;
+    #ifdef WITH_THREAD
+        PyThread_type_lock lock;
+    #endif
 } compobject;
 
 static void
@@ -106,6 +100,9 @@
 	Py_DECREF(self);
 	return NULL;
     }
+    #ifdef WITH_THREAD
+        self->lock = PyThread_allocate_lock();
+    #endif
     return self;
 }
 
@@ -1096,8 +1093,5 @@
 
     PyModule_AddStringConstant(m, "__version__", "1.0");
 
-#ifdef WITH_THREAD
-    zlib_lock = PyThread_allocate_lock();
-#endif /* WITH_THREAD */
     return m;
 }