DCBs now added/removed without locks

This is not globally safe yet, but all other access is directly or
indirectly related to maxadmin, which is irrelevant as far as
performance testing is concerned.

include/maxscale/worker.h

@@ -68,6 +68,22 @@ enum mxs_worker_msg_id
  */
 MXS_WORKER* mxs_worker_get(int worker_id);
 
+/**
+ * Return the worker of the current thread.
+ *
+ * @return The worker instance or NULL if the calling thread is not associated
+ *         with a worker.
+ */
+MXS_WORKER* mxs_worker_get_current();
+
+/**
+ * Return the id of the worker of the current thread.
+ *
+ * @return The worker id or -1 if the calling thread is not associated
+ *         with a worker.
+ */
+int mxs_worker_get_current_id();
+
 /**
  * Return the id of the worker.
  *