Also, you are calling getListData in a static way. You can get the current module via $this->module, where $this is the controller.
Yes, I defined arrFilter like this:
public $arrFilter;
and from the controller class the function getListData is callable without errors. But I don't want to call the function (or better functions, there are 20 and more) through the controller class, and if I want to call it in a static way, i get the error (which I wrote above).
There's not strict way for this kind of problem. What you did is definitely fine. You may also put these shared methods in a separate class, or scatter them into model classes.