From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 24 Mar 2003 15:23:08 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 24 Mar 2003 15:23:08 -0500 Received: from hera.cwi.nl ([192.16.191.8]:29863 "EHLO hera.cwi.nl") by vger.kernel.org with ESMTP id ; Mon, 24 Mar 2003 15:23:06 -0500 From: Andries.Brouwer@cwi.nl Date: Mon, 24 Mar 2003 21:34:14 +0100 (MET) Message-Id: To: Andries.Brouwer@cwi.nl, hch@infradead.org Subject: Re: [PATCH 1/3] revert register_chrdev_region change Cc: akpm@digeo.com, linux-kernel@vger.kernel.org, zippel@linux-m68k.org Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org From: Christoph Hellwig > Yes, it is more elegant to register one or more ranges. > (But ranges of what? Ranges in dev_t space? Or in kdev_t space? In dev_t space. I guess basically everyone will disagree with you on making kdev_t a different representation. This will end up as messy as the internal/external dev_t stuff on some of the SVR4 ports. You are the first to say so. I'll think about it. A. On kdev_t vs. dev_t: kdev_t gives small and fast code, dev_t needs a conditional That was my main reason. I suppose you say that dev_t is a cookie and that the kernel should never want to ask about major and minor, except perhaps at filesystem interfaces. So the 1000+ invocations that we have now should all go away. A reasonable point of view. B. On what is registered: The main question here is what the documented outside reality is. Is that phrased in terms of dev_t intervals? Or is that phrased in terms of (major,minor) pairs? Until convinced otherwise I will hold that users talk about (major,minor) pairs. They do ls -l and see major,minor pairs. They want to do mknod and need a major,minor pair. So I suppose that the documented reality will give a minor range for a given major, or give a major range. Such ranges correspond to kdev_t ranges, not to dev_t ranges. Of course one can avoid the distinction by decreeing that majors 0-255 cannot have more than 256 minors. Andries