From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 17 May 2001 05:33:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 17 May 2001 05:33:46 -0400 Received: from kweetal.tue.nl ([131.155.2.7]:8709 "EHLO kweetal.tue.nl") by vger.kernel.org with ESMTP id ; Thu, 17 May 2001 05:33:31 -0400 Message-ID: <20010517113330.A9270@win.tue.nl> Date: Thu, 17 May 2001 11:33:30 +0200 From: Guest section DW To: Jeff Garzik , Richard Gooch Cc: Linux Kernel Mailing List Subject: Re: LANANA: To Pending Device Number Registrants In-Reply-To: <200105161822.f4GIMo509185@vindaloo.ras.ucalgary.ca> <200105162358.f4GNwll13400@vindaloo.ras.ucalgary.ca> <3B032ACD.E1998F82@mandrakesoft.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.93i In-Reply-To: <3B032ACD.E1998F82@mandrakesoft.com>; from Jeff Garzik on Wed, May 16, 2001 at 09:35:09PM -0400 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 16, 2001 at 09:35:09PM -0400, Jeff Garzik wrote: > To inject a bit of concrete into this discussion, I note that block > devices with dynamically assigned don't work with CONFIG_DEVFS and > devfs=only. Block devices -require- majors currently, due to those > !@#!@# arrays. However, devfs_register_blkdev always returns zero when > devfs=only, even if its a block device and a dynamic major is requested. Jeff, this is a non-issue. These arrays you talk about are removed in a simple edit session - I did it a handful of times - there is no problem there whatsoever. What you are talking about is kernel-internal. We are free to do whatever we like inside the kernel, and we have full information. The only question is how to transmit device identity across the kernel space/user space boundary. Andries [And my solution is to use cookies - 64-bit opaque numbers that carry no information, and are generated at random by the kernel, but with the properties: (i) things that have a device number today keep this number, (ii) the random generation is such that whenever possible chances are good that after a reboot the same device will have the same number.]