From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754236AbYIDA1E (ORCPT ); Wed, 3 Sep 2008 20:27:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752034AbYIDA0y (ORCPT ); Wed, 3 Sep 2008 20:26:54 -0400 Received: from hera.kernel.org ([140.211.167.34]:46727 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751709AbYIDA0x (ORCPT ); Wed, 3 Sep 2008 20:26:53 -0400 Message-ID: <48BF2AEB.1050508@kernel.org> Date: Thu, 04 Sep 2008 02:25:15 +0200 From: Tejun Heo User-Agent: Thunderbird 2.0.0.12 (X11/20071114) MIME-Version: 1.0 To: "H. Peter Anvin" CC: device@lanana.org, Linux Kernel Mailing List , Jens Axboe Subject: Re: regarding major number of block extended devt References: <48BD30F9.6080108@kernel.org> <48BD3313.7090906@kernel.org> <48BD9F36.8000704@zytor.com> <48BE0EDB.20107@kernel.org> <48BEB759.4050503@zytor.com> <48BEB98C.8030303@kernel.org> <48BEBAF0.7070008@zytor.com> <48BEBF34.50006@kernel.org> <48BED351.1060300@zytor.com> In-Reply-To: <48BED351.1060300@zytor.com> X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.0 (hera.kernel.org [127.0.0.1]); Thu, 04 Sep 2008 00:26:41 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, H. Peter Anvin wrote: > Thinking about it some more, one invariant this is *guaranteed* to > violate is: > > partition_number = partition_device - master_device > > Code that needs a partition number (which is common enough) are using > this invariant, because (a) it has held for 17 years and (b) because > there is still no alternative other that relying on fragile naming > scheme hacks. > > (a) we can't do anything about, but (b) we can, by introducing a > partition number attribute in sysfs. Yeah, that would certainly be a nice addition. Also, if partitions are made proper classes, they'll be easily enumerable by /sys/block/*/partitions/*. Jens, what do you think? -- tejun