From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263857AbTDNTEG (for ); Mon, 14 Apr 2003 15:04:06 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263859AbTDNTEG (for ); Mon, 14 Apr 2003 15:04:06 -0400 Received: from inet-mail1.oracle.com ([148.87.2.201]:19445 "EHLO inet-mail1.oracle.com") by vger.kernel.org with ESMTP id S263857AbTDNTEB (for ); Mon, 14 Apr 2003 15:04:01 -0400 Date: Mon, 14 Apr 2003 12:15:15 -0700 From: Joel Becker To: Linus Torvalds Cc: Andries.Brouwer@cwi.nl, akpm@digeo.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] kdevt-diff Message-ID: <20030414191512.GA4917@ca-server1.us.oracle.com> References: <20030414175141.GS4917@ca-server1.us.oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Burt-Line: Trees are cool. User-Agent: Mutt/1.5.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 14, 2003 at 11:00:27AM -0700, Linus Torvalds wrote: > Well, the thing is, we absolutely _do_ need to have the 8+8 split, in > order to make old devices look the same old way for old binaries. Yes, and I support this 100%. > The 16+16 split is not strictly necessary, but Andries pointed out to me > that there are filesystems etc external storage that only support a 32-bit > opaque dev_t, so we'd need to marshall the device number _some_ way for > them anyway, and having a standard way to do that is better than having > everybody come up with their own variations. Sure, but it's a marshall, not a reality. One of the reasons for choosing 64bits is that we can have large spaces for large things. If a driver happens to get a number in the 16:16 space (or the 12:20 space, which I prefer as well), then it could run out of space and end up with the multiple major problem. True, a truly dynamic scheme could make all of this irrelevant, but I was just postulating that complexity isn't strictly necessary. I guess it is a trade off. Do all devices greater than 8:8 become 32:32 and merely are masked to 16:16 on limited filesystems, or do all devices smaller than 16:16/12:20 appear the same on all filesystems, limited or not? JOel -- "You can get more with a kind word and a gun than you can with a kind word alone." - Al Capone Joel Becker Senior Member of Technical Staff Oracle Corporation E-mail: joel.becker@oracle.com Phone: (650) 506-8127