From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261855AbTDUSgQ (ORCPT ); Mon, 21 Apr 2003 14:36:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261863AbTDUSgQ (ORCPT ); Mon, 21 Apr 2003 14:36:16 -0400 Received: from phoenix.infradead.org ([195.224.96.167]:33290 "EHLO phoenix.infradead.org") by vger.kernel.org with ESMTP id S261855AbTDUSfr (ORCPT ); Mon, 21 Apr 2003 14:35:47 -0400 Date: Mon, 21 Apr 2003 19:47:49 +0100 From: Christoph Hellwig To: Linus Torvalds Cc: Roman Zippel , "David S. Miller" , Andries.Brouwer@cwi.nl, linux-kernel@vger.kernel.org Subject: Re: [PATCH] new system call mknod64 Message-ID: <20030421194749.A10963@infradead.org> Mail-Followup-To: Christoph Hellwig , Linus Torvalds , Roman Zippel , "David S. Miller" , Andries.Brouwer@cwi.nl, linux-kernel@vger.kernel.org References: <20030421193546.A10287@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: ; from torvalds@transmeta.com on Mon, Apr 21, 2003 at 11:44:59AM -0700 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 21, 2003 at 11:44:59AM -0700, Linus Torvalds wrote: > We HAVE to do the mapping somewhere. Old applications only use the lower > 16 bits, and that's just something that MUST NOT be broken. > > The question is only _where_ (not whether) we do the mapping. Right now we > keep "dev_t" in teh same format as we give back to user space, and thus we > always map into that format internally. But we don't have to: we can have > an internal format that is different from the one we show users. Why do we need to do a mapping? Old applications just won't see the high bits (they're mapped to whatever overflow value) - values that fit into the old 16bit range should never be remapped.