Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264965AbUF1OPv (ORCPT ); Mon, 28 Jun 2004 10:15:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264966AbUF1OPv (ORCPT ); Mon, 28 Jun 2004 10:15:51 -0400 Received: from host-65-117-135-105.timesys.com ([65.117.135.105]:6592 "EHLO yoda.timesys") by vger.kernel.org with ESMTP id S264965AbUF1OPu (ORCPT ); Mon, 28 Jun 2004 10:15:50 -0400 Date: Mon, 28 Jun 2004 10:15:17 -0400 To: "David S. Miller" Cc: Oliver Neukum , zaitcev@redhat.com, greg@kroah.com, arjanv@redhat.com, jgarzik@redhat.com, tburke@redhat.com, linux-kernel@vger.kernel.org, stern@rowland.harvard.edu, mdharm-usb@one-eyed-alien.net, david-b@pacbell.net Subject: Re: drivers/block/ub.c Message-ID: <20040628141517.GA4311@yoda.timesys> References: <20040626130645.55be13ce@lembas.zaitcev.lan> <200406270631.41102.oliver@neukum.org> <20040626233423.7d4c1189.davem@redhat.com> <200406271242.22490.oliver@neukum.org> <20040627142628.34b60c82.davem@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20040627142628.34b60c82.davem@redhat.com> User-Agent: Mutt/1.5.4i From: Scott Wood Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1181 Lines: 26 On Sun, Jun 27, 2004 at 02:26:28PM -0700, David S. Miller wrote: > On Sun, 27 Jun 2004 12:42:21 +0200 > Oliver Neukum wrote: > > > OK, then it shouldn't be used in this case. However, shouldn't we have > > an attribute like __nopadding__ which does exactly that? > > It would have the same effect. CPU structure layout rules don't pack > (or using other words, add padding) exactly in cases where it is > needed to obtain the necessary alignment. No, it wouldn't, as you could drop the assumption that the base of the struct can be misaligned. Thus, the compiler only needs to generate unaligned loads and stores for fields which are unaligned within the struct, which in this case would be none of them. While it's rather unlikely that a struct like this one would ever need packing, it would help those structs that do need it by reducing the number of fields subjected to unaligned loads and stores. -Scott - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/