From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [PATCH 36/56] microblaze_v2: dma support Date: Tue, 6 May 2008 13:24:04 +0200 Message-ID: <200805061324.06282.arnd@arndb.de> References: <1209901305-6404-1-git-send-email-monstr@seznam.cz> <48202AB6.4010201@seznam.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from moutng.kundenserver.de ([212.227.126.186]:60464 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752631AbYEFLZA convert rfc822-to-8bit (ORCPT ); Tue, 6 May 2008 07:25:00 -0400 In-Reply-To: Content-Disposition: inline Sender: linux-arch-owner@vger.kernel.org List-ID: To: Geert Uytterhoeven Cc: Michal Simek , John Williams , linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, stephen.neuendorffer@xilinx.com, John.Linn@xilinx.com, matthew@wil.cx, will.newton@gmail.com, drepper@redhat.com, microblaze-uclinux@itee.uq.edu.au, grant.likely@secretlab.ca, Michal Simek On Tuesday 06 May 2008, Geert Uytterhoeven wrote: > > struct scatterlist { > > =A0=A0=A0=A0=A0=A0unsigned long page_link; > > =A0=A0=A0=A0=A0=A0unsigned int=A0=A0=A0=A0offset; > > =A0=A0=A0=A0=A0=A0unsigned int=A0=A0=A0=A0length; > > =A0=A0=A0=A0=A0=A0dma_addr_t=A0=A0=A0=A0=A0=A0dma_address; > > }; >=20 > If unsigned long is 32-bit but dma_addr_t is 64-bit, there may be a g= ap > between length and dma_address. >=20 But moving dma_address to the front only has the effect to create impli= cit padding at the end of struct scatterlist, so you don't gain anything either way. It's only an internal definition that can be changed at any time withou= t breaking applications, so I wouldn't worry about it, and better leave it identical to the other architectures. The one thing that should indeed be changed is the addition of 'unsigned long sg_magic' that is needed for CONFIG_DEBUG_SG. Arnd <><