From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E72C1C1B0F2 for ; Wed, 20 Jun 2018 05:45:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A01CD20836 for ; Wed, 20 Jun 2018 05:45:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A01CD20836 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=davemloft.net Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752798AbeFTFpD (ORCPT ); Wed, 20 Jun 2018 01:45:03 -0400 Received: from shards.monkeyblade.net ([23.128.96.9]:55526 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750871AbeFTFpA (ORCPT ); Wed, 20 Jun 2018 01:45:00 -0400 Received: from localhost (unknown [61.102.160.116]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 62F5E14621863; Tue, 19 Jun 2018 22:44:58 -0700 (PDT) Date: Wed, 20 Jun 2018 14:44:36 +0900 (KST) Message-Id: <20180620.144436.2267326438433785984.davem@davemloft.net> To: mdf@kernel.org Cc: keescook@chromium.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] net: nixge: Add __packed attribute to DMA descriptor struct From: David Miller In-Reply-To: <20180619165453.31894-1-mdf@kernel.org> References: <20180619165453.31894-1-mdf@kernel.org> X-Mailer: Mew version 6.7 on Emacs 25.3 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Tue, 19 Jun 2018 22:44:59 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Moritz Fischer Date: Tue, 19 Jun 2018 09:54:53 -0700 > @@ -122,7 +122,7 @@ struct nixge_hw_dma_bd { > u32 sw_id_offset; > u32 reserved5; > u32 reserved6; > -}; > +} __packed; As I understand it, based upon your replies to Florian, this bug doesn't even show up with the current code. The problem only happens with some 64-bit changes you are working on. So, the change is not valid right now. And for the 64-bit changes, I agree with Florian that you should adjust your implementation so that this __packed dance isn't necessary and that you can avoid some MMIOs as well. Thanks.