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=-11.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 CED78C433E0 for ; Mon, 13 Jul 2020 11:18:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9ED55206F0 for ; Mon, 13 Jul 2020 11:18:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729637AbgGMLSV (ORCPT ); Mon, 13 Jul 2020 07:18:21 -0400 Received: from foss.arm.com ([217.140.110.172]:55906 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729027AbgGMLSV (ORCPT ); Mon, 13 Jul 2020 07:18:21 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 870941FB; Mon, 13 Jul 2020 04:18:20 -0700 (PDT) Received: from [192.168.1.84] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id BAAB03F7D8; Mon, 13 Jul 2020 04:18:19 -0700 (PDT) Subject: Re: [PATCH 2/3] firmware: arm_scmi: Remove unneeded __packed attribute To: Cristian Marussi , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: arnd@arndb.de, sudeep.holla@arm.com References: <20200710133919.39792-1-cristian.marussi@arm.com> <20200710133919.39792-2-cristian.marussi@arm.com> From: Steven Price Message-ID: <8683b876-72b9-2c94-12f6-9b9456627a7d@arm.com> Date: Mon, 13 Jul 2020 12:18:00 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: <20200710133919.39792-2-cristian.marussi@arm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/07/2020 14:39, Cristian Marussi wrote: > Remove __packed attribute from struct scmi_event_header. > > Signed-off-by: Cristian Marussi A drive-by review. But this doesn't look safe to me. sizeof(struct scmi_event_header) is used in several places and this change will modify that from 13 to 16, but leave the structure members at the same offset (as the members are naturally aligned). In particular the naïve header size is now bigger than the offset to payld. What is the justification for __packed being 'unneeded'? Perhaps there's some reason in the code why this doesn't matter, but if so I feel this should be included in the commit message. Steve > --- > drivers/firmware/arm_scmi/notify.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/firmware/arm_scmi/notify.c b/drivers/firmware/arm_scmi/notify.c > index c4d006cfde88..752415367305 100644 > --- a/drivers/firmware/arm_scmi/notify.c > +++ b/drivers/firmware/arm_scmi/notify.c > @@ -258,7 +258,7 @@ struct scmi_event_header { > u8 evt_id; > size_t payld_sz; > u8 payld[]; > -} __packed; > +}; > > struct scmi_registered_event; > >