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=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 B5D4EC433FE for ; Fri, 10 Sep 2021 07:52:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A3E0060FC0 for ; Fri, 10 Sep 2021 07:52:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231649AbhIJHxP (ORCPT ); Fri, 10 Sep 2021 03:53:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53080 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231561AbhIJHxP (ORCPT ); Fri, 10 Sep 2021 03:53:15 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B15D4C061574 for ; Fri, 10 Sep 2021 00:52:04 -0700 (PDT) Received: from ptx.hi.pengutronix.de ([2001:67c:670:100:1d::c0]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1mObKG-0008TF-04; Fri, 10 Sep 2021 09:51:56 +0200 Received: from ore by ptx.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1mObKE-0003rS-CR; Fri, 10 Sep 2021 09:51:54 +0200 Date: Fri, 10 Sep 2021 09:51:54 +0200 From: Oleksij Rempel To: Dmitry Torokhov Cc: Alexandru Ardelean , Mark Brown , kernel test robot , kernel@pengutronix.de, linux-kernel@vger.kernel.org, linux-input@vger.kernel.org, linux-spi@vger.kernel.org, David Jander Subject: Re: [PATCH v1] Input: ads7846: ads7846_get_value - fix unaligned pointer value warning Message-ID: <20210910075154.GF26100@pengutronix.de> References: <20210707124115.20028-1-o.rempel@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Uptime: 09:49:56 up 204 days, 11:13, 101 users, load average: 0.19, 0.16, 0.15 User-Agent: Mutt/1.10.1 (2018-07-13) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c0 X-SA-Exim-Mail-From: ore@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-spi@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org Hi Dmitry, On Thu, Sep 09, 2021 at 10:04:16PM -0700, Dmitry Torokhov wrote: > Hi Oleksij, > > On Wed, Jul 07, 2021 at 02:41:15PM +0200, Oleksij Rempel wrote: > > Fix warning reported by the kernel test robot: > > drivers/input/touchscreen/ads7846.c:705:24: warning: taking address > > of packed member 'data' of class or structure 'ads7846_buf' may result > > in an unaligned pointer value [-Waddress-of-packed-member] > > > > Fixes: 6965eece2a89 ("Input: ads7846 - convert to one message") > > Reported-by: kernel test robot > > Signed-off-by: Oleksij Rempel > > --- > > drivers/input/touchscreen/ads7846.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c > > index adb4c2230c31..1987dedac94f 100644 > > --- a/drivers/input/touchscreen/ads7846.c > > +++ b/drivers/input/touchscreen/ads7846.c > > @@ -702,7 +702,7 @@ static int ads7846_get_value(struct ads7846_buf *buf) > > { > > int value; > > > > - value = be16_to_cpup(&buf->data); > > + value = get_unaligned_be16(&buf->data); > > ds7846_buf is declared as packed so I believe using be16_to_cpu(buf->data) > will suffice. The pointer to the data is is off by 8 bits, so it is not naturally aligned. This is why we need to use function which is dealing with unaligned pointers. Regards, Oleksij -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |