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=-2.0 required=3.0 tests=DKIM_ADSP_CUSTOM_MED, FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 F23FBC43603 for ; Fri, 20 Dec 2019 12:15:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D19C62467F for ; Fri, 20 Dec 2019 12:15:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727197AbfLTMPp (ORCPT ); Fri, 20 Dec 2019 07:15:45 -0500 Received: from mga12.intel.com ([192.55.52.136]:5665 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727177AbfLTMPp (ORCPT ); Fri, 20 Dec 2019 07:15:45 -0500 X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 20 Dec 2019 04:15:44 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.69,335,1571727600"; d="scan'208";a="416519636" Received: from smile.fi.intel.com (HELO smile) ([10.237.68.40]) by fmsmga005.fm.intel.com with ESMTP; 20 Dec 2019 04:15:43 -0800 Received: from andy by smile with local (Exim 4.93-RC7) (envelope-from ) id 1iiHC3-0002kc-8y; Fri, 20 Dec 2019 14:15:43 +0200 Date: Fri, 20 Dec 2019 14:15:43 +0200 From: Andy Shevchenko To: Bartosz Golaszewski Cc: Bartosz Golaszewski , Kent Gibson , Linus Walleij , Greg Kroah-Hartman , "open list:GPIO SUBSYSTEM" , Linux Kernel Mailing List Subject: Re: [PATCH v3 12/13] gpiolib: add new ioctl() for monitoring changes in line info Message-ID: <20191220121543.GY32742@smile.fi.intel.com> References: <20191219171528.6348-1-brgl@bgdev.pl> <20191219171528.6348-13-brgl@bgdev.pl> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-gpio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org On Fri, Dec 20, 2019 at 12:25:59PM +0100, Bartosz Golaszewski wrote: > czw., 19 gru 2019 o 19:17 Andy Shevchenko > napisał(a): > > On Thu, Dec 19, 2019 at 7:17 PM Bartosz Golaszewski wrote: ... > > > +/** > > > + * struct gpioline_info_changed - Information about a change in status > > > + * of a GPIO line > > > + * @info: updated line information > > > + * @timestamp: estimate of time of status change occurrence, in nanoseconds > > > + * and GPIOLINE_CHANGED_CONFIG > > > + * @event_type: one of GPIOLINE_CHANGED_REQUESTED, GPIOLINE_CHANGED_RELEASED > > > + */ > > > +struct gpioline_info_changed { > > > > > + struct gpioline_info info; > > > > Is this guaranteed to be always 8 byte aligned? > > I'm expecting to see some comments there and / or here about it. > > > > struct gpioline_info alone is 32-bit aligned but its size is 72 bytes > which works for 64-bit alignment. This new structure's biggest element > in 64-bit, so it's 64-bit aligned on 64-bit arch. We have 72 bytes of > gpioline_info, 8 bytes of timestamp, 32 bytes of event type and 5 * 32 > bytes of padding. Should be fine, but I'll add comments to the header. Yes, what I meant is to add comment at least to struct gpioline_info definition that if somebody would like to change it there (which also might be a problematic here, if there is no versioning scheme / length member). > > > + __u64 timestamp; > > > + __u32 event_type; > > > + __u32 padding[5]; /* for future use */ > > > +}; Offtopic a bit, had you had a chance to look at Buildroot and our scripts I shared? -- With Best Regards, Andy Shevchenko