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=-1.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS 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 8D23AC46470 for ; Wed, 1 May 2019 10:37:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 52E5221670 for ; Wed, 1 May 2019 10:37:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fjfi.cvut.cz header.i=@fjfi.cvut.cz header.b="AS7jt7FK" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726327AbfEAKhJ (ORCPT ); Wed, 1 May 2019 06:37:09 -0400 Received: from mailgw2.fjfi.cvut.cz ([147.32.9.131]:37416 "EHLO mailgw2.fjfi.cvut.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725782AbfEAKhI (ORCPT ); Wed, 1 May 2019 06:37:08 -0400 Received: from localhost (localhost [127.0.0.1]) by mailgw2.fjfi.cvut.cz (Postfix) with ESMTP id 02625A0261; Wed, 1 May 2019 12:37:06 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fjfi.cvut.cz; s=20151024; t=1556707026; i=@fjfi.cvut.cz; bh=xUNgtvQRFKyYsdfzqHIQRM1/8TevvQ9MUZytgCe0Bcg=; h=Date:From:To:cc:Subject:In-Reply-To:References; b=AS7jt7FKvTgOTl13fyJcvaOTmNJ2dZf4ZuuB17hfuzLpXKbkjnJ9YmDqdAUvphajn YYnHoGYNT8phdmDr3oRDhSeVcuZC+Bf6ZNFTZbQaMA+eUDtosG332AHP0oBgX10g6m mKIOk1DPak4GBM7EkEAAILym7uJqpLbBOAHli7fo= X-CTU-FNSPE-Virus-Scanned: amavisd-new at fjfi.cvut.cz Received: from mailgw2.fjfi.cvut.cz ([127.0.0.1]) by localhost (mailgw2.fjfi.cvut.cz [127.0.0.1]) (amavisd-new, port 10022) with ESMTP id sWmveC4fgvN5; Wed, 1 May 2019 12:36:41 +0200 (CEST) Received: from linux.fjfi.cvut.cz (linux.fjfi.cvut.cz [147.32.5.111]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mailgw2.fjfi.cvut.cz (Postfix) with ESMTPS id 5D1DAA00DC; Wed, 1 May 2019 12:36:41 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 mailgw2.fjfi.cvut.cz 5D1DAA00DC Received: by linux.fjfi.cvut.cz (Postfix, from userid 1001) id 147DB6004D; Wed, 1 May 2019 12:36:40 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by linux.fjfi.cvut.cz (Postfix) with ESMTP id E8CC06002A; Wed, 1 May 2019 12:36:40 +0200 (CEST) Date: Wed, 1 May 2019 12:36:40 +0200 (CEST) From: David Kozub To: Jens Axboe , Jonathan Derrick , Scott Bauer , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org cc: Jonas Rabenstein Subject: Re: [PATCH 1/3] block: sed-opal: add ioctl for done-mark of shadow mbr In-Reply-To: <1556666459-17948-2-git-send-email-zub@linux.fjfi.cvut.cz> Message-ID: References: <1556666459-17948-1-git-send-email-zub@linux.fjfi.cvut.cz> <1556666459-17948-2-git-send-email-zub@linux.fjfi.cvut.cz> User-Agent: Alpine 2.21 (LRH 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 1 May 2019, David Kozub wrote: > @@ -104,6 +109,12 @@ struct opal_mbr_data { > __u8 __align[7]; > }; > > +struct opal_mbr_done { > + struct opal_key key; > + __u8 done_flag; > + __u8 __align[7]; > +}; While I just copied opal_mbr_data here, I wonder what is the point of __align in these structs. By itself it just pads the structure to have a size that is a multiple of 8. Is this to make sure that anything that lies past the structure is 8-bytes aligned (assuming the start is 8-bytes aligned too), perhaps for 32bit userspace with 64bit kernel? And if it's this, is it needed for these IOCTL structs? (I can see it being useful for struct opal_key.) Best regards, David