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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 21E91CA9EB5 for ; Mon, 4 Nov 2019 15:01:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DDBA620659 for ; Mon, 4 Nov 2019 15:01:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572879719; bh=Wja1Nou+3B9RfyoLJ0X5VblrpMRkzLjZwzBxYEC726g=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=WuTu4SxYkbH+wKDWdMgZKf5P1QGTANb0jBkU/5L9Hj9bwzXavPBVkwgvsT9zL3Dvc z3XwuEjRVAUBz1ZaH2vGgCyUJkNmLE1GtFZs6wi32HBvge72/fT6gI2fDV7x7xXTMF 6AZxas0VMO8sGxvYB9SrndhA551Y0SQtw84L2Fd4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728848AbfKDPB5 (ORCPT ); Mon, 4 Nov 2019 10:01:57 -0500 Received: from mail.kernel.org ([198.145.29.99]:57602 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727788AbfKDPB5 (ORCPT ); Mon, 4 Nov 2019 10:01:57 -0500 Received: from redsun51.ssa.fujisawa.hgst.com (unknown [199.255.47.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4D34F20656; Mon, 4 Nov 2019 15:01:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572879717; bh=Wja1Nou+3B9RfyoLJ0X5VblrpMRkzLjZwzBxYEC726g=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=UVUOo6v87yZZRNciSy1W9aO3L4qjP6141S7FwkM9ySR5eaddnDq6yN5nz/Vf6mtdh rLv71dWhzUp6lTR7Z0cozX9yvtaZap/fyBCVSAbwXuisIxwZHrYVvwY6V2pDBx52mo gZuIAxz+qsYGeuWg75E20qOeOSTNEaW6BUhRkgfg= Date: Tue, 5 Nov 2019 00:01:51 +0900 From: Keith Busch To: Marta Rybczynska Cc: Charles Machalow , Christoph Hellwig , linux-nvme , axboe , Sagi Grimberg , linux-kernel Subject: Re: [PATCH] nvme: change nvme_passthru_cmd64's result field. Message-ID: <20191104150151.GA26808@redsun51.ssa.fujisawa.hgst.com> References: <20191031050338.12700-1-csm10495@gmail.com> <20191031133921.GA4763@lst.de> <1977598237.90293761.1572878080625.JavaMail.zimbra@kalray.eu> <871357470.90297451.1572879417091.JavaMail.zimbra@kalray.eu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <871357470.90297451.1572879417091.JavaMail.zimbra@kalray.eu> User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 04, 2019 at 03:56:57PM +0100, Marta Rybczynska wrote: > ----- On 4 Nov, 2019, at 15:51, Charles Machalow csm10495@gmail.com wrote: > > > For this one yes, UAPI size changes. Though I believe this IOCTL > > hasn't been in a released Kernel yet (just RC). Technically it may be > > changeable as a fix until the next Kernel is released. I do think its > > a useful enough > > change to warrant a late fix. > > The old one is in UAPI for years. The new one is not yet, right. I'm OK > to change the new structure. To have compatibility you would have to use > the new structure (at least its size) in the user space code. This is > what you'd liek to do? Charles is proposing only to modify the recently introduced 64-bit ioctl struct without touching the existing 32 bit version. He just wanted the lower 32-bits of the 64-bit result to occupy the same space as the 32-bit ioctl's result. That space in the 64-bit version is currently occupied by an implicit struct padding.