From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-6.0 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=unavailable autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id 518037D2F0 for ; Mon, 8 Apr 2019 09:52:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725983AbfDHJwJ (ORCPT ); Mon, 8 Apr 2019 05:52:09 -0400 Received: from szxga05-in.huawei.com ([45.249.212.191]:6707 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725933AbfDHJwJ (ORCPT ); Mon, 8 Apr 2019 05:52:09 -0400 Received: from DGGEMS405-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 633868A0D550D054A9A4; Mon, 8 Apr 2019 17:52:06 +0800 (CST) Received: from [127.0.0.1] (10.177.23.164) by DGGEMS405-HUB.china.huawei.com (10.3.19.205) with Microsoft SMTP Server id 14.3.408.0; Mon, 8 Apr 2019 17:51:59 +0800 Subject: Re: [PATCH v4 0/6] normalize IOMMU dma mode boot options To: Thomas Gleixner References: <20190407124147.13576-1-thunder.leizhen@huawei.com> <5CAABD03.9000301@huawei.com> CC: Hanjun Guo , Jean-Philippe Brucker , John Garry , "Robin Murphy" , Will Deacon , "Joerg Roedel" , Jonathan Corbet , linux-doc , Sebastian Ott , "Gerald Schaefer" , Martin Schwidefsky , Heiko Carstens , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Tony Luck , Fenghua Yu , Ingo Molnar , Borislav Petkov , "H . Peter Anvin" , David Woodhouse , iommu , linux-kernel , linux-s390 , linuxppc-dev , x86 , linux-ia64 From: "Leizhen (ThunderTown)" Message-ID: <5CAB19BC.2040804@huawei.com> Date: Mon, 8 Apr 2019 17:51:56 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.23.164] X-CFilter-Loop: Reflected Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On 2019/4/8 14:32, Thomas Gleixner wrote: > On Mon, 8 Apr 2019, Leizhen (ThunderTown) wrote: >>> >>> This will break systems using boot options as now, and I think >>> this is unacceptable. If you want to do so, just introduce iommu.dma_mode >>> on top of those iommu boot options with dma mode boot options unchanged, >>> and iommu.dma_mode is for all archs but compatible with them. >> >> I just changed the boot options name, but keep the function no change. I added >> all related maintainers/supporters in the "to=" list, maybe we can disuss this. > > Changing the name _IS_ the problem. Think about unattended updates. > >> Should I add some "obsoleted" warnings for old options and keep them for a while? > > No, just keep the old options around for backwards compatibilty sake. We > just do not add new arch specific options in the future. New options need > to use the generic iommu.dma_mode name space. OK, thanks for your advise. > > Thanks, > > tglx > > . > -- Thanks! BestRegards