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=-2.3 required=3.0 tests=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 ECC41C47404 for ; Wed, 2 Oct 2019 21:15:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C1CC121783 for ; Wed, 2 Oct 2019 21:15:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729429AbfJBVPt (ORCPT ); Wed, 2 Oct 2019 17:15:49 -0400 Received: from mga09.intel.com ([134.134.136.24]:23553 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728981AbfJBVPt (ORCPT ); Wed, 2 Oct 2019 17:15:49 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 02 Oct 2019 14:15:49 -0700 X-IronPort-AV: E=Sophos;i="5.67,249,1566889200"; d="scan'208";a="185680165" Received: from ddalessa-mobl.amr.corp.intel.com (HELO [10.254.204.65]) ([10.254.204.65]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/AES256-SHA; 02 Oct 2019 14:15:47 -0700 Subject: Re: [RFC 20/20] RDMA/i40iw: Mark i40iw as deprecated To: Leon Romanovsky , Doug Ledford Cc: "gregkh@linuxfoundation.org" , "Saleem, Shiraz" , "Kirsher, Jeffrey T" , "jgg@mellanox.com" , "netdev@vger.kernel.org" , "linux-rdma@vger.kernel.org" References: <20190926164519.10471-1-jeffrey.t.kirsher@intel.com> <20190926164519.10471-21-jeffrey.t.kirsher@intel.com> <20190926174009.GD14368@unreal> <9DD61F30A802C4429A01CA4200E302A7AC702BDA@fmsmsx123.amr.corp.intel.com> <20190926195517.GA1743170@kroah.com> <20190928055511.GI14368@unreal> From: Dennis Dalessandro Message-ID: <64752160-e8cc-5dcd-d0f9-f26f81057324@intel.com> Date: Wed, 2 Oct 2019 17:15:45 -0400 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <20190928055511.GI14368@unreal> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 9/28/2019 1:55 AM, Leon Romanovsky wrote: > On Fri, Sep 27, 2019 at 04:17:15PM -0400, Doug Ledford wrote: >> On Thu, 2019-09-26 at 21:55 +0200, gregkh@linuxfoundation.org wrote: >>> On Thu, Sep 26, 2019 at 07:49:44PM +0000, Saleem, Shiraz wrote: >>>>> Subject: Re: [RFC 20/20] RDMA/i40iw: Mark i40iw as deprecated >>>>> >>>>> On Thu, Sep 26, 2019 at 09:45:19AM -0700, Jeff Kirsher wrote: >>>>>> From: Shiraz Saleem >>>>>> >>>>>> Mark i40iw as deprecated/obsolete. >>>>>> >>>>>> irdma is the replacement driver that supports X722. >>>>> >>>>> Can you simply delete old one and add MODULE_ALIAS() in new >>>>> driver? >>>>> >>>> >>>> Yes, but we thought typically driver has to be deprecated for a few >>>> cycles before removing it. >>> >>> If you completely replace it with something that works the same, why >>> keep the old one around at all? >>> >>> Unless you don't trust your new code? :) >> >> I have yet to see, in over 20 years of kernel experience, a new driver >> replace an old driver and not initially be more buggy and troublesome >> than the old driver. It takes time and real world usage for the final >> issues to get sorted out. During that time, the fallback is often >> necessary for those real world users. > > How many real users exist in RDMA world who run pure upstream kernel? I doubt too many especially the latest bleeding edge upstream kernel. That could be interesting, but I don't think it's the reality. Distro kernels could certainly still keep the old driver, and that makes a lot of sense. -Denny