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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7F876C54EE9 for ; Wed, 21 Sep 2022 02:29:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229791AbiIUC3E (ORCPT ); Tue, 20 Sep 2022 22:29:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48934 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229518AbiIUC3D (ORCPT ); Tue, 20 Sep 2022 22:29:03 -0400 Received: from out30-56.freemail.mail.aliyun.com (out30-56.freemail.mail.aliyun.com [115.124.30.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B10F840BE0 for ; Tue, 20 Sep 2022 19:29:01 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R111e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046049;MF=chengyou@linux.alibaba.com;NM=1;PH=DS;RN=4;SR=0;TI=SMTPD_---0VQLob7P_1663727338; Received: from 30.221.97.160(mailfrom:chengyou@linux.alibaba.com fp:SMTPD_---0VQLob7P_1663727338) by smtp.aliyun-inc.com; Wed, 21 Sep 2022 10:28:59 +0800 Message-ID: <4f2425e1-4326-c337-5bc5-06400a6cce62@linux.alibaba.com> Date: Wed, 21 Sep 2022 10:28:57 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.2.2 Subject: Re: [PATCH for-next 4/4] RDMA/erdma: Support dynamic mtu To: Leon Romanovsky Cc: jgg@ziepe.ca, linux-rdma@vger.kernel.org, KaiShen@linux.alibaba.com References: <20220909093822.33868-1-chengyou@linux.alibaba.com> <20220909093822.33868-5-chengyou@linux.alibaba.com> Content-Language: en-US From: Cheng Xu In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On 9/20/22 7:32 PM, Leon Romanovsky wrote: > On Fri, Sep 09, 2022 at 05:38:22PM +0800, Cheng Xu wrote: >> Hardware now support jumbo frame for RDMA. So we introduce a new CMDQ >> message to support mtu change notification. >> <...> > > I don't see any backward compatibility here. How can you make sure that > new code that supports MTU change works correctly on old FW/device? > In this case, driver needn't to consider backward compatibility. ERDMA hardware is programmable part of our iaas infrastructure, and can be hot-update without BMs/VMs awareness.Before I submitted this patch, all the FWs has been updated, and support this feature, no old FWs exist. Thanks, Cheng Xu