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 696B0ECAAD8 for ; Wed, 21 Sep 2022 07:36:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229535AbiIUHgC (ORCPT ); Wed, 21 Sep 2022 03:36:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56930 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229764AbiIUHgB (ORCPT ); Wed, 21 Sep 2022 03:36:01 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 16ED983BD4 for ; Wed, 21 Sep 2022 00:36:01 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id A364262F92 for ; Wed, 21 Sep 2022 07:36:00 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 78F20C433D7; Wed, 21 Sep 2022 07:35:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1663745760; bh=7qve/Pa4mSoh4l/jO/2p/CCRRvU3Px/ZW9nT44guToM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=GU7ZvAWPSPbnEr5Kg87dgb/161EGGrRDlbjtv0fSri2+dJEO+liuVVHao3GI+xYcl Ub5WyY/rJTh3+vaN4KnFQmdSY7Nd48g9GSApjkEZwtLp17Z+8Rl9iMFFGFuELOwjoD QhRQuVzQVowchO56p93dD6xIS8UFtAIx4B+DMEXXkH0kaE2u8RGNtdsi/GcQzBuW8k gDckgJR+P0Ys9qBSSKoqr6lFHQVZL4FjHQUf/6wx8azHyQotdQAEchsQXhDrxHOovD uROtB+03QdbB7mHzHcLQVG0j4cXnZQE50A9y6m2NKK43uSQbFakeO/56RPvDppthSI jAyS8lFliZSJQ== Date: Wed, 21 Sep 2022 10:35:55 +0300 From: Leon Romanovsky To: Cheng Xu Cc: jgg@ziepe.ca, linux-rdma@vger.kernel.org, KaiShen@linux.alibaba.com Subject: Re: [PATCH for-next 4/4] RDMA/erdma: Support dynamic mtu Message-ID: References: <20220909093822.33868-1-chengyou@linux.alibaba.com> <20220909093822.33868-5-chengyou@linux.alibaba.com> <4f2425e1-4326-c337-5bc5-06400a6cce62@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4f2425e1-4326-c337-5bc5-06400a6cce62@linux.alibaba.com> Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Wed, Sep 21, 2022 at 10:28:57AM +0800, Cheng Xu wrote: > > > 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. I'm not big fan of such answers, but ok, applied. > > Thanks, > Cheng Xu > >