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=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 E2269C43381 for ; Tue, 26 Mar 2019 00:04:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A9D452080F for ; Tue, 26 Mar 2019 00:04:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553558656; bh=oAf2+dYR0feGej2eMzzvA/IR3p+qHjuUXRD8A92zkIc=; h=Subject:To:Cc:References:From:Date:In-Reply-To:List-ID:From; b=xzjuARGGBnF5qsUkEb1/jU3DVbh7ruhpEF+YhTXeI/DKGhe2V1BzAw4SvZEf8bviX t4zosoHdenoqApOc3jyjoRut1VJz2TkhBsWAzvMSVHr+QpKfYU298sYjJbPqKL9R2D mKxgXm/87EW0UC/EExQoxALQOC8BV4CEn3mdl4S8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729681AbfCZAEP (ORCPT ); Mon, 25 Mar 2019 20:04:15 -0400 Received: from mail.kernel.org ([198.145.29.99]:56266 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726553AbfCZAEO (ORCPT ); Mon, 25 Mar 2019 20:04:14 -0400 Received: from [192.168.1.112] (c-24-9-64-241.hsd1.co.comcast.net [24.9.64.241]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A11482080F; Tue, 26 Mar 2019 00:04:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553558654; bh=oAf2+dYR0feGej2eMzzvA/IR3p+qHjuUXRD8A92zkIc=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=dUe1XSuOZoUCT5ecb+hWErMNV/jHHIRQInc/LtzC+ZHc7EqSm0cMflzrMLtWglzBB qTL5udwlgjvcFDuGGzWuSbtABKT2VphFxPG1wvCQqFJSVaP7BtMy62Rjl6l1afh4CP OVYl+ZAXrKPOBygLzqDURBq0TktqcRsveumMnoEk= Subject: Re: [PATCH] tools: usb: usbip: adding support for older kernel versions To: Brian Norris Cc: David Valleau , LKML , Linux USB Mailing List , Michael Grzeschik , Valentina Manea , Greg Kroah-Hartman , Sasha Levin , shuah References: <20190306214730.6545-1-valleau@chromium.org> <44e151af-b6c4-d0af-3ef1-a5632d079915@kernel.org> <23918a77-2694-fdae-4300-0882c7c940cf@kernel.org> From: shuah Message-ID: <759fcefa-974b-7430-e7cf-64eabd219d61@kernel.org> Date: Mon, 25 Mar 2019 18:04:12 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/25/19 5:02 PM, Brian Norris wrote: > On Mon, Mar 25, 2019 at 3:07 PM shuah wrote: >> On 3/25/19 11:56 AM, Brian Norris wrote: >>> On Mon, Mar 25, 2019 at 8:51 AM shuah wrote: >>>> In general the ABI is stable. >>> >>> No, it really isn't. This commit was a breaking change: > ... >>> But this one is definitely a break: >>> >>> commit 1c9de5bf428612458427943b724bea51abde520a >>> Author: Yuyang Du >>> Date: Thu Jun 8 13:04:10 2017 +0800 >>> >>> usbip: vhci-hcd: Add USB3 SuperSpeed support >>> >>> You can't just arbitrarily add columns to the beginning of a file like >>> that and claim that you're not breaking ABI. And I shouldn't need to >>> remind you that Thou Shalt Not Break User Space. >> >> USB 3.0 driver and tool support went in, I would say it was oversight to >> not make sure the tool continues to work on older kernels. > > While that's true, you're still not grokking my main point when asking > about ABI stability: > > *old* tools should still work on *new* kernels > > The above commit broke that. > Agreed. Let's move forward with the assumption that this won't happen in the future. On a side note, in this specific tool case, the newer version is more secure than the older version. thanks, -- Shuah