From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Subject: tools: usb: usbip: adding support for older kernel versions From: Greg Kroah-Hartman Message-Id: <20190326001353.GA4315@kroah.com> Date: Tue, 26 Mar 2019 09:13:53 +0900 To: Brian Norris Cc: shuah , David Valleau , LKML , Linux USB Mailing List , Michael Grzeschik , Valentina Manea , Sasha Levin List-ID: T24gTW9uLCBNYXIgMjUsIDIwMTkgYXQgMDQ6MDI6MzBQTSAtMDcwMCwgQnJpYW4gTm9ycmlzIHdy b3RlOgo+IE9uIE1vbiwgTWFyIDI1LCAyMDE5IGF0IDM6MDcgUE0gc2h1YWggPHNodWFoQGtlcm5l bC5vcmc+IHdyb3RlOgo+ID4gT24gMy8yNS8xOSAxMTo1NiBBTSwgQnJpYW4gTm9ycmlzIHdyb3Rl Ogo+ID4gPiBPbiBNb24sIE1hciAyNSwgMjAxOSBhdCA4OjUxIEFNIHNodWFoIDxzaHVhaEBrZXJu ZWwub3JnPiB3cm90ZToKPiA+ID4+IEluIGdlbmVyYWwgdGhlIEFCSSBpcyBzdGFibGUuCj4gPiA+ Cj4gPiA+IE5vLCBpdCByZWFsbHkgaXNuJ3QuIFRoaXMgY29tbWl0IHdhcyBhIGJyZWFraW5nIGNo YW5nZToKPiAuLi4KPiA+ID4gQnV0IHRoaXMgb25lIGlzIGRlZmluaXRlbHkgYSBicmVhazoKPiA+ ID4KPiA+ID4gY29tbWl0IDFjOWRlNWJmNDI4NjEyNDU4NDI3OTQzYjcyNGJlYTUxYWJkZTUyMGEK PiA+ID4gQXV0aG9yOiBZdXlhbmcgRHUgPHl1eWFuZy5kdUBpbnRlbC5jb20+Cj4gPiA+IERhdGU6 IFRodSBKdW4gOCAxMzowNDoxMCAyMDE3ICswODAwCj4gPiA+Cj4gPiA+ICAgIHVzYmlwOiB2aGNp LWhjZDogQWRkIFVTQjMgU3VwZXJTcGVlZCBzdXBwb3J0Cj4gPiA+Cj4gPiA+IFlvdSBjYW4ndCBq dXN0IGFyYml0cmFyaWx5IGFkZCBjb2x1bW5zIHRvIHRoZSBiZWdpbm5pbmcgb2YgYSBmaWxlIGxp a2UKPiA+ID4gdGhhdCBhbmQgY2xhaW0gdGhhdCB5b3UncmUgbm90IGJyZWFraW5nIEFCSS4gQW5k IEkgc2hvdWxkbid0IG5lZWQgdG8KPiA+ID4gcmVtaW5kIHlvdSB0aGF0IFRob3UgU2hhbHQgTm90 IEJyZWFrIFVzZXIgU3BhY2UuCj4gPgo+ID4gVVNCIDMuMCBkcml2ZXIgYW5kIHRvb2wgc3VwcG9y dCB3ZW50IGluLCBJIHdvdWxkIHNheSBpdCB3YXMgb3ZlcnNpZ2h0IHRvCj4gPiBub3QgbWFrZSBz dXJlIHRoZSB0b29sIGNvbnRpbnVlcyB0byB3b3JrIG9uIG9sZGVyIGtlcm5lbHMuCj4gCj4gV2hp bGUgdGhhdCdzIHRydWUsIHlvdSdyZSBzdGlsbCBub3QgZ3Jva2tpbmcgbXkgbWFpbiBwb2ludCB3 aGVuIGFza2luZwo+IGFib3V0IEFCSSBzdGFiaWxpdHk6Cj4gCj4gICAqb2xkKiB0b29scyBzaG91 bGQgc3RpbGwgd29yayBvbiAqbmV3KiBrZXJuZWxzCgpGb3Igc29tZSBkZWZpbnRpb24gb2YgIm9s ZCIgYW5kICJuZXciIDopCgpXZSBkbyBicmVhayBsb3dlci1sZXZlbCBhcGlzIGxpa2UgdGhpcyBh dCB0aW1lcywgZm9yIHdoZW4gaXQgbWFrZXMKc2Vuc2UsIGFuZCBmb3Igd2hlbiB0aGUgIm9sZCIg a2VybmVsIGlzIGp1c3QgdG9vIG9sZCAoYW5kIHdoZW4geW91IGNhbgpqdXN0IHJ1biB0aGUgdG9v bCB0aGF0IGNhbWUgd2l0aCB0aGF0IGtlcm5lbCkuCgozLjE4IHdhcyByZWxlYXNlZCBhdCB0aGUg ZW5kIG9mIDIwMTQsIGFuZCBhcyB0aGUgdG9vbCB0aGF0IGNhbWUgd2l0aAp0aGF0IGtlcm5lbCBz dGlsbCB3b3JrcyBqdXN0IGZpbmUsIHlvdSBhcmUganVzdCBwdXNoaW5nIHRoZSBib3VuZHJ5IGhl cmUKcmVhbGx5IGhhcmQgOikKCldoeSBkbyB5b3Ugd2FudCB0byB1cGRhdGUgeW91ciB1c2Vyc3Bh Y2UgdG9vbCBhbmQgbm90IHVwZGF0ZSB5b3VyCmtlcm5lbD8gIFdoYXQgaXMgZm9yY2luZyB5b3Vy IHVzZXJzcGFjZSB0b29sIHRvIGJlIHVwZGF0ZWQ/CgpOb3QgdG8gc2F5IHRoYXQgdGhpcyBzaG91 bGRuJ3QgYmUgZml4ZWQgaWYgYXQgYWxsIHBvc3NpYmxlLCBidXQgcmVhbGl6ZQp0aGF0IHRoaXMg aXMgbm90IHRoZSAibm9ybWFsIiBjYXNlIG9mICJ3ZSBkbyBub3QgYnJlYWsgdXNlcnNwYWNlIiBo ZXJlLApnaXZlbiB0aGUgdG9vbCBpbnZvbHZlZCwgYW5kIHRoZSBhcGlzIGJlaW5nIHVzZWQuCgp0 aGFua3MsCgpncmVnIGstaAo= 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=-2.5 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT 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 25B49C43381 for ; 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Tue, 26 Mar 2019 00:34:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553560501; bh=Ik6pN7fErD8VDFwrY6fD1Eh44qIUCNBjeT1GwChEzyI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=UV22yiTDG/MpmTyvq5Ozo6lpc4xi3hx7Tp6VO8vB+U5QvlyFMOEE9b+M75axkguNn VwGLDVWbU/DFwFGmwQJ7HSLx/geEZKin0Kp0MNgN3U6yjK7mi8HGdHp3uGrBfS2P00 R9zNaLT3iDnRHTzWXfTbLGpHaHNVnrCeDDb6vwwQ= Date: Tue, 26 Mar 2019 09:13:53 +0900 From: Greg Kroah-Hartman To: Brian Norris Cc: shuah , David Valleau , LKML , Linux USB Mailing List , Michael Grzeschik , Valentina Manea , Sasha Levin Subject: Re: [PATCH] tools: usb: usbip: adding support for older kernel versions Message-ID: <20190326001353.GA4315@kroah.com> References: <20190306214730.6545-1-valleau@chromium.org> <44e151af-b6c4-d0af-3ef1-a5632d079915@kernel.org> <23918a77-2694-fdae-4300-0882c7c940cf@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.4 (2019-03-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 25, 2019 at 04:02:30PM -0700, 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 For some defintion of "old" and "new" :) We do break lower-level apis like this at times, for when it makes sense, and for when the "old" kernel is just too old (and when you can just run the tool that came with that kernel). 3.18 was released at the end of 2014, and as the tool that came with that kernel still works just fine, you are just pushing the boundry here really hard :) Why do you want to update your userspace tool and not update your kernel? What is forcing your userspace tool to be updated? Not to say that this shouldn't be fixed if at all possible, but realize that this is not the "normal" case of "we do not break userspace" here, given the tool involved, and the apis being used. thanks, greg k-h