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: <20190326005509.GA32180@kroah.com> Date: Tue, 26 Mar 2019 09:55:09 +0900 To: Brian Norris Cc: shuah , David Valleau , LKML , Linux USB Mailing List , Michael Grzeschik , Valentina Manea , Sasha Levin List-ID: T24gTW9uLCBNYXIgMjUsIDIwMTkgYXQgMDU6NDk6MDdQTSAtMDcwMCwgQnJpYW4gTm9ycmlzIHdy b3RlOgo+ID4gTm90IHRvIHNheSB0aGF0IHRoaXMgc2hvdWxkbid0IGJlIGZpeGVkIGlmIGF0IGFs bCBwb3NzaWJsZSwgYnV0IHJlYWxpemUKPiA+IHRoYXQgdGhpcyBpcyBub3QgdGhlICJub3JtYWwi IGNhc2Ugb2YgIndlIGRvIG5vdCBicmVhayB1c2Vyc3BhY2UiIGhlcmUsCj4gPiBnaXZlbiB0aGUg dG9vbCBpbnZvbHZlZCwgYW5kIHRoZSBhcGlzIGJlaW5nIHVzZWQuCj4gCj4gSSB0aGluayBJIHNv cnQgb2YgdW5kZXJzdGFuZCB3aGF0IHlvdSdyZSBnb2luZyBmb3IgaGVyZSwgYnV0IGNhbiB5b3UK PiBlbGFib3JhdGUgc28gSSBkb24ndCBoYXZlIHRvIGFzc3VtZT8KClRvIGJlIHNwZWNpZmljLCB0 b29scyBhdCB0aGUgInZlcnkgbG93IGxldmVsIiB0aGF0IGFyZSB1c2VkIHRvIGNvbmZpZ3VyZQp0 aGUga2VybmVsIGZvciB1c2Vyc3BhY2UsIG9yIHRvIGludGVyYWN0IHdpdGggdGhlIGtlcm5lbCBz dWNoIHRoYXQgb3RoZXIKcHJvZ3JhbXMgd29yayBvbiB0b3Agb2YgdGhpbmdzIHByb3Blcmx5IChs aWtlIHVkZXYpLCB3ZSBoYXZlIGJyb2tlbiBhcGlzCnN1Y2ggdGhhdCB3ZSBjYW4gZml4IGlzc3Vl cyB3aXRoIG9sZCBtaXN0YWtlcyBhbmQgbW92ZSBvbiB0byBtb3JlIHNlY3VyZQpvciAiY29ycmVj dCIgYXBpcy4KClNvIHdlIGRvIGNoYW5nZSB0aGluZ3MgYXQgdGhpcyBsYXllciBhdCB0aW1lcywg YW5kIG5vcm1hbGx5IG5vIG9uZQpub3RpY2VzIGFzIHRoZXkgaGF2ZSBtb3ZlZCBvbiB0byBuZXdl ciB1c2Vyc3BhY2UgcHJvZ3JhbXMgaW4gdGhlIHBhc3QgMwp5ZWFycy4gIFNvbWV0aW1lcyB3ZSBk byBrZWVwIGtlcm5lbCBzdXBwb3J0IGZvciByZWFsbHkgb2xkIHVzZXJzcGFjZQpzeXN0ZW1zLCB1 bnRpbCB0aGV5IGRpZSBvdXQsIGFuZCB0aGVuIHdlIGNhbiBmaW5hbGx5IGRyb3AgdGhlIGtlcm5l bApjb2RlLiAgQWdhaW4sIHVkZXYgaGFzIGRvbmUgdGhpcyBvdmVyIHRoZSB5ZWFycyBhcyB3ZSB3 b3JrZWQgdG8gZmlndXJlCm91dCBhIHNhbmUgd2F5IHRvIGhhbmRsZSBzdHVmZi4gIFdlIGhhdmUg cm9sbGVkIGJhY2sga2VybmVsIGNoYW5nZXMKdW50aWwgcGVvcGxlIGZpbmFsbHkga2lsbGVkIHRo ZWlyIG9sZCBGZWRvcmEgMyBwcGMzMiBzeXN0ZW1zIGZvcgpleGFtcGxlIDopCgpUbyBiZSBob25l c3QsIHdpdGggdGhlIFVTQjMgc3VwcG9ydCBhZGRlZCB0byB1c2JpcCwgbm8gb25lIG5vdGljZWQg dGhhdAp0aGluZ3MgYnJva2UsIGFuZCB0aGUgZmFjdCB0aGF0IGl0IHRvb2sgNCB5ZWFycyB0byBu b3RpY2UgaW1wbGllcyB0aGF0Cm1heWJlIGl0IHdhc24ndCB0aGF0IGJpZyBvZiBhIGRlYWwgYXMg bm8gb25lIHVzZWQgdGhpcy4gIEJ1dCwgYXMgeW91CnNob3csIHRoYXQgYXNzdW1wdGlvbiB3YXMg bm90IGNvcnJlY3QsIHNvIGlmIHdlIGNhbiBmaXggdGhpbmdzLCB3ZQpzaG91bGQuCgpEaWQgdGhh dCBoZWxwPwoKdGhhbmtzLAoKZ3JlZyBrLWgK 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,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 E98AFC43381 for ; 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Tue, 26 Mar 2019 00:55:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553561721; bh=YHd0EllFEA3WjOjR4Io1FeKzCEZ/Yp9iijFAELuKM4w=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ybpkX2jBwDrR8PKRCzP+LHXdm0IYMrsZHqdRs6FYH/bmc1lZF1cZLN2IIwnU8p2Ac Em2nNXA368LnwMh0I424Gvo/Van+2FIZBDUGsHTq0tgQAuf1OPn8XPzyOhb92yeT3z FoZ92ahSLa+LG4hID8XX76hztf3vZ1bgeWW39wLU= Date: Tue, 26 Mar 2019 09:55:09 +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: <20190326005509.GA32180@kroah.com> References: <20190306214730.6545-1-valleau@chromium.org> <44e151af-b6c4-d0af-3ef1-a5632d079915@kernel.org> <23918a77-2694-fdae-4300-0882c7c940cf@kernel.org> <20190326001353.GA4315@kroah.com> 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 05:49:07PM -0700, Brian Norris wrote: > > 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. > > I think I sort of understand what you're going for here, but can you > elaborate so I don't have to assume? To be specific, tools at the "very low level" that are used to configure the kernel for userspace, or to interact with the kernel such that other programs work on top of things properly (like udev), we have broken apis such that we can fix issues with old mistakes and move on to more secure or "correct" apis. So we do change things at this layer at times, and normally no one notices as they have moved on to newer userspace programs in the past 3 years. Sometimes we do keep kernel support for really old userspace systems, until they die out, and then we can finally drop the kernel code. Again, udev has done this over the years as we worked to figure out a sane way to handle stuff. We have rolled back kernel changes until people finally killed their old Fedora 3 ppc32 systems for example :) To be honest, with the USB3 support added to usbip, no one noticed that things broke, and the fact that it took 4 years to notice implies that maybe it wasn't that big of a deal as no one used this. But, as you show, that assumption was not correct, so if we can fix things, we should. Did that help? thanks, greg k-h