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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 74293C433ED for ; Mon, 10 May 2021 19:07:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 470E36145C for ; Mon, 10 May 2021 19:07:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231766AbhEJTIE (ORCPT ); Mon, 10 May 2021 15:08:04 -0400 Received: from blyat.fensystems.co.uk ([54.246.183.96]:33938 "EHLO blyat.fensystems.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231258AbhEJTID (ORCPT ); Mon, 10 May 2021 15:08:03 -0400 Received: from dolphin.home (unknown [IPv6:2a00:23c6:5495:5e00:72b3:d5ff:feb1:e101]) by blyat.fensystems.co.uk (Postfix) with ESMTPSA id CBAA7442C4; Mon, 10 May 2021 19:06:55 +0000 (UTC) Subject: Re: [PATCH] xen-netback: Check for hotplug-status existence before watching To: =?UTF-8?Q?Marek_Marczykowski-G=c3=b3recki?= Cc: paul@xen.org, xen-devel@lists.xenproject.org, netdev@vger.kernel.org, wei.liu@kernel.org, pdurrant@amazon.com References: <54659eec-e315-5dc5-1578-d91633a80077@xen.org> <20210413152512.903750-1-mbrown@fensystems.co.uk> <404130e4-210d-2214-47a8-833c0463d997@fensystems.co.uk> From: Michael Brown Message-ID: <21f38a92-c8ae-12a7-f1d8-50810c5eb088@fensystems.co.uk> Date: Mon, 10 May 2021 20:06:55 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 10/05/2021 19:53, Marek Marczykowski-Górecki wrote: > On Mon, May 10, 2021 at 07:47:01PM +0100, Michael Brown wrote: >> That doesn't sound plausible to me. In the setup as you describe, how is >> the kernel expected to differentiate between "hotplug script has not yet >> created the node" and "hotplug script does not exist and will therefore >> never create any node"? > > Is the later valid at all? From what I can see in the toolstack, it > always sets some hotplug script (if not specified explicitly - then > "vif-bridge"), I don't see any definitive documentation around that so I can't answer for sure. It's probably best to let one of the Xen guys answer that. If you have a suggested patch, I'm happy to test that it doesn't reintroduce the regression bug that was fixed by this commit. Michael