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 7A507C433F5 for ; Sat, 2 Apr 2022 00:16:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347701AbiDBASU (ORCPT ); Fri, 1 Apr 2022 20:18:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54588 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236739AbiDBAST (ORCPT ); Fri, 1 Apr 2022 20:18:19 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id A1BFE196D4C for ; Fri, 1 Apr 2022 17:16:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1648858587; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=i42/t7QO2AfQCbRsfmhAccqjWn4hDzL3ieQVQ4rCV/E=; b=LSETxtdpiw9fLNM3UpshqA/n1wRt36W4grV4jKqDTYprCAd3sDjrKwW4FSV9vVqawBn7AZ RRSW1QezzrsoiEt8/d8kpAdtMWN4kxNoLl7EEelxQfy2UnjcB7sJxeQj6G3Gjm38VL3Spx yZjF45AtoK4cUYHWsuUpxhb39Z9oexg= Received: from mail-pf1-f198.google.com (mail-pf1-f198.google.com [209.85.210.198]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-310-cHpVSVNNPmCxdLajE-la7g-1; Fri, 01 Apr 2022 20:16:19 -0400 X-MC-Unique: cHpVSVNNPmCxdLajE-la7g-1 Received: by mail-pf1-f198.google.com with SMTP id 77-20020a621450000000b004fa8868a49eso2408664pfu.3 for ; Fri, 01 Apr 2022 17:16:18 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=i42/t7QO2AfQCbRsfmhAccqjWn4hDzL3ieQVQ4rCV/E=; b=LrEQZRD2PxZty0iW08XxRZ3+eDdBPlbj6AvXx3PbgTWagp/e20bbwN7cPz4++m+PBu +IUanb/cK2C+Ub7EOlYVe7RmvNPjpa/87J4eMUrQSLB/Q74LrBTZ4BcXxFERpF5PNE1k nUVH8hNYRW7dgJScpoPcdiQ7YkpSdim4m0MaHJYamtSoHjpRCOMWg5VlkIeJc8hoccRA 9FTf/isYO1fN9r5dDr2+PGSY4nWkPfia8h8F7nhRb0+O/+EQhy0ozSjSIzH3rmHQmtYT q8qAxNyyi9pRTq/GUc2DtC8ogulfUUJUrgBYie/+/1pBvV4LntXYSvimF/EtCsZeSqY+ DyHg== X-Gm-Message-State: AOAM532xXlDdY/pls5oJSzPv3rS3gnjs/gI7Q6zmOakFzmPh8qIhSxyI dW0mlp1f5QTx3+oELnOw7AtElhuIvJkfsHJTaKO3RHnM0KUNwT77JYoKxUmHVAXubVjikx3VnKf 1T1iNw9EGbchZtBgU X-Received: by 2002:a17:90a:8417:b0:1c7:85c9:96b1 with SMTP id j23-20020a17090a841700b001c785c996b1mr14496412pjn.8.1648858577553; Fri, 01 Apr 2022 17:16:17 -0700 (PDT) X-Google-Smtp-Source: ABdhPJyEkGGJ1rSYTj3/bfXJW1o2ofkgRKeClTRjRz2mSgvBqlVMYYitlU1cXUQGxH36NgIvQkqmhA== X-Received: by 2002:a17:90a:8417:b0:1c7:85c9:96b1 with SMTP id j23-20020a17090a841700b001c785c996b1mr14496389pjn.8.1648858577246; Fri, 01 Apr 2022 17:16:17 -0700 (PDT) Received: from fedora19.localdomain (2403-5804-6c4-aa-7079-8927-5a0f-bb55.ip6.aussiebb.net. [2403:5804:6c4:aa:7079:8927:5a0f:bb55]) by smtp.gmail.com with ESMTPSA id q22-20020a056a00085600b004fb308e393csm4445974pfk.178.2022.04.01.17.16.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 01 Apr 2022 17:16:16 -0700 (PDT) Date: Sat, 2 Apr 2022 11:16:12 +1100 From: Ian Wienand To: Andrew Lunn Cc: netdev@vger.kernel.org, "David S. Miller" Subject: Re: [PATCH] net/ethernet : set default assignment identifier to NET_NAME_ENUM Message-ID: References: <20220401063430.1189533-1-iwienand@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Thanks for review On Fri, Apr 01, 2022 at 03:13:27PM +0200, Andrew Lunn wrote: > On Fri, Apr 01, 2022 at 05:34:30PM +1100, Ian Wienand wrote: > > As noted in the original commit 685343fc3ba6 ("net: add > > name_assign_type netdev attribute") > > > > ... when the kernel has given the interface a name using global > > device enumeration based on order of discovery (ethX, wlanY, etc) > > ... are labelled NET_NAME_ENUM. > > > > That describes this case, so set the default for the devices here to > > NET_NAME_ENUM to better help userspace tools to know if they might > > like to rename them. > Is this potentially an ABI change I don't think this counts as an ABI change; it's a fixed-size flag and designed to be updated with more specific information on a case-by-case basis? > and we will get surprises when > interfaces which were not previously renamed now are? It would be nice > to see some justification this is actually safe to do. I came to this through inconsistency of behaviour in a heterogeneous OpenStack cloud environment. Most of the clouds are kvm-based and have NICS using virtio which fills in /sys/class/net//name_assign_type and this bubbles up through udev/systemd/general magic to get the devices renamed. However we have one outlier using Xen and the xen-netfront driver, which I traced to here, where name_assign_type isn't set. So I think it's a consistency win to have it reporting itself as NET_NAME_ENUM here. Thanks, -i