From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: Please revert removal of /sys/class/net/*/features Date: Tue, 10 Apr 2012 13:46:33 -0700 Message-ID: <20120410134633.4456a1b0@nehalam.linuxnetplumber.net> References: <20120410110851.5690739c@nehalam.linuxnetplumber.net> <20120410195956.GA28447@rere.qmqm.pl> <1334089547.2624.4.camel@bwh-desktop.uk.solarflarecom.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: =?UTF-8?B?TWljaGHFgiBNaXJvc8WCYXc=?= , David Miller , To: Ben Hutchings Return-path: Received: from mail.vyatta.com ([76.74.103.46]:35376 "EHLO mail.vyatta.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753595Ab2DJUqg convert rfc822-to-8bit (ORCPT ); Tue, 10 Apr 2012 16:46:36 -0400 In-Reply-To: <1334089547.2624.4.camel@bwh-desktop.uk.solarflarecom.com> Sender: netdev-owner@vger.kernel.org List-ID: On Tue, 10 Apr 2012 21:25:47 +0100 Ben Hutchings wrote: > On Tue, 2012-04-10 at 21:59 +0200, Micha=C5=82 Miros=C5=82aw wrote: > > On Tue, Apr 10, 2012 at 11:08:51AM -0700, Stephen Hemminger wrote: > > > This commit needs to be reverted. It removed an available sysfs f= ile, and sysfs > > > files are part of the ABI. It caused a bug in our current release= of Vyatta because > > > the shell script was using the sysfs file to see if VLAN was supp= orted on a device. > > >=20 > > > An API maybe redundant, but you can't just remove it. > >=20 > > There was a discussion about it before the patch was accepted. It w= as > > concluded that due to features flags changes, the /sys/class/net/*/= features > > was never a stable API. >=20 > For reference: > http://thread.gmane.org/gmane.linux.network/199115/focus=3D199136 >=20 > But note that the VLAN-related feature flags never actually changed > value. >=20 > Ben. >=20 It is actually not a big deal for our product since 3.3 is really early in development cycle and the script can be fixed in that release. Also, we release an image with utilities, scripts and kernel in one release, and don't have to support running new kernels wi= th older userspace. I am more worried that other people might be hit=20 the same thing. What about a patch to keep the old flags values available for backwards compatiablity. Also, when removing a sysfs file, shouldn't the documented feature removal process be used?