From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762809AbcALPfl (ORCPT ); Tue, 12 Jan 2016 10:35:41 -0500 Received: from www62.your-server.de ([213.133.104.62]:38135 "EHLO www62.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752530AbcALPfj (ORCPT ); Tue, 12 Jan 2016 10:35:39 -0500 Message-ID: <56951D49.5020800@iogearbox.net> Date: Tue, 12 Jan 2016 16:35:37 +0100 From: Daniel Borkmann User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 MIME-Version: 1.0 To: Lubomir Rintel CC: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, "David S. Miller" , Jamal Hadi Salim Subject: Re: [PATCH 1/3] ifb: make device count build-time configurable References: <1452599804-27284-1-git-send-email-lkundrak@v3.sk> <5695199E.2040303@iogearbox.net> In-Reply-To: <5695199E.2040303@iogearbox.net> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Authenticated-Sender: daniel@iogearbox.net Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/12/2016 04:19 PM, Daniel Borkmann wrote: > On 01/12/2016 12:56 PM, Lubomir Rintel wrote: >> The devices can be created at run-time for quite some time already and the >> load-time device creation collides with attempts to create the device of >> the same name: >> >> # rmmod ifb >> # ip link add ifb0 type ifb >> RTNETLINK answers: File exists >> >> This is pretty much the same situation as was with the block loop devices >> which was solved by adding a build-time configuration that the >> distributions could use as they deem fit while keeping the default for >> compatibility. >> >> Let's do that here as well. > > Thanks for the set in general, good to see it fixed! > >> Signed-off-by: Lubomir Rintel >> --- > [...] >> +config IFB_COUNT >> + int "Number of ifb devices to pre-create at init time" >> + depends on IFB >> + default 3 > > Should that not be 2? > >> + help >> + Static number of ifb devices to be unconditionally pre-created >> + at init time. >> + >> + This default value can be overwritten on the kernel command >> + line or with module-parameter ifb.numifbs. >> + >> + The historic default is 3. If a mid-2007 version of iproute2 >> + is used (v2.6.23 or later), it can be set to 0, since needed >> + ifb devices can be dynamically allocated via rtnetlink. > > [...] >> -static int numifbs = 2; > ^^^^^^^^^^^^ >> +static int numifbs = CONFIG_IFB_COUNT; >> module_param(numifbs, int, 0); >> MODULE_PARM_DESC(numifbs, "Number of ifb devices"); Btw, perhaps there should also be a pr_info() or the like to warn the user that relying on modprobe creating these devs is deprecated and scheduled for removal in future, so they should switch to ip link instead ...