From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752863AbaINRjV (ORCPT ); Sun, 14 Sep 2014 13:39:21 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:43002 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752750AbaINRjU (ORCPT ); Sun, 14 Sep 2014 13:39:20 -0400 Date: Sun, 14 Sep 2014 10:39:19 -0700 From: Greg KH To: Kirill Tkhai Cc: mmarek@suse.cz, arnd@arndb.de, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, oleg@redhat.com, grant.likely@secretlab.ca, ebiederm@xmission.com, akpm@linux-foundation.org, ktkhai@parallels.com, sam@ravnborg.org Subject: Re: [PATCH 0/3] Implement /proc/built-in file similar to /proc/modules Message-ID: <20140914173919.GA10059@kroah.com> References: <20140914100545.3745.23394.stgit@localhost> <20140914153832.GC4064@kroah.com> <5415D10E.90809@yandex.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5415D10E.90809@yandex.ru> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Sep 14, 2014 at 09:31:58PM +0400, Kirill Tkhai wrote: > On 14.09.2014 19:38, Greg KH wrote: > > On Sun, Sep 14, 2014 at 02:18:13PM +0400, Kirill Tkhai wrote: > >> This series implements a possibility to show the list of built-in drivers > >> to userspace. The names of drivers will be the same as when they are modules. > > > > Have you looked at /sys/modules/ ? Doesn't that show what you want > > here? > > There are only the drivers in "/sys/module" which have parameters. > Drivers without parameters do not appear there. Ah, didn't realize that. Should be easy to fix though, if you really wanted to list the modules. Much better than a random proc file that you have to parse :) > >> So, if your system has "loop" driver then it appears either in /proc/modules > >> or in /proc/built-in and userspace will be able to know about this. > >> > >> Now this is impossible. The only way to get kernel configuration is > >> /proc/config.gz, but CONFIG_* names can change from time to time. Module > >> names are more or less standardized. > > > > Module names aren't "standardized", we change them at times when needed, > > just like CONFIG_ names. > > > > What is your end goal here? As you say, config.gz is the real kernel > > configuration, just having a list of modules built in isn't going to > > help much in getting a working kernel config without it. > > It looks like userspace applications oriented on modules names rather > than on CONFIG_XXX parameters. /proc/config.gz is optional and userspace > applications can't base on it. > > For example, when I compile "loop" module built-in and "loop" is in > /etc/modules, init script warns about this module is not present and > can't be autoloaded. The script does not store CONFIG_XXX <-> module_xxx > conformity. And nobody stores it. > > When iptables wants extra functionality, it requests a module. Etc. > > Nobody is oriented on CONFIG_XXX parameters. It would be simple for > userspace to add a support of /proc/built-in analysing. It's very > similar to /proc/modules. Shouldn't userspace focus on the functionality a module provides, not the module name itself? Can't a test for the loop "module" just test to see if the loop control device is present? Same for iptables (there's modprobe rules for iptable modules I think...) In other words, don't focus on the module names, focus on the userspace function a module provides, there should always be a way to check that at run time (if not, then the module doesn't actually do much...) thanks, greg k-h