From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752953AbZEAGpv (ORCPT ); Fri, 1 May 2009 02:45:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752491AbZEAGpm (ORCPT ); Fri, 1 May 2009 02:45:42 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:49043 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751881AbZEAGpl (ORCPT ); Fri, 1 May 2009 02:45:41 -0400 Date: Thu, 30 Apr 2009 23:43:12 -0700 From: Andrew Morton To: Greg KH Cc: Kay Sievers , linux-kernel , Jan Blunck Subject: Re: [PATCH] driver-core: devtmpfs - driver core maintained /dev tmpfs Message-Id: <20090430234312.a63fa5cf.akpm@linux-foundation.org> In-Reply-To: <20090501061701.GB19234@kroah.com> References: <1241097822.2516.3.camel@poy> <20090430222900.c13b63d5.akpm@linux-foundation.org> <20090501061701.GB19234@kroah.com> X-Mailer: Sylpheed 2.4.8 (GTK+ 2.12.5; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 30 Apr 2009 23:17:01 -0700 Greg KH wrote: > On Thu, Apr 30, 2009 at 10:29:00PM -0700, Andrew Morton wrote: > > On Thu, 30 Apr 2009 15:23:42 +0200 Kay Sievers wrote: > > > > > From: Kay Sievers > > > Subject: driver-core: devtmpfs - driver core maintained /dev tmpfs > > > > > > Devtmpfs lets the kernel create a tmpfs very early at kernel > > > initialization, before any driver core device is registered. Every > > > device with a major/minor will have a device node created in this > > > tmpfs instance. After the rootfs is mounted by the kernel, the > > > populated tmpfs is mounted at /dev. In initramfs, it can be moved > > > to the manually mounted root filesystem before /sbin/init is > > > executed. > > > > Lol, devfs. > > Well, devfs "done right" with hopefully none of the vfs problems the > last devfs had. :) I think Adam Richter's devfs rewrite (which, iirc, was tmpfs-based) would have fixed up these things. But it was never quite completed and came when minds were already made up. I don't understand why we need devfs2, really. What problems are people having with teh existing design? > > > block/bsg.c | 6 > > > drivers/gpu/drm/drm_sysfs.c | 7 > > > drivers/input/input.c | 6 > > > drivers/media/dvb/dvb-core/dvbdev.c | 10 + > > > drivers/usb/core/usb.c | 11 + > > > > These five subsystems were updated, but there are so many others. Why > > these five in particular? > > These are the ones that create a subdirectory in /dev/ None of the > others do. oic. Where is it determined that these subsystems create /dev subdirectories? udev rules? If so, do we need to henceforth keep devfs2 (sorry, I can't resist) in sync with udev?