From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932251AbWGZQue (ORCPT ); Wed, 26 Jul 2006 12:50:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932190AbWGZQue (ORCPT ); Wed, 26 Jul 2006 12:50:34 -0400 Received: from ns.suse.de ([195.135.220.2]:36074 "EHLO mx1.suse.de") by vger.kernel.org with ESMTP id S932251AbWGZQud (ORCPT ); Wed, 26 Jul 2006 12:50:33 -0400 Date: Wed, 26 Jul 2006 09:46:20 -0700 From: Greg KH To: Matthew Wilcox Cc: Greg KH , Stefan Richter , linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH] Multi-threaded device probing Message-ID: <20060726164620.GF9871@suse.de> References: <20060725203028.GA1270@kroah.com> <44C6B881.7030901@s5r6.in-berlin.de> <20060726073132.GE6249@suse.de> <20060726112948.GA13490@parisc-linux.org> <20060726161647.GA9675@kroah.com> <20060726164235.GH22822@parisc-linux.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060726164235.GH22822@parisc-linux.org> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 26, 2006 at 10:42:36AM -0600, Matthew Wilcox wrote: > On Wed, Jul 26, 2006 at 09:16:47AM -0700, Greg KH wrote: > > > I still think we need a method of renaming block devices, but haven't > > > looked into it in enough detail yet. > > > > That could get "interesting"... > > > > But now that we all are using /dev/disk/ and it has persistant device > > names for block devices, I really don't think it's that big of a deal. > > Actually, that's exactly why it's a big deal. The kernel spits out > messages like: > > printk(KERN_DEBUG "%s: Mode Sense: %02x %02x %02x %02x\n", > diskname, buffer[0], buffer[1], buffer[2], buffer[3]); > > where diskname is something like sda. Now the user has to figure out > what sda means in terms of /dev/disk/ and in terms of scsi h:c:t:l and > in terms of which sticky label is on which drive. If we let userspace > change the gendev's disk_name, that printk can be meaningful to the user > in at least one of those senses. No, this comes up all the time. Userspace has at least 3 different mappings to /dev/sda in /dev/disk right now. Which one do you want the kernel to use?: $ tree /dev/disk/ | grep sda1 | |-- scsi-SATA_Maxtor_7L250S0_L59FRPQH_L59FRPQH-part1 -> ../../sda1 | |-- boot -> ../../sda1 `-- 9c0ef40c-6de9-46f6-ac79-32296c667cf1 -> ../../sda1 Userspace should be doing the reverse mapping if it wants to, the kernel should not care about this at all. thanks, greg k-h