From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755442AbbCEMDM (ORCPT ); Thu, 5 Mar 2015 07:03:12 -0500 Received: from mx1.redhat.com ([209.132.183.28]:45204 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755261AbbCEMDJ (ORCPT ); Thu, 5 Mar 2015 07:03:09 -0500 Date: Thu, 5 Mar 2015 13:02:57 +0100 From: Karel Zak To: Sergey Senozhatsky Cc: Minchan Kim , Sergey Senozhatsky , Andrew Morton , Nitin Gupta , linux-kernel@vger.kernel.org, Jerome Marchand Subject: Re: [PATCH 0/2] make automatic device_id generation possible Message-ID: <20150305120257.GX8046@ws.net.home> References: <1425478601-19141-1-git-send-email-sergey.senozhatsky@gmail.com> <20150305001954.GA9563@blaptop> <20150305005829.GC14927@swordfish> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150305005829.GC14927@swordfish> User-Agent: Mutt/1.5.23.1-rc1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 05, 2015 at 09:58:29AM +0900, Sergey Senozhatsky wrote: > Hello, > > On (03/05/15 09:20), Minchan Kim wrote: > > I'm not against but I want to know why we should support > > user-defined device id. What usecase do you have in mind? > > > > hm, you never know what people can come up with. that's probably the > strongest support argument I can provide. I wish there was something > like - my friend Mike has a "device /dev/zram1 is always swap device, > device /dev/zram$(id -u) is a per-user zram device (he finds it useful, I have doubts that promise stable device names is good idea. The usual way is to care about FS/SWAP identifiers (LABEL=, or UUID=), and for example udevd should be able to create a stable /dev/disk/by-* symlinks. So for your friend Mike is better to have UUID= in /etc/fstab and force mkswap or mkfs to use still the same UUID. > user defined id support comes at a price of ~10 lines of code, or even > less. we waste much more code to show ->stats, and not all of them are I think it's not about number of code lines, it's kernel, you have to support it forever, etc. It's easy to add a new feature, but you don't have to do it right now :) Karel -- Karel Zak http://karelzak.blogspot.com