From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4DC8FC433FF for ; Wed, 14 Aug 2019 08:01:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3070D205C9 for ; Wed, 14 Aug 2019 08:01:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726466AbfHNIBp (ORCPT ); Wed, 14 Aug 2019 04:01:45 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57874 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725928AbfHNIBo (ORCPT ); Wed, 14 Aug 2019 04:01:44 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 8CF023001839; Wed, 14 Aug 2019 08:01:44 +0000 (UTC) Received: from gondolin (dhcp-192-232.str.redhat.com [10.33.192.232]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3E88E808D0; Wed, 14 Aug 2019 08:01:38 +0000 (UTC) Date: Wed, 14 Aug 2019 10:01:35 +0200 From: Cornelia Huck To: Parav Pandit Cc: Alex Williamson , Kirti Wankhede , "kvm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "cjia@nvidia.com" Subject: Re: [PATCH v2 0/2] Simplify mtty driver and mdev core Message-ID: <20190814100135.1f60aa42.cohuck@redhat.com> In-Reply-To: References: <20190802065905.45239-1-parav@mellanox.com> <20190808141255.45236-1-parav@mellanox.com> <20190808170247.1fc2c4c4@x1.home> <77ffb1f8-e050-fdf5-e306-0a81614f7a88@nvidia.com> <20190813085246.1d642ae5@x1.home> <20190813111149.027c6a3c@x1.home> Organization: Red Hat GmbH MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.40]); Wed, 14 Aug 2019 08:01:44 +0000 (UTC) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Wed, 14 Aug 2019 05:54:36 +0000 Parav Pandit wrote: > > > I get that part. I prefer to remove the UUID itself from the structure > > > and therefore removing this API makes lot more sense? > > > > Mdev and support tools around mdev are based on UUIDs because it's defined > > in the documentation. > When we introduce newer device naming scheme, it will update the documentation also. > May be that is the time to move to .rst format too. You are aware that there are existing tools that expect a uuid naming scheme, right? > > > I don't think it's as simple as saying "voila, UUID > > dependencies are removed, users are free to use arbitrary strings". We'd need > > to create some kind of naming policy, what characters are allows so that we > > can potentially expand the creation parameters as has been proposed a couple > > times, how do we deal with collisions and races, and why should we make such > > a change when a UUID is a perfectly reasonable devices name. Thanks, > > > Sure, we should define a policy on device naming to be more relaxed. > We have enough examples in-kernel. > Few that I am aware of are netdev (vxlan, macvlan, ipvlan, lot more), rdma etc which has arbitrary device names and ID based device names. > > Collisions and race is already taken care today in the mdev core. Same unique device names continue. I'm still completely missing a rationale _why_ uuids are supposedly bad/restricting/etc. We want to uniquely identify a device, across different types of vendor drivers. An uuid is a unique identifier and even a well-defined one. Tools (e.g. mdevctl) are relying on it for mdev devices today. What is the problem you're trying to solve?