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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CBABEC433EF for ; Sun, 12 Jun 2022 16:23:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229952AbiFLQXL (ORCPT ); Sun, 12 Jun 2022 12:23:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47190 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229554AbiFLQXK (ORCPT ); Sun, 12 Jun 2022 12:23:10 -0400 Received: from mail.enpas.org (zhong.enpas.org [46.38.239.100]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 92AB3579B6; Sun, 12 Jun 2022 09:23:09 -0700 (PDT) Received: from [127.0.0.1] (localhost [127.0.0.1]) by mail.enpas.org (Postfix) with ESMTPSA id EAF23FF9E2; Sun, 12 Jun 2022 16:23:07 +0000 (UTC) Date: Sun, 12 Jun 2022 18:23:02 +0200 From: Max Staudt To: Dario Binacchi Cc: Oliver Hartkopp , linux-kernel@vger.kernel.org, Amarula patchwork , michael@amarulasolutions.com, "David S. Miller" , Eric Dumazet , Jakub Kicinski , Marc Kleine-Budde , Paolo Abeni , Wolfgang Grandegger , linux-can@vger.kernel.org, netdev@vger.kernel.org Subject: Re: [PATCH v2 05/13] can: slcan: simplify the device de-allocation Message-ID: <20220612182302.36bdd9b9.max@enpas.org> In-Reply-To: References: <20220608165116.1575390-1-dario.binacchi@amarulasolutions.com> <20220608165116.1575390-6-dario.binacchi@amarulasolutions.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-can@vger.kernel.org On Sat, 11 Jun 2022 12:46:04 +0200 Dario Binacchi wrote: > > As written before I would like to discuss this change out of your > > patch series "can: slcan: extend supported features" as it is no > > slcan feature extension AND has to be synchronized with the > > drivers/net/slip/slip.c implementation. > > Why do you need to synchronize it with drivers/net/slip/slip.c > implementation ? Because slcan.c is a derivative of slip.c and the code still looks *very* similar, so improvements in one file should be ported to the other and vice versa. This has happened several times now. > > When it has not real benefit and introduces more code and may create > > side effects, this beautification should probably be omitted at all. > > > > I totally agree with you. I would have already dropped it if this > patch didn't make sense. But since I seem to have understood that > this is not the case, I do not understand why it cannot be improved > in this series. This series is mostly about adding netlink support. If there is a point of contention about a beautification, it may be easier to discuss that separately, so the netlink code can be merged while the beautification is still being discussed. On another note, the global array of slcan_devs is really unnecessary and maintaining it is a mess - as seen in some of your patches, that have to account for it in tons of places and get complicated because of it. slcan_devs is probably grandfathered from a very old kernel, since slip.c is about 30 years old, so I suggest to remove it entirely. In fact, it may be easier to patch slcan_devs away first, and that will simplify your open/close patches - your decision :) If you wish to implement the slcan_devs removal, here are some hints: The private struct can just be allocated as part of struct can_priv in slcan_open(), like so: struct net_device *dev; dev = alloc_candev(sizeof(struct slcan), 0); And then accessed like so: struct slcan *sl = netdev_priv(dev); Make sure to add struct can_priv as the first member of struct slcan: /* This must be the first member when using alloc_candev() */ struct can_priv can; > The cover letter highlighted positive reactions to the series because > the module had been requiring these kinds of changes for quite > some time. So, why not take the opportunity to finalize this patch in > this series even if it doesn't extend the supported features ? Because... I can only speak for myself, but I'd merge all the unambiguous stuff first and discuss the difficult stuff later, if there are no interdependencies :) Max