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=-11.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 2D9B0C433E6 for ; Tue, 16 Mar 2021 16:06:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 077C96510C for ; Tue, 16 Mar 2021 16:06:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238466AbhCPQFs (ORCPT ); Tue, 16 Mar 2021 12:05:48 -0400 Received: from mail.kernel.org ([198.145.29.99]:33112 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238443AbhCPQFW (ORCPT ); Tue, 16 Mar 2021 12:05:22 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id D3D2464FA5; Tue, 16 Mar 2021 16:05:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1615910714; bh=ynXJtKVMMF9qJ1oZ8CZr4CxxidViT0otaj5Qh85Igr8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=nrUWNMJdTMGO/qsTCQWubX6dSjFA1MstkMcMXEYTm1uvJ2tYYTLuPC1teEHXOHZo5 /cr9s/1tdBn9FfGhRw+wisrvK57L69OJP7IxYj7QKUIfvo8KV1u6YDQEFoPeckQYRy GieqhEycVMFM8uoHkh/MIpEoxmsts0StDBGOcc7o= Date: Tue, 16 Mar 2021 17:05:11 +0100 From: "gregkh@linuxfoundation.org" To: Sasha Levin Cc: Vladimir Oltean , Andrew Lunn , Florian Fainelli , Vivien Didelot , "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" , Kurt Kanzenbach , Jakub Kicinski , Christian Eggers Subject: Re: [PATCH 5.10 113/290] net: dsa: implement a central TX reallocation procedure Message-ID: References: <20210315135541.921894249@linuxfoundation.org> <20210315135545.737069480@linuxfoundation.org> <20210315195601.auhfy5uafjafgczs@skbuf> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 16, 2021 at 09:54:01AM -0400, Sasha Levin wrote: > On Tue, Mar 16, 2021 at 06:46:10AM +0100, gregkh@linuxfoundation.org wrote: > > On Mon, Mar 15, 2021 at 07:56:02PM +0000, Vladimir Oltean wrote: > > > +Andrew, Vivien, > > > > > > On Mon, Mar 15, 2021 at 02:53:26PM +0100, gregkh@linuxfoundation.org wrote: > > > > From: Greg Kroah-Hartman > > > > > > > > From: Vladimir Oltean > > > > > > > > [ Upstream commit a3b0b6479700a5b0af2c631cb2ec0fb7a0d978f2 ] > > > > > > > > At the moment, taggers are left with the task of ensuring that the skb > > > > headers are writable (which they aren't, if the frames were cloned for > > > > TX timestamping, for flooding by the bridge, etc), and that there is > > > > enough space in the skb data area for the DSA tag to be pushed. > > > > > > > > Moreover, the life of tail taggers is even harder, because they need to > > > > ensure that short frames have enough padding, a problem that normal > > > > taggers don't have. > > > > > > > > The principle of the DSA framework is that everything except for the > > > > most intimate hardware specifics (like in this case, the actual packing > > > > of the DSA tag bits) should be done inside the core, to avoid having > > > > code paths that are very rarely tested. > > > > > > > > So provide a TX reallocation procedure that should cover the known needs > > > > of DSA today. > > > > > > > > Note that this patch also gives the network stack a good hint about the > > > > headroom/tailroom it's going to need. Up till now it wasn't doing that. > > > > So the reallocation procedure should really be there only for the > > > > exceptional cases, and for cloned packets which need to be unshared. > > > > > > > > Signed-off-by: Vladimir Oltean > > > > Tested-by: Christian Eggers # For tail taggers only > > > > Tested-by: Kurt Kanzenbach > > > > Reviewed-by: Florian Fainelli > > > > Signed-off-by: Jakub Kicinski > > > > Signed-off-by: Sasha Levin > > > > --- > > > > > > For context, Sasha explains here: > > > https://www.spinics.net/lists/stable-commits/msg190151.html > > > (the conversation is somewhat truncated, unfortunately, because > > > stable-commits@vger.kernel.org ate my replies) > > > that 13 patches were backported to get the unrelated commit 9200f515c41f > > > ("net: dsa: tag_mtk: fix 802.1ad VLAN egress") to apply cleanly with git-am. > > > > > > I am not strictly against this, even though I would have liked to know > > > that the maintainers were explicitly informed about it. > > > > > > Greg, could you make your stable backporting emails include the output > > > of ./get_maintainer.pl into the list of recipients? Thanks. > > > > I cc: everyone on the signed-off-by list on the patch, why would we need > > to add more? A maintainer should always be on that list automatically. > > Oh, hm, could this be an issue with subsystems that have a shared > maintainership model? In that scenario not all maintainers will sign-off > on a commit. So a shared maintainer trusts their co-maintainer for reviewing patches for Linus's tree and all future kernels, but NOT into an old backported stable tree? I doubt that, trust should be the same for both. thanks, greg k-h