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 5ADE3C433EF for ; Fri, 25 Feb 2022 11:47:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240228AbiBYLsP (ORCPT ); Fri, 25 Feb 2022 06:48:15 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55494 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234885AbiBYLsP (ORCPT ); Fri, 25 Feb 2022 06:48:15 -0500 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E049614FFF9 for ; Fri, 25 Feb 2022 03:47:42 -0800 (PST) Received: from ptx.hi.pengutronix.de ([2001:67c:670:100:1d::c0]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1nNZ4X-0000cR-9q; Fri, 25 Feb 2022 12:47:41 +0100 Received: from ore by ptx.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1nNZ4W-0003kX-1o; Fri, 25 Feb 2022 12:47:40 +0100 Date: Fri, 25 Feb 2022 12:47:40 +0100 From: Oleksij Rempel To: Vladimir Oltean Cc: Woojung Huh , Andrew Lunn , Florian Fainelli , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Vivien Didelot , kernel@pengutronix.de, Jakub Kicinski , UNGLinuxDriver@microchip.com, "David S. Miller" Subject: Re: [PATCH net-next v2 1/1] net: dsa: microchip: ksz9477: implement MTU configuration Message-ID: <20220225114740.GA27407@pengutronix.de> References: <20220223084055.2719969-1-o.rempel@pengutronix.de> <20220223233833.mjknw5ko7hpxj3go@skbuf> <20220224045936.GB4594@pengutronix.de> <20220224093329.hssghouq7hmgxvwb@skbuf> <20220224093827.GC4594@pengutronix.de> <20220224094657.jzhvi67ryhuipor4@skbuf> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20220224094657.jzhvi67ryhuipor4@skbuf> X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Uptime: 11:46:54 up 76 days, 19:32, 91 users, load average: 0.10, 0.17, 0.23 User-Agent: Mutt/1.10.1 (2018-07-13) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c0 X-SA-Exim-Mail-From: ore@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: netdev@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, Feb 24, 2022 at 11:46:57AM +0200, Vladimir Oltean wrote: > So where is it failing exactly? Here I guess, because mtu_limit will be > negative? > > mtu_limit = min_t(int, master->max_mtu, dev->max_mtu); > old_master_mtu = master->mtu; > new_master_mtu = largest_mtu + dsa_tag_protocol_overhead(cpu_dp->tag_ops); > if (new_master_mtu > mtu_limit) > return -ERANGE; > > I don't think we can work around it in DSA, it's garbage in, garbage out. > > In principle, I don't have such a big issue with writing the MTU > register as part of the switch initialization, especially if it's global > and not per port. But tell me something else. You pre-program the MTU > with VLAN_ETH_FRAME_LEN + ETH_FCS_LEN, but in the MTU change procedure, > you also add KSZ9477_INGRESS_TAG_LEN (2) to that. Is that needed at all? > I expect that if it's needed, it's needed in both places. Can you > sustain an iperf3 tcp session over a VLAN upper of a ksz9477 port? > I suspect that the missing VLAN_HLEN is masking a lack of KSZ9477_INGRESS_TAG_LEN. Hm... I assume I need to do something like this: - build kernel with BRIDGE_VLAN_FILTERING - | ip l a name br0 type bridge vlan_filtering 1 ip l s dev br0 up ip l s lan1 master br0 ip l s dev lan1 up bridge vlan add dev lan1 vid 5 pvid untagged ip link add link br0 name vlan5 type vlan id 5 I use lan5@ksz for net boot. As soon as i link lan1@ksz to the br0 with vlan_filtering enabled, the nfs on lan5 will be broken. Currently I have no time to investigate it. I'll try to fix VLAN support in a separate task. What will is acceptable way to proceed with MTU patch? Regards, Oleksij -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |