From patchwork Wed Sep 5 17:39:02 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Wahren X-Patchwork-Id: 966604 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=i2se.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 4259tT1hYxz9sCt for ; Thu, 6 Sep 2018 03:39:13 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727657AbeIEWKW (ORCPT ); Wed, 5 Sep 2018 18:10:22 -0400 Received: from mout.kundenserver.de ([212.227.126.131]:54585 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726497AbeIEWKW (ORCPT ); Wed, 5 Sep 2018 18:10:22 -0400 Received: from null ([172.19.246.7]) by mrelayeu.kundenserver.de (mreue009 [212.227.15.167]) with ESMTPSA (Nemesis) id 1M5wTr-1fwEBg15Cd-007RZ7; Wed, 05 Sep 2018 19:39:03 +0200 Date: Wed, 5 Sep 2018 19:39:02 +0200 (CEST) From: Stefan Wahren To: raghuramchary.jallipalli@microchip.com, unglinuxdriver@microchip.com Cc: davem@davemloft.net, netdev@vger.kernel.org Message-ID: <1102700056.29198.1536169142144@email.1und1.de> Subject: smsc95xx: Invalid max MTU MIME-Version: 1.0 X-Priority: 3 Importance: Medium X-Mailer: Open-Xchange Mailer v7.8.4-Rev36 X-Originating-Client: open-xchange-appsuite X-Provags-ID: V03:K1:8rAgRBUJiroYktHAameP7GjeKD9+/oen0tMyBofGDRQkbz9o+WK um2Pp8zMks8uwtIDwk6wwuwZd1EgBeau9fB9R4gKqr0A6IzUGlSR3TGpqmbBWYdb9PgeuiA HXcecYZVClJDAkZ18lBukZCZeDHd8TGStyzjjMx7JclyXeNRV4e1kxp/67Ew4dAwezCEgsp NNsNcUUEKs8Lv1q69PybQ== X-UI-Out-Filterresults: notjunk:1; V01:K0:1arWo2lIFlU=:RsHQg0P9QTndA5fIlO/52e t89WvFk2VyWPGTb41DFpG6CnMo/HUgqQLvfZo18wGwLeSsx+CteyLdAwbaTeA2qqexW/axauQ gMD7ODJHIM1eWzeOBJEwmnSvZOIxo2gIs6l/xVX5M2SPtOWpp2U+d3PYnK5wOxwIXfbklptSv PvwhMZvKXx3BRYkm70jcFr/SXMqrLR0H/F/YQKbR6pA1AjO2jZlAwUdrA+Iw/67bNHr7HAhw6 +jj0yaNYQAFXgGXDSLTx/z5yfM1PVdF08h9H5bEXy1xe/k8ydt+0/qNZW//prFGSmFh8dWHvv 0H8g7JnkeIkiLwWcdJOypzArGaqyj/qyAzwPerH8TY0kFHdEINe9cDPE/pH86qiQAN3aQ+QMQ DBN/S7cMi4KvUqESTRyb+dSTKTbMNPOz1hZDUymQdzA+OXUszUuvqE67obEvLJyzM/eQrgQ/j RtQWXlndH7qcHkIxbTiBs9SP3UbJ7xQl3KCNoupCJAQy/l6SiZM7qgJduVsoQ8jtQCvyQwG3B CfBCk3JNdsR4xrfYLQdQxcSWzmSXheuHJ/GTA9nRKzZhV0DAeb07tzn5SyLZ4byAGyTP/QHgY OcRI/nffd7iA0oCYsZGyhmA9mEDbjOI+0J0OBB4oENvqbCOvQY3PIyWnpK0koxGBOST5kLZ6o 7kEXa9o86ETvrSEM4f7Sff4KoVu97rvZDe9MQC3zT8g1ju6AKmLqrwWB0Bcq5L7qU0oF4Zp/F dh4hGdb+UBGRlCo6 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hi, recently there was a user who reports that his Raspberry Pi 3B didn't work as expected [1]. The problem is that the smsc95xx driver accepts to high MTU values ( > 9000) from userspace like dhcp-client, but according to the LAN9500 databook the chip seems only capable to handle MTU sizes <= 1500. It looks like that smsc95xx slipped through the cracks during the creation of commit f77f0aee4da4 ("net: use core MTU range checking in USB NIC drivers"). Unfortunately i don't have all the chips listed in this driver. So my questions would be the following patch correct: [1] - https://github.com/raspberrypi/linux/issues/2660 diff --git a/drivers/net/usb/smsc95xx.c b/drivers/net/usb/smsc95xx.c index 06b4d29..420a0e4 100644 --- a/drivers/net/usb/smsc95xx.c +++ b/drivers/net/usb/smsc95xx.c @@ -1318,6 +1318,7 @@ static int smsc95xx_bind(struct usbnet *dev, struct usb_interface *intf) dev->net->ethtool_ops = &smsc95xx_ethtool_ops; dev->net->flags |= IFF_MULTICAST; dev->net->hard_header_len += SMSC95XX_TX_OVERHEAD_CSUM; + dev->net->max_mtu = ETH_DATA_LEN; dev->hard_mtu = dev->net->mtu + dev->net->hard_header_len; pdata->dev = dev;