From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jon Nelson" Subject: Re: [PATCH] via-velocity: don't oops on MTU change. Date: Thu, 15 Nov 2007 20:42:55 -0600 Message-ID: References: <20071114193844.0cab5c7d@freepuppy.rosehill> <20071115082600.GA2366@ff.dom.local> <20071115102005.0cf46f9a@freepuppy.rosehill> <473CD1F6.9030709@o2.pl> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: "Stephen Hemminger" , "Andrew Morton" , "David S. Miller" , netdev@vger.kernel.org, jnelson-kernel-bugzilla@jamponi.net To: "Jarek Poplawski" Return-path: Received: from nf-out-0910.google.com ([64.233.182.187]:31025 "EHLO nf-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934645AbXKPCnE (ORCPT ); Thu, 15 Nov 2007 21:43:04 -0500 Received: by nf-out-0910.google.com with SMTP id g13so696708nfb for ; Thu, 15 Nov 2007 18:43:01 -0800 (PST) In-Reply-To: <473CD1F6.9030709@o2.pl> Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 11/15/07, Jarek Poplawski wrote: .. > Sure! I was only worried velocity_open() treats dev->mtu > a bit different than velocity_change_mtu(), so eg. after: > > velocity_change_mtu() // dev is down > velocity_open() > velocity_change_mtu() // dev is up > > with the same mtu, vptr->rx_buf_sz could be different than after: > > velocity_open() > velocity_change_mtu() // dev is up > > But, probably, I miss someting. There is a snag here: if I change the MTU after the device is UP something ends up rather broken. A tcpdump shows nearly every outgoing frame has a bad TCP checksum (and the card does not support H/W checksumming or it is turned off as reported by ethtool). -- Jon