From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: [PATCH] via-velocity: don't oops on MTU change. Date: Thu, 15 Nov 2007 20:05:20 -0800 Message-ID: <20071115200520.0a887abb@freepuppy.rosehill> 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=US-ASCII Content-Transfer-Encoding: 7bit Cc: "Jarek Poplawski" , "Andrew Morton" , "David S. Miller" , netdev@vger.kernel.org, jnelson-kernel-bugzilla@jamponi.net To: "Jon Nelson" Return-path: Received: from smtp2.linux-foundation.org ([207.189.120.14]:48064 "EHLO smtp2.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756469AbXKPEHN (ORCPT ); Thu, 15 Nov 2007 23:07:13 -0500 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Thu, 15 Nov 2007 20:42:55 -0600 "Jon Nelson" wrote: > 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). > That is a different (and pre-existing bug). -- Stephen Hemminger