Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755960AbcJVT2Q (ORCPT ); Sat, 22 Oct 2016 15:28:16 -0400 Received: from einhorn.in-berlin.de ([192.109.42.8]:50850 "EHLO einhorn.in-berlin.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751241AbcJVT2P (ORCPT ); Sat, 22 Oct 2016 15:28:15 -0400 X-Envelope-From: stefanr@s5r6.in-berlin.de Date: Sat, 22 Oct 2016 21:27:59 +0200 From: Stefan Richter To: Jarod Wilson Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux1394-devel@lists.sourceforge.net Subject: Re: [PATCH net-next v2 7/9] net: use core MTU range checking in misc drivers Message-ID: <20161022212759.228c7642@kant> In-Reply-To: <20161022211606.3b5d137d@kant> References: <20161019023333.15760-1-jarod@redhat.com> <20161020175524.6184-1-jarod@redhat.com> <20161020175524.6184-8-jarod@redhat.com> <20161022211606.3b5d137d@kant> X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.31; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2324 Lines: 68 Adding Cc: linux1394-devel, dropping several Ccs, no additional comment. On Oct 22 Stefan Richter wrote: > On Oct 20 Jarod Wilson wrote: > > firewire-net: > > - set min/max_mtu > > - remove fwnet_change_mtu > [...] > > --- a/drivers/firewire/net.c > > +++ b/drivers/firewire/net.c > > @@ -1349,15 +1349,6 @@ static netdev_tx_t fwnet_tx(struct sk_buff > > *skb, struct net_device *net) return NETDEV_TX_OK; > > } > > > > -static int fwnet_change_mtu(struct net_device *net, int new_mtu) > > -{ > > - if (new_mtu < 68) > > - return -EINVAL; > > - > > - net->mtu = new_mtu; > > - return 0; > > -} > > - > > static const struct ethtool_ops fwnet_ethtool_ops = { > > .get_link = ethtool_op_get_link, > > }; > > @@ -1366,7 +1357,6 @@ static const struct net_device_ops > > fwnet_netdev_ops = { .ndo_open = fwnet_open, > > .ndo_stop = fwnet_stop, > > .ndo_start_xmit = fwnet_tx, > > - .ndo_change_mtu = fwnet_change_mtu, > > }; > > > > static void fwnet_init_dev(struct net_device *net) > > @@ -1435,7 +1425,6 @@ static int fwnet_probe(struct fw_unit *unit, > > struct net_device *net; > > bool allocated_netdev = false; > > struct fwnet_device *dev; > > - unsigned max_mtu; > > int ret; > > union fwnet_hwaddr *ha; > > > > @@ -1478,9 +1467,10 @@ static int fwnet_probe(struct fw_unit *unit, > > * Use the RFC 2734 default 1500 octets or the maximum payload > > * as initial MTU > > */ > > - max_mtu = (1 << (card->max_receive + 1)) > > - - sizeof(struct rfc2734_header) - IEEE1394_GASP_HDR_SIZE; > > - net->mtu = min(1500U, max_mtu); > > + net->max_mtu = (1 << (card->max_receive + 1)) > > + - sizeof(struct rfc2734_header) - IEEE1394_GASP_HDR_SIZE; > > + net->mtu = min(1500U, net->max_mtu); > > + net->min_mtu = ETH_MIN_MTU; > > > > /* Set our hardware address while we're at it */ > > ha = (union fwnet_hwaddr *)net->dev_addr; > > Please preserve the current behavior, i.e. do not enforce any particular > upper bound. (Especially none based on the local link layer controller's > max_receive parameter.) > > BTW, after having read RFC 2734, RFC 3146, and the code, I am convinced > that net->mtu should be initialized to 1500, not less. But such a change > should be done in a separate patch. -- Stefan Richter -======----- =-=- =-==- http://arcgraph.de/sr/