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Groups > linux.kernel > #1506623

Re: [PATCH net-next v2 7/9] net: use core MTU range checking in misc drivers

From Jarod Wilson <jarod@redhat.com>
Newsgroups linux.kernel
Subject Re: [PATCH net-next v2 7/9] net: use core MTU range checking in misc drivers
Date 2016-10-23 03:20 +0200
Message-ID <svfC9-2Bw-5@gated-at.bofh.it> (permalink)
References <stOXn-2Tk-9@gated-at.bofh.it> <supNf-2j8-3@gated-at.bofh.it> <supNg-2j8-41@gated-at.bofh.it> <sv9ZL-7vE-3@gated-at.bofh.it> <sva9r-7yQ-11@gated-at.bofh.it>
Organization linux.* mail to news gateway

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On Sat, Oct 22, 2016 at 09:27:59PM +0200, Stefan Richter wrote:
> 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.

Okay, since it's already merged in net-next, I can do a follow-up patch
here to set max_mtu to ETH_MAX_MTU (65535), which is the largest possible
size the kernel can handle, so far as I can tell. But as long as I'm going
to be in here, if we just want to use an initial mtu of 1500, I could
clean that up at the same time, and entirely remove the max_mtu
calculation stuff, if that's what you think is more correct here.

-- 
Jarod Wilson
jarod@redhat.com

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Thread

[PATCH net-next 0/6] net: use core MTU range checking everywhere Jarod Wilson <jarod@redhat.com> - 2016-10-19 04:40 +0200
  [PATCH net-next 6/6] net: use core MTU range checking in misc drivers Jarod Wilson <jarod@redhat.com> - 2016-10-19 04:40 +0200
    Re: [PATCH net-next 6/6] net: use core MTU range checking in misc drivers Robin Holt <robinmholt@gmail.com> - 2016-10-19 16:40 +0200
    Re: [PATCH net-next 6/6] net: use core MTU range checking in misc  drivers Sabrina Dubroca <sd@queasysnail.net> - 2016-10-19 18:10 +0200
      Re: [PATCH net-next 6/6] net: use core MTU range checking in misc  drivers Stefan Richter <stefanr@s5r6.in-berlin.de> - 2016-10-20 00:50 +0200
        Re: [PATCH net-next 6/6] net: use core MTU range checking in misc  drivers Jarod Wilson <jarod@redhat.com> - 2016-10-20 05:20 +0200
          Re: [PATCH net-next 6/6] net: use core MTU range checking in misc  drivers Stefan Richter <stefanr@s5r6.in-berlin.de> - 2016-10-22 11:40 +0200
            Re: [PATCH net-next 6/6] net: use core MTU range checking in misc  drivers Stefan Richter <stefanr@s5r6.in-berlin.de> - 2016-10-22 21:00 +0200
  Re: [PATCH net-next 0/6] net: use core MTU range checking  everywhere David Miller <davem@davemloft.net> - 2016-10-19 21:20 +0200
    Re: [PATCH net-next 0/6] net: use core MTU range checking everywhere Jarod Wilson <jarod@redhat.com> - 2016-10-19 21:30 +0200
  [PATCH net-next v2 9/9] ipv4/6: use core net MTU range checking Jarod Wilson <jarod@redhat.com> - 2016-10-20 20:00 +0200
  [PATCH net-next v2 3/9] net: use core MTU range checking in wireless drivers Jarod Wilson <jarod@redhat.com> - 2016-10-20 20:00 +0200
    Re: [PATCH net-next v2 3/9] net: use core MTU range checking in  wireless drivers Johannes Berg <johannes@sipsolutions.net> - 2016-10-20 20:30 +0200
      Re: [PATCH net-next v2 3/9] net: use core MTU range checking in  wireless drivers David Miller <davem@davemloft.net> - 2016-10-20 20:50 +0200
  [PATCH net-next v2 1/9] ethernet: use net core MTU range checking in more drivers Jarod Wilson <jarod@redhat.com> - 2016-10-20 20:00 +0200
  [PATCH net-next v2 4/9] net: use core MTU range checking in WAN drivers Jarod Wilson <jarod@redhat.com> - 2016-10-20 20:00 +0200
  [PATCH net-next v2 2/9] net: use core MTU range checking in USB NIC drivers Jarod Wilson <jarod@redhat.com> - 2016-10-20 20:00 +0200
  [PATCH net-next v2 0/9] net: use core MTU range checking everywhere Jarod Wilson <jarod@redhat.com> - 2016-10-20 20:00 +0200
    [PATCH net-next v2 5/9] net: use core MTU range checking in core net infra Jarod Wilson <jarod@redhat.com> - 2016-10-20 20:00 +0200
    [PATCH net-next v2 6/9] net: use core MTU range checking in virt drivers Jarod Wilson <jarod@redhat.com> - 2016-10-20 20:00 +0200
      RE: [PATCH net-next v2 6/9] net: use core MTU range checking in virt  drivers Haiyang Zhang <haiyangz@microsoft.com> - 2016-10-20 20:10 +0200
        RE: [PATCH net-next v2 6/9] net: use core MTU range checking in virt  drivers "Kershner, David A" <David.Kershner@unisys.com> - 2016-10-20 22:50 +0200
      Re: [PATCH net-next v2 6/9] net: use core MTU range checking in virt  drivers "Michael S. Tsirkin" <mst@redhat.com> - 2016-10-20 22:30 +0200
        Re: [PATCH net-next v2 6/9] net: use core MTU range checking in virt  drivers Jarod Wilson <jarod@redhat.com> - 2016-10-21 04:40 +0200
          Re: [PATCH net-next v2 6/9] net: use core MTU range checking in virt  drivers "Michael S. Tsirkin" <mst@redhat.com> - 2016-10-21 05:40 +0200
            Re: [PATCH net-next v2 6/9] net: use core MTU range checking in virt drivers Aaron Conole <aconole@bytheb.org> - 2016-10-21 15:30 +0200
      Re: [PATCH net-next v2 6/9] net: use core MTU range checking in virt  drivers Wei Liu <wei.liu2@citrix.com> - 2016-10-21 12:10 +0200
    [PATCH net-next v2 8/9] s390/net: use net core MTU range checking Jarod Wilson <jarod@redhat.com> - 2016-10-20 20:00 +0200
    [PATCH net-next v2 7/9] net: use core MTU range checking in misc drivers Jarod Wilson <jarod@redhat.com> - 2016-10-20 20:00 +0200
      Re: [PATCH net-next v2 7/9] net: use core MTU range checking in misc drivers Rémi Denis-Courmont <remi@remlab.net> - 2016-10-21 09:00 +0200
      Re: [PATCH net-next v2 7/9] net: use core MTU range checking in misc  drivers Sebastian Reichel <sre@kernel.org> - 2016-10-21 18:30 +0200
      Re: [net-next,v2,7/9] net: use core MTU range checking in misc drivers Sven Eckelmann <sven@narfation.org> - 2016-10-22 09:30 +0200
      Re: [PATCH net-next v2 7/9] net: use core MTU range checking in  misc drivers Stefan Richter <stefanr@s5r6.in-berlin.de> - 2016-10-22 21:20 +0200
        Re: [PATCH net-next v2 7/9] net: use core MTU range checking in  misc drivers Stefan Richter <stefanr@s5r6.in-berlin.de> - 2016-10-22 21:30 +0200
          Re: [PATCH net-next v2 7/9] net: use core MTU range checking in misc  drivers Jarod Wilson <jarod@redhat.com> - 2016-10-23 03:20 +0200
            [PATCH net-next 1/2] firewire: net: fix maximum possible MTU Stefan Richter <stefanr@s5r6.in-berlin.de> - 2016-10-23 16:30 +0200
              [PATCH net-next 2/2] firewire: net: set initial MTU = 1500  unconditionally, fix IPv6 on some CardBus cards Stefan Richter <stefanr@s5r6.in-berlin.de> - 2016-10-23 16:40 +0200
                Re: [PATCH net-next 2/2] firewire: net: set initial MTU = 1500  unconditionally, fix IPv6 on some CardBus cards Jarod Wilson <jarod@redhat.com> - 2016-10-24 04:00 +0200
                [PATCH net-next 2/2 v2] firewire: net: set initial MTU = 1500  unconditionally, fix IPv6 on some CardBus cards Stefan Richter <stefanr@s5r6.in-berlin.de> - 2016-10-24 14:30 +0200
                Re: [PATCH net-next 2/2 v2] firewire: net: set initial MTU = 1500  unconditionally, fix IPv6 on some CardBus cards Jarod Wilson <jarod@redhat.com> - 2016-10-25 05:10 +0200
                Re: [PATCH net-next 2/2] firewire: net: set initial MTU = 1500  unconditionally, fix IPv6 on some CardBus cards David Miller <davem@davemloft.net> - 2016-10-26 23:40 +0200
              Re: [PATCH net-next 1/2] firewire: net: fix maximum possible MTU Jarod Wilson <jarod@redhat.com> - 2016-10-24 04:00 +0200
              Re: [PATCH net-next 1/2] firewire: net: fix maximum possible MTU David Miller <davem@davemloft.net> - 2016-10-26 23:40 +0200
    Re: [PATCH net-next v2 0/9] net: use core MTU range checking  everywhere David Miller <davem@davemloft.net> - 2016-10-20 21:00 +0200

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