From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: [PATCH] Gigabit Ethernet driver of Topcliff PCH
Date: Fri, 03 Sep 2010 15:43:36 +0200
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Cc: Stephen Hemminger <shemminger@vyatta.com>,
	Sam Ravnborg <sam@ravnborg.org>, Joe Perches <joe@perches.com>,
	LKML <linux-kernel@vger.kernel.org>,
	ML netdev <netdev@vger.kernel.org>,
	Greg Rose <gregory.v.rose@intel.com>,
	Maxime Bizon <mbizon@freebox.fr>,
	Kristoffer Glembo <kristoffer@gaisler.com>,
	Ralf Baechle <ralf@linux-mips.org>,
	John Linn <john.linn@xilinx.com>,
	Randy Dunlap <randy.dunlap@oracle.com>,
	"David S. Miller" <davem@davemloft.net>,
	MeeGo <meego-dev@meego.com>, "Wang, Qi" <qi.wang@intel.com>,
	"Wang, Yong Y" <yong.y.wang@intel.com>,
	Andrew <andrew.chih.howe.khor@intel.com>,
	Intel OTC <joel.clark@intel.com>,
	"Foster, Margie" <margie.foster@intel.com>,
	Toshiharu Okada <okada533@dsn.okisemi.com>,
	Tomoya Morinaga <morinaga526@dsn.okisemi.com>,
	Takahiro Shimizu <shimizu394@dsn.okisemi.com>
To: Masayuki Ohtake <masa-korg@dsn.okisemi.com>
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Le vendredi 03 septembre 2010 =C3=A0 22:32 +0900, Masayuki Ohtake a =C3=
=A9crit :
> Hi Eric and Stephen
>=20
> Thank you for your suggestion.
>=20
> I tried modification of "dev->hard_header_len".
> However, there was no changed to a format of SKB received by kernel.
>   [Header:14octet] + [payload]
>=20
> So, I can not a single memcpy.

Hmm, maybe you did this at the wrong place ?

Take a look at other drivers how they do this

(network stack default hard_header_len to 14, in net/ethernet/eth.c,
function ether_setup())


find drivers/net | xargs grep -n hard_header_len

Example in drivers/net/wan/hdlc.c

static void hdlc_setup_dev(struct net_device *dev)
{
        /* Re-init all variables changed by HDLC protocol drivers,
         * including ether_setup() called from hdlc_raw_eth.c.
         */
        dev->flags               =3D IFF_POINTOPOINT | IFF_NOARP;
        dev->priv_flags          =3D IFF_WAN_HDLC;
        dev->mtu                 =3D HDLC_MAX_MTU;
        dev->type                =3D ARPHRD_RAWHDLC;
        dev->hard_header_len     =3D 16;
        dev->addr_len            =3D 0;
        dev->header_ops          =3D &hdlc_null_ops;
}