Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   =?utf-8?Q?Krzysztof_Ha=C5=82asa?= <khalasa@piap.pl>
To:     Xie He <xie.he.0141@gmail.com>
Cc:     "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, Martin Schiller <ms@dev.tdt.de>
Subject: Re: [PATCH net] drivers/net/wan/hdlc_cisco: Add hard_header_len
References: <20200828070752.54444-1-xie.he.0141@gmail.com>
Date:   Fri, 28 Aug 2020 12:37:37 +0200
In-Reply-To: <20200828070752.54444-1-xie.he.0141@gmail.com> (Xie He's message
        of "Fri, 28 Aug 2020 00:07:52 -0700")
Message-ID: <m3pn7b6opa.fsf@t19.piap.pl>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Hello Xie,

Xie He <xie.he.0141@gmail.com> writes:

> This driver didn't set hard_header_len. This patch sets hard_header_len
> for it according to its header_ops->create function.

BTW it's 4 bytes long:

struct hdlc_header {
        u8 address;
        u8 control;
        __be16 protocol;
}__packed;

OTOH hdlc_setup_dev() initializes hard_header_len to 16,
but in this case I guess 4 bytes are better.

Acked-by: Krzysztof Halasa <khc@pm.waw.pl>

> Cc: Martin Schiller <ms@dev.tdt.de>
> Signed-off-by: Xie He <xie.he.0141@gmail.com>
> ---

> --- a/drivers/net/wan/hdlc_cisco.c
> +++ b/drivers/net/wan/hdlc_cisco.c
> @@ -370,6 +370,7 @@ static int cisco_ioctl(struct net_device *dev, struct=
 ifreq *ifr)
>  		memcpy(&state(hdlc)->settings, &new_settings, size);
>  		spin_lock_init(&state(hdlc)->lock);
>  		dev->header_ops =3D &cisco_header_ops;
> +		dev->hard_header_len =3D sizeof(struct hdlc_header);
>  		dev->type =3D ARPHRD_CISCO;
>  		call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE, dev);
>  		netif_dormant_on(dev);

--=20
Krzysztof Halasa

Sie=C4=87 Badawcza =C5=81ukasiewicz
Przemys=C5=82owy Instytut Automatyki i Pomiar=C3=B3w PIAP
Al. Jerozolimskie 202, 02-486 Warszawa