netdev - RE: [PATCH net 1/2] net/mlx4_en: Change min MTU size to ETH_MIN

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Date:   Tue, 4 Dec 2018 17:21:13 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     'Eric Dumazet' <eric.dumazet@...il.com>,
        'Tariq Toukan' <tariqt@...lanox.com>,
        "David S. Miller" <davem@...emloft.net>
CC:     "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        Eran Ben Elisha <eranbe@...lanox.com>
Subject: RE: [PATCH net 1/2] net/mlx4_en: Change min MTU size to ETH_MIN_MTU

From: Eric Dumazet
> Sent: 04 December 2018 17:04
> On 12/04/2018 08:59 AM, David Laight wrote:
> > From: Tariq Toukan
> >> Sent: 02 December 2018 12:35
> >> From: Eran Ben Elisha <eranbe@...lanox.com>
> >>
> >> NIC driver minimal MTU size shall be set to ETH_MIN_MTU, as defined in
> >> the RFC791 and in the network stack. Remove old mlx4_en only define for
> >> it, which was set to wrong value.
> > ...
> >>
> >> -	/* MTU range: 46 - hw-specific max */
> >> -	dev->min_mtu = MLX4_EN_MIN_MTU;
> >> +	/* MTU range: 68 - hw-specific max */
> >> +	dev->min_mtu = ETH_MIN_MTU;
> >>  	dev->max_mtu = priv->max_mtu;
> >
> > Where does 68 come from?
> 
> Min IPv4 MTU per RFC791

Maybe I'm just confused and these are the ranges that the 'maximum mtu'
can be set to.

	David

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