From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andrew Lunn <andrew@lunn.ch>
Subject: Re: [PATCH net-next 11/19] net: usb: aqc111: Add support for
 changing MTU
Date: Sat, 6 Oct 2018 18:56:03 +0200
Message-ID: <20181006165603.GA6990@lunn.ch>
References: <cover.1538734658.git.igor.russkikh@aquantia.com>
 <4217a1b53f61c5da8f6ba69326c7b759174817e7.1538734658.git.igor.russkikh@aquantia.com>
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Cc: "David S . Miller" <davem@davemloft.net>,
        "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
        "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
        Dmitry Bezrukov <Dmitry.Bezrukov@aquantia.com>
To: Igor Russkikh <Igor.Russkikh@aquantia.com>
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> +static int aqc111_change_mtu(struct net_device *net, int new_mtu)
> +{
> +	struct usbnet *dev = netdev_priv(net);
> +	u16 reg16 = 0;
> +	u8 buf[5];
> +
> +	if (new_mtu <= 0 || new_mtu > 16334) {
> +		netdev_info(net, "Invalid MTU %d requested, hw max 16334",
> +			    new_mtu);
> +		return -EINVAL;
> +	}

Please set net->min_mtu, and net->max_mtu, and the core should do this
checking for you. See dev_set_mtu_ext().

	 Andrew