netdev - Re: [PATCH 1/3] aqc111: fix endianness issue in aqc111_change

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Date:   Tue, 14 May 2019 12:37:52 +0000
From:   Igor Russkikh <Igor.Russkikh@...antia.com>
To:     Oliver Neukum <oneukum@...e.com>,
        Dmitry Bezrukov <Dmitry.Bezrukov@...antia.com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: [PATCH 1/3] aqc111: fix endianness issue in aqc111_change_mtu



On 09.05.2019 12:08, Oliver Neukum wrote:
> If the MTU is large enough, the first write to the device
> is just repeated. On BE architectures, however, the first
> word of the command will be swapped a second time and garbage
> will be written. Avoid that.
> 
> Signed-off-by: Oliver Neukum <oneukum@...e.com>
> ---
>  drivers/net/usb/aqc111.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/net/usb/aqc111.c b/drivers/net/usb/aqc111.c
> index aff995be2a31..408df2d335e3 100644
> --- a/drivers/net/usb/aqc111.c
> +++ b/drivers/net/usb/aqc111.c
> @@ -453,6 +453,8 @@ static int aqc111_change_mtu(struct net_device *net, int new_mtu)
>  		reg16 = 0x1420;
>  	else if (dev->net->mtu <= 16334)
>  		reg16 = 0x1A20;
> +	else
> +		return 0;
>  
>  	aqc111_write16_cmd(dev, AQ_ACCESS_MAC, SFR_PAUSE_WATERLVL_LOW,
>  			   2, &reg16);
> 

Since we specify max_mtu at `bind` time, this `else` will never happen.
Only for readability that could be rewritten as

-  	else if (dev->net->mtu <= 16334)
+	else
		reg16 = 0x1A20;

Regards,
  Igor