netdev - Re: [RFC v2 -next 2/2] virtio_net: Read the advised MTU

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Date:	Thu, 17 Mar 2016 17:15:36 -0400
From:	Aaron Conole <aconole@...hat.com>
To:	Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
Cc:	netdev@...r.kernel.org, "Michael S. Tsirkin" <mst@...hat.com>,
	virtualization@...ts.linux-foundation.org,
	linux-kernel@...r.kernel.org
Subject: Re: [RFC v2 -next 2/2] virtio_net: Read the advised MTU

Sergei Shtylyov <sergei.shtylyov@...entembedded.com> writes:

> Hello.
>
> On 3/16/2016 12:04 AM, Aaron Conole wrote:
>
>> This patch checks the feature bit for the VIRTIO_NET_F_MTU feature. If it
>> exists, read the advised MTU and use it.
>>
>> No proper error handling is provided for the case where a user changes the
>> negotiated MTU. A future commit will add proper error handling. Instead, a
>> warning is emitted if the guest changes the device MTU after previously
>> being given advice.
>>
>> Signed-off-by: Aaron Conole <aconole@...heb.org>
>> ---
>> v2:
>> * Whitespace cleanup in the last hunk
>> * Code style change around the pr_warn
>> * Additional test for mtu change before printing warning
>>
>>   drivers/net/virtio_net.c | 12 ++++++++++++
>>   1 file changed, 12 insertions(+)
>>
>> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
>> index 767ab11..429fe01 100644
>> --- a/drivers/net/virtio_net.c
>> +++ b/drivers/net/virtio_net.c
> [...]
>> @@ -1390,8 +1391,11 @@ static const struct ethtool_ops virtnet_ethtool_ops = {
>>
>>   static int virtnet_change_mtu(struct net_device *dev, int new_mtu)
>>   {
>> +	struct virtnet_info *vi = netdev_priv(dev);
>>   	if (new_mtu < MIN_MTU || new_mtu > MAX_MTU)
>>   		return -EINVAL;
>> +	if ((vi->negotiated_mtu) && (dev->mtu != new_mtu))
>
>    Inner parens not needed, please be consistent with the code above.

Okay, I will do that.

Thanks so much for the review (again), Sergei!

-Aaron

> [...]
>
> MBR, Sergei