Hello!
On 02/16/2018 10:42 PM, Florian Fainelli wrote:
>> Allow for changing the MTU within the limit of the maximum size of a
>> descriptor (2048 bytes). Add the callback to change MTU from user-space
>> and take the configurable MTU into account when configuring the
>> hardware.
>>
>> Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>
>> ---
>
>>
>> +static int ravb_change_mtu(struct net_device *ndev, int new_mtu)
>> +{
>> + if (netif_running(ndev))
>> + return -EBUSY;
>> +
>> + ndev->mtu = new_mtu;
>> + netdev_update_features(ndev);
>
> Don't you somehow need to quiesce the RX DMA and make sure you that you
> re-allocate all RX buffers within priv->rx_skb[q][entry] such that they
> will be able to accept a larger buffer size?
>
> If we put the ravb interface under high RX load and we change the MTU on
> the fly, can we crash the kernel?
I thought the netif_running() check guards against that. Does it not?
MBR, Sergei
