Subject: Re: [PATCH net-next v3 2/5] swdevice: add new api to set and del bridge port attributes

From: roopa <[email-masked]>
Date: Fri, 23 Jan 2015 15:10:01 -0800

On 1/23/15, 2:45 PM, roopa wrote:
> On 1/23/15, 8:06 AM, Jiri Pirko wrote:
>> Fri, Jan 23, 2015 at 04:58:57PM CET, [email-masked] wrote:
>>> On 1/23/15, 2:41 AM, Jiri Pirko wrote:
>>>
>>> <snip..>
>>>> +
>>>> +/**
>>>> + *    netdev_switch_port_bridge_dellink - Notify switch device 
>>>> port of bridge
>>>> + *    attribute delete
>>>> + *
>>>> + *    @dev: port device
>>>> + *    @nlh: netlink msg with bridge port attributes
>>>> + *
>>>> + *    Notify switch device port of bridge port attribute delete
>>>> + */
>>>> +int netdev_switch_port_bridge_dellink(struct net_device *dev,
>>>> +                      struct nlmsghdr *nlh, u16 flags)
>>>> +{
>>>> +    const struct net_device_ops *ops = dev->netdev_ops;
>>>> +    struct net_device *lower_dev;
>>>> +    struct list_head *iter;
>>>> +    int ret = 0, err = 0;
>>>> +
>>>> +    if (!(dev->features & NETIF_F_HW_NETFUNC_OFFLOAD))
>>>> +        return err;
>>>> +
>>>> +    if (ops->ndo_bridge_dellink) {
>>>> +        WARN_ON(!ops->ndo_switch_parent_id_get);
>>>> +        return ops->ndo_bridge_dellink(dev, nlh, flags);
>>>> +    }
>>>> +
>>>> +    netdev_for_each_lower_dev(dev, lower_dev, iter) {
>>>> +        err = netdev_switch_port_bridge_dellink(lower_dev, nlh, 
>>>> flags);
>>>> +        if (err)
>>>> +            ret = err;
>>>> +    }
>>>> +
>>>> +    return ret;
>>>> +}
>>>> +EXPORT_SYMBOL(netdev_switch_port_bridge_dellink);
>>>> -- 
>>>> 1.7.10.4
>>>>
>>>> Is there any other place, other than bridge code, this functions are
>>>> suppored to be called from?
>>> No other place today. Its usually the master that implements
>>> ndo_bridge_setlink/dellink.
>>>
>>>> If not, which I consider likely, it would
>>>> make more sense to me to:
>>>>
>>>> - move netdev_for_each_lower_dev iterations directly to bridge code
>>>> - let the masters (bond, team, ..) implement ndo_bridge_*link and do
>>>>    the traversing there (can be in a form of pre-prepared default
>>>>    ndo callback (ndo_dflt_netdev_switch_port_bridge_*link)
>>> But, i am still not understanding why i would modify bond, team and 
>>> other
>>> slaves
>> Well, that is the usual way to propagate ndo calls. People are used to
>> this. It is visible right away in bonding/other code that is propagated
>> some ndo call to slaves. With your code, that is somehow hidden and only
>> dependent on NETIF_F_HW_NETFUNC_OFFLOAD flag.
>>
>> Note that there are only couple of "master drivers" (for this, most 
>> likely
>> only bond and team modifications are needed).
> ndo_bridge_setlink today is only implemented by drivers that implement 
> bridging function.
> So, having the bond and team driver implement it...seems odd.
>
> But if you insist, i am going to do just that.
A side note, I dont see any reason for ndo_bridge_setlink to be renamed 
to ndo_setlink. Because it seems to take the whole netlink msg anyways. 
It can be used to offload other link attributes besides bridging (vxlan 
and so on).
Any thoughts on that ?.