Re: [PATCH net-next v5 09/22] ethtool: implement EVENT notifications

[Florian Fainelli]

On 3/27/2019 7:14 AM, Michal Kubecek wrote:
> On Wed, Mar 27, 2019 at 02:04:28PM +0100, Jiri Pirko wrote:
>> Mon, Mar 25, 2019 at 06:08:21PM CET, mkubecek@xxxxxxx wrote:
>>> Three types of netlink notifications are introduced:
>>>
>>>  - ETHA_EVENT_NEWDEV to notify about newly registered network devices
>>>  - ETHA_EVENT_DELDEV to notify about unregistered network devices
>>>  - ETHA_EVENT_RENAMEDEV to notify about renamed network device
>>>
>>> The notifications are triggered by NETDEV_REGISTER, NETDEV_UNREGISTER and
>>> NETDEV_CHANGENAME notifiers.
>>>
>>> These notifications are intended for applications and daemons monitoring
>>> ethtool events to allow updating the list of existing devices without
>>> having to open another socket for rtnetlink.
>>
>> Wait. You duplicate events that are already going out through RTNETLINK.
>> App should open RTNETLINK in order to get those. Other apps are doing
>> that too. I don't think that duplications like this are desirable :/
> 
> Is there a way to filter or at least recognize these events when using
> rtnetlink? I couldn't find any. The only way seems to be getting every
> RTM_NEWLINK message (there can be quite a lot of those), always perform
> the lookup in my device list and recognize what happened - only to
> almost always find that nothing interesting. It is possible, sure, but
> I would really like to avoid it.

I am afraid you are right about this, would adding a filtering
capability specifically for this in rtnetlink be a better route?
-- 
Florian