Re: [PATCH net v3] rtnl/bond: don't send rtnl msg for unregistered iface

[Andy Gospodarek <gospo@cumulusnetworks.com>]

On Wed, May 13, 2015 at 02:01:05PM +0200, Nicolas Dichtel wrote:
> Le 12/05/2015 19:12, Andy Gospodarek a écrit :
> >On Tue, May 12, 2015 at 05:58:42PM +0200, Jiri Pirko wrote:
> >>Tue, May 12, 2015 at 05:17:45PM CEST, nicolas.dichtel@6wind.com wrote:
> [snip]
> >>>First, nobody seems to care about NETDEV_CHANGEINFODATA (commit
> >>>d4261e565000 says that it was put only to notify userspace). Hence, we can
> >>>call directly rtmsg_ifinfo().
> >>
> >>Please leave this notifier here. Will be needed in very near future for
> >>LAG offloading purposes.
> >
> >I agree with this.  It is extremely useful for a variety of reasons (not
> >just the offload case), so please to do not remove it.
> No problem, I will keep it.
> 
> For my knowledge, can you explain these "variety of reasons"?

I maybe 'variety' was too strong of a word.  :)

The offload case has uses for it in the future as well as the case where
userspace deamons who are not sending the netlink message but are
monitoring netlink messages as a way to track port status.  Deamons that
would help broker multi-host LAGs are one such example.  

Though it does look like the only event that will happen when
NETDEV_CHANGEINFODATA is called is an RTM_NEWLINK, it will get used more
in the future, so please keep it.