Re: [PATCH net v2 06/11] netdevsim: add dummy device notifiers

[Jakub Kicinski <kuba@kernel.org>]

On Thu, 27 Mar 2025 14:04:06 -0700 Stanislav Fomichev wrote:
> > Can we register empty notifiers in nsim (just to make sure it has 
> > a callback) but do the validation in rtnl_net_debug.c
> > I guess we'd need to transform rtnl_net_debug.c a little,
> > make it less rtnl specific, compile under DEBUG_NET and ifdef
> > out the small rtnl parts?  
> 
> s/rtnl_net_debug.c/notifiers_debug.c/ + DEBUG_NET? Or I can keep the
> name and only do the DEBUG_NET part. 

I was thinking lock or locking as in net/core/lock_debug.c
But yeah, it's locking in notifier locking, maybe
net/core/notifier_lock_debug.c then? No strong feelings.

> Not sure what needs to be ifdef-ed out,
> but will take a look (probably just enough to make it compile with
> !CONFIG_DEBUG_NET_SMALL_RTNL ?).

You're right, looking at the code we need all of it.
Somehow I thought its doing extra netns related stuff but it just
register a notifier in each ns. 
I guess we may not need any ifdef at all.

> That should work for the regular notifiers,
> but I think register_netdevice_notifier_dev_net needs a netdev?

Hm. Yes. Not sure if we need anything extra in the notifier for nsim 
or we just want to make make sure it registers one. If the latter
I guess we could export rtnl_net_debug_event (modulo rename) and
call it from netdevsim? I mean - we would probably have the same
exact asserts in both?