Subject: Re: [PATCH net-next 7/9] devlink: allow registering parameters after the instance

From: Jakub Kicinski <[email-masked]>
Date: Thu, 12 Jan 2023 11:20:21 -0800

On Thu, 12 Jan 2023 09:07:43 +0200 Leon Romanovsky wrote:
> As a user, I don't want to see any late dynamic object addition which is
> not triggered by me explicitly. As it doesn't make any sense to add
> various delays per-vendor/kernel in configuration scripts just because
> not everything is ready. Users need predictability, lazy addition of
> objects adds chaos instead.
> 
> Agree with Jakub, it is anti-pattern.

To be clear my preference would be to always construct the three from
the root. Register the main instance, then sub-objects. I mean - you
tried forcing the opposite order and it only succeeded in 90-something
percent of cases. There's always special cases.

I don't understand your concern about user experience here. We have
notifications for each sub-object. Plus I think drivers should hold 
the instance lock throughout the probe routine. I don't see a scenario
in which registering the main instance first would lead to retry/sleep
hacks in user space, do you? I'm talking about devlink and the subobjs
we have specifically.