Thread (29 messages) flat view 29 messages, 4 authors, 2021-10-27

Re: [PATCH net-next] netdevsim: Register and unregister devlink traps on probe/remove device

From: Ido Schimmel <hidden>
Date: 2021-10-26 14:09:58
Also in: lkml

On Tue, Oct 26, 2021 at 10:18:12AM +0300, Leon Romanovsky wrote:
On Tue, Oct 26, 2021 at 09:51:13AM +0300, Ido Schimmel wrote:

<...>
quoted
quoted
Can you please explain why is it so important to touch devlink SW
objects, reallocate them again and again on every reload in mlxsw?
Because that's how reload was defined and implemented. A complete
reload. We are not changing the semantics 4 years later.
Please put your emotions aside and explain me technically why are you
must to do it?
Already did. The current semantics are "devlink-reload provides
mechanism to reinit driver entities, applying devlink-params and
devlink-resources new values. It also provides mechanism to activate
firmware."

And this is exactly what netdevsim and mlxsw are doing. Driver entities
are re-initialized. Your patch breaks that as entities are not
re-initialized, which results in user space breakage. You simply cannot
introduce such regressions.
The proposed semantics was broken for last 4 years, it can even seen as
dead on arrival,
Again with the bombastic statements. It was "dead on arrival" like the
notifications were "impossible"?
because it never worked for us in real production.
Who is "us"? mlx5 that apparently decided to do its own thing?

We are using reload in mlxsw on a daily basis and users are using it to
re-partition ASIC resources and activate firmware. There are tests over
netdevsim implementation that anyone can run for testing purposes. We
also made sure to integrate it into syzkaller:

https://github.com/google/syzkaller/commit/5b49e1f605a770e8f8fcdcbd1a8ff85591fc0c8e
https://github.com/google/syzkaller/commit/04ca72cd45348daab9d896bbec8ea4c2d13455ac
https://github.com/google/syzkaller/commit/6930bbef3b671ae21f74007f9e59efb9b236b93f
https://github.com/google/syzkaller/commit/d45a4d69d83f40579e74fb561e1583db1be0e294
https://github.com/google/syzkaller/commit/510951950dc0ee69cfdaf746061d3dbe31b49fd8

Which is why the regressions you introduced were discovered so quickly.
So I'm fixing bugs without relation to when they were introduced.
We all do
For example, this fix from Jiri [1] for basic design flow was merged almost
two years later after devlink reload was introduced [2], or this patch from
Parav [3] that fixed an issue introduced year before [4].
What is your point? That code has bugs?

By now I have spent more time arguing with you than you spent testing
your patches and it's clear this discussion is not going anywhere.

Are you going to send a revert or I will? This is the fourth time I'm
asking you.
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