From: "Toke Høiland-Jørgensen" <toke@redhat•com>
To: Jakub Kicinski <kuba@kernel•org>
Cc: "David S. Miller" <davem@davemloft•net>,
Eric Dumazet <edumazet@google•com>,
Paolo Abeni <pabeni@redhat•com>, Simon Horman <horms@kernel•org>,
netdev@vger•kernel.org
Subject: Re: [PATCH net-next] rtnetlink: Allow setting IFLA_PERM_ADDRESS at device creation time
Date: Tue, 18 Feb 2025 13:51:42 +0100 [thread overview]
Message-ID: <874j0ro1pd.fsf@toke.dk> (raw)
In-Reply-To: <20250217095150.12cdec05@kernel.org>
Jakub Kicinski <kuba@kernel•org> writes:
> On Thu, 13 Feb 2025 17:13:53 +0100 Toke Høiland-Jørgensen wrote:
>> Jakub Kicinski <kuba@kernel•org> writes:
>>
>> > On Thu, 13 Feb 2025 14:45:22 +0100 Toke Høiland-Jørgensen wrote:
>> >> Eric suggested[0] allowing user-settable values for dev->perm_addr at
>> >> device creation time, instead of mucking about with netdevsim to get a
>> >> virtual device with a permanent address set.
>> >
>> > I vote no. Complicating the core so that its easier for someone
>> > to write a unit test is the wrong engineering trade off.
>> > Use a VM or netdevsim, that's what they are for.
>>
>> Hmm, and you don't see any value in being able to specify a permanent
>> identifier for virtual devices? That bit was not just motivated
>> reasoning on my part... :)
>
> I can't think of any :( Specifying an address is already possible.
Right, but the address can be changed later. Setting the perm_addr makes
it possible for a management daemon to set a unique identifier at device
creation time which is guaranteed to persist through any renames and
address changes that other utilities may perform. That seems like a
useful robustness feature that comes at a relatively low cost (the patch
is fairly small and uncomplicated)?
> Permanent address is a property of the hardware platform.
> Virtual devices OTOH are primarily used by containers,
> which are ephemeral by design. At least that's my mental model.
Sure, any device feature that comes from hardware is only going to fit
virtual devices by analogy. But I don't think the analogy here is super
far fetched (cf the above)? :)
-Toke
next prev parent reply other threads:[~2025-02-18 12:51 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-13 13:45 [PATCH net-next] rtnetlink: Allow setting IFLA_PERM_ADDRESS at device creation time Toke Høiland-Jørgensen
2025-02-13 15:40 ` Jakub Kicinski
2025-02-13 16:13 ` Toke Høiland-Jørgensen
2025-02-17 17:51 ` Jakub Kicinski
2025-02-18 12:51 ` Toke Høiland-Jørgensen [this message]
2025-02-18 14:37 ` Jakub Kicinski
2025-02-18 20:14 ` Toke Høiland-Jørgensen
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