Re: [PATCH v2 net-next] net: Deprecate SO_DEBUG and reclaim SOCK_DBG bit.

[Matthieu Baerts <matttbe@kernel.org>]

Hi Kuniyuki,

On 14/02/2024 20:54, Kuniyuki Iwashima wrote:
> Recently, commit 8e5443d2b866 ("net: remove SOCK_DEBUG leftovers")
> removed the last users of SOCK_DEBUG(), and commit b1dffcf0da22 ("net:
> remove SOCK_DEBUG macro") removed the macro.
> 
> Now is the time to deprecate the oldest socket option.
> 
> Note that setsockopt(SO_DEBUG) is moved not to acquire lock_sock().
> 
> Reviewed-by: Gerd Bayer <gbayer@linux.ibm.com>
> Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
> ---
> v2:
>   * Move setsockopt(SO_DEBUG) code not to acquire lock_sock().

Thank you for the v2!

Good idea to have modified that in net/core/sock.c too!

Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>


I don't think we need to do anything else, but just to be sure: do we
need to tell the userspace this socket option has been deprecated?
SO_DEBUG is a bit particular, so I guess it is fine not to do anything
else, but except by looking at the kernel version, I don't think the
userspace can know it has no more effect.

I didn't find many examples of other deprecated socket options, apart
from SO_BSDCOMPAT. For years, there was a warning, removed a few years
ago: f4ecc748533d ("net: Stop warning about SO_BSDCOMPAT usage"). I
guess we don't want that for SO_DEBUG, right?

Cheers,
Matt
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