Re: [PATCH bpf-next] bpf, unix: Guard sk_msg-dependent code behind CONFIG_NET_SOCK_MSG

[Jakub Sitnicki <jakub@cloudflare.com>]

On Mon, Jun 22, 2026 at 04:11 PM GMT, Kuniyuki Iwashima wrote:
> From: Jakub Sitnicki <jakub@cloudflare.com>
> Date: Mon, 22 Jun 2026 14:58:34 +0200
>> Prepare to decouple BPF_SYSCALL config option from NET_SOCK_MSG.
>> 
>> Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
>> ---
>>  net/unix/unix_bpf.c | 6 ++++++
>
> AFAIU, everyhing in this file is for BPF_SYSCALL && NET_SOCK_MSG,
> or am I missing something ?
>
> I feel that it would be cleaner to add a new Kconfig that depends
> on BPF_SYSCALL and NET_SOCK_MSG, change Makefile obj-$(CONFIG_XXX),
> and guard .psock_update_sk_prot in af_unix.c

What I'm aiming for is to have all code for sockmap-based redirects
behind BPF_SYSCALL && NET_SOCK_MSG, and the rest, which is the
implementation of sockmap container for socket refs, behind just
BPF_SYSCALL.

You're right that in the unix_bpf case, the whole file could be behind
BPF_SYSCALL && NET_SOCK_MSG because while you can keep refs to Unix
sockets in sockmap without doing redirects, it won't be of much use
(there's no sk_lookup or tc-sk_assign).

We can add a new config but I won't be able to follow that pattern for
either tcp_bpf and udp_bpf, which are next in line.