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

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

[Jakub Sitnicki]

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 ++++++
 1 file changed, 6 insertions(+)

diff --git a/net/unix/unix_bpf.c b/net/unix/unix_bpf.c
index f86ff19e9764..5289a04b4993 100644
--- a/net/unix/unix_bpf.c
+++ b/net/unix/unix_bpf.c
@@ -7,6 +7,7 @@
 
 #include "af_unix.h"
 
+#ifdef CONFIG_NET_SOCK_MSG
 #define unix_sk_has_data(__sk, __psock)					\
 		({	!skb_queue_empty(&__sk->sk_receive_queue) ||	\
 			!skb_queue_empty(&__psock->ingress_skb) ||	\
@@ -94,6 +95,7 @@ static int unix_bpf_recvmsg(struct sock *sk, struct msghdr *msg,
 	sk_psock_put(sk, psock);
 	return copied;
 }
+#endif /* CONFIG_NET_SOCK_MSG */
 
 static struct proto *unix_dgram_prot_saved __read_mostly;
 static DEFINE_SPINLOCK(unix_dgram_prot_lock);
@@ -107,8 +109,10 @@ static void unix_dgram_bpf_rebuild_protos(struct proto *prot, const struct proto
 {
 	*prot        = *base;
 	prot->close  = sock_map_close;
+#ifdef CONFIG_NET_SOCK_MSG
 	prot->recvmsg = unix_bpf_recvmsg;
 	prot->sock_is_readable = sk_msg_is_readable;
+#endif
 }
 
 static void unix_stream_bpf_rebuild_protos(struct proto *prot,
@@ -116,8 +120,10 @@ static void unix_stream_bpf_rebuild_protos(struct proto *prot,
 {
 	*prot        = *base;
 	prot->close  = sock_map_close;
+#ifdef CONFIG_NET_SOCK_MSG
 	prot->recvmsg = unix_bpf_recvmsg;
 	prot->sock_is_readable = sk_msg_is_readable;
+#endif
 	prot->unhash  = sock_map_unhash;
 }
 

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

[Kuniyuki Iwashima]

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


>  1 file changed, 6 insertions(+)
> 
> diff --git a/net/unix/unix_bpf.c b/net/unix/unix_bpf.c
> index f86ff19e9764..5289a04b4993 100644
> --- a/net/unix/unix_bpf.c
> +++ b/net/unix/unix_bpf.c
> @@ -7,6 +7,7 @@
>  
>  #include "af_unix.h"
>  
> +#ifdef CONFIG_NET_SOCK_MSG
>  #define unix_sk_has_data(__sk, __psock)					\
>  		({	!skb_queue_empty(&__sk->sk_receive_queue) ||	\
>  			!skb_queue_empty(&__psock->ingress_skb) ||	\
> @@ -94,6 +95,7 @@ static int unix_bpf_recvmsg(struct sock *sk, struct msghdr *msg,
>  	sk_psock_put(sk, psock);
>  	return copied;
>  }
> +#endif /* CONFIG_NET_SOCK_MSG */
>  
>  static struct proto *unix_dgram_prot_saved __read_mostly;
>  static DEFINE_SPINLOCK(unix_dgram_prot_lock);
> @@ -107,8 +109,10 @@ static void unix_dgram_bpf_rebuild_protos(struct proto *prot, const struct proto
>  {
>  	*prot        = *base;
>  	prot->close  = sock_map_close;
> +#ifdef CONFIG_NET_SOCK_MSG
>  	prot->recvmsg = unix_bpf_recvmsg;
>  	prot->sock_is_readable = sk_msg_is_readable;
> +#endif
>  }
>  
>  static void unix_stream_bpf_rebuild_protos(struct proto *prot,
> @@ -116,8 +120,10 @@ static void unix_stream_bpf_rebuild_protos(struct proto *prot,
>  {
>  	*prot        = *base;
>  	prot->close  = sock_map_close;
> +#ifdef CONFIG_NET_SOCK_MSG
>  	prot->recvmsg = unix_bpf_recvmsg;
>  	prot->sock_is_readable = sk_msg_is_readable;
> +#endif
>  	prot->unhash  = sock_map_unhash;
>  }
>  
> 

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

[Jakub Sitnicki]

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.