Re: [PATCH v2 net-next 3/3] tcp: make tcp_v{4,6}_send_check() static: manual merge

[Matthieu Baerts <matttbe@kernel.org>]

Hi Eric,

Thank you for the patch!

On 23/02/2026 11:07, Eric Dumazet wrote:
> tcp_v{4,6}_send_check() are only called from tcp_output.c
> and should be made static so that the compiler does not need
> to put an out of line copy of them.
> 
> Remove (struct inet_connection_sock_af_ops) send_check field
> and use instead @net_header_len.
> 
> Move @net_header_len close to @queue_xmit for data locality
> as both are used in TCP tx fast path.

(...)
> diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h
> index ecb362025c4e5183ec78aef4b45c249da87c19ea..bbc9355871c767b51e3d1a4d2436022a8556416c 100644
> --- a/include/net/inet_connection_sock.h
> +++ b/include/net/inet_connection_sock.h
> @@ -34,7 +34,7 @@ struct tcp_congestion_ops;
>   */
>  struct inet_connection_sock_af_ops {
>  	int	    (*queue_xmit)(struct sock *sk, struct sk_buff *skb, struct flowi *fl);
> -	void	    (*send_check)(struct sock *sk, struct sk_buff *skb);
> +	u16	    net_header_len;
>  	int	    (*rebuild_header)(struct sock *sk);
>  	void	    (*sk_rx_dst_set)(struct sock *sk, const struct sk_buff *skb);
>  	int	    (*conn_request)(struct sock *sk, struct sk_buff *skb);
> @@ -43,7 +43,6 @@ struct inet_connection_sock_af_ops {
>  				      struct dst_entry *dst,
>  				      struct request_sock *req_unhash,
>  				      bool *own_req);
> -	u16	    net_header_len;

FYI, I got a small conflict when merging 'net' in 'net-next' in the
MPTCP tree due to this patch applied in 'net':

  858d2a4f67ff ("tcp: fix potential race in tcp_v6_syn_recv_sock()")

and this one from 'net-next':

  fcd3d039fab6 ("tcp: make tcp_v{4,6}_send_check() static")

The conflict was in the context: here 'net_header_len' has been moved,
while in net-next, the line above has been modified. I'm sharing the 3w
patch resolving the conflict, just in case it can help others. Rerere
cache is available as well:

 https://github.com/multipath-tcp/mptcp-upstream-rr-cache/commit/d58bc4b

Cheers,
Matt
-- 
Sponsored by the NGI0 Core fund.

------------------------ 8< ------------------------
diff --cc include/net/inet_connection_sock.h
index 5cb3056d6ddc,bbc9355871c7..433c2df23076
--- a/include/net/inet_connection_sock.h
+++ b/include/net/inet_connection_sock.h
@@@ -42,10 -42,7 +42,9 @@@ struct inet_connection_sock_af_ops 
  				      struct request_sock *req,
  				      struct dst_entry *dst,
  				      struct request_sock *req_unhash,
 -				      bool *own_req);
 +				      bool *own_req,
 +				      void (*opt_child_init)(struct sock *newsk,
 +							     const struct sock *sk));
- 	u16	    net_header_len;
  	int	    (*setsockopt)(struct sock *sk, int level, int optname,
  				  sockptr_t optval, unsigned int optlen);
  	int	    (*getsockopt)(struct sock *sk, int level, int optname,
------------------------ 8< ------------------------