tcp: remove inet_rtx_syn_ack()

inet_rtx_syn_ack() is a simple wrapper around tcp_rtx_synack(),
if we move req->num_retrans update.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250626153017.2156274-3-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: edumazet

include/net/request_sock.h

@@ -39,8 +39,6 @@ struct request_sock_ops {
 	void		(*syn_ack_timeout)(const struct request_sock *req);
 };
 
-int inet_rtx_syn_ack(const struct sock *parent, struct request_sock *req);
-
 struct saved_syn {
 	u32 mac_hdrlen;
 	u32 network_hdrlen;

net/ipv4/inet_connection_sock.c

@@ -884,15 +884,6 @@ static void syn_ack_recalc(struct request_sock *req,
 		  req->num_timeout >= rskq_defer_accept - 1;
 }
 
-int inet_rtx_syn_ack(const struct sock *parent, struct request_sock *req)
-{
-	int err = tcp_rtx_synack(parent, req);
-
-	if (!err)
-		req->num_retrans++;
-	return err;
-}
-
 static struct request_sock *
 reqsk_alloc_noprof(const struct request_sock_ops *ops, struct sock *sk_listener,
 		   bool attach_listener)
@@ -1132,7 +1123,7 @@ static void reqsk_timer_handler(struct timer_list *t)
 	req->rsk_ops->syn_ack_timeout(req);
 	if (!expire &&
 	    (!resend ||
-	     !inet_rtx_syn_ack(sk_listener, req) ||
+	     !tcp_rtx_synack(sk_listener, req) ||
 	     inet_rsk(req)->acked)) {
 		if (req->num_timeout++ == 0)
 			atomic_dec(&queue->young);

net/ipv4/tcp_minisocks.c

@@ -726,7 +726,7 @@ struct sock *tcp_check_req(struct sock *sk, struct sk_buff *skb,
 					  LINUX_MIB_TCPACKSKIPPEDSYNRECV,
 					  &tcp_rsk(req)->last_oow_ack_time) &&
 
-		    !inet_rtx_syn_ack(sk, req)) {
+		    !tcp_rtx_synack(sk, req)) {
 			unsigned long expires = jiffies;
 
 			expires += reqsk_timeout(req, TCP_RTO_MAX);

net/ipv4/tcp_output.c

@@ -4425,6 +4425,7 @@ int tcp_rtx_synack(const struct sock *sk, struct request_sock *req)
 			tcp_sk_rw(sk)->total_retrans++;
 		}
 		trace_tcp_retransmit_synack(sk, req);
+		req->num_retrans++;
 	}
 	return res;
 }

net/ipv4/tcp_timer.c

@@ -478,7 +478,7 @@ static void tcp_fastopen_synack_timer(struct sock *sk, struct request_sock *req)
 	 * regular retransmit because if the child socket has been accepted
 	 * it's not good to give up too easily.
 	 */
-	inet_rtx_syn_ack(sk, req);
+	tcp_rtx_synack(sk, req);
 	req->num_timeout++;
 	tcp_update_rto_stats(sk);
 	if (!tp->retrans_stamp)