bpf, tcp: Make tcp_bpf_recvmsg static

After commit f747632b608f ("bpf: sockmap: Move generic sockmap
hooks from BPF TCP"), tcp_bpf_recvmsg() is not used out of
tcp_bpf.c, so make it static and remove it from tcp.h. Also move
it to BPF_STREAM_PARSER #ifdef to fix unused function warnings.

Fixes: f747632b608f ("bpf: sockmap: Move generic sockmap hooks from BPF TCP")
Signed-off-by: YueHaibing <[e-mail]>
Signed-off-by: Daniel Borkmann <[e-mail]>
Acked-by: Yonghong Song <[e-mail]>
Link: https://lore.kernel.org/bpf/[e-mail]

include/net/tcp.h

···
 #ifdef CONFIG_NET_SOCK_MSG
 int tcp_bpf_sendmsg_redir(struct sock *sk, struct sk_msg *msg, u32 bytes,
 			  int flags);
-int tcp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
-		    int nonblock, int flags, int *addr_len);
 int __tcp_bpf_recvmsg(struct sock *sk, struct sk_psock *psock,
 		      struct msghdr *msg, int len, int flags);
 #endif /* CONFIG_NET_SOCK_MSG */

net/ipv4/tcp_bpf.c

···
 #include <net/inet_common.h>
 #include <net/tls.h>
 
-static int tcp_bpf_wait_data(struct sock *sk, struct sk_psock *psock,
-			     int flags, long timeo, int *err)
-{
-	DEFINE_WAIT_FUNC(wait, woken_wake_function);
-	int ret = 0;
-
-	if (!timeo)
-		return ret;
-
-	add_wait_queue(sk_sleep(sk), &wait);
-	sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
-	ret = sk_wait_event(sk, &timeo,
-			    !list_empty(&psock->ingress_msg) ||
-			    !skb_queue_empty(&sk->sk_receive_queue), &wait);
-	sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
-	remove_wait_queue(sk_sleep(sk), &wait);
-	return ret;
-}
-
 int __tcp_bpf_recvmsg(struct sock *sk, struct sk_psock *psock,
 		      struct msghdr *msg, int len, int flags)
 {
···
 	return copied;
 }
 EXPORT_SYMBOL_GPL(__tcp_bpf_recvmsg);
-
-int tcp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
-		    int nonblock, int flags, int *addr_len)
-{
-	struct sk_psock *psock;
-	int copied, ret;
-
-	psock = sk_psock_get(sk);
-	if (unlikely(!psock))
-		return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len);
-	if (unlikely(flags & MSG_ERRQUEUE))
-		return inet_recv_error(sk, msg, len, addr_len);
-	if (!skb_queue_empty(&sk->sk_receive_queue) &&
-	    sk_psock_queue_empty(psock))
-		return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len);
-	lock_sock(sk);
-msg_bytes_ready:
-	copied = __tcp_bpf_recvmsg(sk, psock, msg, len, flags);
-	if (!copied) {
-		int data, err = 0;
-		long timeo;
-
-		timeo = sock_rcvtimeo(sk, nonblock);
-		data = tcp_bpf_wait_data(sk, psock, flags, timeo, &err);
-		if (data) {
-			if (!sk_psock_queue_empty(psock))
-				goto msg_bytes_ready;
-			release_sock(sk);
-			sk_psock_put(sk, psock);
-			return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len);
-		}
-		if (err) {
-			ret = err;
-			goto out;
-		}
-		copied = -EAGAIN;
-	}
-	ret = copied;
-out:
-	release_sock(sk);
-	sk_psock_put(sk, psock);
-	return ret;
-}
 
 static int bpf_tcp_ingress(struct sock *sk, struct sk_psock *psock,
 			   struct sk_msg *msg, u32 apply_bytes, int flags)
···
 		empty = list_empty(&psock->ingress_msg);
 	rcu_read_unlock();
 	return !empty;
+}
+
+static int tcp_bpf_wait_data(struct sock *sk, struct sk_psock *psock,
+			     int flags, long timeo, int *err)
+{
+	DEFINE_WAIT_FUNC(wait, woken_wake_function);
+	int ret = 0;
+
+	if (!timeo)
+		return ret;
+
+	add_wait_queue(sk_sleep(sk), &wait);
+	sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
+	ret = sk_wait_event(sk, &timeo,
+			    !list_empty(&psock->ingress_msg) ||
+			    !skb_queue_empty(&sk->sk_receive_queue), &wait);
+	sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
+	remove_wait_queue(sk_sleep(sk), &wait);
+	return ret;
+}
+
+static int tcp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
+		    int nonblock, int flags, int *addr_len)
+{
+	struct sk_psock *psock;
+	int copied, ret;
+
+	psock = sk_psock_get(sk);
+	if (unlikely(!psock))
+		return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len);
+	if (unlikely(flags & MSG_ERRQUEUE))
+		return inet_recv_error(sk, msg, len, addr_len);
+	if (!skb_queue_empty(&sk->sk_receive_queue) &&
+	    sk_psock_queue_empty(psock))
+		return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len);
+	lock_sock(sk);
+msg_bytes_ready:
+	copied = __tcp_bpf_recvmsg(sk, psock, msg, len, flags);
+	if (!copied) {
+		int data, err = 0;
+		long timeo;
+
+		timeo = sock_rcvtimeo(sk, nonblock);
+		data = tcp_bpf_wait_data(sk, psock, flags, timeo, &err);
+		if (data) {
+			if (!sk_psock_queue_empty(psock))
+				goto msg_bytes_ready;
+			release_sock(sk);
+			sk_psock_put(sk, psock);
+			return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len);
+		}
+		if (err) {
+			ret = err;
+			goto out;
+		}
+		copied = -EAGAIN;
+	}
+	ret = copied;
+out:
+	release_sock(sk);
+	sk_psock_put(sk, psock);
+	return ret;
 }
 
 static int tcp_bpf_send_verdict(struct sock *sk, struct sk_psock *psock,