net: factor out __inet_listen_sk() helper

The mptcp protocol maintains an additional socket just to easily
invoke a few stream operations on the first subflow. One of them
is inet_listen().

Factor out an helper operating directly on the (locked) struct sock,
to allow get rid of the above dependency in the next patch without
duplicating the existing code.

No functional changes intended.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/inet_common.h b/include/net/inet_common.h
index 8e97de7009918a87ad86d479072d7261e94c26ee..f50a644d87a9871fbed2dfd49d4bde9d3df0fd92 100644 (file)
--- a/include/net/inet_common.h
+++ b/include/net/inet_common.h
@@ -40,6 +40,7 @@ int inet_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
                 int flags);
 int inet_shutdown(struct socket *sock, int how);
 int inet_listen(struct socket *sock, int backlog);
+int __inet_listen_sk(struct sock *sk, int backlog);
 void inet_sock_destruct(struct sock *sk);
 int inet_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len);
 int inet_bind_sk(struct sock *sk, struct sockaddr *uaddr, int addr_len);

diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 2fd23437c1d2e3d463f2c6620c46c0679fede0f8..c59da65f19d234fcaaf79abf6a80daaa53e27afc 100644 (file)
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -187,24 +187,13 @@ static int inet_autobind(struct sock *sk)
        return 0;
 }
 
-/*
- *     Move a socket into listening state.
- */
-int inet_listen(struct socket *sock, int backlog)
+int __inet_listen_sk(struct sock *sk, int backlog)
 {
-       struct sock *sk = sock->sk;
-       unsigned char old_state;
+       unsigned char old_state = sk->sk_state;
        int err, tcp_fastopen;
 
-       lock_sock(sk);
-
-       err = -EINVAL;
-       if (sock->state != SS_UNCONNECTED || sock->type != SOCK_STREAM)
-               goto out;
-
-       old_state = sk->sk_state;
        if (!((1 << old_state) & (TCPF_CLOSE | TCPF_LISTEN)))
-               goto out;
+               return -EINVAL;
 
        WRITE_ONCE(sk->sk_max_ack_backlog, backlog);
        /* Really, if the socket is already in listen state
@@ -227,10 +216,27 @@ int inet_listen(struct socket *sock, int backlog)
 
                err = inet_csk_listen_start(sk);
                if (err)
-                       goto out;
+                       return err;
+
                tcp_call_bpf(sk, BPF_SOCK_OPS_TCP_LISTEN_CB, 0, NULL);
        }
-       err = 0;
+       return 0;
+}
+
+/*
+ *     Move a socket into listening state.
+ */
+int inet_listen(struct socket *sock, int backlog)
+{
+       struct sock *sk = sock->sk;
+       int err = -EINVAL;
+
+       lock_sock(sk);
+
+       if (sock->state != SS_UNCONNECTED || sock->type != SOCK_STREAM)
+               goto out;
+
+       err = __inet_listen_sk(sk, backlog);
 
 out:
        release_sock(sk);