mptcp: refactor mptcp_stream_accept()

Rewrite the mptcp socket accept op, leveraging the new
__inet_accept() helper.

This way we can avoid acquiring the new socket lock twice
and we can avoid a couple of indirect calls.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 08dc53f..2d331b2 100644 (file)
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -3747,6 +3747,7 @@ static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
 {
        struct mptcp_sock *msk = mptcp_sk(sock->sk);
        struct socket *ssock;
+       struct sock *newsk;
        int err;
 
        pr_debug("msk=%p", msk);
@@ -3758,17 +3759,20 @@ static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
        if (!ssock)
                return -EINVAL;
 
-       err = ssock->ops->accept(sock, newsock, flags, kern);
-       if (err == 0 && !mptcp_is_tcpsk(newsock->sk)) {
-               struct mptcp_sock *msk = mptcp_sk(newsock->sk);
+       newsk = mptcp_accept(sock->sk, flags, &err, kern);
+       if (!newsk)
+               return err;
+
+       lock_sock(newsk);
+
+       __inet_accept(sock, newsock, newsk);
+       if (!mptcp_is_tcpsk(newsock->sk)) {
+               struct mptcp_sock *msk = mptcp_sk(newsk);
                struct mptcp_subflow_context *subflow;
-               struct sock *newsk = newsock->sk;
 
                set_bit(SOCK_CUSTOM_SOCKOPT, &newsock->flags);
                msk->in_accept_queue = 0;
 
-               lock_sock(newsk);
-
                /* set ssk->sk_socket of accept()ed flows to mptcp socket.
                 * This is needed so NOSPACE flag can be set from tcp stack.
                 */
@@ -3789,11 +3793,10 @@ static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
                        if (unlikely(list_empty(&msk->conn_list)))
                                inet_sk_state_store(newsk, TCP_CLOSE);
                }
-
-               release_sock(newsk);
        }
+       release_sock(newsk);
 
-       return err;
+       return 0;
 }
 
 static __poll_t mptcp_check_writeable(struct mptcp_sock *msk)