Commit ccae357c authored by Paolo Abeni's avatar Paolo Abeni Committed by David S. Miller
Browse files

mptcp: avoid additional __inet_stream_connect() call 



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

We are going to remove the first subflow socket soon, so avoid
the additional indirection via at connect time, calling directly
into the sock-level connect() ops.

The sk-level connect never return -EINPROGRESS, cleanup the error
path accordingly. Additionally, the ssk status on error is always
TCP_CLOSE. Avoid unneeded access to the subflow sk state.

No functional change intended.

Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
Reviewed-by: default avatarMat Martineau <martineau@kernel.org>
Signed-off-by: default avatarMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 131a6277

net/mptcp/protocol.c

+33 −16
Original line number Diff line number Diff line
@@ -3589,22 +3589,24 @@ static int mptcp_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) 
	struct mptcp_sock *msk = mptcp_sk(sk);

	struct socket *ssock;

	int err = -EINVAL;

	struct sock *ssk;



	ssock = __mptcp_nmpc_socket(msk);

	if (IS_ERR(ssock))

		return PTR_ERR(ssock);



	inet_sk_state_store(sk, TCP_SYN_SENT);

	subflow = mptcp_subflow_ctx(ssock->sk);

	ssk = msk->first;

	subflow = mptcp_subflow_ctx(ssk);

#ifdef CONFIG_TCP_MD5SIG

	/* no MPTCP if MD5SIG is enabled on this socket or we may run out of

	 * TCP option space.

	 */

	if (rcu_access_pointer(tcp_sk(ssock->sk)->md5sig_info))

	if (rcu_access_pointer(tcp_sk(ssk)->md5sig_info))

		mptcp_subflow_early_fallback(msk, subflow);

#endif

	if (subflow->request_mptcp && mptcp_token_new_connect(ssock->sk)) {

		MPTCP_INC_STATS(sock_net(ssock->sk), MPTCP_MIB_TOKENFALLBACKINIT);

	if (subflow->request_mptcp && mptcp_token_new_connect(ssk)) {

		MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_TOKENFALLBACKINIT);

		mptcp_subflow_early_fallback(msk, subflow);

	}

	if (likely(!__mptcp_check_fallback(msk)))
@@ -3613,27 +3615,42 @@ static int mptcp_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) 
	/* if reaching here via the fastopen/sendmsg path, the caller already

	 * acquired the subflow socket lock, too.

	 */

	if (msk->fastopening)

		err = __inet_stream_connect(ssock, uaddr, addr_len, O_NONBLOCK, 1);

	else

		err = inet_stream_connect(ssock, uaddr, addr_len, O_NONBLOCK);

	inet_sk(sk)->defer_connect = inet_sk(ssock->sk)->defer_connect;

	if (!msk->fastopening)

		lock_sock(ssk);



	/* the following mirrors closely a very small chunk of code from

	 * __inet_stream_connect()

	 */

	if (ssk->sk_state != TCP_CLOSE)

		goto out;



	if (BPF_CGROUP_PRE_CONNECT_ENABLED(ssk)) {

		err = ssk->sk_prot->pre_connect(ssk, uaddr, addr_len);

		if (err)

			goto out;

	}



	err = ssk->sk_prot->connect(ssk, uaddr, addr_len);

	if (err < 0)

		goto out;



	inet_sk(sk)->defer_connect = inet_sk(ssk)->defer_connect;



out:

	if (!msk->fastopening)

		release_sock(ssk);



	/* on successful connect, the msk state will be moved to established by

	 * subflow_finish_connect()

	 */

	if (unlikely(err && err != -EINPROGRESS)) {

	if (unlikely(err)) {

		/* avoid leaving a dangling token in an unconnected socket */

		mptcp_token_destroy(msk);

		inet_sk_state_store(sk, inet_sk_state_load(ssock->sk));

		inet_sk_state_store(sk, TCP_CLOSE);

		return err;

	}



	mptcp_copy_inaddrs(sk, ssock->sk);



	/* silence EINPROGRESS and let the caller inet_stream_connect

	 * handle the connection in progress

	 */

	mptcp_copy_inaddrs(sk, ssk);

	return 0;

}