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mptcp: avoid additional __inet_stream_connect() call

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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: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Paolo Abeni 2023-08-11 17:57:15 +02:00 committed by David S. Miller
parent 131a627751
commit ccae357c1c
1 changed files with 33 additions and 16 deletions
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49
net/mptcp/protocol.c
View file

@ -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;
}