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mptcp: cleanup accept and poll

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After the previous patch,  msk->subflow will never be deleted during
the whole msk lifetime. We don't need anymore to acquire references to
it in mptcp_stream_accept() and we can use the listener subflow accept
queue to simplify mptcp_poll() for listener socket.

Overall this removes a lock pair and 4 more atomic operations per
accept().

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Paolo Abeni
2022-01-06 16:20:17 -08:00
committed by David S. Miller
parent b29fcfb54c
commit 71ba088ce0
3 changed files with 7 additions and 20 deletions
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25
net/mptcp/protocol.c
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@ -3493,17 +3493,9 @@ static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
pr_debug("msk=%p", msk);
lock_sock(sock->sk);
if (sock->sk->sk_state != TCP_LISTEN)
goto unlock_fail;
ssock = __mptcp_nmpc_socket(msk);
if (!ssock)
goto unlock_fail;
clear_bit(MPTCP_DATA_READY, &msk->flags);
sock_hold(ssock->sk);
release_sock(sock->sk);
return -EINVAL;
err = ssock->ops->accept(sock, newsock, flags, kern);
if (err == 0 && !mptcp_is_tcpsk(newsock->sk)) {
@ -3543,14 +3535,7 @@ static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
release_sock(newsk);
}
if (inet_csk_listen_poll(ssock->sk))
set_bit(MPTCP_DATA_READY, &msk->flags);
sock_put(ssock->sk);
return err;
unlock_fail:
release_sock(sock->sk);
return -EINVAL;
}
static __poll_t mptcp_check_readable(struct mptcp_sock *msk)
@ -3596,8 +3581,12 @@ static __poll_t mptcp_poll(struct file *file, struct socket *sock,
state = inet_sk_state_load(sk);
pr_debug("msk=%p state=%d flags=%lx", msk, state, msk->flags);
if (state == TCP_LISTEN)
return test_bit(MPTCP_DATA_READY, &msk->flags) ? EPOLLIN | EPOLLRDNORM : 0;
if (state == TCP_LISTEN) {
if (WARN_ON_ONCE(!msk->subflow || !msk->subflow->sk))
return 0;
return inet_csk_listen_poll(msk->subflow->sk);
}
if (state != TCP_SYN_SENT && state != TCP_SYN_RECV) {
mask |= mptcp_check_readable(msk);