From 7439d687b79cbbd971c6a170be9aefda4a564be4 Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Fri, 27 Nov 2020 11:10:26 +0100 Subject: mptcp: avoid a few atomic ops in the rx path Extending the data_lock scope in mptcp_incoming_option we can use that to protect both snd_una and wnd_end. In the typical case, we will have a single atomic op instead of 2 Acked-by: Florian Westphal Signed-off-by: Paolo Abeni Reviewed-by: Mat Martineau Signed-off-by: Jakub Kicinski --- net/mptcp/protocol.c | 34 ++++++++++++++++------------------ 1 file changed, 16 insertions(+), 18 deletions(-) (limited to 'net/mptcp/protocol.c') diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 75b4c4c50dbb..51f92f3096bf 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -60,7 +60,7 @@ static struct socket *__mptcp_nmpc_socket(const struct mptcp_sock *msk) /* Returns end sequence number of the receiver's advertised window */ static u64 mptcp_wnd_end(const struct mptcp_sock *msk) { - return atomic64_read(&msk->wnd_end); + return READ_ONCE(msk->wnd_end); } static bool mptcp_is_tcpsk(struct sock *sk) @@ -358,7 +358,7 @@ static void mptcp_check_data_fin_ack(struct sock *sk) /* Look for an acknowledged DATA_FIN */ if (((1 << sk->sk_state) & (TCPF_FIN_WAIT1 | TCPF_CLOSING | TCPF_LAST_ACK)) && - msk->write_seq == atomic64_read(&msk->snd_una)) { + msk->write_seq == READ_ONCE(msk->snd_una)) { mptcp_stop_timer(sk); WRITE_ONCE(msk->snd_data_fin_enable, 0); @@ -764,7 +764,7 @@ bool mptcp_schedule_work(struct sock *sk) return false; } -void mptcp_data_acked(struct sock *sk) +void __mptcp_data_acked(struct sock *sk) { mptcp_reset_timer(sk); @@ -997,11 +997,11 @@ static void mptcp_clean_una(struct sock *sk) * plain TCP */ if (__mptcp_check_fallback(msk)) - atomic64_set(&msk->snd_una, msk->snd_nxt); + msk->snd_una = READ_ONCE(msk->snd_nxt); - mptcp_data_lock(sk); - snd_una = atomic64_read(&msk->snd_una); + mptcp_data_lock(sk); + snd_una = msk->snd_una; list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) { if (after64(dfrag->data_seq + dfrag->data_len, snd_una)) break; @@ -1282,10 +1282,12 @@ static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk, /* Zero window and all data acked? Probe. */ avail_size = mptcp_check_allowed_size(msk, data_seq, avail_size); if (avail_size == 0) { - if (skb || atomic64_read(&msk->snd_una) != msk->snd_nxt) + u64 snd_una = READ_ONCE(msk->snd_una); + + if (skb || snd_una != msk->snd_nxt) return 0; zero_window_probe = true; - data_seq = atomic64_read(&msk->snd_una) - 1; + data_seq = snd_una - 1; avail_size = 1; } @@ -1994,12 +1996,8 @@ static void mptcp_retransmit_handler(struct sock *sk) { struct mptcp_sock *msk = mptcp_sk(sk); - if (atomic64_read(&msk->snd_una) == READ_ONCE(msk->snd_nxt)) { - mptcp_stop_timer(sk); - } else { - set_bit(MPTCP_WORK_RTX, &msk->flags); - mptcp_schedule_work(sk); - } + set_bit(MPTCP_WORK_RTX, &msk->flags); + mptcp_schedule_work(sk); } static void mptcp_retransmit_timer(struct timer_list *t) @@ -2621,8 +2619,8 @@ struct sock *mptcp_sk_clone(const struct sock *sk, msk->write_seq = subflow_req->idsn + 1; msk->snd_nxt = msk->write_seq; - atomic64_set(&msk->snd_una, msk->write_seq); - atomic64_set(&msk->wnd_end, msk->snd_nxt + req->rsk_rcv_wnd); + msk->snd_una = msk->write_seq; + msk->wnd_end = msk->snd_nxt + req->rsk_rcv_wnd; if (mp_opt->mp_capable) { msk->can_ack = true; @@ -2658,7 +2656,7 @@ void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk) if (msk->rcvq_space.space == 0) msk->rcvq_space.space = TCP_INIT_CWND * TCP_MSS_DEFAULT; - atomic64_set(&msk->wnd_end, msk->snd_nxt + tcp_sk(ssk)->snd_wnd); + WRITE_ONCE(msk->wnd_end, msk->snd_nxt + tcp_sk(ssk)->snd_wnd); } static struct sock *mptcp_accept(struct sock *sk, int flags, int *err, @@ -2918,7 +2916,7 @@ void mptcp_finish_connect(struct sock *ssk) WRITE_ONCE(msk->ack_seq, ack_seq); WRITE_ONCE(msk->rcv_wnd_sent, ack_seq); WRITE_ONCE(msk->can_ack, 1); - atomic64_set(&msk->snd_una, msk->write_seq); + WRITE_ONCE(msk->snd_una, msk->write_seq); mptcp_pm_new_connection(msk, 0); -- cgit v1.2.3