From d440a4e27acdede686b974b62a6b2b2bd7914437 Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Fri, 2 Feb 2024 12:40:08 +0100 Subject: [PATCH] mptcp: annotate lockless access for the tx path The mptcp-level TX path info (write_seq, bytes_sent, snd_nxt) are under the msk socket lock protection, and are accessed lockless in a few spots. Always mark the write operations with WRITE_ONCE, read operations outside the lock with READ_ONCE and drop the annotation for read under such lock. To simplify the annotations move mptcp_pending_data_fin_ack() from __mptcp_data_acked() to __mptcp_clean_una(), under the msk socket lock, where such call would belong. Signed-off-by: Paolo Abeni Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Signed-off-by: David S. Miller --- net/mptcp/options.c | 2 +- net/mptcp/protocol.c | 15 +++++++-------- net/mptcp/protocol.h | 2 +- 3 files changed, 9 insertions(+), 10 deletions(-) diff --git a/net/mptcp/options.c b/net/mptcp/options.c index 5e2b130d86804..9b31a0a06265d 100644 --- a/net/mptcp/options.c +++ b/net/mptcp/options.c @@ -1060,7 +1060,7 @@ static void ack_update_msk(struct mptcp_sock *msk, msk->wnd_end = new_wnd_end; /* this assumes mptcp_incoming_options() is invoked after tcp_ack() */ - if (after64(msk->wnd_end, READ_ONCE(msk->snd_nxt))) + if (after64(msk->wnd_end, snd_nxt)) __mptcp_check_push(sk, ssk); if (after64(new_snd_una, old_snd_una)) { diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 874f019c5093a..b1c24ac3630ff 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -1033,13 +1033,15 @@ static void __mptcp_clean_una(struct sock *sk) msk->recovery = false; out: - if (snd_una == READ_ONCE(msk->snd_nxt) && - snd_una == READ_ONCE(msk->write_seq)) { + if (snd_una == msk->snd_nxt && snd_una == msk->write_seq) { if (mptcp_rtx_timer_pending(sk) && !mptcp_data_fin_enabled(msk)) mptcp_stop_rtx_timer(sk); } else { mptcp_reset_rtx_timer(sk); } + + if (mptcp_pending_data_fin_ack(sk)) + mptcp_schedule_work(sk); } static void __mptcp_clean_una_wakeup(struct sock *sk) @@ -1499,7 +1501,7 @@ static void mptcp_update_post_push(struct mptcp_sock *msk, */ if (likely(after64(snd_nxt_new, msk->snd_nxt))) { msk->bytes_sent += snd_nxt_new - msk->snd_nxt; - msk->snd_nxt = snd_nxt_new; + WRITE_ONCE(msk->snd_nxt, snd_nxt_new); } } @@ -3200,8 +3202,8 @@ struct sock *mptcp_sk_clone_init(const struct sock *sk, if (mp_opt->suboptions & OPTION_MPTCP_CSUMREQD) WRITE_ONCE(msk->csum_enabled, true); - msk->write_seq = subflow_req->idsn + 1; - msk->snd_nxt = msk->write_seq; + WRITE_ONCE(msk->write_seq, subflow_req->idsn + 1); + WRITE_ONCE(msk->snd_nxt, msk->write_seq); msk->snd_una = msk->write_seq; msk->wnd_end = msk->snd_nxt + req->rsk_rcv_wnd; msk->setsockopt_seq = mptcp_sk(sk)->setsockopt_seq; @@ -3303,9 +3305,6 @@ void __mptcp_data_acked(struct sock *sk) __mptcp_clean_una(sk); else __set_bit(MPTCP_CLEAN_UNA, &mptcp_sk(sk)->cb_flags); - - if (mptcp_pending_data_fin_ack(sk)) - mptcp_schedule_work(sk); } void __mptcp_check_push(struct sock *sk, struct sock *ssk) diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index 13b8cf8ec7044..421dede93e2b7 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -402,7 +402,7 @@ static inline struct mptcp_data_frag *mptcp_rtx_head(struct sock *sk) { struct mptcp_sock *msk = mptcp_sk(sk); - if (msk->snd_una == READ_ONCE(msk->snd_nxt)) + if (msk->snd_una == msk->snd_nxt) return NULL; return list_first_entry_or_null(&msk->rtx_queue, struct mptcp_data_frag, list);