From b111d8fbd2cbc63e05f3adfbbe0d4df655dfcc5b Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Fri, 23 Feb 2024 17:14:16 +0100 Subject: mptcp: fix potential wake-up event loss After the blamed commit below, the send buffer auto-tuning can happen after that the mptcp_propagate_sndbuf() completes - via the delegated action infrastructure. We must check for write space even after such change or we risk missing the wake-up event. Fixes: 8005184fd1ca ("mptcp: refactor sndbuf auto-tuning") Cc: stable@vger.kernel.org Signed-off-by: Paolo Abeni Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Link: https://lore.kernel.org/r/20240223-upstream-net-20240223-misc-fixes-v1-6-162e87e48497@kernel.org Signed-off-by: Jakub Kicinski --- net/mptcp/protocol.h | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) (limited to 'net/mptcp') diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index 631a7f445f34..07f6242afc1a 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -790,6 +790,16 @@ static inline bool mptcp_data_fin_enabled(const struct mptcp_sock *msk) READ_ONCE(msk->write_seq) == READ_ONCE(msk->snd_nxt); } +static inline void mptcp_write_space(struct sock *sk) +{ + if (sk_stream_is_writeable(sk)) { + /* pairs with memory barrier in mptcp_poll */ + smp_mb(); + if (test_and_clear_bit(MPTCP_NOSPACE, &mptcp_sk(sk)->flags)) + sk_stream_write_space(sk); + } +} + static inline void __mptcp_sync_sndbuf(struct sock *sk) { struct mptcp_subflow_context *subflow; @@ -808,6 +818,7 @@ static inline void __mptcp_sync_sndbuf(struct sock *sk) /* the msk max wmem limit is * tcp wmem[2] */ WRITE_ONCE(sk->sk_sndbuf, new_sndbuf); + mptcp_write_space(sk); } /* The called held both the msk socket and the subflow socket locks, @@ -838,16 +849,6 @@ static inline void mptcp_propagate_sndbuf(struct sock *sk, struct sock *ssk) local_bh_enable(); } -static inline void mptcp_write_space(struct sock *sk) -{ - if (sk_stream_is_writeable(sk)) { - /* pairs with memory barrier in mptcp_poll */ - smp_mb(); - if (test_and_clear_bit(MPTCP_NOSPACE, &mptcp_sk(sk)->flags)) - sk_stream_write_space(sk); - } -} - void mptcp_destroy_common(struct mptcp_sock *msk, unsigned int flags); #define MPTCP_TOKEN_MAX_RETRIES 4 -- cgit v1.2.3