Commit b111d8fb authored by Paolo Abeni's avatar Paolo Abeni Committed by Jakub Kicinski
Browse files

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: 8005184f ("mptcp: refactor sndbuf auto-tuning")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
Reviewed-by: default avatarMat Martineau <martineau@kernel.org>
Signed-off-by: default avatarMatthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://lore.kernel.org/r/20240223-upstream-net-20240223-misc-fixes-v1-6-162e87e48497@kernel.org


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent adf1bb78

net/mptcp/protocol.h

+11 −10
Original line number Diff line number Diff line
@@ -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 <nr_subflows> * 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