From: Geliang Tang <geliang.tang@xxxxxxxx> commit 0530020a7c8f2204e784f0dbdc882bbd961fdbde upstream. This patch adds a new member allow_infinite_fallback in mptcp_sock, which is initialized to 'true' when the connection begins and is set to 'false' on any retransmit or successful MP_JOIN. Only do infinite mapping fallback if there is a single subflow AND there have been no retransmissions AND there have never been any MP_JOINs. Suggested-by: Paolo Abeni <pabeni@xxxxxxxxxx> Signed-off-by: Geliang Tang <geliang.tang@xxxxxxxx> Signed-off-by: Mat Martineau <mathew.j.martineau@xxxxxxxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Stable-dep-of: e32d262c89e2 ("mptcp: handle consistently DSS corruption") [ Conflicts in protocol.c, because commit 3e5014909b56 ("mptcp: cleanup MPJ subflow list handling") is not in this version. This commit is linked to a new feature, changing the context around. The new line can still be added at the same place. Conflicts in protocol.h, because commit 4f6e14bd19d6 ("mptcp: support TCP_CORK and TCP_NODELAY") is not in this version. This commit is linked to a new feature, changing the context around. The new line can still be added at the same place. Conflicts in subflow.c, because commit 0348c690ed37 ("mptcp: add the fallback check") is not in this version. This commit is linked to a new feature, changing the context around. The new line can still be added at the same place. Extra conflicts in v5.10, because the context has been changed. ] Signed-off-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/mptcp/protocol.c | 6 +++++- net/mptcp/protocol.h | 1 + net/mptcp/subflow.c | 1 + 3 files changed, 7 insertions(+), 1 deletion(-) --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -1810,9 +1810,11 @@ static void mptcp_worker(struct work_str if (!mptcp_ext_cache_refill(msk)) break; } - if (copied) + if (copied) { tcp_push(ssk, msg.msg_flags, mss_now, tcp_sk(ssk)->nonagle, size_goal); + WRITE_ONCE(msk->allow_infinite_fallback, false); + } dfrag->data_seq = orig_write_seq; dfrag->offset = orig_offset; @@ -1845,6 +1847,7 @@ static int __mptcp_init_sock(struct sock msk->first = NULL; inet_csk(sk)->icsk_sync_mss = mptcp_sync_mss; + WRITE_ONCE(msk->allow_infinite_fallback, true); mptcp_pm_data_init(msk); @@ -2543,6 +2546,7 @@ bool mptcp_finish_join(struct sock *sk) if (parent_sock && !sk->sk_socket) mptcp_sock_graft(sk, parent_sock); subflow->map_seq = READ_ONCE(msk->ack_seq); + WRITE_ONCE(msk->allow_infinite_fallback, false); return true; } --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -213,6 +213,7 @@ struct mptcp_sock { bool rcv_data_fin; bool snd_data_fin_enable; bool use_64bit_ack; /* Set when we received a 64-bit DSN */ + bool allow_infinite_fallback; spinlock_t join_list_lock; struct work_struct work; struct sk_buff *ooo_last_skb; --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -1179,6 +1179,7 @@ int __mptcp_subflow_connect(struct sock list_add_tail(&subflow->node, &msk->join_list); spin_unlock_bh(&msk->join_list_lock); + WRITE_ONCE(msk->allow_infinite_fallback, false); return err; failed: Patches currently in stable-queue which might be from matttbe@xxxxxxxxxx are queue-5.10/mptcp-track-and-update-contiguous-data-status.patch queue-5.10/mptcp-handle-consistently-dss-corruption.patch queue-5.10/tcp-fix-mptcp-dss-corruption-due-to-large-pmtu-xmit.patch