From: Paolo Abeni Date: Fri, 21 Nov 2025 17:02:04 +0000 (+0100) Subject: mptcp: cleanup fallback data fin reception X-Git-Tag: v6.19-rc1~170^2~85^2~9 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=85f22b8e1e9db00a7003bf3c0e0a60d19718e083;p=thirdparty%2Fkernel%2Flinux.git mptcp: cleanup fallback data fin reception MPTCP currently generate a dummy data_fin for fallback socket when the fallback subflow has completed data reception using the current ack_seq. We are going to introduce backlog usage for the msk soon, even for fallback sockets: the ack_seq value will not match the most recent sequence number seen by the fallback subflow socket, as it will ignore data_seq sitting in the backlog. Instead use the last map sequence number to set the data_fin, as fallback (dummy) map sequences are always in sequence. Reviewed-by: Geliang Tang Tested-by: Geliang Tang Signed-off-by: Paolo Abeni Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20251121-net-next-mptcp-memcg-backlog-imp-v1-5-1f34b6c1e0b1@kernel.org Signed-off-by: Jakub Kicinski --- diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index 72b7efe388db9..1f7311afd48d4 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -1285,6 +1285,7 @@ static bool subflow_is_done(const struct sock *sk) /* sched mptcp worker for subflow cleanup if no more data is pending */ static void subflow_sched_work_if_closed(struct mptcp_sock *msk, struct sock *ssk) { + const struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); struct sock *sk = (struct sock *)msk; if (likely(ssk->sk_state != TCP_CLOSE && @@ -1303,7 +1304,8 @@ static void subflow_sched_work_if_closed(struct mptcp_sock *msk, struct sock *ss */ if (__mptcp_check_fallback(msk) && subflow_is_done(ssk) && msk->first == ssk && - mptcp_update_rcv_data_fin(msk, READ_ONCE(msk->ack_seq), true)) + mptcp_update_rcv_data_fin(msk, subflow->map_seq + + subflow->map_data_len, true)) mptcp_schedule_work(sk); }