mptcp: do not miss early first subflow close event notification

The MPTCP protocol is not currently emitting the NL event when the first
subflow is closed before msk accept() time.

By replacing the in use close helper is such scenario, implicitly introduce
the missing notification. Note that in such scenario we want to be sure
that mptcp_close_ssk() will not trigger any PM work, move the msk state
change update earlier, so that the previous patch will offer such
guarantee.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Geliang Tang <geliang@kernel.org>
Tested-by: Geliang Tang <geliang@kernel.org>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251121-net-next-mptcp-memcg-backlog-imp-v1-8-1f34b6c1e0b1@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index df4be41..2ee76c8 100644 (file)
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -4052,10 +4052,10 @@ static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
                 * deal with bad peers not doing a complete shutdown.
                 */
                if (unlikely(inet_sk_state_load(msk->first) == TCP_CLOSE)) {
-                       __mptcp_close_ssk(newsk, msk->first,
-                                         mptcp_subflow_ctx(msk->first), 0);
                        if (unlikely(list_is_singular(&msk->conn_list)))
                                mptcp_set_state(newsk, TCP_CLOSE);
+                       mptcp_close_ssk(newsk, msk->first,
+                                       mptcp_subflow_ctx(msk->first));
                }
        } else {
 tcpfallback: