This series it amied at fixing:

https://github.com/multipath-tcp/mptcp_net-next/issues/33

patch 3/5 do the main work, while patch 4 and 5 should
reduce the server load avoid creating unneeded children.

Patch 1 and 2 are somewhat related cleanup.

Patch 2 && 5 are likely the most controversial. Any
feedback more than welcome!

Paolo Abeni (5):
  mptcp: cleanup subflow_finish_connect()
  subflow: explicitly check for plain tcp rsk
  subflow: use rsk_ops->send_reset()
  subflow: introduce and use mptcp_can_accept_new_subflow()
  subflow: do not create child subflow for fallback MP_JOIN

 net/mptcp/subflow.c | 76 +++++++++++++++++++++++++--------------------
 1 file changed, 42 insertions(+), 34 deletions(-)

-- 
2.26.2