From: Menglong Dong <imagedong@tencent.com>

In the 1th patch, we do some code cleanup with replease 'sock->sk'
with 'sk'. In the 2th patch, we add statistics for mptcp socket in
use. In the 3th patch, we make mptcp_connect can exit when receive
'SIGUSR1' with '-r' flag. And in the 4th patch, we add the testing
for this commit.

Changes since v5:
- introduce MPTCP_INUSE flag to store if msk is in use, as I find
  that it's not correct to check is a msk is in use by
  !sk_unhashed(sk) in mptcp_destroy_common(), because the token
  can be release in mptcp_check_fastclose()
- add the 3th patch
- reuse __chk_nr in 4th patch

Changes since v4:
- rebase to solve merge conflict

Changes since v3:
- rename MPTCP_DESTROIED to MPTCP_DESTROYED in the 2th patch

Changes since v2:
- add testing

Changes since v1:
- split the code cleanup into the 1th patch.
- decrease the statistics for listening mptcp socket inuse with
  mptcp_listen_inuse_dec()
- add MPTCP_DESTROIED flags to store if mptcp_destroy_common() was
  called on the msk. For fallback case, we need to decrease the
  statistics only once, and mptcp_destroy_common() can be called
  more than once.

Menglong Dong (4):
  mptcp: introduce 'sk' to replace 'sock->sk' in mptcp_listen()
  mptcp: add statistics for mptcp socket in use
  selftest: mptcp: exit from copyfd_io_poll() when receive SIGUSR1
  selftest: mptcp: add test for mptcp socket in use

 net/mptcp/protocol.c                          | 21 ++++++---
 net/mptcp/protocol.h                          | 13 +++++
 net/mptcp/subflow.c                           |  1 +
 tools/testing/selftests/net/mptcp/diag.sh     | 47 +++++++++++++++++--
 .../selftests/net/mptcp/mptcp_connect.c       |  4 +-
 5 files changed, 72 insertions(+), 14 deletions(-)

-- 
2.37.2