[PATCH v6 mptcp-next 0/7] mptcp: improve subflow creation on errors

[Paolo Abeni <pabeni@redhat.com>]

This iteration tries to add address the feedback on v5, namely
test counter update and locking in write_options. The latter
required quite significant changes in patch 5/7.

Additionally the series now includes the pending cleanup, as
they depends on the previous patches. No changes there WRT the
previous iteration.

Currently when a subflow connection fails - either the TCP
connection is reset by the peer, or the MPJ handshake never
completes - the in kernel PM don't perform any further action.
Notably no additional subflow creation is attempted.

This series is aimed at improving the in-kernel path manager
behavior in the above scenario:
- each endpoint is used only once per connection (patch 2/4)
- on failure we try to move to the next subflow, if any
  (patch 3/4)

The first patch is minor cleanup, and the last patch adds
specific self-tests.

This should address/close:
https://github.com/multipath-tcp/mptcp_net-next/issues/235
https://github.com/multipath-tcp/mptcp_net-next/issues/242

Paolo Abeni (7):
  mptcp: fix per socket endpoint accounting.
  mptcp: clean-up MPJ option writing.
  mptcp: keep track of local endpoint still available for each msk
  mptcp: do not block subflows creation on errors
  selftests: mptcp: add tests for subflow creation failure
  mptcp: cleanup MPJ subflow list handling
  mptcp: avoid atomic bit manipulation when possible

 net/mptcp/options.c                           |  44 ++--
 net/mptcp/pm.c                                |  24 ++-
 net/mptcp/pm_netlink.c                        | 188 +++++++++++-------
 net/mptcp/protocol.c                          | 158 +++++++--------
 net/mptcp/protocol.h                          |  46 +++--
 net/mptcp/sockopt.c                           |  24 +--
 net/mptcp/subflow.c                           |   9 +-
 tools/testing/selftests/net/mptcp/config      |   1 +
 .../testing/selftests/net/mptcp/mptcp_join.sh |  83 +++++++-
 9 files changed, 350 insertions(+), 227 deletions(-)

-- 
2.33.1