This is a very early RFC to discuss a different approch to solve the
data transfer stall reported by Geliang and Gang.

There are a few open points documented into the individual patches, the
goal here is describe with some detail the intended architecture.

Note that the diffstat is biases by the quite large patch 2/6, which
contains mechanical transformation of existing code; "real" changes are
noticiable smaller.

Paolo Abeni (6):
  mptcp: move checks vs rcvbuf size earlier in the RX path
  mptcp: sync mptcp skb cb layout with tcp one
  tcp: expose the tcp_collapse_ofo_queue() helper to mptcp usage, too
  mptcp: implemented OoO queue pruning
  mptcp: refine coalescing conditions
  mptcp: unclone skbs before coalescing them, when needed

 include/net/tcp.h    |   4 ++
 net/ipv4/tcp_input.c |  55 ++++++++++------
 net/mptcp/mib.c      |   3 +
 net/mptcp/mib.h      |   3 +
 net/mptcp/options.c  |  35 +++++++++-
 net/mptcp/protocol.c | 154 +++++++++++++++++++++++++++++++------------
 net/mptcp/protocol.h |   7 +-
 7 files changed, 195 insertions(+), 66 deletions(-)

-- 
2.53.0

Hi Paolo,

Thank you for your modifications, that's great!

Our CI did some validations and here is its report:

- KVM Validation: normal (except selftest_mptcp_join): Unstable: 1 failed test(s): selftest_mptcp_connect_checksum ⚠️ 
- KVM Validation: normal (only selftest_mptcp_join): Unstable: 1 failed test(s): selftest_mptcp_join ⚠️ 
- KVM Validation: debug (except selftest_mptcp_join): Unstable: 2 failed test(s): packetdrill_dss selftest_mptcp_connect_checksum ⚠️ 
- KVM Validation: debug (only selftest_mptcp_join): Unstable: 1 failed test(s): selftest_mptcp_join ⚠️ 
- KVM Validation: btf-normal (only bpftest_all): Unstable: 2 failed test(s): bpftest_test_progs-no_alu32_mptcp bpftest_test_progs_mptcp ⚠️ 
- KVM Validation: btf-debug (only bpftest_all): Unstable: 2 failed test(s): bpftest_test_progs-cpuv4_mptcp bpftest_test_progs_mptcp ⚠️ 
- Task: https://github.com/multipath-tcp/mptcp_net-next/actions/runs/24661753570

Initiator: Patchew Applier
Commits: https://github.com/multipath-tcp/mptcp_net-next/commits/d6ebb747f78c
Patchwork: https://patchwork.kernel.org/project/mptcp/list/?series=1083242


If there are some issues, you can reproduce them using the same environment as
the one used by the CI thanks to a docker image, e.g.:

    $ cd [kernel source code]
    $ docker run -v "${PWD}:${PWD}:rw" -w "${PWD}" --privileged --rm -it \
        --pull always mptcp/mptcp-upstream-virtme-docker:latest \
        auto-normal

For more details:

    https://github.com/multipath-tcp/mptcp-upstream-virtme-docker


Please note that despite all the efforts that have been already done to have a
stable tests suite when executed on a public CI like here, it is possible some
reported issues are not due to your modifications. Still, do not hesitate to
help us improve that ;-)

Cheers,
MPTCP GH Action bot
Bot operated by Matthieu Baerts (NGI0 Core)