Merge branch 'mptcp-more-misc-fixes-for-v6-8'

Merge branch 'mptcp-more-misc-fixes-for-v6-8'

Matthieu Baerts says:

====================
mptcp: more misc. fixes for v6.8

This series includes 6 types of fixes:

- Patch 1 fixes v4 mapped in v6 addresses support for the userspace PM,
  when asking to delete a subflow. It was done everywhere else, but not
  there. Patch 2 validates the modification, thanks to a subtest in
  mptcp_join.sh. These patches can be backported up to v5.19.

- Patch 3 is a small fix for a recent bug-fix patch, just to avoid
  printing an irrelevant warning (pr_warn()) once. It can be backported
  up to v5.6, alongside the bug-fix that has been introduced in the
  v6.8-rc5.

- Patches 4 to 6 are fixes for bugs found by Paolo while working on
  TCP_NOTSENT_LOWAT support for MPTCP. These fixes can improve the
  performances in some cases. Patches can be backported up to v5.6,
  v5.11 and v6.7 respectively.

- Patch 7 makes sure 'ss -M' is available when starting MPTCP Join
  selftest as it is required for some subtests since v5.18.

- Patch 8 fixes a possible double-free on socket dismantle. The issue
  always existed, but was unnoticed because it was not causing any
  problem so far. This fix can be backported up to v5.6.

- Patch 9 is a fix for a very recent patch causing lockdep warnings in
  subflow diag. The patch causing the regression -- which fixes another
  issue present since v5.7 -- should be part of the future v6.8-rc6.
  Patch 10 validates the modification, thanks to a new subtest in
  diag.sh.
====================

Link: https://lore.kernel.org/r/20240223-upstream-net-20240223-misc-fixes-v1-0-162e87e48497@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>