ip6mr: No RTNL for RTNL_FAMILY_IP6MR rtnetlink.

This series is the IPv6 version of

  https://lore.kernel.org/netdev/20260228221800.1082070-1-k...

and removes RTNL from ip6mr rtnetlink handlers.

After this series, there are a few RTNL left in net/ipv6/ip6mr.c
and such users will be converted to per-netns RTNL in another
series.


Patch 1 extends the ipmr selftest to exercise most of the RTNL
 paths in net/ipv6/ipmr.c

Patch 2 - 6 converts RTM_GETROUTE handlers to RCU.

Patch 7 removes struct fib_dump_filter.rtnl_held.

Patch 8 use RCU for mr_table for CONFIG_IPV6_MROUTE_MULTIPLE_TABLES=n
 for ->exit_rtnl().

Patch 9 move fib_rules_unregister() to ->exit()

Patch 10 - 12 converts ->exit_batch() to ->exit_rtnl() to
 save one RTNL in cleanup_net().

Patch 13 removes unnecessary RTNL during setup_net() failure.

Patch 14 drops RTNL for MRT6_(ADD|DEL)_MFC(_PROXY)?.

Patch 15 misc clean up


Changes:
  v3:
    Patch 1 : Use XFAIL_ADD()

  v2: https://lore.kernel.org/netdev/20260410211726.1668756-1-k...
    Add patch 8 & 9 for ->exit_rtnl() conversion and
     drop 2 trivial patches (patch 2 & 14 in v1)

  v1: https://lore.kernel.org/netdev/20260407212001.2368593-1-k...


Kuniyuki Iwashima (15):
  selftest: net: Extend ipmr.c for IP6MR.
  ip6mr: Annotate access to mrt->mroute_do_{pim,assert,wrvifwhole}.
  ip6mr: Use MAXMIFS in mr6_msgsize().
  ip6mr: Allocate skb earlier in ip6mr_rtm_getroute().
  ip6mr: Convert ip6mr_rtm_getroute() to RCU.
  ip6mr: Convert ip6mr_rtm_dumproute() to RCU.
  net: Remove rtnl_held of struct fib_dump_filter.
  ip6mr: Free mr_table after RCU grace period.
  ip6mr: Call fib_rules_unregister() without RTNL.
  ip6mr: Move unregister_netdevice_many() out of mroute_clean_tables().
  ip6mr: Move unregister_netdevice_many() out of ip6mr_free_table().
  ip6mr: Convert ip6mr_net_exit_batch() to ->exit_rtnl().
  ip6mr: Remove RTNL in ip6mr_rules_init() and ip6mr_net_init().
  ip6mr: Replace RTNL with a dedicated mutex for MFC.
  ip6mr: Define net->ipv6.{ip6mr_notifier_ops,ipmr_seq} under
    CONFIG_IPV6_MROUTE.

 include/net/ip_fib.h                          |   1 -
 include/net/netns/ipv6.h                      |   5 +-
 net/ipv4/fib_frontend.c                       |  19 +-
 net/ipv4/ipmr.c                               |   4 +-
 net/ipv6/ip6_fib.c                            |   1 -
 net/ipv6/ip6mr.c                              | 299 +++++++++++-------
 net/mpls/af_mpls.c                            |   6 +-
 tools/testing/selftests/net/forwarding/ipmr.c | 189 +++++++----
 8 files changed, 312 insertions(+), 212 deletions(-)

-- 
2.54.0.1032.g2f8565e1d1-goog