[PATCH v4 net-next 00/15] net: more factorization in cleanup_net() paths

[Eric Dumazet <edumazet@google.com>]

This series is inspired by recent syzbot reports hinting to RTNL and
workqueue abuses.

rtnl_lock() is unfair to (single threaded) cleanup_net(), because
many threads can cause contention on it.

This series adds a new (struct pernet_operations) method,
so that cleanup_net() can hold RTNL longer once it finally
acquires it.

It also factorizes unregister_netdevice_many(), to further
reduce stalls in cleanup_net().

v4: Changed geneve patch (Antoine Tenart feedback)
    Changed vxlan patch (Paolo Abeni feedback)
    Link: https://lore.kernel.org/netdev/CANn89iLJrrJs+6Vc==Un4rVKcpV0Eof4F_4w1_wQGxUCE2FWAg@mail.gmail.com/T/#u

v3: Dropped "net: convert default_device_exit_batch() to exit_batch_rtnl method"
    Jakub (and KASAN) reported issues with bridge, but the root cause was with this patch.
    default_device_exit_batch() is the catch-all method, it includes "lo" device dismantle.

v2: Antoine Tenart feedback in
      https://lore.kernel.org/netdev/170688415193.5216.10499830272732622816@kwain/
    - Added bond_net_pre_exit() method to make sure bond_destroy_sysfs()
      is called before we unregister the devices in bond_net_exit_batch_rtnl()


Eric Dumazet (15):
  net: add exit_batch_rtnl() method
  nexthop: convert nexthop_net_exit_batch to exit_batch_rtnl method
  bareudp: use exit_batch_rtnl() method
  bonding: use exit_batch_rtnl() method
  geneve: use exit_batch_rtnl() method
  gtp: use exit_batch_rtnl() method
  ipv4: add __unregister_nexthop_notifier()
  vxlan: use exit_batch_rtnl() method
  ip6_gre: use exit_batch_rtnl() method
  ip6_tunnel: use exit_batch_rtnl() method
  ip6_vti: use exit_batch_rtnl() method
  sit: use exit_batch_rtnl() method
  ip_tunnel: use exit_batch_rtnl() method
  bridge: use exit_batch_rtnl() method
  xfrm: interface: use exit_batch_rtnl() method

 drivers/net/bareudp.c           | 13 +++------
 drivers/net/bonding/bond_main.c | 37 ++++++++++++++++--------
 drivers/net/geneve.c            | 23 +++++++--------
 drivers/net/gtp.c               | 20 ++++++-------
 drivers/net/vxlan/vxlan_core.c  | 50 +++++++++++++--------------------
 include/net/ip_tunnels.h        |  3 +-
 include/net/net_namespace.h     |  3 ++
 include/net/nexthop.h           |  1 +
 net/bridge/br.c                 | 15 ++++------
 net/core/net_namespace.c        | 31 +++++++++++++++++++-
 net/ipv4/ip_gre.c               | 24 ++++++++++------
 net/ipv4/ip_tunnel.c            | 10 +++----
 net/ipv4/ip_vti.c               |  8 ++++--
 net/ipv4/ipip.c                 |  8 ++++--
 net/ipv4/nexthop.c              | 38 ++++++++++++++++---------
 net/ipv6/ip6_gre.c              | 12 ++++----
 net/ipv6/ip6_tunnel.c           | 12 ++++----
 net/ipv6/ip6_vti.c              | 12 ++++----
 net/ipv6/sit.c                  | 13 ++++-----
 net/xfrm/xfrm_interface_core.c  | 14 ++++-----
 20 files changed, 190 insertions(+), 157 deletions(-)

-- 
2.43.0.594.gd9cf4e227d-goog