[PATCH net-next 0/2] hsr: lockless hsr_fill_info()

[Eric Dumazet <edumazet@google.com>]

hsr_fill_info() currently relies on RTNL being held, because
hsr_port_get_hsr() walks hsr->ports with hsr_for_each_port_rtnl().

- Patch 1 annotates the data-race around hsr->sequence_nr, which
  is incremented from the transmit paths under hsr->seqnr_lock but
  read without it.

- Patch 2 converts hsr_fill_info() to RCU, using a local RCU
  variant of hsr_port_get_hsr().

hsr->ports is already an RCU protected list: ports are added with
list_add_tail_rcu(), removed with list_del_rcu() and freed with
kfree_rcu(), and the data path already iterates over it with
hsr_for_each_port().

This is part of a larger effort to remove the RTNL dependency from
rtnl_link_ops->fill_info().

Eric Dumazet (2):
  hsr: annotate data-race around hsr->sequence_nr
  hsr: no longer rely on RTNL in hsr_fill_info()

 net/hsr/hsr_device.c  |  2 +-
 net/hsr/hsr_forward.c |  2 +-
 net/hsr/hsr_netlink.c | 35 ++++++++++++++++++++++++++---------
 3 files changed, 28 insertions(+), 11 deletions(-)

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2.55.0.1032.g73a4cd73de-goog