[PATCH net-next 0/2] vlan: lockless vlan_fill_info()

[Eric Dumazet <edumazet@google.com>]

vlan_fill_info() currently relies on RTNL being held, because it
uses rcu_dereference_rtnl() to walk vlan->egress_priority_map[].

While auditing the fields exposed there, it appears that
vlan->flags, vlan->ingress_priority_map[] and vlan->nr_*_mappings
are written under RTNL but already read from lockless contexts
(RX, TX, /proc/net/vlan/<dev> and vlan_get_size()).

- Patch 1 adds the missing READ_ONCE()/WRITE_ONCE() annotations.

- Patch 2 converts vlan_fill_info() to RCU.

vlan->egress_priority_map[] needed no work: it is already updated
with rcu_assign_pointer() and freed with kfree_rcu().

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

Eric Dumazet (2):
  vlan: annotate data-races in vlan_dev_priv fields
  vlan: no longer rely on RTNL in vlan_fill_info()

 net/8021q/vlan.h         |  2 +-
 net/8021q/vlan_core.c    |  2 +-
 net/8021q/vlan_dev.c     | 37 ++++++++++++++++------------
 net/8021q/vlan_netlink.c | 52 ++++++++++++++++++++++++----------------
 net/8021q/vlanproc.c     | 18 +++++++-------
 5 files changed, 65 insertions(+), 46 deletions(-)

-- 
2.55.0.1032.g73a4cd73de-goog