[ovs-git] [ovn-org/ovn] ba7eb7: pinctrl: Fix race condition when explicitly cleari...

[Dumitru Ceara]

  Branch: refs/heads/branch-20.12
  Home:   https://github.com/ovn-org/ovn
  Commit: ba7eb7ae6df44005c13cb669c1c2703f936cfdc0
      https://github.com/ovn-org/ovn/commit/ba7eb7ae6df44005c13cb669c1c2703f936cfdc0
  Author: Dumitru Ceara <dceara at redhat.com>
  Date:   2021-01-07 (Thu, 07 Jan 2021)

  Changed paths:
    M controller/pinctrl.c

  Log Message:
  -----------
  pinctrl: Fix race condition when explicitly clearing IGMP groups.

When a user flushes the IGMP Groups ("ovn-sbctl ip-multicast-flush")
there's no guarantee that the ovn-controller main thread runs soon after
the pinctrl thread has flushed the in-memory IGMP groups, in
ip_mcast_snoop_flush().

To avoid unnecessarily waking the main thread just clear the local
IGMP_Group records in the main thread.

This scenario is quite hard to encounter in real deployments but every
now and then we hit it in CI.

Fixes: 70ff8243040f ("OVN: Add IGMP SB definitions and ovn-controller support")
Signed-off-by: Dumitru Ceara <dceara at redhat.com>
Signed-off-by: Numan Siddique <numans at ovn.org>

(cherry-picked from master commit 143275e7e1d92d0b58364813bf4e411eb6587056)