diff options
| author | Toke Høiland-Jørgensen <toke@redhat.com> | 2025-12-11 12:50:05 +0100 |
|---|---|---|
| committer | Paolo Abeni <pabeni@redhat.com> | 2025-12-22 12:25:11 +0100 |
| commit | 5498227676303e3ffa9a3a46214af96bc3e81314 (patch) | |
| tree | a9b42fb881d7278ab1a3067f17f8100a350b2fe3 /net | |
| parent | 1e5a541420b8c6d87d88eb50b6b978cdeafee1c9 (diff) | |
net: openvswitch: Avoid needlessly taking the RTNL on vport destroy
The openvswitch teardown code will immediately call
ovs_netdev_detach_dev() in response to a NETDEV_UNREGISTER notification.
It will then start the dp_notify_work workqueue, which will later end up
calling the vport destroy() callback. This callback takes the RTNL to do
another ovs_netdev_detach_port(), which in this case is unnecessary.
This causes extra pressure on the RTNL, in some cases leading to
"unregister_netdevice: waiting for XX to become free" warnings on
teardown.
We can straight-forwardly avoid the extra RTNL lock acquisition by
checking the device flags before taking the lock, and skip the locking
altogether if the IFF_OVS_DATAPATH flag has already been unset.
Fixes: b07c26511e94 ("openvswitch: fix vport-netdev unregister")
Tested-by: Adrian Moreno <amorenoz@redhat.com>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: Eelco Chaudron <echaudro@redhat.com>
Acked-by: Aaron Conole <aconole@redhat.com>
Link: https://patch.msgid.link/20251211115006.228876-1-toke@redhat.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Diffstat (limited to 'net')
| -rw-r--r-- | net/openvswitch/vport-netdev.c | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/net/openvswitch/vport-netdev.c b/net/openvswitch/vport-netdev.c index 91a11067e458..6574f9bcdc02 100644 --- a/net/openvswitch/vport-netdev.c +++ b/net/openvswitch/vport-netdev.c @@ -160,10 +160,19 @@ void ovs_netdev_detach_dev(struct vport *vport) static void netdev_destroy(struct vport *vport) { - rtnl_lock(); - if (netif_is_ovs_port(vport->dev)) - ovs_netdev_detach_dev(vport); - rtnl_unlock(); + /* When called from ovs_db_notify_wq() after a dp_device_event(), the + * port has already been detached, so we can avoid taking the RTNL by + * checking this first. + */ + if (netif_is_ovs_port(vport->dev)) { + rtnl_lock(); + /* Check again while holding the lock to ensure we don't race + * with the netdev notifier and detach twice. + */ + if (netif_is_ovs_port(vport->dev)) + ovs_netdev_detach_dev(vport); + rtnl_unlock(); + } call_rcu(&vport->rcu, vport_netdev_free); } |