net: remove type_check from dev_get_nest_level()

The idea for type_check in dev_get_nest_level() was to count the number
of nested devices of the same type (currently, only macvlan or vlan
devices).
This prevented the false positive lockdep warning on configurations such
as:

eth0 <--- macvlan0 <--- vlan0 <--- macvlan1

However, this doesn't prevent a warning on a configuration such as:

eth0 <--- macvlan0 <--- vlan0
eth1 <--- vlan1 <--- macvlan1

In this case, all the locks end up with a nesting subclass of 1, so
lockdep thinks that there is still a deadlock:

- in the first case we have (macvlan_netdev_addr_lock_key, 1) and then
  take (vlan_netdev_xmit_lock_key, 1)
- in the second case, we have (vlan_netdev_xmit_lock_key, 1) and then
  take (macvlan_netdev_addr_lock_key, 1)

By removing the linktype check in dev_get_nest_level() and always
incrementing the nesting depth, lockdep considers this configuration
valid.

Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index cd9b53834bf6..3234fcdea317 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -1315,7 +1315,7 @@ int macvlan_common_newlink(struct net *src_net, struct net_device *dev,
         vlan->dev      = dev;
         vlan->port     = port;
         vlan->set_features = MACVLAN_FEATURES;
-        vlan->nest_level = dev_get_nest_level(lowerdev, netif_is_macvlan) + 1;
+        vlan->nest_level = dev_get_nest_level(lowerdev) + 1;
 
         vlan->mode     = MACVLAN_MODE_VEPA;
         if (data && data[IFLA_MACVLAN_MODE])