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>
952fcfd08c