Messages in this thread | | | Date | Sat, 5 May 2018 20:51:45 +0200 | From | Andrew Lunn <> | Subject | Re: [PATCH] net: dsa: drop some VLAs in switch.c |
| |
> > You could make the bitmap part of the dsa_switch structure. This is > > allocated by dsa_switch_alloc() and is passed the number of ports. > > Doing the allocation there means you don't need to worry about it > > failing in dsa_switch_mdb_add() or dsa_switch_vlan_add(). > > Are dsa_switch_mdb_add() and dsa_switch_vlan_add() guaranteed to be > single-threaded?
Yes, that is the interesting question here.... against each other, or themselves?
They are called from a notifier chain. It is the same notifier chain for both dsa_switch_mdb_add() and dsa_switch_vlan_add().
notifier_call_chain() itself appears to not provide any guarantees about the same handler being called in parallel.
It is dsa_port_notify() which is calling the notifier_call_chain(). This is being called by both dsa_port_vlan_add() and dsa_port_mdb_add() in dsa_slave_port_obj_add(). This is a switchdev op. switchdev_port_obj_add_now() does have ASSERT_RTNL(); So that should serialize everything.
Andrew
| |