Hi,
>> Does DSA offer any protection against concurrent calls of
>> dsa_switch_ops?
This is something I thought about for a while. Since DSA offers an
abstraction of different net stack entry points to its drivers, like
netlink (bridge, etc.) or ioctl (ethtool), it would make sense to add a
mutex at the DSA layer.
It would naturally go in the dsa_switch structure, and be (un)locked by
DSA core. But a switch fabric might be composed of multiple devices, so
this locking must happen at the dsa_switch_tree level. The entry points
to the DSA core are the dsa_port structure, either accessed via a master
interface's dsa_ptr pointer, or via a slave interface's private data.
So ideally the locking of the control path must occur when notifying an
operation to every device of the tree, i.e. in dsa_port_notify:
mutex_lock(&dst->lock);
err = raw_notifier_call_chain(&dst->nh, e, v);
mutex_lock(&dst->lock);
Unfortunately the code is not ready for that yet, because not all calls
to ds->ops->foo are centralized yet. But we are slowly going that way.
In the meantime, DSA drivers handle locking themselves when necessary.
Thanks,
Vivien
