Messages in this thread | | | Date | Mon, 28 Dec 2020 14:26:53 -0800 | From | Jakub Kicinski <> | Subject | Re: [PATCH net 2/2] net: switchdev: don't set port_obj_info->handled true when -EOPNOTSUPP |
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On Wed, 23 Dec 2020 15:45:33 +0100 Rasmus Villemoes wrote: > It's not true that switchdev_port_obj_notify() only inspects the > ->handled field of "struct switchdev_notifier_port_obj_info" if > call_switchdev_blocking_notifiers() returns 0 - there's a WARN_ON() > triggering for a non-zero return combined with ->handled not being > true. But the real problem here is that -EOPNOTSUPP is not being > properly handled. > > The wrapper functions switchdev_handle_port_obj_add() et al change a > return value of -EOPNOTSUPP to 0, and the treatment of ->handled in > switchdev_port_obj_notify() seems to be designed to change that back > to -EOPNOTSUPP in case nobody actually acted on the notifier (i.e., > everybody returned -EOPNOTSUPP). > > Currently, as soon as some device down the stack passes the check_cb() > check, ->handled gets set to true, which means that > switchdev_port_obj_notify() cannot actually ever return -EOPNOTSUPP. > > This, for example, means that the detection of hardware offload > support in the MRP code is broken - br_mrp_set_ring_role() always ends > up setting mrp->ring_role_offloaded to 1, despite not a single > mainline driver implementing any of the SWITCHDEV_OBJ_ID*_MRP. So > since the MRP code thinks the generation of MRP test frames has been > offloaded, no such frames are actually put on the wire. > > So, continue to set ->handled true if any callback returns success or > any error distinct from -EOPNOTSUPP. But if all the callbacks return > -EOPNOTSUPP, make sure that ->handled stays false, so the logic in > switchdev_port_obj_notify() can propagate that information. > > Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Please make sure you CC the folks who may have something to say about this - Jiri, Ivan, Ido, Florian, etc.
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