Hi Andrew,

Andrew Lunn [off-list ref] writes:

Getting the frames to the bridge as requested turned up an issue or
three. The offload_fwd_mark is not being set by DSA, so the bridge
floods the received frames back to the switch ports, resulting in
duplication since the hardware has already flooded the packet. Fixing
that turned up an issue with the meaning of
SWITCHDEV_ATTR_ID_PORT_PARENT_ID in DSA. A DSA fabric of three
switches needs to look to the software bridge as a single
switch. Otherwise the offload_fwd_mark does not work, and we get
duplication on the non-ingress switch. But each switch returned a
different value. And they were not unique.

[...]

Is the SWITCHDEV_ATTR_ID_PORT_PARENT_ID change acceptable?

So here we need to return the switch fabric (tree) ID instead of a
single switch chip ID. I think we are not supposed to change it, but
there's definitly something wrong with them and we must fix it.

The same issue happens with the physical port IDs, where the net devices
of two disjoint trees on a system will have the same phys_*_id
attributes, because we do not include the tree ID in them.

(not sure if this affects your patchset though.)


Thanks,

        Vivien