On Wed, Oct 28, 2020 at 08:42:15AM +0100, Kurt Kanzenbach wrote: > From: Vladimir Oltean <vladimir.oltean@xxxxxxx> > > Some switches rely on unique pvids to ensure port separation in > standalone mode, because they don't have a port forwarding matrix > configurable in hardware. So, setups like a group of 2 uppers with the > same VLAN, swp0.100 and swp1.100, will cause traffic tagged with VLAN > 100 to be autonomously forwarded between these switch ports, in spite > of there being no bridge between swp0 and swp1. > > These drivers need to prevent this from happening. They need to have > VLAN filtering enabled in standalone mode (so they'll drop frames tagged > with unknown VLANs) and they can only accept an 8021q upper on a port as > long as it isn't installed on any other port too. So give them the > chance to veto bad user requests. > > Signed-off-by: Vladimir Oltean <vladimir.oltean@xxxxxxx> > Signed-off-by: Kurt Kanzenbach <kurt@xxxxxxxxxxxxx> > --- In case reviewers have doubts about this new DSA operation in general. I would expect that when LAG support is merged, some drivers will support it, but not any tx_type, but e.g. just NETDEV_LAG_TX_TYPE_HASH. So it would also be helpful in that case, so they could veto other types of bond interfaces cleanly. So I do see the need for a generic "prechangeupper" operation given to drivers.
