In preparation of disabling flooding towards the CPU in standalone ports
mode, identify the addresses requested by upper interfaces and use the
new API for DSA FDB isolation to request the hardware driver to offload
these as FDB or MDB objects. The objects belong to the user port's
database, and are installed pointing towards the CPU port.

Because dev_uc_add()/dev_mc_add() is VLAN-unaware, we offload to the
port standalone database addresses with VID 0 (also VLAN-unaware).
So this excludes switches with global VLAN filtering from supporting
unicast filtering, because there, it is possible for a port of a switch
to join a VLAN-aware bridge, and this changes the VLAN awareness of
standalone ports, requiring VLAN-aware standalone host FDB entries.
For the same reason, hellcreek, which requires VLAN awareness in
standalone mode, is also exempted from unicast filtering.

We create "standalone" variants of dsa_port_host_fdb_add() and
dsa_port_host_mdb_add() (and the _del coresponding functions).

We also create a separate work item type for handling deferred
standalone host FDB/MDB entries compared to the switchdev one.
This is done for the purpose of clarity - the procedure for offloading a
bridge FDB entry is different than offloading a standalone one, and
the switchdev event work handles only FDBs anyway, not MDBs.
Deferral is needed for standalone entries because ndo_set_rx_mode runs
in atomic context. We could probably optimize things a little by first
queuing up all entries that need to be offloaded, and scheduling the
work item just once, but the data structures that we can pass through
__dev_uc_sync() and __dev_mc_sync() are limiting (there is nothing like
a void *priv), so we'd have to keep the list of queued events somewhere
in struct dsa_switch, and possibly a lock for it. Too complicated for
now.

Adding the address to the master is handled by dev_uc_sync(), adding it
to the hardware is handled by __dev_uc_sync(). So this is the reason why
dsa_port_standalone_host_fdb_add() does not call dev_uc_add(). Not that
it had the rtnl_mutex anyway - ndo_set_rx_mode has it, but is atomic.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>