net/mlx5: Bridge, implement mdb offload

net/mlx5: Bridge, implement mdb offload

Implement support for add/del SWITCHDEV_OBJ_ID_PORT_MDB events. For mdb
destination addresses configure egress table rules to replicate to per-port
multicast tables of all ports that are member of the multicast group as
illustrated by 'MDB1' rule in the following diagram:

                                                                                                                            +--------+--+
                                                                                    +---------------------------------------> Port 1 |  |
                                                                                    |                                       +-^------+--+
                                                                                    |                                         |
                                                                                    |                                         |
                                       +-----------------------------------------+  |     +---------------------------+       |
                                       | EGRESS table                            |  |  +--> PORT 1 multicast table    |       |
+----------------------------------+   +-----------------------------------------+  |  |  +---------------------------+       |
| INGRESS table                    |   |                                         |  |  |  |                           |       |
+----------------------------------+   | dst_mac=P1,vlan=X -> pop vlan, goto P1  +--+  |  | FG0:                      |       |
|                                  |   | dst_mac=P1,vlan=Y -> pop vlan, goto P1  |     |  | src_port=dst_port -> drop |       |
| src_mac=M1,vlan=X -> goto egress +---> dst_mac=P2,vlan=X -> pop vlan, goto P2  +--+  |  | FG1:                      |       |
| ...                              |   | dst_mac=P2,vlan=Y -> goto P2            |  |  |  | VLAN X -> pop, goto port  |       |
|                                  |   | dst_mac=MDB1,vlan=Y -> goto mcast P1,P2 +-----+  | ...                       |       |
+----------------------------------+   |                                         |  |  |  | VLAN Y -> pop, goto port  +-------+
                                       +-----------------------------------------+  |  |  | FG3:                      |
                                                                                    |  |  | matchall -> goto port     |
                                                                                    |  |  |                           |
                                                                                    |  |  +---------------------------+
                                                                                    |  |
                                                                                    |  |
                                                                                    |  |                                    +--------+--+
                                                                                    +---------------------------------------> Port 2 |  |
                                                                                       |                                    +-^------+--+
                                                                                       |                                      |
                                                                                       |                                      |
                                                                                       |  +---------------------------+       |
                                                                                       +--> PORT 2 multicast table    |       |
                                                                                          +---------------------------+       |
                                                                                          |                           |       |
                                                                                          | FG0:                      |       |
                                                                                          | src_port=dst_port -> drop |       |
                                                                                          | FG1:                      |       |
                                                                                          | VLAN X -> pop, goto port  |       |
                                                                                          | ...                       |       |
                                                                                          |                           |       |
                                                                                          | FG3:                      |       |
                                                                                          | matchall -> goto port     +-------+
                                                                                          |                           |
                                                                                          +---------------------------+

MDB is managed by extending mlx5 bridge to store an entry in
mlx5_esw_bridge->mdb_list linked list (used to iterate over all offloaded
MDBs) and mlx5_esw_bridge->mdb_ht hash table (used to lookup existing MDB
by MAC+VLAN). Every MDB entry can be attached to arbitrary amount of bridge
ports that are stored in mlx5_esw_bridge_mdb_entry->ports xarray in order
to allow both efficient lookup of the port and also iteration over all
ports that the entry is attached to. Every time MDB is attached/detached
to/from a port, the hardware rule is recreated with list of destinations
corresponding to all attached ports. When the entry is detached from the
last port it is removed from mdb and destroyed which means that the ports
xarray also acts as implicit reference counting mechanism.

Signed-off-by: Vlad Buslov <vladbu@nvidia.com>
Reviewed-by: Maor Dickman <maord@nvidia.com>
Reviewed-by: Roi Dayan <roid@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>