[v4,net-next,0/5] net: dsa: Link aggregation support

Message

Tobias Waldekranz Dec. 16, 2020, 4 p.m. UTC

Start of by adding an extra notification when adding a port to a bond,
this allows static LAGs to be offloaded using the bonding driver.

Then add the generic support required to offload link aggregates to
drivers built on top of the DSA subsystem.

Finally, implement offloading for the mv88e6xxx driver, i.e. Marvell's
LinkStreet family.

Supported LAG implementations:
- Bonding
- Team

Supported modes:
- Isolated. The LAG may be used as a regular interface outside of any
  bridge.
- Bridged. The LAG may be added to a bridge, in which case switching
  is offloaded between the LAG and any other switch ports. I.e. the
  LAG behaves just like a port from this perspective.

In bridged mode, the following is supported:
- STP filtering.
- VLAN filtering.
- Multicast filtering. The bridge correctly snoops IGMP and configures
  the proper groups if snooping is enabled. Static groups can also be
  configured. MLD seems to work, but has not been extensively tested.
- Unicast filtering. Automatic learning works. Static entries are
  _not_ supported. This will be added in a later series as it requires
  some more general refactoring in mv88e6xxx before I can test it.

v3 -> v4:
- Remove `struct dsa_lag`, leaving only a linear mapping to/from
  ID/netdev that drivers can opt-in to.
- Always fallback to a software LAG if offloading is not possible.
- mv88e6xxx: Do not offload unless the LAG mode matches what the
  hardware can do (hash based balancing).

v2 -> v3:
- Skip unnecessary RCU protection of the LAG device pointer, as
  suggested by Vladimir.
- Refcount LAGs with a plain refcount_t instead of `struct kref`, as
  suggested by Vladimir.

v1 -> v2:
- Allocate LAGs from a static pool to avoid late errors under memory
  pressure, as suggested by Andrew.

RFC -> v1:
- Properly propagate MDB operations.
- Support for bonding in addition to team.
- Fixed a locking bug in mv88e6xxx.
- Make sure ports are disabled-by-default in mv88e6xxx.
- Support for both DSA and EDSA tagging.

Tobias Waldekranz (5):
  net: bonding: Notify ports about their initial state
  net: dsa: Don't offload port attributes on standalone ports
  net: dsa: Link aggregation support
  net: dsa: mv88e6xxx: Link aggregation support
  net: dsa: tag_dsa: Support reception of packets from LAG devices

 drivers/net/bonding/bond_main.c     |   2 +
 drivers/net/dsa/mv88e6xxx/chip.c    | 298 +++++++++++++++++++++++++++-
 drivers/net/dsa/mv88e6xxx/global2.c |   8 +-
 drivers/net/dsa/mv88e6xxx/global2.h |   5 +
 drivers/net/dsa/mv88e6xxx/port.c    |  21 ++
 drivers/net/dsa/mv88e6xxx/port.h    |   5 +
 include/net/dsa.h                   |  60 ++++++
 net/dsa/dsa.c                       |  12 +-
 net/dsa/dsa2.c                      |  74 +++++++
 net/dsa/dsa_priv.h                  |  36 ++++
 net/dsa/port.c                      |  79 ++++++++
 net/dsa/slave.c                     |  71 ++++++-
 net/dsa/switch.c                    |  50 +++++
 net/dsa/tag_dsa.c                   |  17 +-
 14 files changed, 722 insertions(+), 16 deletions(-)