mlxsw: Preparations for out-of-order-operations patches

The mlxsw driver currently makes the assumption that the user applies configuration in a bottom-up manner. Thus netdevices need to be added to the bridge before IP addresses are configured on that bridge or SVI added on top of it. Enslaving a netdevice to another netdevice that already has uppers is in fact forbidden by mlxsw for this reason. Despite this safety, it is rather easy to get into situations where the offloaded configuration is just plain wrong.

As an example, take a front panel port, configure an IP address: it gets a RIF. Now enslave the port to a bridge, and the RIF is gone. Remove the port from the bridge again, but the RIF never comes back. There is a number of similar situations, where changing the configuration there and back utterly breaks the offload.

Over the course of the following several patchsets, mlxsw code is going to be adjusted to diminish the space of wrongly offloaded configurations. Ideally the offload state will reflect the actual state, regardless of the sequence of operation used to construct that state.

No functional changes are intended in this patchset yet. Rather the patches prepare the codebase for easier introduction of functional changes in later patchsets.

- In patch #1, extract a helper to join a RIF of a given port, if there is one. In patch #2, use it in a newly-added helper to join a LAG interface.

- In patches #3, #4 and #5, add helpers that abstract away the rif->dev access. This will make it simpler in the future to change the way the deduction is done. In patch #6, do this for deduction from nexthop group info to RIF.

- In patch #7, add a helper to destroy a RIF. So far RIF was destroyed simply by kfree'ing it.

- In patch #8, add a helper to check if any IP addresses are configured on a netdevice. This helper will be useful later.

- In patch #9, add a helper to migrate a RIF. This will be a convenient place to put extensions later on.

- Patch #10 move IPIP initialization up to make ipip_ops_arr available earlier.

Petr Machata (10):
mlxsw: spectrum_router: Extract a helper from
mlxsw_sp_port_vlan_router_join()
mlxsw: spectrum_router: Add a helper specifically for joining a LAG
mlxsw: spectrum_router: Access rif->dev through a helper
mlxsw: spectrum_router: Access rif->dev from params in
mlxsw_sp_rif_create()
mlxsw: spectrum_router: Access nh->rif->dev through a helper
mlxsw: spectrum_router: Access nhgi->rif through a helper
mlxsw: spectrum_router: Extract a helper to free a RIF
mlxsw: spectrum_router: Add a helper to check if netdev has addresses
mlxsw: spectrum_router: Extract a helper for RIF migration
mlxsw: spectrum_router: Move IPIP init up

 .../net/ethernet/mellanox/mlxsw/spectrum.c    |   4 +-
 .../net/ethernet/mellanox/mlxsw/spectrum.h    |   4 -
 .../ethernet/mellanox/mlxsw/spectrum_router.c | 311 ++++++++++++------
 .../ethernet/mellanox/mlxsw/spectrum_router.h |   3 +
 4 files changed, 212 insertions(+), 110 deletions(-)

2.40.1