Merge branch 'devlink-instances-relationships'

Jiri Pirko says:

====================
expose devlink instances relationships

From: Jiri Pirko <jiri@nvidia.com>

Currently, the user can instantiate new SF using "devlink port add"
command. That creates an E-switch representor devlink port.

When user activates this SF, there is an auxiliary device created and
probed for it which leads to SF devlink instance creation.

There is 1:1 relationship between E-switch representor devlink port and
the SF auxiliary device devlink instance.

Also, for example in mlx5, one devlink instance is created for
PCI device and one is created for an auxiliary device that represents
the uplink port. The relation between these is invisible to the user.

Patches #1-#3 and #5 are small preparations.

Patch #4 adds netnsid attribute for nested devlink if that in a
different namespace.

Patch #5 is the main one in this set, introduces the relationship
tracking infrastructure later on used to track SFs, linecards and
devlink instance relationships with nested devlink instances.

Expose the relation to the user by introducing new netlink attribute
DEVLINK_PORT_FN_ATTR_DEVLINK which contains the devlink instance related
to devlink port function. This is done by patch #8.
Patch #9 implements this in mlx5 driver.

Patch #10 converts the linecard nested devlink handling to the newly
introduced rel infrastructure.

Patch #11 benefits from the rel infra and introduces possiblitily to
have relation between devlink instances.
Patch #12 implements this in mlx5 driver.

Examples:
$ devlink dev
pci/0000:08:00.0: nested_devlink auxiliary/mlx5_core.eth.0
pci/0000:08:00.1: nested_devlink auxiliary/mlx5_core.eth.1
auxiliary/mlx5_core.eth.1
auxiliary/mlx5_core.eth.0

$ devlink port add pci/0000:08:00.0 flavour pcisf pfnum 0 sfnum 106
pci/0000:08:00.0/32768: type eth netdev eth4 flavour pcisf controller 0 pfnum 0 sfnum 106 splittable false
  function:
    hw_addr 00:00:00:00:00:00 state inactive opstate detached roce enable
$ devlink port function set pci/0000:08:00.0/32768 state active
$ devlink port show pci/0000:08:00.0/32768
pci/0000:08:00.0/32768: type eth netdev eth4 flavour pcisf controller 0 pfnum 0 sfnum 106 splittable false
  function:
    hw_addr 00:00:00:00:00:00 state active opstate attached roce enable nested_devlink auxiliary/mlx5_core.sf.2

$ devlink port show pci/0000:08:00.0/32768
pci/0000:08:00.0/32768: type eth netdev eth4 flavour pcisf controller 0 pfnum 0 sfnum 106 splittable false
  function:
    hw_addr 00:00:00:00:00:00 state active opstate attached roce enable nested_devlink auxiliary/mlx5_core.sf.2 nested_devlink_netns ns1
====================

Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>