Merge branch 'net-fix-netdev-to-devlink_port-linkage-and-expose-to-user'

Merge branch 'net-fix-netdev-to-devlink_port-linkage-and-expose-to-user'

Jiri Pirko says:

====================
net: fix netdev to devlink_port linkage and expose to user

Currently, the info about linkage from netdev to the related
devlink_port instance is done using ndo_get_devlink_port().
This is not sufficient, as it is up to the driver to implement it and
some of them don't do that. Also it leads to a lot of unnecessary
boilerplate code in all the drivers.

Instead of that, introduce a possibility for driver to expose this
relationship by new SET_NETDEV_DEVLINK_PORT macro which stores it into
dev->devlink_port. It is ensured by the driver init/fini flows that
the devlink_port pointer does not change during the netdev lifetime.
Devlink port is always registered before netdev register and
unregistered after netdev unregister.

Benefit from this linkage setup and remove explicit calls from driver
to devlink_port_type_eth_set() and clear(). Many of the driver
didn't use it correctly anyway. Let the devlink.c to track associated
netdev events and adjust type and type pointer accordingly. Also
use this events to to keep track on ifname change and remove RTNL lock
taking from devlink_nl_port_fill().

Finally, remove the ndo_get_devlink_port() ndo which is no longer used
and expose devlink_port handle as a new netdev netlink attribute to the
user. That way, during the ifname->devlink_port lookup, userspace app
does not have to dump whole devlink port list and instead it can just
do a simple RTM_GETLINK query.
====================

Link: https://lore.kernel.org/r/20221102160211.662752-1-jiri@resnulli.us
Signed-off-by: Jakub Kicinski <kuba@kernel.org>