Merge branch 'netdevsim-implement-proper-device-model'

Merge branch 'netdevsim-implement-proper-device-model'

Jiri Pirko says:

====================
netdevsim: implement proper device model

Currently the model of netdevsim is a bit odd in multiple ways.
1) devlink instance is not in any way related with actual netdevsim
   netdevices. Instead, it is created per-namespace.
2) multi-port netdevsim device is done using "link" attribute.
3) netdevsim bus is there only to have something to bind the netdev to,
   it really does not act as a bus.
4) netdevsim instances are created by "ip link add" which is great for
   soft devices with no hw backend. The rtnl core allocates netdev and
   calls into driver holding rtnl mutex. For hw-backed devices, this
   flow is wrong as it breaks order in which things are done.

This patchset adjust netdevsim to fix all above.

In order to support proper devlink and devlink port instances and to be
able to emulate real devices, there is need to implement bus probe and
instantiate everything from there. User can specify device id and port
count to be instantianted. For example:

$ echo "10 4" > /sys/bus/netdevsim/new_device

Then devlink shows this:

$ devlink dev
netdevsim/netdevsim10

$ devlink port
netdevsim/netdevsim10/0: type eth netdev eni0np1 flavour physical
netdevsim/netdevsim10/1: type eth netdev eni0np2 flavour physical
netdevsim/netdevsim10/2: type eth netdev eni0np3 flavour physical
netdevsim/netdevsim10/3: type eth netdev eni0np4 flavour physical

There is possible to add and delete ports using their indexes
during netdevsim device lifetime like this:

Then devlink shows this:

$ devlink port
netdevsim/netdevsim10/1: type eth netdev eni10np2 flavour physical
netdevsim/netdevsim10/2: type eth netdev eni10np3 flavour physical
netdevsim/netdevsim10/3: type eth netdev eni10np4 flavour physical
netdevsim/netdevsim10/43: type eth netdev eni10np44 flavour physical

Debugfs topology is also adjusted a bit. The rest stays the same as
before.

Udev bits are merged un systemd upstream git:
https://github.com/systemd/systemd/commit/eaa9d507d85509c8bf727356e3884ec54b0fc646

See individual patches for changelog.
====================

Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>