Merge branch 'per-netns-notifier'

Jiri Pirko says:

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net: introduce per-netns netdevice notifiers and use them in mlxsw

Some drivers, like mlxsw, are not interested in notifications coming in
for netdevices from other network namespaces. So introduce per-netns
notifiers and allow to reduce overhead by listening only for
notifications from the same netns.

This is also a preparation for upcoming patchset "devlink: allow devlink
instances to change network namespace". This resolves deadlock during
reload mlxsw into initial netns made possible by
328fbe747ad4 ("net: Close race between {un, }register_netdevice_notifier() and setup_net()/cleanup_net()").
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Signed-off-by: David S. Miller <davem@davemloft.net>