Merge branch 'vsock-virtio-hot-unplug'

Stefano Garzarella says:

====================
vsock/virtio: fix issues on device hot-unplug

These patches try to handle the hot-unplug of vsock virtio transport device in
a proper way.

Maybe move the vsock_core_init()/vsock_core_exit() functions in the module_init
and module_exit of vsock_virtio_transport module can't be the best way, but the
architecture of vsock_core forces us to this approach for now.

The vsock_core proto_ops expect a valid pointer to the transport device, so we
can't call vsock_core_exit() until there are open sockets.

v2 -> v3:
 - Rebased on master

v1 -> v2:
 - Fixed commit message of patch 1.
 - Added Reviewed-by, Acked-by tags by Stefan
====================

Signed-off-by: David S. Miller <davem@davemloft.net>