K 10
svn:author
V 5
sephe
K 8
svn:date
V 27
2016-09-28T04:34:21.882402Z
K 7
svn:log
V 635
hyperv/hn: Suspend and resume the backend properly upon MTU change.

Suspend:
- Prevent the backend from being touched on TX path.
- Clear the RNDIS RX filter, and wait for RX to drain.
- Make sure that NVS see the chimney sending buffer and RXBUF
  disconnection, before unlink these buffers from the channel.

Resume:
- Reconfigure the RNDIS filter.
- Allow TX path to work on the backend.
- Kick start the TX eof task, in case the OACTIVE is set.

This fixes various panics, when the interface has traffic and MTU
is being changed.

MFC after:	1 week
Sponsored by:	Microsoft
Differential Revision:	https://reviews.freebsd.org/D8046

END