[PATCH 2/5] hv: add helpers to handle hv_util device state

[Olaf Hering]

On Sun, Sep 20, Greg KH wrote:

> Just use a lock, that's what it is there for.

How would that help? It might help because it enforces ordering. But
that requires that all three utils get refactored to deal with the
introduced locking. I will let KY comment on this.

The issue I see with fcopy is that after or while fcopy_respond_to_host
runs an interrupt triggers which also calls into
hv_fcopy_onchannelcallback.  It was most likely caused by a logic change
in "recent" vmbus updates because this did not happen before. At least,
the fcopy hang was not seen earler. Maybe the bug did just not trigger
up to now for other reasons...

Olaf