K 10
svn:author
V 3
mav
K 8
svn:date
V 27
2019-08-21T02:17:39.630060Z
K 7
svn:log
V 278
Formalize NVMe controller consumer life cycle.

This fixes possible double call of fail_fn, for example on hot removal.
It also allows ctrlr_fn to safely return NULL cookie in case of failure
and not get useless ns_fn or fail_fn call with NULL cookie later.

MFC after:	2 weeks

END