K 10
svn:author
V 3
cem
K 8
svn:date
V 27
2018-10-20T19:42:38.850052Z
K 7
svn:log
V 535
dev_refthread: Do not initialize *ref when reference was not acquired

Like the companion API devvn_refthread, leave *ref uninitialized when a
reference was not acquired.  Initializing to 1 provides a vaguely
correct-looking but bogus value for broken callers to (mistakenly) pass to
dev_relthread() when refthread fails.

Make it even more clear to consumers that dev_relthread is only valid when
dev_refthread succeeds.

Reviewed by:	kib, markj
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D16885

END