K 10
svn:author
V 6
adrian
K 8
svn:date
V 27
2015-01-26T04:04:57.322837Z
K 7
svn:log
V 264
Call WITNESS_WARN() in callout_drain() to check whether any locks are
being held before sleeping.

This has bitten me (in ath(4)) once before and I'd like to see this
not bite anyone else.

Differential Revision:	D1638
Reviewed by:	jhb, hselasky
MFC after:	1 week

END