K 10
svn:author
V 3
mjg
K 8
svn:date
V 27
2017-10-05T13:01:18.312252Z
K 7
svn:log
V 239
locks: partially tidy up waiting on readers

spin first instant of instantly re-readoing and don't re-read after
spinning is finished - the state is already known.

Note the code is subject to significant changes later.

MFC after:	1 week

END