zvol_geom_bio_strategy should handle its own use of the zvol
suspend reader lock and ensure the zilog exists when needed.
A few other places using the zvol zilog should use the suspend
reader lock as well.
Simplify consumers of zvol_geom_bio_strategy, fix the locking, and
while in here, use the boolean_t constants with doread.
Reviewed-by: Matt Macy <mmacy@FreeBSD.org>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#10381
c0eb5c35ef