[ Upstream commit 32dab682 ]

Use kzalloc() to allocate auxiliary buffer structure initialized
with all zeroes to avoid random value in trace output.

Avoid double access to SBD hardware flags.
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>