To prevent cache being stopped before async start finialize has finished, stop
routine have to check if worker responsible for finalizing is not running
anymore.
To create link between start finalize and stop functions, work_struct had to be
moved from attach_context to cache_priv.
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>
To make cache stop as simple as possibe and to reduce number of errors, stop
context should be allocated during cache initialize.
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>