This will make the object relationship cleaner and the asynchronous detach operation easier to implement. Signed-off-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com> Change-Id: I5030dc9eb8f607247f08b4524d37ec2b74826a93 Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/4430 Tested-by: SPDK CI Jenkins <sys_sgci@intel.com> Reviewed-by: Ben Walker <benjamin.walker@intel.com> Reviewed-by: Jim Harris <james.r.harris@intel.com> Reviewed-by: Aleksey Marchuk <alexeymar@mellanox.com>