This patch makes bdevperf_construct_targets_tasks() asynchronous by using spdk_for_each_channel(). The next patch will make performance_dump() asynchronous even when shutdown case by using spdk_for_each_channel(). Signed-off-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com> Change-Id: I1ebf39fe89a944d977d6f1808cf8607e8f477758 Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/644 Tested-by: SPDK CI Jenkins <sys_sgci@intel.com> Reviewed-by: Jim Harris <james.r.harris@intel.com> Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>