We should use `ns->registrants` to count the number of registered
controllers(REGCTL) for Reservation Report command, as `subsystem->ctrlrs`
only list current active sessions(controllers).
Also use the output data buffer directly so that we don't need to calloc/free
during the process of Reservation Report command.
Fix#1928
Change-Id: I650224b751a08416208b8a504b82debff31e92fd
Signed-off-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/7822
Community-CI: Broadcom CI
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: wanghailiang <hailiangx.e.wang@intel.com>
6b372f419d