nvme_allocate_request_null
*req = nvme_allocate_request_null(M_WAITOK, cb_fn, cb_arg);
req = nvme_allocate_request_null(M_WAITOK, nvme_pt_done, pt);
req = nvme_allocate_request_null(M_WAITOK, nvme_npc_done, npc);
req = nvme_allocate_request_null(M_WAITOK, nvme_ctrlr_async_event_cb,
req = nvme_allocate_request_null(M_WAITOK, cb_fn, cb_arg);
req = nvme_allocate_request_null(M_WAITOK, cb_fn, cb_arg);
req = nvme_allocate_request_null(M_WAITOK, cb_fn, cb_arg);
req = nvme_allocate_request_null(M_WAITOK, cb_fn, cb_arg);
req = nvme_allocate_request_null(M_WAITOK, cb_fn, cb_arg);
req = nvme_allocate_request_null(M_NOWAIT, cb_fn, cb_arg);
req = nvme_allocate_request_null(M_WAITOK, cb_fn, cb_arg);
req = nvme_allocate_request_null(M_NOWAIT, cb_fn, cb_arg);
req = nvme_allocate_request_null(M_NOWAIT, nvme_sim_nvmeio_done,