nvme_ns_ioctl
return nvme_ns_ioctl(ns, cmd, argp, flags, open_for_write);
return nvme_ns_ioctl(ns, cmd, argp, 0, open_for_write);
ret = nvme_ns_ioctl(ns, cmd, argp, flags, open_for_write);
ret = nvme_ns_ioctl(ns, cmd, argp, 0, open_for_write);