UBLK_QID_OFF
return ((pos - UBLKSRV_IO_BUF_OFFSET) >> UBLK_QID_OFF) &
#define UBLKSRV_IO_BUF_TOTAL_BITS (UBLK_QID_OFF + UBLK_QID_BITS)
((__u64)q_id << UBLK_QID_OFF | (__u64)tag << UBLK_TAG_OFF);