scsi_setup_cdb() function initializes a group 0, 1, 2, 4, or 5 type of command descriptor block pointed to by cdbp using cmd, addr, cnt, othr_cdb_data.
addr should be set to 0 for commands having no addressing information (for example, group 0 READ command for sequential access devices). othr_cdb_data
should be additional CDB data for Group 4 commands; otherwise, it should be set to 0.
scsi_setup_cdb() function does not set the LUN bits in CDB as the makecom(9F) functions do. Also, the fixed bit for sequential access device commands is not set.