illumos gate

In scsi_hba_attach_setup(9F), it states:

The flags SCSI_HBA_TRAN_CDB and SCSI_HBA_TRAN_SCB are only valid when tran_setup_pkt() is used. See tran_setup_pkt(9E) for information on using these flags.

However, tran_setup_pkt(9E) never explicitly mentions either flag. Instead, we have

If the HBA driver chose not to preallocate memory for pkt_cdbp and/or pkt_scbp, it must allocate the requested memory at this time and point pkt_cdbp and pkt_scbp to the allocated memory.

The intention is that when SCSI_HBA_TRAN_CDB and/or SCSI_HBA_TRAN_SCB are passed to scsi_hba_attach_setup(9F), then SCSA will perform these respective preallocations for a scsi_pkt(9S) on behalf of the driver.

It would be helpful to explicitly mention the flags to make their intention and use clearer.