The SCSI_PASS_THROUGH structure is used in conjunction with an IOCTL_SCSI_PASS_THROUGH_DIRECT request to instruct the port driver to send an embedded SCSI command to the target device.

typedef struct _SCSI_PASS_THROUGH_DIRECT {
  USHORT  Length;
  UCHAR  ScsiStatus;
  UCHAR  PathId;
  UCHAR  TargetId;
  UCHAR  Lun;
  UCHAR  CdbLength;
  UCHAR  SenseInfoLength;
  UCHAR  DataIn;
  ULONG  DataTransferLength;
  ULONG  TimeOutValue;
  PVOID  DataBuffer;
  ULONG  SenseInfoOffset;
  UCHAR  Cdb[16];
}SCSI_PASS_THROUGH_DIRECT, *PSCSI_PASS_THROUGH_DIRECT;

Members

Length

Contains the value of sizeof(SCSI_PASS_THROUGH_DIRECT).

ScsiStatus

Reports the SCSI status that was returned by the HBA or the target device.

PathId

Indicates the SCSI port or bus for the request.

TargetId

Indicates the target controller or device on the bus.

Lun

Indicates the logical unit number of the device.

CdbLength

Indicates the size in bytes of the SCSI command descriptor block.

SenseInfoLength

Indicates the size in bytes of the request-sense buffer.

DataIn

Indicates whether the SCSI command will read or write data. This field must have one of three values:

Data Transfer Type	Meaning
SCSI_IOCTL_DATA_IN	Read data from the device.
SCSI_IOCTL_DATA_OUT	Write data to the device.
SCSI_IOCTL_DATA_UNSPECIFIED	No data transferred.

DataTransferLength

Indicates the size in bytes of the data buffer. Many devices transfer chunks of data of pre-defined length. The value in DataTransferLength must be an integral multiple of this pre-defined, minimum length that is specified by the device. If an underrun occurs, the miniport driver must update this member to the number of bytes actually transferred.

TimeOutValue

Indicates the interval in seconds that the request can execute before the OS-specific port driver might consider it timed out.

DataBuffer

Pointer to the data buffer.

SenseInfoOffset

Contains an offset from the beginning of this structure to the request-sense buffer.

Cdb

Specifies the SCSI command descriptor block to be sent to the target device.

Comments

The SCSI_PASS_THROUGH_DIRECT structure is used with IOCTL_SCSI_PASS_THROUGH_DIRECT. With this request, the system locks down the buffer in user memory and the device accesses this memory directly. For a double-buffered equivalent of this device control request see IOCTL_SCSI_PASS_THROUGH and SCSI_PASS_THROUGH.

The members of SCSI_PASS_THROUGH_DIRECT correspond roughly to the members of a SCSI_REQUEST_BLOCK structure. The values of the DataIn member correspond to the SCSI_IOCTL_DATA_IN, SCSI_IOCTL_DATA_OUT, and SCSI_IOCTL_DATA_UNSPECIFIED flags assigned to SrbFlags member of SCSI_REQUEST_BLOCK.

Requirements

Headers: Declared in ntddscsi.h. Include ntddscsi.h.

See Also

IOCTL_SCSI_PASS_THROUGH, IOCTL_SCSI_PASS_THROUGH_DIRECT,SCSI_PASS_THROUGH, SCSI_REQUEST_BLOCK