SCSI_PASS_THROUGH structure (ntddscsi.h)
The SCSI_PASS_THROUGH structure is used in conjunction with an IOCTL_SCSI_PASS_THROUGH request to instruct the port driver to send an embedded SCSI command to the target device.
Syntax
typedef struct _SCSI_PASS_THROUGH {
USHORT Length;
UCHAR ScsiStatus;
UCHAR PathId;
UCHAR TargetId;
UCHAR Lun;
UCHAR CdbLength;
UCHAR SenseInfoLength;
UCHAR DataIn;
ULONG DataTransferLength;
ULONG TimeOutValue;
ULONG_PTR DataBufferOffset;
ULONG SenseInfoOffset;
UCHAR Cdb[16];
} SCSI_PASS_THROUGH, *PSCSI_PASS_THROUGH;
Members
Length
Contains the value of sizeof(SCSI_PASS_THROUGH).
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
This field must have one of three values:
#######
DataTransferLength
Indicates the size in bytes of the data buffer. Many devices transfer chunks of data of predefined length. The value in DataTransferLength must be an integral multiple of this predefined, 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 port driver considers it timed out.
DataBufferOffset
Contains an offset from the beginning of this structure to the data buffer. The offset must respect the data alignment requirements of the device.
SenseInfoOffset
Offset from the beginning of this structure to the request-sense buffer.
Cdb[16]
Specifies the SCSI command descriptor block to be sent to the target device.
Remarks
The SCSI_PASS_THROUGH structure is used with IOCTL_SCSI_PASS_THROUGH, which is a buffered device control request. To bypass buffering in system memory, callers should use IOCTL_SCSI_PASS_THROUGH_DIRECT. When handling an IOCTL_SCSI_PASS_THROUGH_DIRECT request, the system locks down the buffer in user memory and the device accesses this memory directly.
The members of SCSI_PASS_THROUGH 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
| Requirement | Value |
|---|---|
| Header | ntddscsi.h (include Ntddscsi.h) |