STORAGE_REQUEST_BLOCK structure (storport.h)
The STORAGE_REQUEST_BLOCK is the extended format SCSI Request Block (SRB) structure. The structure provides for the addition of extended data associated with an SRB function.
Note
The SCSI port driver and SCSI miniport driver models may be altered or unavailable in the future. Instead, we recommend using the Storport driver and Storport miniport driver models.
Syntax
typedef struct _STORAGE_REQUEST_BLOCK {
USHORT Length;
UCHAR Function;
UCHAR SrbStatus;
ULONG ReservedUlong1;
ULONG Signature;
ULONG Version;
ULONG SrbLength;
ULONG SrbFunction;
ULONG SrbFlags;
ULONG ReservedUlong2;
ULONG RequestTag;
USHORT RequestPriority;
USHORT RequestAttribute;
ULONG TimeOutValue;
union {
ULONG SystemStatus;
ULONG RequestTagHigh4Bytes;
} DUMMYUNIONNAME;
ULONG SystemStatus;
ULONG ZeroGuard1;
ULONG AddressOffset;
ULONG NumSrbExData;
ULONG DataTransferLength;
PVOID POINTER_ALIGN DataBuffer;
PVOID POINTER_ALIGN ZeroGuard2;
PVOID POINTER_ALIGN OriginalRequest;
PVOID POINTER_ALIGN ClassContext;
PVOID POINTER_ALIGN PortContext;
PVOID POINTER_ALIGN MiniportContext;
_STORAGE_REQUEST_BLOCK POINTER_ALIGN *NextSrb;
struct _STORAGE_REQUEST_BLOCK;
ULONG SrbExDataOffset[ANYSIZE_ARRAY];
} STORAGE_REQUEST_BLOCK, *PSTORAGE_REQUEST_BLOCK;
Members
Length
Specifies the size of the SRB header for compatibility with the SCSI_REQUEST_BLOCK structure. This is equal to the offset of the Signature member of this structure.
Function
Set to SRB_FUNCTION_STORAGE_REQUEST_BLOCK to indicate that this is an extended SRB. Unlike in SCSI_REQUEST_BLOCK, the SRB function identifier is in the SrbFunction member instead.
SrbStatus
Returns the status of the completed request. This member should be set by the miniport driver before it notifies the operating system-specific driver that the request has completed by calling StorPortNotification with RequestComplete. The value of this member can be one of the following:
| Value | Meaning |
|---|---|
| SRB_STATUS_PENDING | Indicates the request is in progress. The operating system-specific port driver initializes SrbStatus to this value. |
| SRB_STATUS_SUCCESS | Indicates the request was completed successfully. |
| SRB_STATUS_ABORTED | Indicates the request was aborted as directed by the port driver. A miniport driver sets this status in the NextSrb member for a successful SRB_FUNCTION_ABORT_COMMAND request. |
| SRB_STATUS_ABORT_FAILED | Indicates an attempt to abort the request failed. Return this status for an SRB_FUNCTION_ABORT_COMMAND request when the specified request cannot be located. |
| SRB_STATUS_ERROR | Indicates the request was completed with an error in the SCSI bus status. |
| SRB_STATUS_BUSY | Indicates the miniport driver or target device could not accept the request at this time. The operating system-specific port driver will resubmit the request later. |
| SRB_STATUS_INTERNAL_ERROR | Indicates that the Storport driver could not deliver the request to the miniport driver or target device. In such cases, status is recorded in InternalStatus. |
| SRB_STATUS_INVALID_REQUEST | Indicates the miniport driver does not support the given request. |
| SRB_STATUS_NO_DEVICE | Indicates the device did not respond. |
| SRB_STATUS_TIMEOUT | Indicates the request timed out. |
| SRB_STATUS_SELECTION_TIMEOUT | Indicates the SCSI device selection timed out. |
| SRB_STATUS_COMMAND_TIMEOUT | Indicates the target did not complete the command within the time limit. |
| SRB_STATUS_MESSAGE_REJECTED | Indicates the target rejected a message. This is normally returned only for such message-type requests as SRB_FUNCTION_TERMINATE_IO. |
| SRB_STATUS_BUS_RESET | Indicates a bus reset occurred while this request was being executed. |
| SRB_STATUS_PARITY_ERROR | Indicates a parity error occurred on the SCSI bus and that a retry failed. |
| SRB_STATUS_REQUEST_SENSE_FAILED | Indicates the request-sense command failed. This is returned only if the host bus adapter (HBA) performs auto request sense and the miniport driver set AutoRequestSense to TRUE in the PORT_CONFIGURATION_INFORMATION for this HBA. |
| SRB_STATUS_NO_HBA | Indicates the HBA does not respond. |
| SRB_STATUS_DATA_OVERRUN | Indicates that a data overrun or underrun error occurred. The miniport driver also must update the SRB's DataTransferLength member to indicate how much data actually was transferred if an underrun occurs. |
| SRB_STATUS_UNEXPECTED_BUS_FREE | Indicates the target disconnected unexpectedly. |
| SRB_STATUS_PHASE_SEQUENCE_FAILURE | Indicates the HBA detected an illegal phase sequence failure error. |
| SRB_STATUS_REQUEST_FLUSHED | Indicates the request for status was stopped. |
| SRB_STATUS_BAD_FUNCTION | Indicates the SRB Function code is not supported. |
| SRB_STATUS_INVALID_PATH_ID | Indicates the PathId specified in the SRB does not exist. |
| SRB_STATUS_INVALID_TARGET_ID | Indicates the TargetID value in the SRB is invalid. |
| SRB_STATUS_INVALID_LUN | Indicates the Lun value in the SRB is invalid. |
| SRB_STATUS_ERROR_RECOVERY | Indicates the request was completed with an error in the SCSI bus status and that the SCSI INITIATE RECOVERY message was received. |
| SRB_STATUS_AUTOSENSE_VALID | Indicates information returned in the SenseInfoBuffer is valid. |
| SRB_STATUS_QUEUE_FROZEN | A miniport driver should never set the SrbStatus member to this value. The Windows port driver can set this value to inform a storage class driver that its queue of requests for a particular peripheral has been frozen. |
| SRB_STATUS_NOT_POWERED | A indicates the request failed because the target is not powered. For requests with SRB_FLAGS_NO_KEEP_AWAKE set in SrbFlags, requests sent to LUNs that are powered down will fail with this status. |
| SRB_STATUS_LINK_DOWN | Indicates the request failed because link is down. |
| SRB_STATUS_BAD_SRB_BLOCK_LENGTH | Indicates the request failed because SRB length was invalid. |
ReservedUlong1
Reserved. Set to 0.
Signature
The signature of the extended SRB format. This is set to SRB_SIGNATURE.
Version
The version of the structure used. The current version is STORAGE_REQUEST_BLOCK_VERSION_1.
SrbLength
The length of this extended SRB, in bytes, including this structure, address and any SRB extended data.
SrbFunction
Specifies the operation to be performed, which can be one of these values:
| Value | Meaning |
|---|---|
| SRB_FUNCTION_EXECUTE_SCSI (0x00) | A SCSI device I/O request should be executed on the target logical unit. When NumSrbExData > 0, one or more of the following extended request block structures are located at the offsets specified in SrbExDataOffset: SRBEX_DATA_SCSI_CDB16, SRBEX_DATA_SCSI_CDB32, SRBEX_DATA_SCSI_CDB_VAR, SRBEX_DATA_BIDIRECTIONAL, SRBEX_DATA_IO_INFO |
| SRB_FUNCTION_IO_CONTROL (0x02) | The request is an I/O control request, originating in a user-mode application with a dedicated HBA. The SRB DataBuffer points to an SRB_IO_CONTROL header followed by the data area. The value in DataBuffer can be used by the driver, regardless of the value of MapBuffers. Only the SRB Function, SrbFlags, TimeOutValue, DataBuffer, and DataTransferLength members are valid, along with the SrbExtension member if the miniport driver requested SRB extensions when it initialized. If a miniport driver controls an application-dedicated HBA so that it supports this request, the miniport driver should execute the request and notify the operating system-specific port driver when the SRB has completed, using the normal mechanism of calls to StorPortNotification with RequestComplete and NextRequest. |
| SRB_FUNCTION_RECEIVE_EVENT (0x03) | The HBA should be prepared to receive an asynchronous event notification from the addressed target. The SRB DataBuffer member indicates where the data should be placed. NOTE: This function is not sent to the miniport by Storport. |
| SRB_FUNCTION_SHUTDOWN (0x07) | The system is being shut down. A miniport driver can receive several of these notifications before all system activity actually stops. However, the last shutdown notification will occur after the last start I/O. Extended SRB data is not required for this function. |
| SRB_FUNCTION_FLUSH (0x08) | The miniport driver should flush any cached data for the target device. This request is sent to the miniport driver only if it set CachesData to TRUE in the PORT_CONFIGURATION_INFORMATION for the HBA. Extended SRB data is not required for this function. |
| SRB_FUNCTION_ABORT_COMMAND (0x10) | A SCSIMESS_ABORT message should be sent to cancel the request pointed to by the NextSrb member. If this is a tagged-queue request, a SCSIMESS_ABORT_WITH_TAG message should be used instead. If the indicated request has been completed, this request should be completed normally. Extended SRB data is not required for this function. NOTE: This function is not sent to the miniport by Storport. |
| SRB_FUNCTION_RELEASE_RECOVERY (0x11) | A SCSIMESS_RELEASE_RECOVERY message should be sent to the target controller. Extended SRB data is not required for this function. NOTE: This function is not sent to the miniport by Storport. |
| SRB_FUNCTION_RESET_BUS (0x12) | The SCSI bus should be reset using the SCSIMESS_BUS_DEVICE_RESET message. A miniport driver receives this request only if a given request has timed out and a subsequent request to abort the timed-out request also has timed out. Extended SRB data is not required for this function. |
| SRB_FUNCTION_TERMINATE_IO (0x14) | A SCSIMESS_TERMINATE_IO_PROCESS message should be sent to cancel the request pointed to by the NextSrb member. If the indicated request has already completed, this request should be completed normally. Extended SRB data is not required for this function. NOTE: This function is not sent to the miniport by Storport. |
| SRB_FUNCTION_RESET_DEVICE (0x16) | The SCSI target controller should be reset using the SCSIMESS_BUS_DEVICE_RESET message. The miniport driver should complete any active requests for the target controller. Extended SRB data is not required for this function. |
| SRB_FUNCTION_WMI (0x17) | The request is a power extended request formatted as a SRBEX_DATA_WMI structure. The offset to extended request data is located at SrbExDataOffset[0]. |
| SRB_FUNCTION_LOCK_QUEUE (0x18) | Holds requests that are queued by the port driver for a particular logical unit, typically while a power request is being processed. Only the SRB Length, Function, SrbFlags, and OriginalRequest members are valid. When the queue is locked, only requests with SrbFlags ORed with SRB_FLAGS_BYPASS_LOCKED_QUEUE will be processed. SCSI miniport drivers do not process SRB_FUNCTION_LOCK_QUEUE requests. |
| SRB_FUNCTION_UNLOCK_QUEUE (0x19) | Releases the port driver's queue for a logical unit that was previously locked with SRB_FUNCTION_LOCK_QUEUE. The SrbFlags of the unlock request must be ORed with SRB_FLAGS_BYPASS_LOCKED_QUEUE. Only the SRB Length, Function, SrbFlags, and OriginalRequest members are valid. SCSI miniport drivers do not process SRB_FUNCTION_UNLOCK_QUEUE requests. |
| SRB_FUNCTION_QUIESCE_DEVICE (0x1A) | The request is only between a storage class and storage port driver and is not be sent to miniport. This function serves as a wait by the class driver for port driver to complete all outstanding I/Os. |
| SRB_FUNCTION_RESET_LOGICAL_UNIT (0x20) | The logical unit should be reset, if possible. The HBA miniport driver should complete any active requests for the logical unit. Extended SRB data is not required for this function. Storport supports this type of reset, but SCSI port does not. |
| SRB_FUNCTION_POWER (0x24) | The request is a power extended request formatted as a SRBEX_DATA_POWER structure. The offset to extended request data is located at SrbExDataOffset[0]. |
| SRB_FUNCTION_PNP (0x25) | The request is a PnP extended request formatted as a SRBEX_DATA_PNP structure. The offset to extended request data is located at SrbExDataOffset[0]. |
| SRB_FUNCTION_DUMP_POINTERS (0x26) | A request with this function is sent to a Storport miniport driver that is used to control the disk that holds the crash dump data. The request collects information needed from the miniport driver to support crash dump and hibernation. See the MINIPORT_DUMP_POINTERS structure. A physical miniport driver must set the STOR_FEATURE_DUMP_POINTERS flag in the FeatureSupport member of its HW_INITIALIZATION_DATA to receive a request with this function. |
| SRB_FUNCTION_FREE_DUMP_POINTERS (0x27) | A request with this function is sent to a Storport miniport driver to release any resources allocated during a previous request for SRB_FUNCTION_DUMP_POINTERS. |
SrbFlags
Indicates various parameters and options for the request. SrbFlags is read-only, except when SRB_FLAGS_UNSPECIFIED_DIRECTION is set and miniport drivers of subordinate DMA adapters are required to update SRB_FLAGS_DATA_IN or SRB_FLAGS_DATA_OUT. This member can have one or more of these flags set.
| Flag | Meaning |
|---|---|
| SRB_FLAGS_QUEUE_ACTION_ENABLE | Indicates tagged-queue actions are to be enabled. |
| SRB_FLAGS_DISABLE_AUTOSENSE | Indicates request-sense information should not be returned. |
| SRB_FLAGS_DATA_IN | Indicates data will be transferred from the device to the system. |
| SRB_FLAGS_DATA_OUT | Indicates data will be transferred from the system to the device. |
| SRB_FLAGS_UNSPECIFIED_DIRECTION | Defined for backward compatibility with the ASPI/CAM SCSI interfaces, this flag indicates that the transfer direction could be either of the preceding, because both of the preceding flags are set. If this flag is set, a miniport driver should determine the transfer direction by examining the data phase for the target on the SCSI bus. |
| SRB_FLAGS_NO_DATA_TRANSFER | Indicates no data transfer with this request. If this is set, the flags SRB_FLAGS_DATA_OUT, SRB_FLAGS_DATA_IN, and SRB_FLAGS_UNSPECIFIED_DIRECTION are clear. |
| SRB_FLAGS_DISABLE_SYNCH_TRANSFER | Indicates the HBA, if possible, should perform asynchronous I/O for this transfer request. If synchronous I/O was negotiated previously, the HBA must renegotiate for asynchronous I/O before performing the transfer. |
| SRB_FLAGS_DISABLE_DISCONNECT | Indicates the HBA should not allow the target to disconnect from the SCSI bus during processing of this request. |
| SRB_FLAGS_BYPASS_FROZEN_QUEUE | This flag is irrelevant to miniport drivers. |
| SRB_FLAGS_NO_QUEUE_FREEZE | This flag is irrelevant to miniport drivers. |
| SRB_FLAGS_IS_ACTIVE | This flag is irrelevant to miniport drivers. |
| SRB_FLAGS_ALLOCATED_FROM_ZONE | This flag is irrelevant to miniport drivers and is obsolete to new Windows class drivers. To a Windows legacy class driver, this indicates whether the SRB was allocated from a zone buffer. If this flag is set, the class driver must call ExInterlockedFreeToZone to release the SRB; otherwise, it must call ExFreePool. New class drivers should use lookaside lists rather than zone buffers. |
| SRB_FLAGS_SGLIST_FROM_POOL | This flag is irrelevant to miniport drivers. To the class driver, this indicates that memory for a scatter/gather list was allocated from a nonpaged pool. If this flag is set, the class driver must call ExFreePool to release the memory after the SRB is completed. |
| SRB_FLAGS_BYPASS_LOCKED_QUEUE | This flag is irrelevant to miniport drivers. To the port driver, this flag indicates that the request should be processed whether the logical-unit queue is locked or not. A higher-level driver must set this flag to send an SRB_FUNCTION_UNLOCK_QUEUE request. |
| SRB_FLAGS_NO_KEEP_AWAKE | This flag is irrelevant to miniport drivers. A Windows class driver uses this flag to indicate to the port driver to fail the request rather than powering up the device to handle this request. |
| SRB_FLAGS_FREE_SENSE_BUFFER | Indicates that either the port or the miniport driver has allocated a buffer for sense data. This informs the class driver that it must free the sense data buffer after extracting the data. |
| SRB_FLAGS_D3_PROCESSING | Indicates that the request is part of D3 processing. Miniports that support runtime power control should not call StorPortPoFxActivateComponent or StorPortPoFxIdleComponent with these requests. |
| SRB_FLAGS_ADAPTER_CACHE_ENABLE | Indicates that the adapter can cache data. |
ReservedUlong2
Reserved. Set to 0.
RequestTag
Contains the queue-tag value assigned by the operating system-specific port driver. If this member is used for tagged queuing, the HBA supports internal queuing of requests to logical units (LUs) and the miniport driver set TaggedQueueing to TRUE in the PORT_CONFIGURATION_INFORMATION for this HBA.
RequestPriority
The priority assignment for the SRB. Can be one of the following values.
| Value | Meaning |
|---|---|
| StorIoPriorityVeryLow (0) | Very low priority. |
| StorIoPriorityLow (1) | Low priority. |
| StorIoPriorityNormal (2) | Normal priority. |
| StorIoPriorityHigh (3) | High priority. |
| StorIoPriorityCritical (4) | Critical priority. |
RequestAttribute
Indicates the tagged-queuing message to be used when the SRB_FLAGS_QUEUE_ACTION_ENABLE flag is set. The value can be one of the following: SRB_SIMPLE_TAG_REQUEST, SRB_HEAD_OF_QUEUE_TAG_REQUEST, or SRB_ORDERED_QUEUE_TAG_REQUEST.
TimeOutValue
Indicates the interval, in seconds, that the request can execute before the operating system-specific port driver might consider it timed out. Miniport drivers are not required to time requests because the port driver already does.
DUMMYUNIONNAME
Embedded union.
DUMMYUNIONNAME.SystemStatus
Used to store system failure status information in SrbStatus failure conditions (for example, SRB_STATUS_INTERNAL_ERROR).
DUMMYUNIONNAME.RequestTagHigh4Bytes
Used to store high four bytes of unique tag if unique tag feature is enabled.
SystemStatus
Used by the Storport driver, instead of SrbStatus, to report the status of the completed request whenever the request cannot be delivered to the miniport driver. In such cases, SrbStatus is set to SRB_STATUS_INTERNAL_ERROR. This member is used exclusively for communication between the Storport and the class driver and should not be used by miniport drivers.
ZeroGuard1
A guard area to protect against drivers that interpret this structure as SCSI_REQUEST_BLOCK. Set to 0.
AddressOffset
The offset of the storage request address from the beginning of this structure. This offset locates a STOR_ADDRESS structure that contains the address for the request.
NumSrbExData
The count of extended SRB data blocks for this request.
DataTransferLength
Indicates the size, in bytes, of the data buffer. If an underrun occurs, the miniport driver must update this member to the number of bytes actually transferred.
DataBuffer
Points to the data buffer. Miniport drivers should not use this value as a data pointer unless the miniport driver set MapBuffers to TRUE in the PORT_CONFIGURATION_INFORMATION for the HBA. In the case of SRB_FUNCTION_IO_CONTROL requests, however, miniport drivers can use this value as a data pointer regardless of the value of MapBuffers.
ZeroGuard2
A guard area to protect against drivers that interpret this structure as SCSI_REQUEST_BLOCK. Set to 0.
OriginalRequest
Points to the IRP for this request. This member is irrelevant to miniport drivers.
ClassContext
Points to a class driver context data for this request. This member is irrelevant to miniport drivers.
PortContext
Points to a port driver context data for this request. This member is irrelevant to miniport drivers.
MiniportContext
Points to the Srb extension. A miniport driver must not use this member if it set SrbExtensionSize to zero in HW_INITIALIZATION_DATA. The memory at MiniportContext is not initialized by the operating system-specific port driver, and the miniport driver-determined data can be accessed directly by the HBA. The corresponding physical address can be obtained by calling StorportGetPhysicalAddress with the MiniportContext pointer.
NextSrb
Indicates the STORAGE_REQUEST_BLOCK to which this request applies. Only a small subset of requests use a second SRB, for example SRB_FUNCTION_ABORT_COMMAND.
_STORAGE_REQUEST_BLOCK
SrbExDataOffset[ANYSIZE_ARRAY]
An array of offsets specifying the location of extended data blocks for the SRB. This array is empty if NumSrbExData = 0.
Remarks
Starting in Windows 8, an extended SRB type is supported with the use of the STORAGE_REQUEST_BLOCK structure. STORAGE_REQUEST_BLOCK extends SRB functions, allowing extended data blocks for the SRB function to be added to the request. Support for SRB requests using the SCSI_REQUEST_BLOCK structure will continue.
If NumSrbExData > 0, the offsets for the SRB extended data blocks are in the SrbExDataOffset array. Each offset is relative to the beginning of this structure and points to a SRBEX_DATA structure containing the extended data block.
The target device address for the SRB is in a STOR_ADDRESS structure indicated by AddressOffset.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Available in Windows 8 and later versions of Windows. |
| Header | storport.h (include Storport.h, Srb.h, Minitape.h) |