IO_STACK_LOCATION

The IO_STACK_LOCATION structure defines an I/O stack location, which is an entry in the I/O stack that is associated with each IRP. Each I/O stack location in an IRP has some common members and some request-type-specific members.

typedef struct _IO_STACK_LOCATION {
  UCHAR  MajorFunction;
  UCHAR  MinorFunction;
  UCHAR  Flags;
  UCHAR  Control;
  union {
        //
        // Parameters for IRP_MJ_CREATE 
        //
        struct {
            PIO_SECURITY_CONTEXT SecurityContext;
            ULONG Options;
            USHORT POINTER_ALIGNMENT FileAttributes;
            USHORT ShareAccess;
            ULONG POINTER_ALIGNMENT EaLength;
        } Create;
        //
        // Parameters for IRP_MJ_READ 
        //
        struct {
            ULONG Length;
            ULONG POINTER_ALIGNMENT Key;
            LARGE_INTEGER ByteOffset;
        } Read;
        //
        // Parameters for IRP_MJ_WRITE 
        //
        struct {
            ULONG Length;
            ULONG POINTER_ALIGNMENT Key;
            LARGE_INTEGER ByteOffset;
        } Write;
        //
        // Parameters for IRP_MJ_QUERY_INFORMATION 
        //
        struct {
            ULONG Length;
            FILE_INFORMATION_CLASS POINTER_ALIGNMENT FileInformationClass;
        } QueryFile;
        //
        // Parameters for IRP_MJ_SET_INFORMATION 
        //
        struct {
            ULONG Length;
            FILE_INFORMATION_CLASS POINTER_ALIGNMENT FileInformationClass;
            PFILE_OBJECT FileObject;
            union {
                struct {
                    BOOLEAN ReplaceIfExists;
                    BOOLEAN AdvanceOnly;
                };
                ULONG ClusterCount;
                HANDLE DeleteHandle;
            };
        } SetFile;
        //
        // Parameters for IRP_MJ_QUERY_VOLUME_INFORMATION 
        //
        struct {
            ULONG Length;
            FS_INFORMATION_CLASS POINTER_ALIGNMENT FsInformationClass;
        } QueryVolume;
        //
        // Parameters for IRP_MJ_DEVICE_CONTROL and IRP_MJ_INTERNAL_DEVICE_CONTROL 
        //
        struct {
            ULONG OutputBufferLength;
            ULONG POINTER_ALIGNMENT InputBufferLength;
            ULONG POINTER_ALIGNMENT IoControlCode;
            PVOID Type3InputBuffer;
        } DeviceIoControl;
        //
        // Nonsystem service parameters.
        //
        // Parameters for IRP_MN_MOUNT_VOLUME 
        //
        struct {
            PVOID DoNotUse1;
            PDEVICE_OBJECT DeviceObject;
        } MountVolume;
        //
        // Parameters for IRP_MN_VERIFY_VOLUME 
        //
        struct {
            PVOID DoNotUse1;
            PDEVICE_OBJECT DeviceObject;
        } VerifyVolume;
        //
        // Parameters for Scsi using IRP_MJ_INTERNAL_DEVICE_CONTROL 
        //
        struct {
            struct _SCSI_REQUEST_BLOCK *Srb;
        } Scsi;
        //
        // Parameters for IRP_MN_QUERY_DEVICE_RELATIONS 
        //
        struct {
            DEVICE_RELATION_TYPE Type;
        } QueryDeviceRelations;
        //
        // Parameters for IRP_MN_QUERY_INTERFACE 
        //
        struct {
            CONST GUID *InterfaceType;
            USHORT Size;
            USHORT Version;
            PINTERFACE Interface;
            PVOID InterfaceSpecificData;
        } QueryInterface;
        //
        // Parameters for IRP_MN_QUERY_CAPABILITIES 
        //
        struct {
            PDEVICE_CAPABILITIES Capabilities;
        } DeviceCapabilities;
        //
        // Parameters for IRP_MN_FILTER_RESOURCE_REQUIREMENTS 
        //
        struct {
            PIO_RESOURCE_REQUIREMENTS_LIST IoResourceRequirementList;
        } FilterResourceRequirements;
        //
        // Parameters for IRP_MN_READ_CONFIG and IRP_MN_WRITE_CONFIG 
        //
        struct {
            ULONG WhichSpace;
            PVOID Buffer;
            ULONG Offset;
            ULONG POINTER_ALIGNMENT Length;
        } ReadWriteConfig;
        //
        // Parameters for IRP_MN_SET_LOCK 
        //
        struct {
            BOOLEAN Lock;
        } SetLock;
        //
        // Parameters for IRP_MN_QUERY_ID 
        //
        struct {
            BUS_QUERY_ID_TYPE IdType;
        } QueryId;
        //
        // Parameters for IRP_MN_QUERY_DEVICE_TEXT 
        //
        struct {
            DEVICE_TEXT_TYPE DeviceTextType;
            LCID POINTER_ALIGNMENT LocaleId;
        } QueryDeviceText;
        //
        // Parameters for IRP_MN_DEVICE_USAGE_NOTIFICATION 
        //
        struct {
            BOOLEAN InPath;
            BOOLEAN Reserved[3];
            DEVICE_USAGE_NOTIFICATION_TYPE POINTER_ALIGNMENT Type;
        } UsageNotification;
        //
        // Parameters for IRP_MN_WAIT_WAKE 
        //
        struct {
            SYSTEM_POWER_STATE PowerState;
        } WaitWake;
        //
        // Parameter for IRP_MN_POWER_SEQUENCE 
        //
        struct {
            PPOWER_SEQUENCE PowerSequence;
        } PowerSequence;
        //
        // Parameters for IRP_MN_SET_POWER and IRP_MN_QUERY_POWER 
        //
        struct {
            ULONG SystemContext;
            POWER_STATE_TYPE POINTER_ALIGNMENT Type;
            POWER_STATE POINTER_ALIGNMENT State;
            POWER_ACTION POINTER_ALIGNMENT ShutdownType;
        } Power;
        //
        // Parameters for IRP_MN_START_DEVICE 
        //
        struct {
            PCM_RESOURCE_LIST AllocatedResources;
            PCM_RESOURCE_LIST AllocatedResourcesTranslated;
        } StartDevice;
        //
        // Parameters for WMI Minor IRPs 
        //
        struct {
            ULONG_PTR ProviderId;
            PVOID DataPath;
            ULONG BufferSize;
            PVOID Buffer;
        } WMI;
        //
        // Others - driver-specific
        //
        struct {
            PVOID Argument1;
            PVOID Argument2;
            PVOID Argument3;
            PVOID Argument4;
        } Others;
    } Parameters;
  PDEVICE_OBJECT  DeviceObject;
  PFILE_OBJECT  FileObject;
  .
  .
} IO_STACK_LOCATION, *PIO_STACK_LOCATION;

Members

MajorFunction: The IRP major function code indicating the type of I/O operation to be performed.
MinorFunction: A subfunction code for MajorFunction. The PnP Manager, the Power Manager, file system drivers, and SCSI class drivers set this member for some requests.
Flags: Request-type-specific values used almost exclusively by file system drivers. Removable-media device drivers check whether this member is set with SL_OVERRIDE_VERIFY_VOLUME for read requests to determine whether to continue the read operation even if the device object’s Flags is set with DO_VERIFY_VOLUME. Intermediate drivers layered over a removable-media device driver must copy this member into the I/O stack location of the next-lower driver in all incoming IRP_MJ_READ requests.
Control: Drivers can check this member to determine whether it is set with SL_PENDING_RETURNED. Drivers have read-only access to this member.
Parameters: A union that depends on the major and minor IRP function code values contained in MajorFunction and MinorFunction. For more information, see IRP Major Function Codes.
DeviceObject: A pointer to the driver-created DEVICE_OBJECT structure representing the target physical, logical, or virtual device for which this driver is to handle the IRP.
FileObject: A pointer to a FILE_OBJECT structure that represents the file object, if any, that is associated with DeviceObject pointer.

Headers

Defined in wdm.h and ntddk.h. Include wdm.h or ntddk.h.

Comments

For each IRP, there is one IO_STACK_LOCATION structure for each driver in a driver stack. Each IRP's set of I/O stack locations is appended to the IRP, following the IRP structure.

Every higher-level driver is responsible for setting up the I/O stack location for the next-lower driver in each IRP. A driver must call IoGetCurrentIrpStackLocation to get a pointer to its own stack location for each IRP. Higher-level drivers can call IoGetNextIrpStackLocation to get a pointer to the next-lower driver’s stack location.

The higher-level driver must set up the stack location contents before calling IoCallDriver to pass an IRP to the lower-level driver. If the driver will pass the input IRP on to the next lower-level driver, the dispatch routine should call IoSkipCurrentIrpStackLocation or IoCopyCurrentIrpStackLocationToNext to set up the I/O stack location of the next-lower driver.

A higher-level driver’s call to IoCallDriver sets the DeviceObject member to the next-lower-level driver’s target device object, in the I/O stack location of the lower driver. The I/O Manager passes each higher-level driver’s IoCompletion routine a pointer to its own device object when the IoCompletion routine is called on completion of the IRP.

If a higher-level driver allocates IRPs to make requests of its own, its IoCompletion routine is passed a NULL DeviceObject pointer if that driver neither allocates a stack location for itself nor sets up the DeviceObject pointer in its own stack location of the newly allocated IRP.

In some cases, a higher-level driver layered over a mass-storage device driver is responsible for splitting up large transfer requests for the underlying device driver. In particular, SCSI class drivers must check the Parameters.Read.Length and Parameters.Write.Length, determine whether the size of the requested transfer exceeds the underlying HBA’s transfer capabilities, and, if so, split the Length of the original request into a sequence of partial transfers to satisfy the original IRP.

IO_STACK_LOCATION

Members

Headers

Comments

See Also