The IoStartPacket routine calls the driver's StartIo routine with the given IRP or inserts the IRP into the device queue associated with the given device object if the device is already busy.
VOID IoStartPacket( _In_ PDEVICE_OBJECT DeviceObject, _In_ PIRP Irp, _In_opt_ PULONG Key, _In_opt_ PDRIVER_CANCEL CancelFunction );
Pointer to the target device object for the IRP.
Pointer to the IRP to be processed.
Pointer to a value that determines where to insert the packet into the device queue. If this is zero, the packet is inserted at the tail of the device queue.
Specifies the entry point for a driver-supplied Cancel routine.
If the driver is already busy processing a request for the target device object, then the packet is queued in the device queue. Otherwise, this routine calls the driver's StartIo routine with the specified IRP.
If a non-NULL CancelFunction pointer is supplied, it is set in the IRP so the driver's Cancel routine is called if the IRP is canceled before its completion.
Drivers that do not have a StartIo routine cannot call IoStartPacket.
Callers of IoStartPacket must be running at IRQL <= DISPATCH_LEVEL. Usually, this routine is called from a device driver's Dispatch routine at IRQL = PASSIVE_LEVEL.
|Windows version||Available starting with Windows 2000.|
|Header||ntifs.h (include Wdm.h, Ntddk.h, Ntifs.h)|
|IRQL||"<= DISPATCH_LEVEL (see Remarks section)"|