Windows Driver Model >> C/C++
Deferred Procedure Call(DPC)
參考資訊:
1. Source Code
一般在處理中斷副程式(ISR),由於中斷是一個相當高優先級別的事件,因此,不能停留太久(不能處理太久),否則將拖垮系統,針對中斷事件,如果需要比較長的處理時間,取而代之,會安排一個Deferred Procedure Call(DPC)處理,DPC是一個高優先級別的排程,但比中斷更低的優先級別。
main.c
#include <wdm.h> #define DEV_NAME L"\\Device\\MyDriver" #define SYM_NAME L"\\DosDevices\\MyDriver" KDPC stDPC={0}; PDEVICE_OBJECT pNextDevice=NULL; void DPC_Handler(struct _KDPC *Dpc, PVOID DeferredContext, PVOID SystemArgument1, PVOID SystemArgument2) { DbgPrint("DPC_Handler\n"); } NTSTATUS AddDevice(PDRIVER_OBJECT pOurDriver, PDEVICE_OBJECT pPhyDevice) { PDEVICE_OBJECT pOurDevice=NULL; UNICODE_STRING usDeviceName; UNICODE_STRING usSymboName; RtlInitUnicodeString(&usDeviceName, DEV_NAME); IoCreateDevice(pOurDriver, 0, &usDeviceName, FILE_DEVICE_UNKNOWN, 0, FALSE, &pOurDevice); RtlInitUnicodeString(&usSymboName, SYM_NAME); IoCreateSymbolicLink(&usSymboName, &usDeviceName); pNextDevice = IoAttachDeviceToDeviceStack(pOurDevice, pPhyDevice); pOurDevice->Flags&= ~DO_DEVICE_INITIALIZING; pOurDevice->Flags|= DO_BUFFERED_IO; KeInitializeDpc(&stDPC, DPC_Handler, pOurDevice); return STATUS_SUCCESS; } void Unload(PDRIVER_OBJECT pOurDriver) { pOurDriver = pOurDriver; } NTSTATUS IrpPnp(PDEVICE_OBJECT pOurDevice, PIRP pIrp) { PIO_STACK_LOCATION psk = IoGetCurrentIrpStackLocation(pIrp); UNICODE_STRING usSymboName; if(psk->MinorFunction == IRP_MN_START_DEVICE){ KeInsertQueueDpc(&stDPC, 0, 0); } else if(psk->MinorFunction == IRP_MN_REMOVE_DEVICE){ RtlInitUnicodeString(&usSymboName, SYM_NAME); IoDeleteSymbolicLink(&usSymboName); IoDetachDevice(pNextDevice); IoDeleteDevice(pOurDevice); } IoSkipCurrentIrpStackLocation(pIrp); return IoCallDriver(pNextDevice, pIrp); } NTSTATUS DriverEntry(PDRIVER_OBJECT pOurDriver, PUNICODE_STRING pOurRegistry) { pOurDriver->MajorFunction[IRP_MJ_PNP] = IrpPnp; pOurDriver->DriverExtension->AddDevice = AddDevice; pOurDriver->DriverUnload = Unload; return STATUS_SUCCESS; }
IRP_MN_START_DEVICE插入一個新的DPC Task
結果