From bd7c2fd95080d576a6393bd2d619e49eee98a8a4 Mon Sep 17 00:00:00 2001
From: Dmitry Fleytman <dfleytma@redhat.com>
Date: Sat, 5 Apr 2014 22:02:13 +0300
Subject: [PATCH] UsbDk: Simplify QDR processing

QDR processing greatly simplified by using "Forward-Wait-Process"
scheme instead of "Forward-Completion-Workitem-Process".

Signed-off-by: Dmitry Fleytman <dfleytma@redhat.com>
---
 UsbDk/FilterDevice.cpp | 61 +++++++++++++-----------------------------
 UsbDk/FilterDevice.h   | 12 +--------
 2 files changed, 20 insertions(+), 53 deletions(-)

diff --git a/UsbDk/FilterDevice.cpp b/UsbDk/FilterDevice.cpp
index dcadf36..fb86f36 100644
--- a/UsbDk/FilterDevice.cpp
+++ b/UsbDk/FilterDevice.cpp
@@ -5,6 +5,7 @@
 #include "ControlDevice.h"
 #include "RedirectorDevice.h"
 #include "UsbDkNames.h"
+#include "Irp.h"
 
 void CUsbDkChildDevice::Dump()
 {
@@ -35,41 +36,28 @@ NTSTATUS CUsbDkFilterDeviceInit::Configure(PFN_WDFDEVICE_WDM_IRP_PREPROCESS QDRP
 
 NTSTATUS CUsbDkFilterDevice::QDRPreProcess(PIRP Irp)
 {
-    PDEVICE_OBJECT wdmDevice = WdfDeviceWdmGetDeviceObject(m_Device);
-    PIO_STACK_LOCATION  irpStack = IoGetCurrentIrpStackLocation(Irp);
+    PIO_STACK_LOCATION irpStack = IoGetCurrentIrpStackLocation(Irp);
 
     if (BusRelations != irpStack->Parameters.QueryDeviceRelations.Type)
     {
         IoSkipCurrentIrpStackLocation(Irp);
+        return WdfDeviceWdmDispatchPreprocessedIrp(m_Device, Irp);
     }
     else
     {
         IoCopyCurrentIrpStackLocationToNext(Irp);
-        IoSetCompletionRoutineEx(wdmDevice,
-                                 Irp,
-                                 (PIO_COMPLETION_ROUTINE) CUsbDkFilterDevice::QDRPostProcessWrap,
-                                 this,
-                                 TRUE, FALSE, FALSE);
+
+        auto status = CIrp::ForwardAndWait(Irp, [this, Irp]()
+                                                { return WdfDeviceWdmDispatchPreprocessedIrp(m_Device, Irp); });
+
+        if (NT_SUCCESS(status))
+        {
+            QDRPostProcess(Irp);
+        }
+
+        IoCompleteRequest(Irp, IO_NO_INCREMENT);
+        return status;
     }
-
-    return WdfDeviceWdmDispatchPreprocessedIrp(m_Device, Irp);
-}
-
-NTSTATUS CUsbDkFilterDevice::QDRPostProcess(PIRP Irp)
-{
-    if (Irp->PendingReturned)
-    {
-        IoMarkIrpPending(Irp);
-    }
-
-    ASSERT(m_QDRIrp == nullptr);
-
-    TraceEvents(TRACE_LEVEL_INFORMATION, TRACE_FILTERDEVICE, "%!FUNC! Queuing work item");
-
-    m_QDRIrp = Irp;
-    m_QDRCompletionWorkItem.Enqueue();
-
-    return STATUS_MORE_PROCESSING_REQUIRED;
 }
 
 class CDeviceRelations
@@ -247,22 +235,15 @@ void CUsbDkFilterDevice::FillRelationsArray(CDeviceRelations &Relations)
                               });
 }
 
-void CUsbDkFilterDevice::QDRPostProcessWi()
+void CUsbDkFilterDevice::QDRPostProcess(PIRP Irp)
 {
-    ASSERT(m_QDRIrp != NULL);
-
     TraceEvents(TRACE_LEVEL_INFORMATION, TRACE_FILTERDEVICE, "%!FUNC! Entry");
 
-    CDeviceRelations Relations((PDEVICE_RELATIONS)m_QDRIrp->IoStatus.Information);
+    CDeviceRelations Relations((PDEVICE_RELATIONS)Irp->IoStatus.Information);
 
     DropRemovedDevices(Relations);
     AddNewDevices(Relations);
     FillRelationsArray(Relations);
-
-    auto QDRIrp = m_QDRIrp;
-    m_QDRIrp = NULL;
-
-    IoCompleteRequest(QDRIrp, IO_NO_INCREMENT);
 }
 
 CUsbDkFilterDevice::~CUsbDkFilterDevice()
@@ -324,18 +305,14 @@ NTSTATUS CUsbDkFilterDevice::CreateFilterDevice(PWDFDEVICE_INIT DevInit)
 
     if (ShouldAttach())
     {
-        status = m_QDRCompletionWorkItem.Create(m_Device);
-
-        ULONG traceLevel = NT_SUCCESS(status) ? TRACE_LEVEL_INFORMATION : TRACE_LEVEL_ERROR;
-        TraceEvents(traceLevel, TRACE_FILTERDEVICE, "%!FUNC! Attachment status: %!STATUS!", status);
+        TraceEvents(TRACE_LEVEL_INFORMATION, TRACE_FILTERDEVICE, "%!FUNC! Attached");
+        return STATUS_SUCCESS;
     }
     else
     {
-        status = STATUS_NOT_SUPPORTED;
         TraceEvents(TRACE_LEVEL_INFORMATION, TRACE_FILTERDEVICE, "%!FUNC! Not attached");
+        return STATUS_NOT_SUPPORTED;
     }
-
-    return status;
 }
 
 void CUsbDkFilterDevice::ContextCleanup(_In_ WDFOBJECT DeviceObject)
diff --git a/UsbDk/FilterDevice.h b/UsbDk/FilterDevice.h
index 11c8f95..6f2c3d6 100644
--- a/UsbDk/FilterDevice.h
+++ b/UsbDk/FilterDevice.h
@@ -84,7 +84,6 @@ class CUsbDkFilterDevice : public CWdfDevice, public CAllocatable<NonPagedPool,
 {
 public:
     CUsbDkFilterDevice()
-        : m_QDRCompletionWorkItem(CUsbDkFilterDevice::QDRPostProcessWiWrap, this)
     {}
 
     ~CUsbDkFilterDevice();
@@ -118,13 +117,7 @@ private:
     { return UsbDkFilterGetContext(Device)->UsbDkFilter->QDRPreProcess(Irp); }
     NTSTATUS QDRPreProcess(PIRP Irp);
 
-    static NTSTATUS QDRPostProcessWrap(_In_  PDEVICE_OBJECT, _In_  PIRP Irp, _In_  CUsbDkFilterDevice *This)
-    { return This->QDRPostProcess(Irp); }
-    NTSTATUS QDRPostProcess(PIRP Irp);
-
-    static VOID CUsbDkFilterDevice::QDRPostProcessWiWrap(_In_ PVOID This)
-    { static_cast<CUsbDkFilterDevice*>(This)->QDRPostProcessWi(); }
-    void CUsbDkFilterDevice::QDRPostProcessWi();
+    void CUsbDkFilterDevice::QDRPostProcess(PIRP Irp);
 
     bool ShouldAttach();
 
@@ -136,9 +129,6 @@ private:
     void ApplyRedirectionPolicy(CUsbDkChildDevice &Device);
     void FillRelationsArray(CDeviceRelations &Relations);
 
-    CWdfWorkitem m_QDRCompletionWorkItem;
-
-    PIRP m_QDRIrp = nullptr;
     CUsbDkControlDevice *m_ControlDevice = nullptr;
 
     WDFDRIVER m_Driver = WDF_NO_HANDLE;