BazisLib::DDK::IrpQueue Class Reference
#include <irpqueue.h>
Collaboration diagram for BazisLib::DDK::IrpQueue:
Public Member Functions | |
| IrpQueue () | |
| ~IrpQueue () | |
| bool | EnqueuePacket (PIRP pIrp, void *pContext) |
| PIRP | DequeuePacket (void **ppContext) |
| void | Shutdown () |
| bool | IsShutDown () |
| int | GetPacketCount () |
| void * | operator new (unsigned size) |
Private Attributes | |
| PIRP | m_pFirstIrp |
| PIRP | m_pLastIrp |
| bool | m_bShutdown |
| bool | m_bLastPacketDequeued |
| KSemaphore | m_Semaphore |
| KSpinLock | m_QueueSpinLock |
| int | m_PacketCount |
Detailed Description
This class represents a thread-safe IRP queue. It is internally used by the Device class. Use the Device::EnqueuePacket() method to add an IRP to device queue. This class is used instead of native IoStartPacket()/StartIo() mechanism because the latter does not ensure that the IRP started with IoStartPacket() will be processed from the dispatcher thread, that can be vital in some cases (for example, in virtual disk drivers when FSD call in the same thread that dispatches a call from FSD may cause infrequent crashes caused by TLS-like IoSetTopLevelIrp().
- Remarks:
- This class uses IRP::Tail::Overlay::DriverContext for storing pointers in the following way: [0] - Next queued IRP pointer [1] - IRP context. Usually contains the IncomingIrp flags.
DO NOT create any instances of this class in paged memory. Always use new() operator.
See comments in the beginning of IRP.H for use example.
Constructor & Destructor Documentation
| BazisLib::DDK::IrpQueue::IrpQueue | ( | ) |
| BazisLib::DDK::IrpQueue::~IrpQueue | ( | ) |
Member Function Documentation
| PIRP BazisLib::DDK::IrpQueue::DequeuePacket | ( | void ** | ppContext | ) |
Dequeues a packet from the queue. If the queue is empty, waits for a new packet to be enqueued.
- Returns:
- The method returns NULL only if the queue was shut down AND there are no more enqueued packets left. That way, shutdown operation does not cause any packet to be lost.
| bool BazisLib::DDK::IrpQueue::EnqueuePacket | ( | PIRP | pIrp, | |
| void * | pContext | |||
| ) |
Adds a new packet to the end of the queue and signals the semaphore.
- Returns:
- The method returns false if the queue was shut down using Shutdown() method. In other case the method returns true.
| int BazisLib::DDK::IrpQueue::GetPacketCount | ( | ) | [inline] |
| bool BazisLib::DDK::IrpQueue::IsShutDown | ( | ) | [inline] |
| void* BazisLib::DDK::IrpQueue::operator new | ( | unsigned | size | ) | [inline] |
| void BazisLib::DDK::IrpQueue::Shutdown | ( | ) | [inline] |
Shuts down the IRP queue. A queue that is shut down fails to enqueue packets
Here is the call graph for this function:
Member Data Documentation
bool BazisLib::DDK::IrpQueue::m_bLastPacketDequeued [private] |
bool BazisLib::DDK::IrpQueue::m_bShutdown [private] |
int BazisLib::DDK::IrpQueue::m_PacketCount [private] |
PIRP BazisLib::DDK::IrpQueue::m_pFirstIrp [private] |
PIRP BazisLib::DDK::IrpQueue::m_pLastIrp [private] |
The documentation for this class was generated from the following file:
- bzsddk/irpqueue.h