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295 lines
9.1 KiB
C
295 lines
9.1 KiB
C
/*
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* Cancel-Safe Queue Library
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* Copyright (c) 2004, Vizzini (vizzini@plasmic.com)
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* Licensed under the GNU GPL for the ReactOS project
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*
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* This header defines the interface to the ReactOS Cancel-Safe Queue library.
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* This interface is based on and is similar to the Microsoft Cancel-Safe
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* Queue interface.
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*
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* BACKGROUND
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*
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* IRP queuing is a royal pain in the butt, due to the fact that there are
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* tons of built-in race conditions. IRP handling is difficult in general,
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* but the cancel logic has been particularly complicated due to some subtle
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* races, coupled with the fact that the system interfaces have changed over
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* time.
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*
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* Walter Oney (2nd. Ed. of Programming the Windows Driver Model) states a
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* common opinion among driver developers when he says that it is foolish
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* to try to roll your own cancel logic. There are only a very few people
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* who have gotten it right in the past. He suggests, instead, that you
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* either use his own well-tested code, or use the code in the Microsoft
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* Cancel-Safe Queue Library.
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*
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* We cannot do either, of course, due to copyright issues. I have therefore
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* created this clone of the Microsoft library in order to concentrate all
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* of the IRP-queuing bugs in one place. I'm quite sure there are problems
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* here, so if you are a driver writer, I'd be glad to hear your feedback.
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*
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* Apart from that, please try to use these routines, rather than building
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* your own. If you think you have found a bug, please bring it up with me
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* or on-list, as this is complicated and non-obvious stuff. Don't just
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* change this and hope for the best!
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*
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* USAGE
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*
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* This library follows exactly the same interface as the Microsoft Cancel-Safe
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* Queue routines (IoCsqXxx()). As such, the authoritative reference is the
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* current DDK. There is also a DDK sample called "cancel" that has an
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* example of how to use this code. I have also provided a sample driver
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* that makes use of this queue. Finally, please do read the header and the
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* source if you're curious about the inner workings of these routines.
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*/
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#ifndef _REACTOS_CSQ_H
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#define _REACTOS_CSQ_H
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/*
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* Prevent including the CSQ definitions twice. They're present in NTDDK
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* now too, except the *_EX versions.
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*/
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#ifndef IO_TYPE_CSQ_IRP_CONTEXT
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struct _IO_CSQ;
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/*
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* CSQ Callbacks
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*
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* The cancel-safe queue is implemented as a set of IoCsqXxx() OS routines
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* copuled with a set of driver callbacks to handle the basic operations of
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* the queue. You need to supply one of each of these functions in your own
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* driver. These routines are also documented in the DDK under CsqXxx().
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* That is the authoritative documentation.
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*/
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/*
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* Function to insert an IRP in the queue. No need to worry about locking;
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* just tack it onto your list or something.
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*
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* Sample implementation:
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*
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VOID NTAPI CsqInsertIrp(PIO_CSQ Csq, PIRP Irp)
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{
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KdPrint(("Inserting IRP 0x%x into CSQ\n", Irp));
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InsertTailList(&IrpQueue, &Irp->Tail.Overlay.ListEntry);
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}
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*
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*/
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typedef VOID (NTAPI *PIO_CSQ_INSERT_IRP) (struct _IO_CSQ *Csq,
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PIRP Irp);
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/*
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* Function to remove an IRP from the queue.
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*
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* Sample:
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*
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VOID NTAPI CsqRemoveIrp(PIO_CSQ Csq, PIRP Irp)
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{
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KdPrint(("Removing IRP 0x%x from CSQ\n", Irp));
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RemoveEntryList(&Irp->Tail.Overlay.ListEntry);
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}
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*
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*/
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typedef VOID (NTAPI *PIO_CSQ_REMOVE_IRP) (struct _IO_CSQ *Csq,
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PIRP Irp);
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/*
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* Function to look for an IRP in the queue
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*
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* Sample:
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*
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PIRP NTAPI CsqPeekNextIrp(PIO_CSQ Csq, PIRP Irp, PVOID PeekContext)
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{
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KdPrint(("Peeking for next IRP\n"));
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if(Irp)
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return CONTAINING_RECORD(&Irp->Tail.Overlay.ListEntry.Flink, IRP, Tail.Overlay.ListEntry);
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if(IsListEmpty(&IrpQueue))
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return NULL;
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return CONTAINING_RECORD(IrpQueue.Flink, IRP, Tail.Overlay.ListEntry);
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}
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*
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*/
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typedef PIRP (NTAPI *PIO_CSQ_PEEK_NEXT_IRP) (struct _IO_CSQ *Csq,
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PIRP Irp,
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PVOID PeekContext);
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/*
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* Lock the queue. This can be a spinlock, a mutex, or whatever
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* else floats your boat.
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*
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* Sample:
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*
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VOID NTAPI CsqAcquireLock(PIO_CSQ Csq, PKIRQL Irql)
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{
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KdPrint(("Acquiring spin lock\n"));
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KeAcquireSpinLock(&IrpQueueLock, Irql);
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}
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*
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*/
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typedef VOID (NTAPI *PIO_CSQ_ACQUIRE_LOCK) (struct _IO_CSQ *Csq,
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PKIRQL Irql);
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/*
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* Unlock the queue:
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*
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VOID NTAPI CsqReleaseLock(PIO_CSQ Csq, KIRQL Irql)
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{
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KdPrint(("Releasing spin lock\n"));
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KeReleaseSpinLock(&IrpQueueLock, Irql);
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}
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*
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*/
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typedef VOID (NTAPI *PIO_CSQ_RELEASE_LOCK) (struct _IO_CSQ *Csq,
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KIRQL Irql);
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/*
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* Finally, this is called by the queue library when it wants to complete
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* a canceled IRP.
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*
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* Sample:
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*
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VOID NTAPI CsqCompleteCancelledIrp(PIO_CSQ Csq, PIRP Irp)
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{
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KdPrint(("cancelling irp 0x%x\n", Irp));
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Irp->IoStatus.Status = STATUS_CANCELLED;
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Irp->IoStatus.Information = 0;
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IoCompleteRequest(Irp, IO_NO_INCREMENT);
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}
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*
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*/
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typedef VOID (NTAPI *PIO_CSQ_COMPLETE_CANCELED_IRP) (struct _IO_CSQ *Csq,
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PIRP Irp);
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/*
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* STRUCTURES
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*
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* NOTE: Please do not use these directly. You will make incompatible code
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* if you do. Always only use the documented IoCsqXxx() interfaces and you
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* will amass much Good Karma.
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*/
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#define IO_TYPE_CSQ_IRP_CONTEXT 1
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#define IO_TYPE_CSQ 2
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/*
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* IO_CSQ - Queue control structure
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*/
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typedef struct _IO_CSQ {
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ULONG Type;
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PIO_CSQ_INSERT_IRP CsqInsertIrp;
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PIO_CSQ_REMOVE_IRP CsqRemoveIrp;
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PIO_CSQ_PEEK_NEXT_IRP CsqPeekNextIrp;
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PIO_CSQ_ACQUIRE_LOCK CsqAcquireLock;
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PIO_CSQ_RELEASE_LOCK CsqReleaseLock;
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PIO_CSQ_COMPLETE_CANCELED_IRP CsqCompleteCanceledIrp;
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PVOID ReservePointer; /* must be NULL */
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} IO_CSQ, *PIO_CSQ;
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/*
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* IO_CSQ_IRP_CONTEXT - Context used to track an IRP in the CSQ
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*/
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typedef struct _IO_CSQ_IRP_CONTEXT {
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ULONG Type;
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PIRP Irp;
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PIO_CSQ Csq;
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} IO_CSQ_IRP_CONTEXT, *PIO_CSQ_IRP_CONTEXT;
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#endif /* IO_TYPE_CSQ_IRP_CONTEXT */
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/* See IO_TYPE_CSQ_* above */
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#define IO_TYPE_CSQ_EX 3
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/*
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* Function to insert an IRP into the queue with extended context information.
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* This is useful if you need to be able to de-queue particular IRPs more
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* easily in some cases.
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*
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* Same deal as above; sample implementation:
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*
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NTSTATUS NTAPI CsqInsertIrpEx(PIO_CSQ Csq, PIRP Irp, PVOID InsertContext)
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{
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CsqInsertIrp(Csq, Irp);
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return STATUS_PENDING;
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}
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*
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*/
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typedef NTSTATUS (NTAPI *PIO_CSQ_INSERT_IRP_EX) (struct _IO_CSQ *Csq,
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PIRP Irp,
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PVOID InsertContext);
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/*
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* CANCEL-SAFE QUEUE DDIs
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*
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* These device driver interfaces are called to make use of the queue. Again,
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* authoritative documentation for these functions is in the DDK. The csqtest
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* driver also makes use of some of them.
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*/
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/*
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* Call this in DriverEntry or similar in order to set up the Csq structure.
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* As long as the Csq struct and the functions you pass in are resident,
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* there are no IRQL restrictions.
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*/
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NTKERNELAPI
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NTSTATUS NTAPI IoCsqInitialize(PIO_CSQ Csq,
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PIO_CSQ_INSERT_IRP CsqInsertIrp,
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PIO_CSQ_REMOVE_IRP CsqRemoveIrp,
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PIO_CSQ_PEEK_NEXT_IRP CsqPeekNextIrp,
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PIO_CSQ_ACQUIRE_LOCK CsqAcquireLock,
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PIO_CSQ_RELEASE_LOCK CsqReleaseLock,
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PIO_CSQ_COMPLETE_CANCELED_IRP CsqCompleteCanceledIrp);
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/*
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* Same as above, except you provide a CsqInsertIrpEx routine instead of
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* CsqInsertIrp. This eventually allows you to supply extra tracking
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* information for use with the queue.
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*/
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NTKERNELAPI
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NTSTATUS NTAPI IoCsqInitializeEx(PIO_CSQ Csq,
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PIO_CSQ_INSERT_IRP_EX CsqInsertIrpEx,
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PIO_CSQ_REMOVE_IRP CsqRemoveIrp,
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PIO_CSQ_PEEK_NEXT_IRP CsqPeekNextIrp,
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PIO_CSQ_ACQUIRE_LOCK CsqAcquireLock,
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PIO_CSQ_RELEASE_LOCK CsqReleaseLock,
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PIO_CSQ_COMPLETE_CANCELED_IRP CsqCompleteCanceledIrp);
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/*
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* Insert an IRP into the queue
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*/
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NTKERNELAPI
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VOID NTAPI IoCsqInsertIrp(PIO_CSQ Csq,
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PIRP Irp,
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PIO_CSQ_IRP_CONTEXT Context);
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/*
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* Insert an IRP into the queue, with special context maintained that
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* makes it easy to find IRPs in the queue
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*/
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NTKERNELAPI
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NTSTATUS NTAPI IoCsqInsertIrpEx(PIO_CSQ Csq,
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PIRP Irp,
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PIO_CSQ_IRP_CONTEXT Context,
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PVOID InsertContext);
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/*
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* Remove a particular IRP from the queue
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*/
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NTKERNELAPI
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PIRP NTAPI IoCsqRemoveIrp(PIO_CSQ Csq,
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PIO_CSQ_IRP_CONTEXT Context);
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/*
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* Remove the next IRP from the queue
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*/
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NTKERNELAPI
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PIRP NTAPI IoCsqRemoveNextIrp(PIO_CSQ Csq,
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PVOID PeekContext);
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#endif /* _REACTOS_CSQ_H */
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