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ReactOS implementation of cancel-safe queue library

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svn path=/trunk/; revision=8093
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Vizzini 2004-02-08 17:51:32 +00:00
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reactos/drivers/lib/csq/GNUmakefile Normal file
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PATH_TO_TOP = ../../..
TARGET_TYPE = driver_library
TARGET_NAME = csq
TARGET_NORC = yes
TARGET_CFLAGS = -Wall -Werror
TARGET_OBJECTS = csq.o
#TARGET_GCCLIBS = gcc
include $(PATH_TO_TOP)/rules.mak
include $(TOOLS_PATH)/helper.mk

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reactos/drivers/lib/csq/MAKEFILE Normal file
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#
# DO NOT EDIT THIS FILE!!! Edit .\sources. if you want to add a new source
# file to this component. This file merely indirects to the real make file
# that is shared by all the driver components of the Windows NT DDK
#
!INCLUDE $(NTMAKEENV)\makefile.def

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reactos/drivers/lib/csq/SOURCES Normal file
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TARGETNAME=csq
TARGETTYPE=DRIVER_LIBRARY
TARGETPATH=obj
SOURCES=csq.c

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reactos/drivers/lib/csq/csq.c Normal file
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/*
* ReactOS Cancel-Safe Queue library
* Copyright (c) 2004, Vizzini (vizzini@plasmic.com)
* Licensed under the GNU GPL for the ReactOS project
*
* This file implements the ReactOS CSQ library. For background and overview
* information on these routines, read csq.h. For the authoritative reference
* to using these routines, see the current DDK (IoCsqXXX and CsqXxx callbacks).
*
* There are a couple of subtle races that this library is designed to avoid.
* Please read the code (particularly IoCsqInsertIrpEx and IoCsqRemoveIrp) for
* some details.
*
* In general, we try here to avoid the race between these queue/dequeue
* interfaces and our own cancel routine. This library supplies a cancel
* routine that is used in all IRPs that are queued to it. The major race
* conditions surround the proper handling of in-between cases, such as in-progress
* queue and de-queue operations.
*
* When you're thinking about these operations, keep in mind that three or four
* processors can have queue and dequeue operations in progress simultaneously,
* and a user thread may cancel any IRP at any time. Also, these operations don't
* all happen at DISPATCH_LEVEL all of the time, so thread switching on a single
* processor can create races too.
*/
#define __NTDRIVER__
#include <ntddk.h>
#include "csq.h"
VOID NTAPI IopCsqCancelRoutine(PDEVICE_OBJECT DeviceObject,
PIRP Irp)
/*
* FUNCTION: Cancel routine that is installed on any IRP that this library manages
* ARGUMENTS:
* [Called back by the system]
* NOTES:
* - We assume that Irp->Tail.Overlay.DriverContext[3] has either a IO_CSQ
* or an IO_CSQ_IRP_CONTEXT in it, but we have to figure out which it is
* - By the time this routine executes, the I/O Manager has already cleared
* the cancel routine pointer in the IRP, so it will only be canceled once
* - Because of this, we're guaranteed that Irp is valid the whole time
* - Don't forget to release the cancel spinlock ASAP --> #1 hot lock in the
* system
* - May be called at high IRQL
*/
{
PIO_CSQ Csq;
KIRQL Irql;
/* First things first: */
IoReleaseCancelSpinLock(Irp->CancelIrql);
/* We could either get a context or just a csq */
Csq = (PIO_CSQ)Irp->Tail.Overlay.DriverContext[3];
if(Csq->Type == IO_TYPE_CSQ_IRP_CONTEXT)
{
PIO_CSQ_IRP_CONTEXT Context = (PIO_CSQ_IRP_CONTEXT)Csq;
Csq = Context->Csq;
/* clean up context while we're here */
Context->Irp = NULL;
}
/* Now that we have our CSQ, complete the IRP */
Csq->CsqAcquireLock(Csq, &Irql);
{
Csq->CsqRemoveIrp(Csq, Irp);
Csq->CsqCompleteCanceledIrp(Csq, Irp);
}
Csq->CsqReleaseLock(Csq, Irql);
}
NTSTATUS NTAPI IoCsqInitialize(PIO_CSQ Csq,
PIO_CSQ_INSERT_IRP CsqInsertIrp,
PIO_CSQ_REMOVE_IRP CsqRemoveIrp,
PIO_CSQ_PEEK_NEXT_IRP CsqPeekNextIrp,
PIO_CSQ_ACQUIRE_LOCK CsqAcquireLock,
PIO_CSQ_RELEASE_LOCK CsqReleaseLock,
PIO_CSQ_COMPLETE_CANCELED_IRP CsqCompleteCanceledIrp)
/*
* FUNCTION: Set up a CSQ struct to initialize the queue
* ARGUMENTS:
* Csq: Caller-allocated non-paged space for our IO_CSQ to be initialized
* CsqInsertIrp: Insert routine
* CsqRemoveIrp: Remove routine
* CsqPeekNextIrp: Routine to paeek at the next IRP in queue
* CsqAcquireLock: Acquire the queue's lock
* CsqReleaseLock: Release the queue's lock
* CsqCompleteCanceledIrp: Routine to complete IRPs when they are canceled
* RETURNS:
* - STATUS_SUCCESS in all cases
* NOTES:
* - Csq must be non-paged, as the queue is manipulated with a held spinlock
*/
{
Csq->Type = IO_TYPE_CSQ;
Csq->CsqInsertIrp = CsqInsertIrp;
Csq->CsqRemoveIrp = CsqRemoveIrp;
Csq->CsqPeekNextIrp = CsqPeekNextIrp;
Csq->CsqAcquireLock = CsqAcquireLock;
Csq->CsqReleaseLock = CsqReleaseLock;
Csq->CsqCompleteCanceledIrp = CsqCompleteCanceledIrp;
Csq->ReservePointer = NULL;
return STATUS_SUCCESS;
}
NTSTATUS NTAPI IoCsqInitializeEx(PIO_CSQ Csq,
PIO_CSQ_INSERT_IRP_EX CsqInsertIrpEx,
PIO_CSQ_REMOVE_IRP CsqRemoveIrp,
PIO_CSQ_PEEK_NEXT_IRP CsqPeekNextIrp,
PIO_CSQ_ACQUIRE_LOCK CsqAcquireLock,
PIO_CSQ_RELEASE_LOCK CsqReleaseLock,
PIO_CSQ_COMPLETE_CANCELED_IRP CsqCompleteCanceledIrp)
/*
* FUNCTION: Set up a CSQ struct to initialize the queue (extended version)
* ARGUMENTS:
* Csq: Caller-allocated non-paged space for our IO_CSQ to be initialized
* CsqInsertIrpEx: Extended insert routine
* CsqRemoveIrp: Remove routine
* CsqPeekNextIrp: Routine to paeek at the next IRP in queue
* CsqAcquireLock: Acquire the queue's lock
* CsqReleaseLock: Release the queue's lock
* CsqCompleteCanceledIrp: Routine to complete IRPs when they are canceled
* RETURNS:
* - STATUS_SUCCESS in all cases
* NOTES:
* - Csq must be non-paged, as the queue is manipulated with a held spinlock
*/
{
Csq->Type = IO_TYPE_CSQ_EX;
Csq->CsqInsertIrp = (PIO_CSQ_INSERT_IRP)CsqInsertIrpEx;
Csq->CsqRemoveIrp = CsqRemoveIrp;
Csq->CsqPeekNextIrp = CsqPeekNextIrp;
Csq->CsqAcquireLock = CsqAcquireLock;
Csq->CsqReleaseLock = CsqReleaseLock;
Csq->CsqCompleteCanceledIrp = CsqCompleteCanceledIrp;
Csq->ReservePointer = NULL;
return STATUS_SUCCESS;
}
VOID NTAPI IoCsqInsertIrp(PIO_CSQ Csq,
PIRP Irp,
PIO_CSQ_IRP_CONTEXT Context)
/*
* FUNCTION: Insert an IRP into the CSQ
* ARGUMENTS:
* Csq: Pointer to the initialized CSQ
* Irp: Pointer to the IRP to queue
* Context: Context record to track the IRP while queued
* NOTES:
* - Just passes through to IoCsqInsertIrpEx, with no InsertContext
*/
{
IoCsqInsertIrpEx(Csq, Irp, Context, 0);
}
NTSTATUS NTAPI IoCsqInsertIrpEx(PIO_CSQ Csq,
PIRP Irp,
PIO_CSQ_IRP_CONTEXT Context,
PVOID InsertContext)
/*
* FUNCTION: Insert an IRP into the CSQ, with additional tracking context
* ARGUMENTS:
* Csq: Pointer to the initialized CSQ
* Irp: Pointer to the IRP to queue
* Context: Context record to track the IRP while queued
* InsertContext: additional data that is passed through to CsqInsertIrpEx
* NOTES:
* - Passes the additional context through to the driver-supplied callback,
* which can be used with more sophistocated queues
* - Marks the IRP pending in all cases
* - Guaranteed to not queue a canceled IRP
* - This is complicated logic, and is patterend after the Microsoft library.
* I'm sure I have gotten the details wrong on a fine point or two, but
* basically this works with the MS-supplied samples.
*/
{
NTSTATUS Retval = STATUS_SUCCESS;
KIRQL Irql;
Csq->CsqAcquireLock(Csq, &Irql);
do
{
/* mark all irps pending -- says so in the cancel sample */
IoMarkIrpPending(Irp);
/* set up the context if we have one */
if(Context)
{
Context->Type = IO_TYPE_CSQ_IRP_CONTEXT;
Context->Irp = Irp;
Context->Csq = Csq;
Irp->Tail.Overlay.DriverContext[3] = Context;
}
else
Irp->Tail.Overlay.DriverContext[3] = Csq;
/*
* NOTE! This is very sensitive to order. If you set the cancel routine
* *before* you queue the IRP, our cancel routine will get called back for
* an IRP that isn't in its queue.
*
* There are three possibilities:
* 1) We get an IRP, we queue it, and it is valid the whole way
* 2) We get an IRP, and the IO manager cancels it before we're done here
* 3) We get an IRP, queue it, and the IO manager cancels it.
*
* #2 is is a booger.
*
* When the IO manger receives a request to cancel an IRP, it sets the cancel
* bit in the IRP's control byte to TRUE. Then, it looks to see if a cancel
* routine is set. If it isn't, the IO manager just returns to the caller.
* If there *is* a routine, it gets called.
*
* If we test for cancel first and then set the cancel routine, there is a spot
* between test and set that the IO manager can cancel us without our knowledge,
* so we miss a cancel request. That is bad.
*
* If we set a routine first and then test for cancel, we race with our completion
* routine: We set the routine, the IO Manager sets cancel, we test cancel and find
* it is TRUE. Meanwhile the IO manager has called our cancel routine already, so
* we can't complete the IRP because it'll rip it out from under the cancel routine.
*
* The IO manager does us a favor though: it nulls out the cancel routine in the IRP
* before calling it. Therefore, if we test to see if the cancel routine is NULL
* (after we have just set it), that means our own cancel routine is already working
* on the IRP, and we can just return quietly. Otherwise, we have to de-queue the
* IRP and cancel it ourselves.
*
* We have to go through all of this mess because this API guarantees that we will
* never return having left a canceled IRP in the queue.
*/
/* Step 1: Queue the IRP */
if(Csq->Type == IO_TYPE_CSQ)
Csq->CsqInsertIrp(Csq, Irp);
else
{
PIO_CSQ_INSERT_IRP_EX pCsqInsertIrpEx = (PIO_CSQ_INSERT_IRP_EX)Csq->CsqInsertIrp;
Retval = pCsqInsertIrpEx(Csq, Irp, InsertContext);
if(Retval != STATUS_SUCCESS)
break;
}
/* Step 2: Set our cancel routine */
IoSetCancelRoutine(Irp, IopCsqCancelRoutine);
/* Step 3: Deal with an IRP that is already canceled */
if(!Irp->Cancel)
break;
/*
* Since we're canceled, see if our cancel routine is already running
* If this is NULL, the IO Manager has already called our cancel routine
*/
if(!IoSetCancelRoutine(Irp, NULL))
break;
/* OK, looks like we have to de-queue and complete this ourselves */
Csq->CsqRemoveIrp(Csq, Irp);
Csq->CsqCompleteCanceledIrp(Csq, Irp);
if(Context)
Context->Irp = NULL;
}
while(0);
Csq->CsqReleaseLock(Csq, Irql);
return Retval;
}
PIRP NTAPI IoCsqRemoveIrp(PIO_CSQ Csq,
PIO_CSQ_IRP_CONTEXT Context)
/*
* FUNCTION: Remove anb IRP from the queue
* ARGUMENTS:
* Csq: Queue to remove the IRP from
* Context: Context record containing the IRP to be dequeued
* RETURNS:
* - Pointer to an IRP if we found it
* NOTES:
* - Don't forget that we can be canceled any time up to the point
* where we unset our cancel routine
*/
{
KIRQL Irql;
PIRP Irp = NULL;
Csq->CsqAcquireLock(Csq, &Irql);
do
{
/* It's possible that this IRP could have been canceled */
Irp = Context->Irp;
if(!Irp)
break;
/* Unset the cancel routine and see if it has already been canceled */
if(!IoSetCancelRoutine(Irp, NULL))
{
/*
* already gone, return NULL --> NOTE that we cannot touch this IRP *or* the context,
* since the context is being simultaneously twiddled by the cancel routine
*/
Irp = NULL;
break;
}
/* This IRP is valid and is ours. Dequeue it, fix it up, and return */
Csq->CsqRemoveIrp(Csq, Irp);
Context = (PIO_CSQ_IRP_CONTEXT)InterlockedExchange(Irp->Tail.Overlay.DriverContext[3], 0);
if(Context && Context->Type == IO_TYPE_CSQ_IRP_CONTEXT)
Context->Irp = NULL;
}
while(0);
Csq->CsqReleaseLock(Csq, Irql);
return Irp;
}
PIRP NTAPI IoCsqRemoveNextIrp(PIO_CSQ Csq,
PVOID PeekContext)
/*
* FUNCTION: IoCsqRemoveNextIrp - Removes the next IRP from the queue
* ARGUMENTS:
* Csq: Queue to remove the IRP from
* PeekContext: Identifier of the IRP to be removed
* RETURNS:
* Pointer to the IRP that was removed, or NULL if one
* could not be found
* NOTES:
* - This function is sensitive to yet another race condition.
* The basic idea is that we have to return the first IRP that
* we get that matches the PeekContext >that is not already canceled<.
* Therefore, we have to do a trick similar to the one done in Insert
* above.
*/
{
KIRQL Irql;
PIRP Irp = NULL;
PIO_CSQ_IRP_CONTEXT Context;
Csq->CsqAcquireLock(Csq, &Irql);
while((Irp = Csq->CsqPeekNextIrp(Csq, Irp, PeekContext)))
{
/*
* If the cancel routine is gone, we're already canceled,
* and are spinning on the queue lock in our own cancel
* routine. Move on to the next candidate.
*/
if(!IoSetCancelRoutine(Irp, NULL))
continue;
Csq->CsqRemoveIrp(Csq, Irp);
/* Unset the context stuff and return */
Context = (PIO_CSQ_IRP_CONTEXT)InterlockedExchange(Irp->Tail.Overlay.DriverContext[3], 0);
if(Context && Context->Type == IO_TYPE_CSQ_IRP_CONTEXT)
Context->Irp = NULL;
}
Csq->CsqReleaseLock(Csq, Irql);
return Irp;
}

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reactos/drivers/lib/csq/csq.def Normal file
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LIBRARY CSQ
DESCRIPTION "ReactOS Cancel-Safe Queue Library"
EXPORTS
IoCsqInitialize
IoCsqInitializeEx
IoCsqInsertIrp
IoCsqInsertIrpEx
IoCsqRemoveIrp
IoCsqRemoveNextIrp

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reactos/drivers/lib/csq/csq.edf Normal file
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LIBRARY csq.lib
EXPORTS
IoCsqInitialize=IoCsqInitialize@28
IoCsqInitializeEx=IoCsqInitializeEx@28
IoCsqInsertIrp=IoCsqInsertIrp@12
IoCsqInsertIrpEx=IoCsqInsertIrpEx@16
IoCsqRemoveIrp=IoCsqRemoveIrp@8
IoCsqRemoveNextIrp=IoCsqRemoveNextIrp@8

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