Leaked source code of windows server 2003
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85 lines
1.8 KiB

/*++
Copyright (C) Microsoft Corporation, 1991 - 1999
Module Name:
clntirp.c
Abstract:
Client IRP queuing routines for CLASSPNP
Environment:
kernel mode only
Notes:
Revision History:
--*/
#include "classp.h"
#include "debug.h"
/*
* EnqueueDeferredClientIrp
*
* Note: we currently do not support Cancel for storage irps.
*/
VOID EnqueueDeferredClientIrp(PCLASS_PRIVATE_FDO_DATA FdoData, PIRP Irp)
{
KIRQL oldIrql;
KeAcquireSpinLock(&FdoData->SpinLock, &oldIrql);
InsertTailList(&FdoData->DeferredClientIrpList, &Irp->Tail.Overlay.ListEntry);
KeReleaseSpinLock(&FdoData->SpinLock, oldIrql);
}
/*
* DequeueDeferredClientIrp
*
*/
PIRP DequeueDeferredClientIrp(PCLASS_PRIVATE_FDO_DATA FdoData)
{
PIRP irp;
/*
* The DeferredClientIrpList is almost always empty.
* We don't want to grab the spinlock every time we check it (which is on every xfer completion)
* so check once first before we grab the spinlock.
*/
if (IsListEmpty(&FdoData->DeferredClientIrpList)){
irp = NULL;
}
else {
PLIST_ENTRY listEntry;
KIRQL oldIrql;
KeAcquireSpinLock(&FdoData->SpinLock, &oldIrql);
if (IsListEmpty(&FdoData->DeferredClientIrpList)){
listEntry = NULL;
}
else {
listEntry = RemoveHeadList(&FdoData->DeferredClientIrpList);
}
KeReleaseSpinLock(&FdoData->SpinLock, oldIrql);
if (listEntry == NULL) {
irp = NULL;
}
else {
irp = CONTAINING_RECORD(listEntry, IRP, Tail.Overlay.ListEntry);
ASSERT(irp->Type == IO_TYPE_IRP);
InitializeListHead(&irp->Tail.Overlay.ListEntry);
}
}
return irp;
}