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fixed some bugs in ExWaitForRundownProtectionRelease() and ExReleaseRundownProtectionEx()

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svn path=/trunk/; revision=13699
This commit is contained in:
Thomas Bluemel 2005-02-20 23:56:47 +00:00
parent 96969f6dc7
commit 502d8150de
1 changed files with 47 additions and 38 deletions
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55
reactos/ntoskrnl/ex/rundown.c
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@ -1,4 +1,4 @@
/* $Id:$ /* $Id$
* *
* COPYRIGHT: See COPYING in the top level directory * COPYRIGHT: See COPYING in the top level directory
* PROJECT: ReactOS kernel * PROJECT: ReactOS kernel
@ -118,23 +118,27 @@ ExReleaseRundownProtectionEx (
/* Get Pointer */ /* Get Pointer */
PRUNDOWN_DESCRIPTOR RundownDescriptor = (PRUNDOWN_DESCRIPTOR)((ULONG_PTR)RunRef->Ptr & ~EX_RUNDOWN_ACTIVE); PRUNDOWN_DESCRIPTOR RundownDescriptor = (PRUNDOWN_DESCRIPTOR)((ULONG_PTR)RunRef->Ptr & ~EX_RUNDOWN_ACTIVE);
/* Decrease Reference Count by RundownDescriptor->References */ ASSERT(RundownDescriptor != NULL);
Current = RundownDescriptor->References;
/* Decrease RundownDescriptor->References by Count references */
for (;;) for (;;)
{ {
ULONG_PTR PrevCount, NewCount; ULONG_PTR PrevCount, NewCount;
if ((Current >> EX_RUNDOWN_COUNT_SHIFT) == RundownDescriptor->References) if ((Count >> EX_RUNDOWN_COUNT_SHIFT) == Current)
{ {
NewCount = 0; NewCount = 0;
} }
else else
{ {
NewCount = (((Current >> EX_RUNDOWN_COUNT_SHIFT) - RundownDescriptor->References) << EX_RUNDOWN_COUNT_SHIFT) | EX_RUNDOWN_ACTIVE; NewCount = ((RundownDescriptor->References - (Count >> EX_RUNDOWN_COUNT_SHIFT)) << EX_RUNDOWN_COUNT_SHIFT) | EX_RUNDOWN_ACTIVE;
} }
#ifdef _WIN64 #ifdef _WIN64
PrevCount = (ULONG_PTR)InterlockedCompareExchange64((LONGLONG*)&RunRef->Count, (LONGLONG)NewCount, (LONGLONG)Current); PrevCount = (ULONG_PTR)InterlockedCompareExchange64((LONGLONG*)&RundownDescriptor->References, (LONGLONG)NewCount, (LONGLONG)Current);
#else #else
PrevCount = (ULONG_PTR)InterlockedCompareExchange((LONG*)&RunRef->Count, (LONG)NewCount, (LONG)Current); PrevCount = (ULONG_PTR)InterlockedCompareExchange((LONG*)&RundownDescriptor->References, (LONG)NewCount, (LONG)Current);
#endif #endif
if (PrevCount == Current) if (PrevCount == Current)
{ {
@ -212,40 +216,45 @@ ExWaitForRundownProtectionRelease (
ULONG_PTR PrevCount, NewPtr, PrevPtr; ULONG_PTR PrevCount, NewPtr, PrevPtr;
RUNDOWN_DESCRIPTOR RundownDescriptor; RUNDOWN_DESCRIPTOR RundownDescriptor;
#ifdef _WIN64 PrevCount = RunRef->Count;
PrevCount = (ULONG_PTR)InterlockedCompareExchange64((LONGLONG*)&RunRef->Ptr, (LONGLONG)EX_RUNDOWN_ACTIVE, 0LL);
#else
PrevCount = (ULONG_PTR)InterlockedCompareExchange((LONG*)&RunRef->Ptr, EX_RUNDOWN_ACTIVE, 0);
#endif
if (PrevCount == 0 || if (PrevCount != 0 && !(PrevCount & EX_RUNDOWN_ACTIVE))
PrevCount & EX_RUNDOWN_ACTIVE)
{ {
return;
}
/* save the reference counter */ /* save the reference counter */
RundownDescriptor.References = PrevCount >> EX_RUNDOWN_COUNT_SHIFT; RundownDescriptor.References = PrevCount >> EX_RUNDOWN_COUNT_SHIFT;
/* Pending references... wait on them to be closed with an event */ /* Pending references... wait on them to be closed with an event */
KeInitializeEvent(&RundownDescriptor.RundownEvent, NotificationEvent, FALSE); KeInitializeEvent(&RundownDescriptor.RundownEvent, NotificationEvent, FALSE);
NewPtr = (ULONG_PTR)&RundownDescriptor | EX_RUNDOWN_ACTIVE; ASSERT(!((ULONG_PTR)&RundownDescriptor & EX_RUNDOWN_ACTIVE));
PrevCount = EX_RUNDOWN_ACTIVE;
do NewPtr = (ULONG_PTR)&RundownDescriptor | EX_RUNDOWN_ACTIVE;
for (;;)
{ {
#ifdef _WIN64 #ifdef _WIN64
PrevPtr = (ULONG_PTR)InterlockedCompareExchange64((LONGLONG*)&RunRef->Ptr, (LONGLONG)NewPtr, (LONGLONG)PrevCount); PrevPtr = (ULONG_PTR)InterlockedCompareExchange64((LONGLONG*)&RunRef->Ptr, (LONGLONG)NewPtr, (LONGLONG)PrevCount);
#else #else
PrevPtr = (ULONG_PTR)InterlockedCompareExchange((LONG*)&RunRef->Ptr, (LONG)NewPtr, (LONG)PrevCount); PrevPtr = (ULONG_PTR)InterlockedCompareExchange((LONG*)&RunRef->Ptr, (LONG)NewPtr, (LONG)PrevCount);
#endif #endif
if (PrevPtr == PrevCount)
PrevCount = PrevPtr; {
} while (PrevPtr != PrevCount);
/* Wait for whoever needs to release to notify us */ /* Wait for whoever needs to release to notify us */
KeWaitForSingleObject(&RundownDescriptor.RundownEvent, Executive, KernelMode, FALSE, NULL); KeWaitForSingleObject(&RundownDescriptor.RundownEvent, Executive, KernelMode, FALSE, NULL);
break;
}
else if (PrevPtr == 0 || (PrevPtr & EX_RUNDOWN_ACTIVE))
{
/* some one else was faster, let's just bail */
break;
}
PrevCount = PrevPtr;
/* save the changed reference counter and try again */
RundownDescriptor.References = PrevCount >> EX_RUNDOWN_COUNT_SHIFT;
}
}
} }
/* EOF */ /* EOF */