ntoskrnl.exe: Implement KeReleaseSpinLockFromDpcLevel().

dlls/ntoskrnl.exe/ntoskrnl.exe.spec

@@ -594,7 +594,7 @@
 @ stdcall KeReleaseMutex(ptr long)
 @ stdcall KeReleaseSemaphore(ptr long long long)
 @ stdcall -arch=arm,arm64,x86_64 KeReleaseSpinLock(ptr long)
-@ stub KeReleaseSpinLockFromDpcLevel
+@ stdcall KeReleaseSpinLockFromDpcLevel(ptr)
 @ stub KeRemoveByKeyDeviceQueue
 @ stub KeRemoveByKeyDeviceQueueIfBusy
 @ stub KeRemoveDeviceQueue

dlls/ntoskrnl.exe/sync.c

@@ -386,7 +386,6 @@ void WINAPI KeInitializeSpinLock( KSPIN_LOCK *lock )
     *lock = 0;
 }
 
-#ifndef __i386__
 static inline void small_pause(void)
 {
 #ifdef __x86_64__
@@ -397,6 +396,16 @@ static inline void small_pause(void)
 }
 
 /***********************************************************************
+ *           KeReleaseSpinLockFromDpcLevel (NTOSKRNL.EXE.@)
+ */
+void WINAPI KeReleaseSpinLockFromDpcLevel( KSPIN_LOCK *lock )
+{
+    TRACE("lock %p.\n", lock);
+    InterlockedExchangePointer( (void **)lock, 0 );
+}
+
+#ifndef __i386__
+/***********************************************************************
  *           KeReleaseSpinLock (NTOSKRNL.EXE.@)
  */
 void WINAPI KeReleaseSpinLock( KSPIN_LOCK *lock, KIRQL irql )

include/ddk/wdm.h

@@ -1443,6 +1443,7 @@ ULONG     WINAPI KeQueryTimeIncrement(void);
 LONG      WINAPI KeReleaseMutex(PRKMUTEX,BOOLEAN);
 LONG      WINAPI KeReleaseSemaphore(PRKSEMAPHORE,KPRIORITY,LONG,BOOLEAN);
 void      WINAPI KeReleaseSpinLock(KSPIN_LOCK*,KIRQL);
+void      WINAPI KeReleaseSpinLockFromDpcLevel(KSPIN_LOCK*);
 LONG      WINAPI KeResetEvent(PRKEVENT);
 LONG      WINAPI KeSetEvent(PRKEVENT,KPRIORITY,BOOLEAN);
 KPRIORITY WINAPI KeSetPriorityThread(PKTHREAD,KPRIORITY);