diff --git a/reactos/include/ddk/winddk.h b/reactos/include/ddk/winddk.h
index 77677999c07..d663f2ff8ab 100644
--- a/reactos/include/ddk/winddk.h
+++ b/reactos/include/ddk/winddk.h
@@ -8849,12 +8849,6 @@ NTAPI
 IoGetRelatedDeviceObject(
   IN PFILE_OBJECT  FileObject);
 
-NTKERNELAPI
-ULONG
-NTAPI
-IoGetRemainingStackSize(
-  VOID);
-
 NTKERNELAPI
 VOID
 NTAPI
@@ -8862,6 +8856,20 @@ IoGetStackLimits(
   OUT PULONG_PTR  LowLimit,
   OUT PULONG_PTR  HighLimit);
 
+FORCEINLINE
+ULONG_PTR
+IoGetRemainingStackSize(
+  VOID
+)
+{
+    ULONG_PTR End, Begin;
+    ULONG_PTR Result;
+
+    IoGetStackLimits(&Begin, &End);
+    Result = (ULONG_PTR)(&End) - Begin;
+    return Result;
+}
+
 NTKERNELAPI
 VOID
 NTAPI