diff --git a/reactos/drivers/filesystems/npfs/create.c b/reactos/drivers/filesystems/npfs/create.c
index 3b35bdacd5f..3be21ad2879 100644
--- a/reactos/drivers/filesystems/npfs/create.c
+++ b/reactos/drivers/filesystems/npfs/create.c
@@ -133,9 +133,11 @@ NpfsFindListeningServerInstance(PNPFS_FCB Fcb)
             IoAcquireCancelSpinLock(&oldIrql);
             if (!Irp->Cancel)
             {
-                (void)IoSetCancelRoutine(Irp, NULL);
-                IoReleaseCancelSpinLock(oldIrql);
-                return Waiter->Ccb;
+                if (IoSetCancelRoutine(Irp, NULL) != NULL)
+                {
+                    IoReleaseCancelSpinLock(oldIrql);
+                    return Waiter->Ccb;
+                }
             }
             IoReleaseCancelSpinLock(oldIrql);
         }
@@ -868,11 +870,7 @@ NpfsCleanup(PDEVICE_OBJECT DeviceObject,
                 RemoveEntryList(Entry);
                 tmpIrp = CONTAINING_RECORD(WaitEntry, IRP, Tail.Overlay.DriverContext);
                 IoAcquireCancelSpinLock(&oldIrql);
-                if (!tmpIrp->Cancel)
-                {
-                    (void)IoSetCancelRoutine(tmpIrp, NULL);
-                    Complete = TRUE;
-                }
+                Complete = (NULL != IoSetCancelRoutine(tmpIrp, NULL));
                 IoReleaseCancelSpinLock(oldIrql);
                 if (Complete)
                 {
diff --git a/reactos/drivers/filesystems/npfs/fsctrl.c b/reactos/drivers/filesystems/npfs/fsctrl.c
index e1bcf1dafb9..f9f1fee945c 100644
--- a/reactos/drivers/filesystems/npfs/fsctrl.c
+++ b/reactos/drivers/filesystems/npfs/fsctrl.c
@@ -57,12 +57,11 @@ NpfsAddListeningServerInstance(PIRP Irp,
 
     KeLockMutex(&Ccb->Fcb->CcbListLock);
 
-    IoMarkIrpPending(Irp);
-    InsertTailList(&Ccb->Fcb->WaiterListHead, &Entry->Entry);
-
     IoAcquireCancelSpinLock(&oldIrql);
     if (!Irp->Cancel)
     {
+        IoMarkIrpPending(Irp);
+        InsertTailList(&Ccb->Fcb->WaiterListHead, &Entry->Entry);
         (void)IoSetCancelRoutine(Irp, NpfsListeningCancelRoutine);
         IoReleaseCancelSpinLock(oldIrql);
         KeUnlockMutex(&Ccb->Fcb->CcbListLock);
@@ -289,7 +288,7 @@ NpfsDisconnectPipe(PNPFS_CCB Ccb)
             {
                 RemoveEntryList(Entry);
                 Irp = CONTAINING_RECORD(Entry, IRP, Tail.Overlay.DriverContext);
-                Complete = (NULL == IoSetCancelRoutine(Irp, NULL));
+                Complete = (NULL != IoSetCancelRoutine(Irp, NULL));
                 break;
             }
             Entry = Entry->Flink;