diff --git a/arch/s390/pci/pci_insn.c b/arch/s390/pci/pci_insn.c
index 28d863aaafea..4dd58b196cea 100644
--- a/arch/s390/pci/pci_insn.c
+++ b/arch/s390/pci/pci_insn.c
@@ -365,10 +365,7 @@ EXPORT_SYMBOL_GPL(zpci_write_block);
 
 static inline void __pciwb_mio(void)
 {
-	unsigned long unused = 0;
-
-	asm volatile (".insn    rre,0xb9d50000,%[op],%[op]\n"
-		      : [op] "+d" (unused));
+	asm volatile (".insn    rre,0xb9d50000,0,0\n");
 }
 
 void zpci_barrier(void)