diff --git a/arch/s390/kernel/cpcmd.c b/arch/s390/kernel/cpcmd.c
index 6c89f30c8e31ea39f181fe610dffada543254129..d8c1131e081568927e7f4460aa4febd912c869bf 100644
--- a/arch/s390/kernel/cpcmd.c
+++ b/arch/s390/kernel/cpcmd.c
@@ -2,7 +2,7 @@
  *  arch/s390/kernel/cpcmd.c
  *
  *  S390 version
- *    Copyright (C) 1999,2005 IBM Deutschland Entwicklung GmbH, IBM Corporation
+ *    Copyright IBM Corp. 1999,2007
  *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
  *               Christian Borntraeger (cborntra@de.ibm.com),
  */
@@ -21,6 +21,49 @@
 static DEFINE_SPINLOCK(cpcmd_lock);
 static char cpcmd_buf[241];
 
+static int diag8_noresponse(int cmdlen)
+{
+	register unsigned long reg2 asm ("2") = (addr_t) cpcmd_buf;
+	register unsigned long reg3 asm ("3") = cmdlen;
+
+	asm volatile(
+#ifndef CONFIG_64BIT
+		"	diag	%1,%0,0x8\n"
+#else /* CONFIG_64BIT */
+		"	sam31\n"
+		"	diag	%1,%0,0x8\n"
+		"	sam64\n"
+#endif /* CONFIG_64BIT */
+		: "+d" (reg3) : "d" (reg2) : "cc");
+	return reg3;
+}
+
+static int diag8_response(int cmdlen, char *response, int *rlen)
+{
+	register unsigned long reg2 asm ("2") = (addr_t) cpcmd_buf;
+	register unsigned long reg3 asm ("3") = (addr_t) response;
+	register unsigned long reg4 asm ("4") = cmdlen | 0x40000000L;
+	register unsigned long reg5 asm ("5") = *rlen;
+
+	asm volatile(
+#ifndef CONFIG_64BIT
+		"	diag	%2,%0,0x8\n"
+		"	brc	8,1f\n"
+		"	ar	%1,%4\n"
+#else /* CONFIG_64BIT */
+		"	sam31\n"
+		"	diag	%2,%0,0x8\n"
+		"	sam64\n"
+		"	brc	8,1f\n"
+		"	agr	%1,%4\n"
+#endif /* CONFIG_64BIT */
+		"1:\n"
+		: "+d" (reg4), "+d" (reg5)
+		: "d" (reg2), "d" (reg3), "d" (*rlen) : "cc");
+	*rlen = reg5;
+	return reg4;
+}
+
 /*
  * __cpcmd has some restrictions over cpcmd
  *  - the response buffer must reside below 2GB (if any)
@@ -28,59 +71,27 @@ static char cpcmd_buf[241];
  */
 int  __cpcmd(const char *cmd, char *response, int rlen, int *response_code)
 {
-	unsigned cmdlen;
-	int return_code, return_len;
+	int cmdlen;
+	int rc;
+	int response_len;
 
 	cmdlen = strlen(cmd);
 	BUG_ON(cmdlen > 240);
 	memcpy(cpcmd_buf, cmd, cmdlen);
 	ASCEBC(cpcmd_buf, cmdlen);
 
-	if (response != NULL && rlen > 0) {
-		register unsigned long reg2 asm ("2") = (addr_t) cpcmd_buf;
-		register unsigned long reg3 asm ("3") = (addr_t) response;
-		register unsigned long reg4 asm ("4") = cmdlen | 0x40000000L;
-		register unsigned long reg5 asm ("5") = rlen;
-
+	if (response) {
 		memset(response, 0, rlen);
-		asm volatile(
-#ifndef CONFIG_64BIT
-			"	diag	%2,%0,0x8\n"
-			"	brc	8,1f\n"
-			"	ar	%1,%4\n"
-#else /* CONFIG_64BIT */
-			"	sam31\n"
-			"	diag	%2,%0,0x8\n"
-			"	sam64\n"
-			"	brc	8,1f\n"
-			"	agr	%1,%4\n"
-#endif /* CONFIG_64BIT */
-			"1:\n"
-			: "+d" (reg4), "+d" (reg5)
-			: "d" (reg2), "d" (reg3), "d" (rlen) : "cc");
-		return_code = (int) reg4;
-		return_len = (int) reg5;
-                EBCASC(response, rlen);
+		response_len = rlen;
+		rc = diag8_response(cmdlen, response, &rlen);
+		EBCASC(response, response_len);
         } else {
-		register unsigned long reg2 asm ("2") = (addr_t) cpcmd_buf;
-		register unsigned long reg3 asm ("3") = cmdlen;
-		return_len = 0;
-		asm volatile(
-#ifndef CONFIG_64BIT
-			"	diag	%1,%0,0x8\n"
-#else /* CONFIG_64BIT */
-			"	sam31\n"
-			"	diag	%1,%0,0x8\n"
-			"	sam64\n"
-#endif /* CONFIG_64BIT */
-			: "+d" (reg3) : "d" (reg2) : "cc");
-		return_code = (int) reg3;
+		rc = diag8_noresponse(cmdlen);
         }
-	if (response_code != NULL)
-		*response_code = return_code;
-	return return_len;
+	if (response_code)
+		*response_code = rc;
+	return rlen;
 }
-
 EXPORT_SYMBOL(__cpcmd);
 
 int cpcmd(const char *cmd, char *response, int rlen, int *response_code)
@@ -109,5 +120,4 @@ int cpcmd(const char *cmd, char *response, int rlen, int *response_code)
 	}
 	return len;
 }
-
 EXPORT_SYMBOL(cpcmd);