diff --git a/drivers/s390/cio/css.c b/drivers/s390/cio/css.c
index b43f769d445e..5e217bbf8797 100644
--- a/drivers/s390/cio/css.c
+++ b/drivers/s390/cio/css.c
@@ -32,7 +32,7 @@
 
 int css_init_done = 0;
 static int need_reprobe = 0;
-static int max_ssid = 0;
+int max_ssid;
 
 struct channel_subsystem *channel_subsystems[__MAX_CSSID + 1];
 
@@ -879,6 +879,18 @@ static int __init css_bus_init(void)
 	if (ret)
 		goto out;
 
+	/* Try to enable MSS. */
+	ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
+	switch (ret) {
+	case 0: /* Success. */
+		max_ssid = __MAX_SSID;
+		break;
+	case -ENOMEM:
+		goto out;
+	default:
+		max_ssid = 0;
+	}
+
 	ret = slow_subchannel_init();
 	if (ret)
 		goto out;
@@ -890,17 +902,6 @@ static int __init css_bus_init(void)
 	if ((ret = bus_register(&css_bus_type)))
 		goto out;
 
-	/* Try to enable MSS. */
-	ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
-	switch (ret) {
-	case 0: /* Success. */
-		max_ssid = __MAX_SSID;
-		break;
-	case -ENOMEM:
-		goto out_bus;
-	default:
-		max_ssid = 0;
-	}
 	/* Setup css structure. */
 	for (i = 0; i <= __MAX_CSSID; i++) {
 		struct channel_subsystem *css;
@@ -966,7 +967,6 @@ out_unregister:
 					   &dev_attr_cm_enable);
 		device_unregister(&css->device);
 	}
-out_bus:
 	bus_unregister(&css_bus_type);
 out:
 	crw_unregister_handler(CRW_RSC_CSS);
diff --git a/drivers/s390/cio/css.h b/drivers/s390/cio/css.h
index 54acdaade86e..68d6b0bf151c 100644
--- a/drivers/s390/cio/css.h
+++ b/drivers/s390/cio/css.h
@@ -111,6 +111,7 @@ extern void css_sch_device_unregister(struct subchannel *);
 extern int css_probe_device(struct subchannel_id);
 extern struct subchannel *get_subchannel_by_schid(struct subchannel_id);
 extern int css_init_done;
+extern int max_ssid;
 int for_each_subchannel_staged(int (*fn_known)(struct subchannel *, void *),
 			       int (*fn_unknown)(struct subchannel_id,
 			       void *), void *data);
diff --git a/drivers/s390/cio/idset.c b/drivers/s390/cio/idset.c
index 77e42cb127bb..5c88faf5b897 100644
--- a/drivers/s390/cio/idset.c
+++ b/drivers/s390/cio/idset.c
@@ -78,7 +78,7 @@ static inline int idset_get_first(struct idset *set, int *ssid, int *id)
 
 struct idset *idset_sch_new(void)
 {
-	return idset_new(__MAX_SSID + 1, __MAX_SUBCHANNEL + 1);
+	return idset_new(max_ssid + 1, __MAX_SUBCHANNEL + 1);
 }
 
 void idset_sch_add(struct idset *set, struct subchannel_id schid)