diff --git a/drivers/s390/block/dasd_devmap.c b/drivers/s390/block/dasd_devmap.c
index 29e48b2ab7121c089846b206de7cae3bfc2cd160..9d0c6e1a0e664a87beb7764eb32653ff8c1614fc 100644
--- a/drivers/s390/block/dasd_devmap.c
+++ b/drivers/s390/block/dasd_devmap.c
@@ -48,18 +48,20 @@ struct dasd_devmap {
 };
 
 /*
- * dasd_servermap is used to store the server_id of all storage servers
- * accessed by DASD device driver.
+ * dasd_server_ssid_map contains a globally unique storage server subsystem ID.
+ * dasd_server_ssid_list contains the list of all subsystem IDs accessed by
+ * the DASD device driver.
  */
-struct dasd_servermap {
+struct dasd_server_ssid_map {
 	struct list_head list;
 	struct server_id {
 		char vendor[4];
 		char serial[15];
 	} sid;
+	__u16 ssid;
 };
 
-static struct list_head dasd_serverlist;
+static struct list_head dasd_server_ssid_list;
 
 /*
  * Parameter parsing functions for dasd= parameter. The syntax is:
@@ -878,8 +880,9 @@ dasd_get_uid(struct ccw_device *cdev, struct dasd_uid *uid)
 
 /*
  * Register the given device unique identifier into devmap struct.
- * In addition check if the related storage server is already contained in the
- * dasd_serverlist. If server is not contained, create new entry.
+ * In addition check if the related storage server subsystem ID is already
+ * contained in the dasd_server_ssid_list. If subsystem ID is not contained,
+ * create new entry.
  * Return 0 if server was already in serverlist,
  *	  1 if the server was added successful
  *	 <0 in case of error.
@@ -888,26 +891,27 @@ int
 dasd_set_uid(struct ccw_device *cdev, struct dasd_uid *uid)
 {
 	struct dasd_devmap *devmap;
-	struct dasd_servermap *srv, *tmp;
+	struct dasd_server_ssid_map *srv, *tmp;
 
 	devmap = dasd_find_busid(cdev->dev.bus_id);
 	if (IS_ERR(devmap))
 		return PTR_ERR(devmap);
 
-	/* generate entry for servermap */
-	srv = (struct dasd_servermap *)
-		kzalloc(sizeof(struct dasd_servermap), GFP_KERNEL);
+	/* generate entry for server_ssid_map */
+	srv = (struct dasd_server_ssid_map *)
+		kzalloc(sizeof(struct dasd_server_ssid_map), GFP_KERNEL);
 	if (!srv)
 		return -ENOMEM;
 	strncpy(srv->sid.vendor, uid->vendor, sizeof(srv->sid.vendor) - 1);
 	strncpy(srv->sid.serial, uid->serial, sizeof(srv->sid.serial) - 1);
+	srv->ssid = uid->ssid;
 
 	/* server is already contained ? */
 	spin_lock(&dasd_devmap_lock);
 	devmap->uid = *uid;
-	list_for_each_entry(tmp, &dasd_serverlist, list) {
+	list_for_each_entry(tmp, &dasd_server_ssid_list, list) {
 		if (!memcmp(&srv->sid, &tmp->sid,
-			    sizeof(struct dasd_servermap))) {
+			    sizeof(struct dasd_server_ssid_map))) {
 			kfree(srv);
 			srv = NULL;
 			break;
@@ -916,7 +920,7 @@ dasd_set_uid(struct ccw_device *cdev, struct dasd_uid *uid)
 
 	/* add servermap to serverlist */
 	if (srv)
-		list_add(&srv->list, &dasd_serverlist);
+		list_add(&srv->list, &dasd_server_ssid_list);
 	spin_unlock(&dasd_devmap_lock);
 
 	return (srv ? 1 : 0);
@@ -987,7 +991,7 @@ dasd_devmap_init(void)
 		INIT_LIST_HEAD(&dasd_hashlists[i]);
 
 	/* Initialize servermap structure. */
-	INIT_LIST_HEAD(&dasd_serverlist);
+	INIT_LIST_HEAD(&dasd_server_ssid_list);
 	return 0;
 }