[S390] dasd: Add support for enhanced VM UID

When z/VM provides two virtual devices (minidisks) that reside on the
same real device, both will receive the configuration data from the
real device and thus get the same uid. To fix this problem, z/VM
provides an additional configuration data record that allows to
distinguish between minidisks.
z/VM APAR VM64273 needs be installed so this fix has an effect.

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 13 insertions, 3 deletions

diff --git a/drivers/s390/block/dasd_devmap.c b/drivers/s390/block/dasd_devmap.c
index d774e79476fe..cd3335c1c307 100644
--- a/drivers/s390/block/dasd_devmap.c
+++ b/drivers/s390/block/dasd_devmap.c
@@ -913,7 +913,8 @@ dasd_vendor_show(struct device *dev, struct device_attribute *attr, char *buf)
 static DEVICE_ATTR(vendor, 0444, dasd_vendor_show, NULL);
 
 #define UID_STRLEN ( /* vendor */ 3 + 1 + /* serial    */ 14 + 1 +\
-                     /* SSID   */ 4 + 1 + /* unit addr */ 2 + 1)
+                     /* SSID   */ 4 + 1 + /* unit addr */ 2 + 1 +\
+                     /* vduit */ 32 + 1)
 
 static ssize_t
 dasd_uid_show(struct device *dev, struct device_attribute *attr, char *buf)
@@ -945,8 +946,17 @@ dasd_uid_show(struct device *dev, struct device_attribute *attr, char *buf)
                 sprintf(ua_string, "%02x", uid->real_unit_addr);
                 break;
         }
-        snprintf(uid_string, sizeof(uid_string), "%s.%s.%04x.%s",
-                 uid->vendor, uid->serial, uid->ssid, ua_string);
+        if (strlen(uid->vduit) > 0)
+                snprintf(uid_string, sizeof(uid_string),
+                         "%s.%s.%04x.%s.%s",
+                         uid->vendor, uid->serial,
+                         uid->ssid, ua_string,
+                         uid->vduit);
+        else
+                snprintf(uid_string, sizeof(uid_string),
+                         "%s.%s.%04x.%s",
+                         uid->vendor, uid->serial,
+                         uid->ssid, ua_string);
         spin_unlock(&dasd_devmap_lock);
         return snprintf(buf, PAGE_SIZE, "%s\n", uid_string);
 }