dasd: use aliases for formatted devices during format

Formatting of a previously formatted device is slower than newly
format a device when alias devices are available.
For already formatted devices the alias devices are not used for
formatting.

Fix the alias handling for already formatted devices.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index 1e50626..5e8442c 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -285,6 +285,12 @@
 {
 	int rc;
 
+	if (device->discipline->basic_to_known) {
+		rc = device->discipline->basic_to_known(device);
+		if (rc)
+			return rc;
+	}
+
 	if (device->block) {
 		dasd_profile_exit(&device->block->profile);
 		debugfs_remove(device->block->debugfs_dentry);
@@ -375,11 +381,6 @@
 {
 	int rc;
 
-	if (device->discipline->ready_to_basic) {
-		rc = device->discipline->ready_to_basic(device);
-		if (rc)
-			return rc;
-	}
 	device->state = DASD_STATE_BASIC;
 	if (device->block) {
 		struct dasd_block *block = device->block;