[S390] dasd: re-initialize read_conf buffer for retries

The buffer for read configuration data has to be initialized with an
EBCDIC string to show support for extended UIDs to z/VM.
If this read configuration data CQR needs to be retried, the buffer
may have changed in between. So re-initialize the buffer to get a
correct extended UID under z/VM.

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_int.h b/drivers/s390/block/dasd_int.h
index 1dd12bd..563bf8a 100644
--- a/drivers/s390/block/dasd_int.h
+++ b/drivers/s390/block/dasd_int.h
@@ -643,6 +643,7 @@
 dasd_smalloc_request(int , int, int, struct dasd_device *);
 void dasd_kfree_request(struct dasd_ccw_req *, struct dasd_device *);
 void dasd_sfree_request(struct dasd_ccw_req *, struct dasd_device *);
+void dasd_wakeup_cb(struct dasd_ccw_req *, void *);
 
 static inline int
 dasd_kmalloc_set_cda(struct ccw1 *ccw, void *cda, struct dasd_device *device)