[S390] dasd: use idal for device characteristics

If the rdc_buffer is above 2G we need indirect addresssing so we have
to use an idaw to give the rdc_buffer to the ccw.
If the rdc_buffer is under 2G nothing changes.
Signed-off-by: NStefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/block/dasd.c

@@ -2533,6 +2533,7 @@ static struct dasd_ccw_req *dasd_generic_build_rdc(struct dasd_device *device,
 {
 	struct dasd_ccw_req *cqr;
 	struct ccw1 *ccw;
+	unsigned long *idaw;
 
 	cqr = dasd_smalloc_request(magic, 1 /* RDC */, rdc_buffer_size, device);
 
@@ -2546,9 +2547,17 @@ static struct dasd_ccw_req *dasd_generic_build_rdc(struct dasd_device *device,
 
 	ccw = cqr->cpaddr;
 	ccw->cmd_code = CCW_CMD_RDC;
-	ccw->cda = (__u32)(addr_t)rdc_buffer;
-	ccw->count = rdc_buffer_size;
+	if (idal_is_needed(rdc_buffer, rdc_buffer_size)) {
+		idaw = (unsigned long *) (cqr->data);
+		ccw->cda = (__u32)(addr_t) idaw;
+		ccw->flags = CCW_FLAG_IDA;
+		idaw = idal_create_words(idaw, rdc_buffer, rdc_buffer_size);
+	} else {
+		ccw->cda = (__u32)(addr_t) rdc_buffer;
+		ccw->flags = 0;
+	}
 
+	ccw->count = rdc_buffer_size;
 	cqr->startdev = device;
 	cqr->memdev = device;
 	cqr->expires = 10*HZ;