[S390] dasd: fix possible NULL pointer errors

Fix possible NULL pointer in DASD messages and correct discipline
checking.

Signed-off-by: Stefan Haberland <[e-mail]>
Signed-off-by: Martin Schwidefsky <[e-mail]>

drivers/s390/block/dasd.c

···
 	if (device == NULL ||
 	    device != dasd_device_from_cdev_locked(cdev) ||
 	    strncmp(device->discipline->ebcname, (char *) &cqr->magic, 4)) {
-		DBF_DEV_EVENT(DBF_DEBUG, device, "invalid device in request: "
-			      "bus_id %s", dev_name(&cdev->dev));
+		DBF_EVENT_DEVID(DBF_DEBUG, cdev, "%s",
+				"invalid device in request");
 		return;
 	}
 
···
 	device = (struct dasd_device *) cqr->startdev;
 	if (!device ||
 	    strncmp(device->discipline->ebcname, (char *) &cqr->magic, 4)) {
-		DBF_DEV_EVENT(DBF_DEBUG, device, "invalid device in request: "
-			      "bus_id %s", dev_name(&cdev->dev));
+		DBF_EVENT_DEVID(DBF_DEBUG, cdev, "%s",
+				"invalid device in request");
 		return;
 	}
 

drivers/s390/block/dasd_eckd.c

···
 	len += sprintf(page + len, KERN_ERR PRINTK_HEADER
 		       " in req: %p CS: 0x%02X DS: 0x%02X CC: 0x%02X RC: %d\n",
 		       req, scsw_cstat(&irb->scsw), scsw_dstat(&irb->scsw),
-		       scsw_cc(&irb->scsw), req->intrc);
+		       scsw_cc(&irb->scsw), req ? req->intrc : 0);
 	len += sprintf(page + len, KERN_ERR PRINTK_HEADER
 		       " device %s: Failing CCW: %p\n",
 		       dev_name(&device->cdev->dev),

drivers/s390/block/dasd_ioctl.c

···
 	struct ccw_dev_id dev_id;
 
 	base = block->base;
-	if (!base->discipline->fill_info)
+	if (!base->discipline || !base->discipline->fill_info)
 		return -EINVAL;
 
 	dasd_info = kzalloc(sizeof(struct dasd_information2_t), GFP_KERNEL);
···
 	dasd_info->features |=
 		((base->features & DASD_FEATURE_READONLY) != 0);
 
-	if (base->discipline)
-		memcpy(dasd_info->type, base->discipline->name, 4);
-	else
-		memcpy(dasd_info->type, "none", 4);
+	memcpy(dasd_info->type, base->discipline->name, 4);
 
 	if (block->request_queue->request_fn) {
 		struct list_head *l;

drivers/s390/block/dasd_proc.c

···
 	/* Print device number. */
 	seq_printf(m, "%s", dev_name(&device->cdev->dev));
 	/* Print discipline string. */
-	if (device != NULL && device->discipline != NULL)
+	if (device->discipline != NULL)
 		seq_printf(m, "(%s)", device->discipline->name);
 	else
 		seq_printf(m, "(none)");
···
 	substr = (device->features & DASD_FEATURE_READONLY) ? "(ro)" : " ";
 	seq_printf(m, "%4s: ", substr);
 	/* Print device status information. */
-	switch ((device != NULL) ? device->state : -1) {
-	case -1:
-		seq_printf(m, "unknown");
-		break;
+	switch (device->state) {
 	case DASD_STATE_NEW:
 		seq_printf(m, "new");
 		break;