s390/block/dcssblk: add error handling support for add_disk()

We never checked for errors on add_disk() as this function
returned void. Now that this is fixed, use the shiny new
error handling.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Link: https://lore.kernel.org/r/20210927220232.1071926-6-mcgrof@kernel.orgSigned-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

drivers/s390/block/dcssblk.c

@@ -696,7 +696,9 @@ dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char
 	}
 
 	get_device(&dev_info->dev);
-	device_add_disk(&dev_info->dev, dev_info->gd, NULL);
+	rc = device_add_disk(&dev_info->dev, dev_info->gd, NULL);
+	if (rc)
+		goto out_dax;
 
 	switch (dev_info->segment_type) {
 		case SEG_TYPE_SR:
@@ -712,6 +714,10 @@ dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char
 	rc = count;
 	goto out;
 
+out_dax:
+	put_device(&dev_info->dev);
+	kill_dax(dev_info->dax_dev);
+	put_dax(dev_info->dax_dev);
 put_dev:
 	list_del(&dev_info->lh);
 	blk_cleanup_disk(dev_info->gd);