Subject: blkfront: Fix an unlikely xenbus crasher.

Getting partition 0 should not fail, but if it does we won't continue.

Signed-off-by: Daniel Stodden <daniel.stodden@xxxxxxxxxx>
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>

--- a/drivers/xen/blkfront/blkfront.c
+++ b/drivers/xen/blkfront/blkfront.c
@@ -285,8 +285,10 @@
 
 	case XenbusStateClosing:
 		bd = bdget(info->dev);
-		if (bd == NULL)
+		if (bd == NULL) {
 			xenbus_dev_fatal(dev, -ENODEV, "bdget failed");
+			break;
+		}
 
 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,17)
 		down(&bd->bd_sem);