diff --git a/[refs] b/[refs]
index ebe1a4f8821c..4a39e587840d 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: b9fc02968c5dd3c0461b4bb126499a17b13fb86e
+refs/heads/master: a4c348580e65c95d4b278bb6f154f622df12b893
diff --git a/trunk/drivers/block/Kconfig b/trunk/drivers/block/Kconfig
index 9abb64689712..717d6e4e18d3 100644
--- a/trunk/drivers/block/Kconfig
+++ b/trunk/drivers/block/Kconfig
@@ -478,6 +478,19 @@ config XEN_BLKDEV_BACKEND
 	  block devices to other guests via a high-performance shared-memory
 	  interface.
 
+	  The corresponding Linux frontend driver is enabled by the
+	  CONFIG_XEN_BLKDEV_FRONTEND configuration option.
+
+	  The backend driver attaches itself to a any block device specified
+	  in the XenBus configuration. There are no limits to what the block
+	  device as long as it has a major and minor.
+
+	  If you are compiling a kernel to run in a Xen block backend driver
+	  domain (often this is domain 0) you should say Y here. To
+	  compile this driver as a module, chose M here: the module
+	  will be called xen-blkback.
+
+
 config VIRTIO_BLK
 	tristate "Virtio block driver (EXPERIMENTAL)"
 	depends on EXPERIMENTAL && VIRTIO