xen/blkback: Move it from drivers/xen to drivers/block

.. and modify the Makefile and Kconfig files appropriately.

Signed-off-by: Konrad Rzeszutek Wilk <[e-mail]>

drivers/block/Kconfig

···
 	  block device driver.  It communicates with a back-end driver
 	  in another domain which drives the actual block device.
 
+config XEN_BLKDEV_BACKEND
+	tristate "Block-device backend driver"
+	depends on XEN_BACKEND
+	help
+	  The block-device backend driver allows the kernel to export its
+	  block devices to other guests via a high-performance shared-memory
+	  interface.
+
 config VIRTIO_BLK
 	tristate "Virtio block driver (EXPERIMENTAL)"
 	depends on EXPERIMENTAL && VIRTIO

drivers/block/Makefile

···
 obj-$(CONFIG_BLK_DEV_HD)	+= hd.o
 
 obj-$(CONFIG_XEN_BLKDEV_FRONTEND)	+= xen-blkfront.o
+obj-$(CONFIG_XEN_BLKDEV_BACKEND)	+= xen-blkback/
 obj-$(CONFIG_BLK_DEV_DRBD)     += drbd/
 obj-$(CONFIG_BLK_DEV_RBD)     += rbd.o
 

drivers/xen/Kconfig

···
 	  Support for backend device drivers that provide I/O services
 	  to other virtual machines.
 
-config XEN_BLKDEV_BACKEND
-	tristate "Block-device backend driver"
-	depends on XEN_BACKEND && BLOCK
-	help
-	  The block-device backend driver allows the kernel to export its
-	  block devices to other guests via a high-performance shared-memory
-	  interface.
-
 config XENFS
 	tristate "Xen filesystem"
 	default y

drivers/xen/Makefile

···
 obj-$(CONFIG_XEN_DEV_EVTCHN)	+= xen-evtchn.o
 obj-$(CONFIG_XEN_GNTDEV)	+= xen-gntdev.o
 obj-$(CONFIG_XEN_GRANT_DEV_ALLOC)	+= xen-gntalloc.o
-obj-$(CONFIG_XEN_BLKDEV_BACKEND)	+= blkback/
 obj-$(CONFIG_XENFS)		+= xenfs/
 obj-$(CONFIG_XEN_SYS_HYPERVISOR)	+= sys-hypervisor.o
 obj-$(CONFIG_XEN_PLATFORM_PCI)	+= xen-platform-pci.o