[PATCH] UML: remove the COW block driver

The code is still there but it's not built.  Below is a patch which removes
it totally.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/um/Kconfig_block

@@ -29,19 +29,9 @@ config BLK_DEV_UBD_SYNC
         wise choice too.  In all other cases (for example, if you're just
         playing around with User-Mode Linux) you can choose N.
 
-# Turn this back on when the driver actually works
-#
-#config BLK_DEV_COW
-#	tristate "COW block device"
-#	help
-#	This is a layered driver which sits above two other block devices.
-#	One is read-only, and the other is a read-write layer which stores
-#	all changes.  This provides the illusion that the read-only layer
-#	can be mounted read-write and changed.
-
 config BLK_DEV_COW_COMMON
 	bool
-	default BLK_DEV_COW || BLK_DEV_UBD
+	default BLK_DEV_UBD
 
 config BLK_DEV_LOOP
 	tristate "Loopback device support"

arch/um/drivers/Makefile

@@ -39,7 +39,6 @@ obj-$(CONFIG_PTY_CHAN) += pty.o
 obj-$(CONFIG_TTY_CHAN) += tty.o 
 obj-$(CONFIG_XTERM_CHAN) += xterm.o xterm_kern.o
 obj-$(CONFIG_UML_WATCHDOG) += harddog.o
-obj-$(CONFIG_BLK_DEV_COW) += cow_kern.o
 obj-$(CONFIG_BLK_DEV_COW_COMMON) += cow_user.o
 
 obj-y += stdio_console.o $(CHAN_OBJS)