Staging: virtual block device driver (ramzswap)

Creates RAM based block devices (/dev/ramzswapX) which can be
used (only) as swap disks. Pages swapped to these are compressed
and stored in memory itself.

The module is called ramzswap.ko. It depends on:
 - xvmalloc memory allocator (compiled with this driver)
 - lzo_compress.ko
 - lzo_decompress.ko

See ramzswap.txt for usage details.

Signed-off-by: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/Kconfig

@@ -123,6 +123,8 @@ source "drivers/staging/sep/Kconfig"
 
 source "drivers/staging/iio/Kconfig"
 
+source "drivers/staging/ramzswap/Kconfig"
+
 source "drivers/staging/strip/Kconfig"
 
 source "drivers/staging/arlan/Kconfig"

drivers/staging/Makefile

@@ -43,6 +43,7 @@ obj-$(CONFIG_VME_BUS)		+= vme/
 obj-$(CONFIG_RAR_REGISTER)	+= rar/
 obj-$(CONFIG_DX_SEP)		+= sep/
 obj-$(CONFIG_IIO)		+= iio/
+obj-$(CONFIG_RAMZSWAP)		+= ramzswap/
 obj-$(CONFIG_STRIP)		+= strip/
 obj-$(CONFIG_ARLAN)		+= arlan/
 obj-$(CONFIG_WAVELAN)		+= wavelan/

drivers/staging/ramzswap/Kconfig

@@ -0,0 +1,21 @@
+config RAMZSWAP
+	tristate "Compressed in-memory swap device (ramzswap)"
+	depends on SWAP
+	select LZO_COMPRESS
+	select LZO_DECOMPRESS
+	default n
+	help
+	  Creates virtual block devices which can be used (only) as a swap
+	  disks. Pages swapped to these disks are compressed and stored in
+	  memory itself.
+
+	  See ramzswap.txt for more information.
+	  Project home: http://compcache.googlecode.com/
+
+config RAMZSWAP_STATS
+	bool "Enable ramzswap stats"
+	depends on RAMZSWAP
+	default y
+	help
+	  Enable statistics collection for ramzswap. This adds only a minimal
+	  overhead. In unsure, say Y.

drivers/staging/ramzswap/Makefile

@@ -0,0 +1,3 @@
+ramzswap-objs	:=	ramzswap_drv.o xvmalloc.o
+
+obj-$(CONFIG_RAMZSWAP)	+=	ramzswap.o