Staging: remove cowloop driver

The author has found a number of problems with the current version
of this driver in the current kernel, and is reworking it to get
things working again.  Because of that, it would be better to remove
the driver now and add it back in a future kernel release.

Cc: H.J. Thomassen <hjt@ATComputing.nl>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/Kconfig

@@ -127,7 +127,5 @@ source "drivers/staging/sep/Kconfig"
 
 source "drivers/staging/iio/Kconfig"
 
-source "drivers/staging/cowloop/Kconfig"
-
 endif # !STAGING_EXCLUDE_BUILD
 endif # STAGING

drivers/staging/Makefile

@@ -45,4 +45,3 @@ obj-$(CONFIG_VME_BUS)		+= vme/
 obj-$(CONFIG_RAR_REGISTER)	+= rar/
 obj-$(CONFIG_DX_SEP)		+= sep/
 obj-$(CONFIG_IIO)		+= iio/
-obj-$(CONFIG_COWLOOP)		+= cowloop/

drivers/staging/cowloop/Kconfig

-config COWLOOP
-	tristate "copy-on-write pseudo Block Driver"
-	depends on BLOCK
-	default n
-	---help---
-	  Cowloop is a "copy-on-write" pseudo block driver. It can be
-	  stacked on top of a "real" block driver, and catches all write
-	  operations on their way from the file systems layer above to
-	  the real driver below, effectively shielding the lower driver
-	  from those write accesses. The requests are then diverted to
-	  an ordinary file, located somewhere else (configurable). Later
-	  read requests are checked to see whether they can be serviced
-	  by the "real" block driver below, or must be pulled in from
-	  the diverted location. More information and userspace tools to
-	  use the driver are on the project's website
-	  http://www.ATComputing.nl/cowloop/

drivers/staging/cowloop/Makefile

-obj-$(CONFIG_COWLOOP)	+= cowloop.o

drivers/staging/cowloop/TODO

-TODO:
-	- checkpatch.pl cleanups
-	- run sparse to ensure clean
-	- fix up 32/64bit ioctl issues
-	- move proc file usage to debugfs
-	- audit ioctls
-	- add documentation
-	- get linux-fsdevel to review it
-
-Please send patches to "H.J. Thomassen" <hjt@ATComputing.nl> and
-Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/cowloop/cowloop.h

-/*
-** DO NOT MODIFY THESE VALUES (would make old cowfiles unusable)
-*/
-#define	MAPUNIT		1024		/* blocksize for bit in bitmap       */
-#define	MUSHIFT		10		/* bitshift  for bit in bitmap       */
-#define	MUMASK		0x3ff		/* bitmask   for bit in bitmap       */
-
-#define	COWMAGIC	0x574f437f	/* byte-swapped '7f C O W'           */
-#define	COWDIRTY	0x01
-#define	COWPACKED	0x02
-#define	COWVERSION	1
-
-struct cowhead
-{
-	int		magic;		/* identifies a cowfile              */
-	short		version;	/* version of cowhead                */
-	short		flags;    	/* flags indicating status           */
-	unsigned long	mapunit;	/* blocksize per bit in bitmap       */
-	unsigned long	mapsize;	/* total size of bitmap (bytes)      */
-	unsigned long	doffset;	/* start-offset datablocks in cow    */
-	unsigned long	rdoblocks;	/* size of related read-only file    */
-	unsigned long	rdofingerprint;	/* fingerprint of read-only file     */
-	unsigned long	cowused;	/* number of datablocks used in cow  */
-};
-
-#define COWDEVDIR	"/dev/cow/"
-#define COWDEVICE	COWDEVDIR "%ld"
-#define COWCONTROL	COWDEVDIR "ctl"
-
-#define MAXCOWS		1024
-#define COWCTL		(MAXCOWS-1)	/* minor number of /dev/cow/ctl     */
-
-#define COWPROCDIR	"/proc/cow/"
-#define COWPROCFILE	COWPROCDIR "%d"
-
-/*
-** ioctl related stuff
-*/
-#define ANYDEV		((unsigned long)-1)
-
-struct cowpair
-{
-	unsigned char	*rdofile;	/* pathname of the rdofile           */
-	unsigned char	*cowfile;	/* pathname of the cowfile           */
-	unsigned short	rdoflen;	/* length of rdofile pathname        */
-	unsigned short	cowflen;	/* length of cowfile pathname        */
-	unsigned long	device;		/* requested/returned device number  */
-};
-
-struct cowwatch
-{
-	int      	flags;		/* request flags                     */
-	unsigned long	device;		/* requested device number           */
-	unsigned long	threshold;	/* continue if free Kb < threshold   */
-	unsigned long	totalkb;	/* ret: total filesystem size (Kb)   */
-	unsigned long	availkb;	/* ret: free  filesystem size (Kb)   */
-};
-
-#define	WATCHWAIT	0x01		/* block until threshold reached     */
-
-#define	COWSYNC		_IO  ('C', 1)
-#define	COWMKPAIR	_IOW ('C', 2, struct cowpair)
-#define	COWRMPAIR	_IOW ('C', 3, unsigned long)
-#define	COWWATCH	_IOW ('C', 4, struct cowwatch)
-#define	COWCLOSE	_IOW ('C', 5, unsigned long)
-#define	COWRDOPEN	_IOW ('C', 6, unsigned long)