zram/xvmalloc: create CONFIG_ZRAM_DEBUG for debug code

Add a debug config flag to enable debug printk output and future
debug code.

Signed-off-by: Robert Jennings <rcj@linux.vnet.ibm.com>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/zram/Kconfig

@@ -15,3 +15,11 @@ config ZRAM
 
 	  See zram.txt for more information.
 	  Project home: http://compcache.googlecode.com/
+
+config ZRAM_DEBUG
+	bool "Compressed RAM block device debug support"
+	depends on ZRAM
+	default n
+	help
+	  This option adds additional debugging code to the compressed
+	  RAM block device driver.

drivers/staging/zram/xvmalloc.c

@@ -10,6 +10,10 @@
  * Released under the terms of GNU General Public License Version 2.0
  */
 
+#ifdef CONFIG_ZRAM_DEBUG
+#define DEBUG
+#endif
+
 #include <linux/bitops.h>
 #include <linux/errno.h>
 #include <linux/highmem.h>

drivers/staging/zram/zram_drv.c

@@ -15,6 +15,10 @@
 #define KMSG_COMPONENT "zram"
 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
 
+#ifdef CONFIG_ZRAM_DEBUG
+#define DEBUG
+#endif
+
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/bio.h>