zcache/debug: Coalesce all debug under CONFIG_ZCACHE_DEBUG

and also define this extra attribute in the Kconfig entry.
Acked-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/zcache/Kconfig

@@ -10,6 +10,14 @@ config ZCACHE
 	  memory to store clean page cache pages and swap in RAM,
 	  providing a noticeable reduction in disk I/O.
 
+config ZCACHE_DEBUG
+	bool "Enable debug statistics"
+	depends on DEBUG_FS && ZCACHE
+	default n
+	help
+	  This is used to provide an debugfs directory with counters of
+	  how zcache is doing. You probably want to set this to 'N'.
+
 config RAMSTER
 	bool "Cross-machine RAM capacity sharing, aka peer-to-peer tmem"
 	depends on CONFIGFS_FS=y && SYSFS=y && !HIGHMEM && ZCACHE=y

drivers/staging/zcache/debug.c

 #include <linux/atomic.h>
 #include "debug.h"
 
-#ifdef CONFIG_DEBUG_FS
+#ifdef CONFIG_ZCACHE_DEBUG
 #include <linux/debugfs.h>
 
 #define ATTR(x)  { .name = #x, .val = &zcache_##x, }

drivers/staging/zcache/zcache-main.c

@@ -306,7 +306,7 @@ static void zcache_free_page(struct page *page)
 		max_pageframes = curr_pageframes;
 	if (curr_pageframes < min_pageframes)
 		min_pageframes = curr_pageframes;
-#ifdef ZCACHE_DEBUG
+#ifdef CONFIG_ZCACHE_DEBUG
 	if (curr_pageframes > 2L || curr_pageframes < -2L) {
 		/* pr_info here */
 	}
@@ -1774,7 +1774,7 @@ static int __init zcache_init(void)
 		old_ops = zcache_cleancache_register_ops();
 		pr_info("%s: cleancache enabled using kernel transcendent "
 			"memory and compression buddies\n", namestr);
-#ifdef ZCACHE_DEBUG
+#ifdef CONFIG_ZCACHE_DEBUG
 		pr_info("%s: cleancache: ignorenonactive = %d\n",
 			namestr, !disable_cleancache_ignore_nonactive);
 #endif
@@ -1789,7 +1789,7 @@ static int __init zcache_init(void)
 			frontswap_tmem_exclusive_gets(true);
 		pr_info("%s: frontswap enabled using kernel transcendent "
 			"memory and compression buddies\n", namestr);
-#ifdef ZCACHE_DEBUG
+#ifdef CONFIG_ZCACHE_DEBUG
 		pr_info("%s: frontswap: excl gets = %d active only = %d\n",
 			namestr, frontswap_has_exclusive_gets,
 			!disable_frontswap_ignore_nonactive);