make all kref debugging checks new config option.

Signed-off-by: Akinobu Mita <mita@miraclelinux.com>
CC: Greg KH <greg@kroah.com>
CC: Patrick Mochel <mochel@osdl.org>

 lib/Kconfig.debug |    7 +++++++
 lib/kref.c        |   30 +++++++++++++++++++++++++-----
 2 files changed, 32 insertions(+), 5 deletions(-)

Index: 2.6-git/lib/Kconfig.debug
===================================================================
--- 2.6-git.orig/lib/Kconfig.debug
+++ 2.6-git/lib/Kconfig.debug
@@ -130,6 +130,13 @@ config DEBUG_KOBJECT
 	  If you say Y here, some extra kobject debugging messages will be sent
 	  to the syslog. 
 
+config DEBUG_KREF
+	bool "kref debugging"
+	depends on DEBUG_KERNEL
+	help
+	  This option enables addition error checking for kref,
+	  library routines for handling generic reference counted objects.
+
 config DEBUG_HIGHMEM
 	bool "Highmem debugging"
 	depends on DEBUG_KERNEL && HIGHMEM
Index: 2.6-git/lib/kref.c
===================================================================
--- 2.6-git.orig/lib/kref.c
+++ 2.6-git/lib/kref.c
@@ -20,16 +20,38 @@
  */
 void kref_init(struct kref *kref)
 {
-	atomic_set(&kref->refcount,1);
+	atomic_set(&kref->refcount, 1);
 }
 
+#ifdef CONFIG_DEBUG_KREF
+static void kref_get_debug_check(struct kref *kref)
+{
+	WARN_ON(!atomic_read(&kref->refcount));
+}
+static void kref_put_debug_check(struct kref *kref,
+				void (*release)(struct kref *kref))
+{
+	WARN_ON(atomic_read(&kref->refcount) < 1);
+	WARN_ON(release == NULL);
+	WARN_ON(release == (void (*)(struct kref *))kfree);
+}
+#else
+static void kref_get_debug_check(struct kref *kref)
+{
+}
+static void kref_put_debug_check(struct kref *kref,
+				void (*release)(struct kref *kref))
+{
+}
+#endif
+
 /**
  * kref_get - increment refcount for object.
  * @kref: object.
  */
 void kref_get(struct kref *kref)
 {
-	WARN_ON(!atomic_read(&kref->refcount));
+	kref_get_debug_check(kref);
 	atomic_inc(&kref->refcount);
 }
 
@@ -49,9 +71,7 @@ void kref_get(struct kref *kref)
  */
 int kref_put(struct kref *kref, void (*release)(struct kref *kref))
 {
-	WARN_ON(atomic_read(&kref->refcount) < 1);
-	WARN_ON(release == NULL);
-	WARN_ON(release == (void (*)(struct kref *))kfree);
+	kref_put_debug_check(kref, release);
 
 	/*
 	 * if current count is one, we are the last user and can release object

--