[PATCH] sysfs: (driver/base) if show/store is missing return -EIO

sysfs: fix drivers/base so if an attribute doesn't implement
       show or store method read/write will return -EIO
       instead of 0.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/base/class.c b/drivers/base/class.c
index ff33ebb..344b8cd 100644
--- a/drivers/base/class.c
+++ b/drivers/base/class.c
@@ -26,7 +26,7 @@
 {
 	struct class_attribute * class_attr = to_class_attr(attr);
 	struct class * dc = to_class(kobj);
-	ssize_t ret = 0;
+	ssize_t ret = -EIO;
 
 	if (class_attr->show)
 		ret = class_attr->show(dc, buf);
@@ -39,7 +39,7 @@
 {
 	struct class_attribute * class_attr = to_class_attr(attr);
 	struct class * dc = to_class(kobj);
-	ssize_t ret = 0;
+	ssize_t ret = -EIO;
 
 	if (class_attr->store)
 		ret = class_attr->store(dc, buf, count);