class_attribute
ssize_t (*show)(struct class *, struct class_attribute *, char *);
ssize_t (*store)(struct class *, struct class_attribute *, const char *, size_t);
const void *(*namespace)(struct class *, const struct class_attribute *);
struct class_attribute class_attr_##_name = \
struct class_attribute attr;
struct class_attribute *attr, char *buf)
class_create_file(struct class *class, const struct class_attribute *attr)
class_remove_file(struct class *class, const struct class_attribute *attr)
struct class_attribute *dattr;
dattr = container_of(attr, struct class_attribute, attr);
struct class_attribute *dattr;
dattr = container_of(attr, struct class_attribute, attr);