(type *) ((char *) __mptr - offsetof(type, member));})
#endif
+/* Convert from a base type to a parent type, with compile time checking. */
+#ifdef __GNUC__
+#define DO_UPCAST(type, field, dev) ( __extension__ ( { \
+ char __attribute__((unused)) offset_must_be_zero[ \
+ -offsetof(type, field)]; \
+ container_of(dev, type, field);}))
+#else
+#define DO_UPCAST(type, field, dev) container_of(dev, type, field)
+#endif
+
#define typeof_field(type, field) typeof(((type *)0)->field)
#define type_check(t1,t2) ((t1*)0 - (t2*)0)