+The return value from container_of() is a pointer to the corresponding
+container type. So, for example, a pointer "kp" to a struct kobject
+embedded *within* a struct uio_map could be converted to a pointer to the
+*containing* uio_map structure with:
+
+ struct uio_map *u_map = container_of(kp, struct uio_map, kobj);
+
+For convenience, programmers often define a simple macro for "back-casting"
+kobject pointers to the containing type. Exactly this happens in the
+earlier drivers/uio/uio.c, as you can see here:
+
+ struct uio_map {
+ struct kobject kobj;
+ struct uio_mem *mem;
+ };
+
+ #define to_map(map) container_of(map, struct uio_map, kobj)
+
+where the macro argument "map" is a pointer to the struct kobject in
+question. That macro is subsequently invoked with:
+
+ struct uio_map *map = to_map(kobj);