container_of、containof、offsetof、offsetofend

#ifndef offsetof
#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
#endif


#ifndef sizeof_field
#define sizeof_field(TYPE, MEMBER) sizeof((((TYPE *)0)->MEMBER))
#endif

#ifndef offsetofend
#define offsetofend(TYPE, MEMBER) (offsetof(TYPE, MEMBER) + sizeof_field(TYPE, MEMBER))
#endif

#ifndef containof
 #ifdef offsetof
  #define containof(ptr, type, member) ((type *) ((char *)(ptr) - offsetof(type, member)))
 #else
  #define containof(ptr, type, member) ((type *)((char *)(ptr) - (size_t)&((type *)0)->member))
 #endif
#endif 


/**
 * container_of - cast a member of a structure out to the containing structure
 * @ptr:    the pointer to the member.
 * @type:   the type of the container struct this is embedded in.
 * @member: the name of the member within the struct.
 *
 */
#ifndef container_of
#define container_of(ptr, type, member) ({          \
	const typeof(((type *)0)->member)*__mptr = (ptr);    \
		     (type *)((char *)__mptr - offsetof(type, member)); })
#endif

/**
 * offsetofend(TYPE, MEMBER)
 *
 * @TYPE: The type of the structure
 * @MEMBER: The member within the structure to get the end offset of
 */
#ifndef offsetofend
#define offsetofend(TYPE, MEMBER) (offsetof(TYPE, MEMBER)	+ sizeof(((TYPE *)0)->MEMBER))
#endif