参考：
#define offsetof(type, member) (size_t)&(((type*)0)->member)
#define container_of(ptr, type, member) ({ const typeof( ((type *)0)->member ) *__mptr = (ptr); (type *)( (char *)__mptr - offsetof(type,member) );})
（六）linux内核中的offsetof与container_of宏
原文：https://www.cnblogs.com/walkinginthesun/p/9858813.html