linux內核中 container_of 的宏;直接使用#include <stddef.h>中的container_of 出現編譯過不了;
所以把這個宏摘抄出來
#define __compiler_offsetof(a,b) __builtin_offsetof(a,b)
#undef offsetof
#ifdef __compiler_offsetof
#define offsetof(TYPE,MEMBER) __compiler_offsetof(TYPE,MEMBER)
#else
#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
#endif
#define container_of(ptr, type, member) ({ \
const typeof( ((type *)0)->member ) *__mptr = (ptr); \
(type *)( (char *)__mptr - offsetof(type,member) );})