1struct list_head {
2	struct list_head *next;
3};
4
5#define LIST_HEAD(name) \
6	struct list_head name = { &(name) }
7
8static inline int list_empty(const struct list_head *head)
9{
10	return head->next == head;
11}
12
13static inline void list_add(struct list_head *new, struct list_head *head)
14{
15	new->next = head->next;
16	head->next = new;
17}
18
19static inline void list_del(struct list_head *entry, struct list_head *prev)
20{
21	prev->next = entry->next;
22	entry->next = entry;
23}
24
25#define list_for_each_safe(pos, n, head) \
26	for (n = (head), pos = (head)->next; pos != (head); \
27	     n = pos, pos = n->next)
28
29#undef offsetof
30#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
31
32#define container_of(ptr, type, member) ({			\
33	const typeof( ((type *)0)->member ) *__mptr = (ptr);	\
34	(type *)( (char *)__mptr - offsetof(type,member) );})
35
36#ifdef DEBUG
37#define pynl_dbg(fmt, ...) \
38	fprintf(stderr, "%s: " fmt, __func__, __VA_ARGS__)
39#else
40#define pynl_dbg(fmt, ...)
41#endif
42