#ifndef _LINUX_LIST_NULLS_H
#define _LINUX_LIST_NULLS_H


struct hlist_nulls_head {
	struct hlist_nulls_node *first;
};

struct hlist_nulls_node {
	struct hlist_nulls_node *next, **pprev;
};
#define INIT_HLIST_NULLS_HEAD(ptr, nulls) \
	((ptr)->first = (struct hlist_nulls_node *) (1UL | (((long)nulls) << 1)))

#define hlist_nulls_entry(ptr, type, member) container_of(ptr,type,member)
static inline int is_a_nulls(const struct hlist_nulls_node *ptr)
{
	return ((unsigned long)ptr & 1);
}

static inline unsigned long get_nulls_value(const struct hlist_nulls_node *ptr)
{
	return ((unsigned long)ptr) >> 1;
}

static inline int hlist_nulls_unhashed(const struct hlist_nulls_node *h)
{
	return !h->pprev;
}

static inline int hlist_nulls_empty(const struct hlist_nulls_head *h)
{
	return is_a_nulls(h->first);
}

static inline void hlist_nulls_add_head(struct hlist_nulls_node *n,
					struct hlist_nulls_head *h)
{
	struct hlist_nulls_node *first = h->first;

	n->next = first;
	n->pprev = &h->first;
	h->first = n;
	if (!is_a_nulls(first))
		first->pprev = &n->next;
}

static inline void __hlist_nulls_del(struct hlist_nulls_node *n)
{
	struct hlist_nulls_node *next = n->next;
	struct hlist_nulls_node **pprev = n->pprev;
	*pprev = next;
	if (!is_a_nulls(next))
		next->pprev = pprev;
}

static inline void hlist_nulls_del(struct hlist_nulls_node *n)
{
	__hlist_nulls_del(n);
	n->pprev = LIST_POISON2;
}

#define hlist_nulls_for_each_entry(tpos, pos, head, member)		       \
	for (pos = (head)->first;					       \
	     (!is_a_nulls(pos)) &&					       \
		({ tpos = hlist_nulls_entry(pos, typeof(*tpos), member); 1;}); \
	     pos = pos->next)

#define hlist_nulls_for_each_entry_from(tpos, pos, member)	\
	for (; (!is_a_nulls(pos)) && 				\
		({ tpos = hlist_nulls_entry(pos, typeof(*tpos), member); 1;}); \
	     pos = pos->next)

#endif