/* Public domain. */

#ifndef _LINUX_LLIST_H
#define _LINUX_LLIST_H

#include <sys/atomic.h>

struct llist_node {
        struct llist_node *next;
};

struct llist_head {
        struct llist_node *first;
};

#define llist_entry(ptr, type, member)  container_of(ptr, type, member)

static inline struct llist_node *
llist_del_all(struct llist_head *head)
{
        return atomic_swap_ptr(&head->first, NULL);
}

static inline struct llist_node *
llist_del_first(struct llist_head *head)
{
        struct llist_node *first, *next;

        do {
                first = head->first;
                if (first == NULL)
                        return NULL;
                next = first->next;
        } while (atomic_cas_ptr(&head->first, first, next) != first);

        return first;
}

static inline bool
llist_add(struct llist_node *new, struct llist_head *head)
{
        struct llist_node *first;

        do {
                new->next = first = head->first;
        } while (atomic_cas_ptr(&head->first, first, new) != first);

        return (first == NULL);
}

static inline bool
llist_add_batch(struct llist_node *new_first, struct llist_node *new_last,
    struct llist_head *head)
{
        struct llist_node *first;

        do {
                new_last->next = first = head->first;
        } while (atomic_cas_ptr(&head->first, first, new_first) != first);

        return (first == NULL);
}

static inline void
init_llist_head(struct llist_head *head)
{
        head->first = NULL;
}

static inline bool
llist_empty(struct llist_head *head)
{
        return (head->first == NULL);
}

#define llist_for_each_safe(pos, n, node)                               \
        for ((pos) = (node);                                            \
            (pos) != NULL &&                                            \
            ((n) = (pos)->next, pos);                                   \
            (pos) = (n))

#define llist_for_each_entry_safe(pos, n, node, member)                 \
        for (pos = llist_entry((node), __typeof(*pos), member);         \
            ((uintptr_t)(pos) + offsetof(typeof(*(pos)), member)) != 0 && \
            (n = llist_entry(pos->member.next, __typeof(*pos), member), pos); \
            pos = n)

#define llist_for_each_entry(pos, node, member)                         \
        for ((pos) = llist_entry((node), __typeof(*(pos)), member);     \
            ((uintptr_t)(pos) + offsetof(typeof(*(pos)), member)) != 0; \
            (pos) = llist_entry((pos)->member.next, __typeof(*(pos)), member))

#endif