usermode/library/common/list.h

#ifndef _LIST_H
#define _LIST_H

#include <stddef.h>

#define container_of(ptr, type, member) ({                \
  const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
  (type *)( (char *)__mptr - offsetof(type,member) );})

static inline void prefetch(const void *x) {;}

/*
 * These are non-NULL pointers that will result in page faults
 * under normal circumstances, used to verify that nobody uses
 * non-initialized list entries.
 */
#define LIST_POISON1  ((void *) 0x00100100)
#define LIST_POISON2  ((void *) 0x00200200)


/*
 * Simple doubly linked list implementation.
 *
 * Some of the internal functions ("__xxx") are useful when
 * manipulating whole lists rather than single entries, as
 * sometimes we already know the next/prev entries and we can
 * generate better code by using them directly rather than
 * using the generic single-entry routines.
 */

struct list_head {
        struct list_head *next, *prev;
};

#define LIST_HEAD_INIT(name) { &(name), &(name) }

#define LIST_HEAD(name) \
        struct list_head name = LIST_HEAD_INIT(name)

static inline void INIT_LIST_HEAD(struct list_head *list)
{
        list->next = list;
        list->prev = list;
}

/*
 * Insert a new entry between two known consecutive entries.
 *
 * This is only for internal list manipulation where we know
 * the prev/next entries already!
 */
static inline void __list_add(struct list_head *_new,
                              struct list_head *prev,
                              struct list_head *next)
{
        next->prev = _new;
        _new->next = next;
        _new->prev = prev;
        prev->next = _new;
}

static inline void list_add(struct list_head *_new, struct list_head *head)
{
        __list_add(_new, head, head->next);
}

static inline void list_add_tail(struct list_head *_new, struct list_head *head)
{
        __list_add(_new, head->prev, head);
}

/*
 * Delete a list entry by making the prev/next entries
 * point to each other.
 *
 * This is only for internal list manipulation where we know
 * the prev/next entries already!
 */
static inline void __list_del(struct list_head * prev, struct list_head * next)
{
        next->prev = prev;
        prev->next = next;
}

static inline void list_del(struct list_head *entry)
{
        __list_del(entry->prev, entry->next);
        entry->next = (struct list_head *) LIST_POISON1;
        entry->prev = (struct list_head *) LIST_POISON2;
}

static inline void list_replace(struct list_head *old,
                                struct list_head *_new)
{
        _new->next = old->next;
        _new->next->prev = _new;
        _new->prev = old->prev;
        _new->prev->next = _new;
}

static inline void list_replace_init(struct list_head *old,
                                        struct list_head *_new)
{
        list_replace(old, _new);
        INIT_LIST_HEAD(old);
}

static inline void list_del_init(struct list_head *entry)
{
        __list_del(entry->prev, entry->next);
        INIT_LIST_HEAD(entry);
}

static inline void list_move(struct list_head *list, struct list_head *head)
{
        __list_del(list->prev, list->next);
        list_add(list, head);
}

static inline void list_move_tail(struct list_head *list,
                                  struct list_head *head)
{
        __list_del(list->prev, list->next);
        list_add_tail(list, head);
}

static inline int list_is_last(const struct list_head *list,
                                const struct list_head *head)
{
        return list->next == head;
}

static inline int list_empty(const struct list_head *head)
{
        return head->next == head;
}

static inline int list_empty_careful(const struct list_head *head)
{
        struct list_head *next = head->next;
        return (next == head) && (next == head->prev);
}

static inline void __list_splice(struct list_head *list,
                                 struct list_head *head)
{
        struct list_head *first = list->next;
        struct list_head *last = list->prev;
        struct list_head *at = head->next;

        first->prev = head;
        head->next = first;

        last->next = at;
        at->prev = last;
}

static inline void list_splice(struct list_head *list, struct list_head *head)
{
        if (!list_empty(list))
                __list_splice(list, head);
}

static inline void list_splice_init(struct list_head *list,
                                    struct list_head *head)
{
        if (!list_empty(list)) {
                __list_splice(list, head);
                INIT_LIST_HEAD(list);
        }
}

#define list_entry(ptr, type, member) \
        container_of(ptr, type, member)

#define list_for_each(pos, head) \
        for (pos = (head)->next; prefetch(pos->next), pos != (head); \
                pos = pos->next)

#define __list_for_each(pos, head) \
        for (pos = (head)->next; pos != (head); pos = pos->next)

#define list_for_each_prev(pos, head) \
        for (pos = (head)->prev; prefetch(pos->prev), pos != (head); \
                pos = pos->prev)

#define list_for_each_safe(pos, n, head) \
        for (pos = (head)->next, n = pos->next; pos != (head); \
                pos = n, n = pos->next)

#define list_for_each_entry(pos, head, member)                          \
        for (pos = list_entry((head)->next, typeof(*pos), member);      \
             prefetch(pos->member.next), &pos->member != (head);        \
             pos = list_entry(pos->member.next, typeof(*pos), member))

#define list_for_each_entry_reverse(pos, head, member)                  \
        for (pos = list_entry((head)->prev, typeof(*pos), member);      \
             prefetch(pos->member.prev), &pos->member != (head);        \
             pos = list_entry(pos->member.prev, typeof(*pos), member))

#define list_prepare_entry(pos, head, member) \
        ((pos) ? : list_entry(head, typeof(*pos), member))

#define list_for_each_entry_continue(pos, head, member)                 \
        for (pos = list_entry(pos->member.next, typeof(*pos), member);  \
             prefetch(pos->member.next), &pos->member != (head);        \
             pos = list_entry(pos->member.next, typeof(*pos), member))

#define list_for_each_entry_from(pos, head, member)                     \
        for (; prefetch(pos->member.next), &pos->member != (head);      \
             pos = list_entry(pos->member.next, typeof(*pos), member))

#define list_for_each_entry_safe(pos, n, head, member)                  \
        for (pos = list_entry((head)->next, typeof(*pos), member),      \
                n = list_entry(pos->member.next, typeof(*pos), member); \
             &pos->member != (head);                                    \
             pos = n, n = list_entry(n->member.next, typeof(*n), member))

#define list_for_each_entry_safe_continue(pos, n, head, member)                 \
        for (pos = list_entry(pos->member.next, typeof(*pos), member),          \
                n = list_entry(pos->member.next, typeof(*pos), member);         \
             &pos->member != (head);                                            \
             pos = n, n = list_entry(n->member.next, typeof(*n), member))

#define list_for_each_entry_safe_from(pos, n, head, member)                     \
        for (n = list_entry(pos->member.next, typeof(*pos), member);            \
             &pos->member != (head);                                            \
             pos = n, n = list_entry(n->member.next, typeof(*n), member))

#define list_for_each_entry_safe_reverse(pos, n, head, member)          \
        for (pos = list_entry((head)->prev, typeof(*pos), member),      \
                n = list_entry(pos->member.prev, typeof(*pos), member); \
             &pos->member != (head);                                    \
             pos = n, n = list_entry(n->member.prev, typeof(*n), member))


/*
 * Double linked lists with a single pointer list head.
 * Mostly useful for hash tables where the two pointer list head is
 * too wasteful.
 * You lose the ability to access the tail in O(1).
 */

struct hlist_head {
        struct hlist_node *first;
};

struct hlist_node {
        struct hlist_node *next, **pprev;
};

#define HLIST_HEAD_INIT { .first = NULL }
#define HLIST_HEAD(name) struct hlist_head name = {  .first = NULL }
#define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL)
static inline void INIT_HLIST_NODE(struct hlist_node *h)
{
        h->next = NULL;
        h->pprev = NULL;
}

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

static inline int hlist_empty(const struct hlist_head *h)
{
        return !h->first;
}

static inline void __hlist_del(struct hlist_node *n)
{
        struct hlist_node *next = n->next;
        struct hlist_node **pprev = n->pprev;
        *pprev = next;
        if (next)
                next->pprev = pprev;
}

static inline void hlist_del(struct hlist_node *n)
{
        __hlist_del(n);
        n->next = (struct hlist_node *) LIST_POISON1;
        n->pprev = (struct hlist_node **) LIST_POISON2;
}


static inline void hlist_del_init(struct hlist_node *n)
{
        if (!hlist_unhashed(n)) {
                __hlist_del(n);
                INIT_HLIST_NODE(n);
        }
}


static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h)
{
        struct hlist_node *first = h->first;
        n->next = first;
        if (first)
                first->pprev = &n->next;
        h->first = n;
        n->pprev = &h->first;
}


/* next must be != NULL */
static inline void hlist_add_before(struct hlist_node *n,
                                        struct hlist_node *next)
{
        n->pprev = next->pprev;
        n->next = next;
        next->pprev = &n->next;
        *(n->pprev) = n;
}

static inline void hlist_add_after(struct hlist_node *n,
                                        struct hlist_node *next)
{
        next->next = n->next;
        n->next = next;
        next->pprev = &n->next;

        if(next->next)
                next->next->pprev  = &next->next;
}


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

#define hlist_for_each(pos, head) \
        for (pos = (head)->first; pos && ({ prefetch(pos->next); 1; }); \
             pos = pos->next)

#define hlist_for_each_safe(pos, n, head) \
        for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \
             pos = n)

#define hlist_for_each_entry(tpos, pos, head, member)                    \
        for (pos = (head)->first;                                        \
             pos && ({ prefetch(pos->next); 1;}) &&                      \
                ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
             pos = pos->next)

#define hlist_for_each_entry_continue(tpos, pos, member)                 \
        for (pos = (pos)->next;                                          \
             pos && ({ prefetch(pos->next); 1;}) &&                      \
                ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
             pos = pos->next)

#define hlist_for_each_entry_from(tpos, pos, member)                     \
        for (; pos && ({ prefetch(pos->next); 1;}) &&                    \
                ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
             pos = pos->next)

#define hlist_for_each_entry_safe(tpos, pos, n, head, member)            \
        for (pos = (head)->first;                                        \
             pos && ({ n = pos->next; 1; }) &&                           \
                ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
             pos = n)

#define hlist_for_each_entry_rcu(tpos, pos, head, member)                \
        for (pos = (head)->first;                                        \
             rcu_dereference(pos) && ({ prefetch(pos->next); 1;}) &&     \
                ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
             pos = pos->next)

#endif /* _LIST_H */

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