flist.h

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#ifndef _LINUX_FLIST_H
#define _LINUX_FLIST_H

#include <stdlib.h>

#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));             \
        })

/*
 * 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 flist_head {
        struct flist_head *next, *prev;
};

#define FLIST_HEAD_INIT(name)                                                  \
        {                                                                      \
                &(name), &(name)                                               \
        }

#define FLIST_HEAD(name) struct flist_head name = FLIST_HEAD_INIT(name)

#define INIT_FLIST_HEAD(ptr)                                                   \
        do {                                                                   \
                (ptr)->next = (ptr);                                           \
                (ptr)->prev = (ptr);                                           \
        } while (0)

/*
 * 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 __flist_add(struct flist_head *new_entry,
                               struct flist_head *prev, struct flist_head *next)
{
        next->prev = new_entry;
        new_entry->next = next;
        new_entry->prev = prev;
        prev->next = new_entry;
}

static inline void flist_add(struct flist_head *new_entry,
                             struct flist_head *head)
{
        __flist_add(new_entry, head, head->next);
}

static inline void flist_add_tail(struct flist_head *new_entry,
                                  struct flist_head *head)
{
        __flist_add(new_entry, 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 __flist_del(struct flist_head *prev, struct flist_head *next)
{
        next->prev = prev;
        prev->next = next;
}

static inline void flist_del(struct flist_head *entry)
{
        __flist_del(entry->prev, entry->next);
        entry->next = NULL;
        entry->prev = NULL;
}

static inline void flist_del_init(struct flist_head *entry)
{
        __flist_del(entry->prev, entry->next);
        INIT_FLIST_HEAD(entry);
}

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

static inline void __flist_splice(const struct flist_head *list,
                                  struct flist_head *prev,
                                  struct flist_head *next)
{
        struct flist_head *first = list->next;
        struct flist_head *last = list->prev;

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

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

static inline void flist_splice(const struct flist_head *list,
                                struct flist_head *head)
{
        if (!flist_empty(list))
                __flist_splice(list, head, head->next);
}

static inline void flist_splice_init(struct flist_head *list,
                                     struct flist_head *head)
{
        if (!flist_empty(list)) {
                __flist_splice(list, head, head->next);
                INIT_FLIST_HEAD(list);
        }
}

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

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

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

extern void flist_sort(void *priv, struct flist_head *head,
                       int (*cmp)(void *priv, struct flist_head *a,
                                  struct flist_head *b));

#endif