FreeBSD/Linux Kernel Cross Reference
sys/include/linux/list.h

     #ifndef _LINUX_LIST_H
     #define _LINUX_LIST_H
     
     #include <linux/types.h>
     #include <linux/stddef.h>
     #include <linux/poison.h>
     #include <linux/const.h>
     
     /*
     * 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.
     */
    
    #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!
     */
    #ifndef CONFIG_DEBUG_LIST
    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;
    }
    #else
    extern void __list_add(struct list_head *new,
                                  struct list_head *prev,
                                  struct list_head *next);
    #endif
    
    /**
     * list_add - add a new entry
     * @new: new entry to be added
     * @head: list head to add it after
     *
     * Insert a new entry after the specified head.
     * This is good for implementing stacks.
     */
    static inline void list_add(struct list_head *new, struct list_head *head)
    {
            __list_add(new, head, head->next);
    }
    
    
    /**
     * list_add_tail - add a new entry
     * @new: new entry to be added
     * @head: list head to add it before
     *
     * Insert a new entry before the specified head.
     * This is useful for implementing queues.
     */
    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;
    }
    
    /**
     * list_del - deletes entry from list.
     * @entry: the element to delete from the list.
     * Note: list_empty() on entry does not return true after this, the entry is
     * in an undefined state.
     */
    #ifndef CONFIG_DEBUG_LIST
    static inline void __list_del_entry(struct list_head *entry)
   {
           __list_del(entry->prev, entry->next);
   }
   
   static inline void list_del(struct list_head *entry)
   {
           __list_del(entry->prev, entry->next);
           entry->next = LIST_POISON1;
           entry->prev = LIST_POISON2;
   }
   #else
   extern void __list_del_entry(struct list_head *entry);
   extern void list_del(struct list_head *entry);
   #endif
   
   /**
    * list_replace - replace old entry by new one
    * @old : the element to be replaced
    * @new : the new element to insert
    *
    * If @old was empty, it will be overwritten.
    */
   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);
   }
   
   /**
    * list_del_init - deletes entry from list and reinitialize it.
    * @entry: the element to delete from the list.
    */
   static inline void list_del_init(struct list_head *entry)
   {
           __list_del_entry(entry);
           INIT_LIST_HEAD(entry);
   }
   
   /**
    * list_move - delete from one list and add as another's head
    * @list: the entry to move
    * @head: the head that will precede our entry
    */
   static inline void list_move(struct list_head *list, struct list_head *head)
   {
           __list_del_entry(list);
           list_add(list, head);
   }
   
   /**
    * list_move_tail - delete from one list and add as another's tail
    * @list: the entry to move
    * @head: the head that will follow our entry
    */
   static inline void list_move_tail(struct list_head *list,
                                     struct list_head *head)
   {
           __list_del_entry(list);
           list_add_tail(list, head);
   }
   
   /**
    * list_is_last - tests whether @list is the last entry in list @head
    * @list: the entry to test
    * @head: the head of the list
    */
   static inline int list_is_last(const struct list_head *list,
                                   const struct list_head *head)
   {
           return list->next == head;
   }
   
   /**
    * list_empty - tests whether a list is empty
    * @head: the list to test.
    */
   static inline int list_empty(const struct list_head *head)
   {
           return head->next == head;
   }
   
   /**
    * list_empty_careful - tests whether a list is empty and not being modified
    * @head: the list to test
    *
    * Description:
    * tests whether a list is empty _and_ checks that no other CPU might be
    * in the process of modifying either member (next or prev)
    *
    * NOTE: using list_empty_careful() without synchronization
    * can only be safe if the only activity that can happen
    * to the list entry is list_del_init(). Eg. it cannot be used
    * if another CPU could re-list_add() it.
    */
   static inline int list_empty_careful(const struct list_head *head)
   {
           struct list_head *next = head->next;
           return (next == head) && (next == head->prev);
   }
   
   /**
    * list_rotate_left - rotate the list to the left
    * @head: the head of the list
    */
   static inline void list_rotate_left(struct list_head *head)
   {
           struct list_head *first;
   
           if (!list_empty(head)) {
                   first = head->next;
                   list_move_tail(first, head);
           }
   }
   
   /**
    * list_is_singular - tests whether a list has just one entry.
    * @head: the list to test.
    */
   static inline int list_is_singular(const struct list_head *head)
   {
           return !list_empty(head) && (head->next == head->prev);
   }
   
   static inline void __list_cut_position(struct list_head *list,
                   struct list_head *head, struct list_head *entry)
   {
           struct list_head *new_first = entry->next;
           list->next = head->next;
           list->next->prev = list;
           list->prev = entry;
           entry->next = list;
           head->next = new_first;
           new_first->prev = head;
   }
   
   /**
    * list_cut_position - cut a list into two
    * @list: a new list to add all removed entries
    * @head: a list with entries
    * @entry: an entry within head, could be the head itself
    *      and if so we won't cut the list
    *
    * This helper moves the initial part of @head, up to and
    * including @entry, from @head to @list. You should
    * pass on @entry an element you know is on @head. @list
    * should be an empty list or a list you do not care about
    * losing its data.
    *
    */
   static inline void list_cut_position(struct list_head *list,
                   struct list_head *head, struct list_head *entry)
   {
           if (list_empty(head))
                   return;
           if (list_is_singular(head) &&
                   (head->next != entry && head != entry))
                   return;
           if (entry == head)
                   INIT_LIST_HEAD(list);
           else
                   __list_cut_position(list, head, entry);
   }
   
   static inline void __list_splice(const struct list_head *list,
                                    struct list_head *prev,
                                    struct list_head *next)
   {
           struct list_head *first = list->next;
           struct list_head *last = list->prev;
   
           first->prev = prev;
           prev->next = first;
   
           last->next = next;
           next->prev = last;
   }
   
   /**
    * list_splice - join two lists, this is designed for stacks
    * @list: the new list to add.
    * @head: the place to add it in the first list.
    */
   static inline void list_splice(const struct list_head *list,
                                   struct list_head *head)
   {
           if (!list_empty(list))
                   __list_splice(list, head, head->next);
   }
   
   /**
    * list_splice_tail - join two lists, each list being a queue
    * @list: the new list to add.
    * @head: the place to add it in the first list.
    */
   static inline void list_splice_tail(struct list_head *list,
                                   struct list_head *head)
   {
           if (!list_empty(list))
                   __list_splice(list, head->prev, head);
   }
   
   /**
    * list_splice_init - join two lists and reinitialise the emptied list.
    * @list: the new list to add.
    * @head: the place to add it in the first list.
    *
    * The list at @list is reinitialised
    */
   static inline void list_splice_init(struct list_head *list,
                                       struct list_head *head)
   {
           if (!list_empty(list)) {
                   __list_splice(list, head, head->next);
                   INIT_LIST_HEAD(list);
           }
   }
   
   /**
    * list_splice_tail_init - join two lists and reinitialise the emptied list
    * @list: the new list to add.
    * @head: the place to add it in the first list.
    *
    * Each of the lists is a queue.
    * The list at @list is reinitialised
    */
   static inline void list_splice_tail_init(struct list_head *list,
                                            struct list_head *head)
   {
           if (!list_empty(list)) {
                   __list_splice(list, head->prev, head);
                   INIT_LIST_HEAD(list);
           }
   }
   
   /**
    * list_entry - get the struct for this entry
    * @ptr:        the &struct list_head pointer.
    * @type:       the type of the struct this is embedded in.
    * @member:     the name of the list_struct within the struct.
    */
   #define list_entry(ptr, type, member) \
           container_of(ptr, type, member)
   
   /**
    * list_first_entry - get the first element from a list
    * @ptr:        the list head to take the element from.
    * @type:       the type of the struct this is embedded in.
    * @member:     the name of the list_struct within the struct.
    *
    * Note, that list is expected to be not empty.
    */
   #define list_first_entry(ptr, type, member) \
           list_entry((ptr)->next, type, member)
   
   /**
    * list_for_each        -       iterate over a list
    * @pos:        the &struct list_head to use as a loop cursor.
    * @head:       the head for your list.
    */
   #define list_for_each(pos, head) \
           for (pos = (head)->next; pos != (head); pos = pos->next)
   
   /**
    * __list_for_each      -       iterate over a list
    * @pos:        the &struct list_head to use as a loop cursor.
    * @head:       the head for your list.
    *
    * This variant doesn't differ from list_for_each() any more.
    * We don't do prefetching in either case.
    */
   #define __list_for_each(pos, head) \
           for (pos = (head)->next; pos != (head); pos = pos->next)
   
   /**
    * list_for_each_prev   -       iterate over a list backwards
    * @pos:        the &struct list_head to use as a loop cursor.
    * @head:       the head for your list.
    */
   #define list_for_each_prev(pos, head) \
           for (pos = (head)->prev; pos != (head); pos = pos->prev)
   
   /**
    * list_for_each_safe - iterate over a list safe against removal of list entry
    * @pos:        the &struct list_head to use as a loop cursor.
    * @n:          another &struct list_head to use as temporary storage
    * @head:       the head for your list.
    */
   #define list_for_each_safe(pos, n, head) \
           for (pos = (head)->next, n = pos->next; pos != (head); \
                   pos = n, n = pos->next)
   
   /**
    * list_for_each_prev_safe - iterate over a list backwards safe against removal of list entry
    * @pos:        the &struct list_head to use as a loop cursor.
    * @n:          another &struct list_head to use as temporary storage
    * @head:       the head for your list.
    */
   #define list_for_each_prev_safe(pos, n, head) \
           for (pos = (head)->prev, n = pos->prev; \
                pos != (head); \
                pos = n, n = pos->prev)
   
   /**
    * list_for_each_entry  -       iterate over list of given type
    * @pos:        the type * to use as a loop cursor.
    * @head:       the head for your list.
    * @member:     the name of the list_struct within the struct.
    */
   #define list_for_each_entry(pos, head, member)                          \
           for (pos = list_entry((head)->next, typeof(*pos), member);      \
                &pos->member != (head);    \
                pos = list_entry(pos->member.next, typeof(*pos), member))
   
   /**
    * list_for_each_entry_reverse - iterate backwards over list of given type.
    * @pos:        the type * to use as a loop cursor.
    * @head:       the head for your list.
    * @member:     the name of the list_struct within the struct.
    */
   #define list_for_each_entry_reverse(pos, head, member)                  \
           for (pos = list_entry((head)->prev, typeof(*pos), member);      \
                &pos->member != (head);    \
                pos = list_entry(pos->member.prev, typeof(*pos), member))
   
   /**
    * list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue()
    * @pos:        the type * to use as a start point
    * @head:       the head of the list
    * @member:     the name of the list_struct within the struct.
    *
    * Prepares a pos entry for use as a start point in list_for_each_entry_continue().
    */
   #define list_prepare_entry(pos, head, member) \
           ((pos) ? : list_entry(head, typeof(*pos), member))
   
   /**
    * list_for_each_entry_continue - continue iteration over list of given type
    * @pos:        the type * to use as a loop cursor.
    * @head:       the head for your list.
    * @member:     the name of the list_struct within the struct.
    *
    * Continue to iterate over list of given type, continuing after
    * the current position.
    */
   #define list_for_each_entry_continue(pos, head, member)                 \
           for (pos = list_entry(pos->member.next, typeof(*pos), member);  \
                &pos->member != (head);    \
                pos = list_entry(pos->member.next, typeof(*pos), member))
   
   /**
    * list_for_each_entry_continue_reverse - iterate backwards from the given point
    * @pos:        the type * to use as a loop cursor.
    * @head:       the head for your list.
    * @member:     the name of the list_struct within the struct.
    *
    * Start to iterate over list of given type backwards, continuing after
    * the current position.
    */
   #define list_for_each_entry_continue_reverse(pos, head, member)         \
           for (pos = list_entry(pos->member.prev, typeof(*pos), member);  \
                &pos->member != (head);    \
                pos = list_entry(pos->member.prev, typeof(*pos), member))
   
   /**
    * list_for_each_entry_from - iterate over list of given type from the current point
    * @pos:        the type * to use as a loop cursor.
    * @head:       the head for your list.
    * @member:     the name of the list_struct within the struct.
    *
    * Iterate over list of given type, continuing from current position.
    */
   #define list_for_each_entry_from(pos, head, member)                     \
           for (; &pos->member != (head);  \
                pos = list_entry(pos->member.next, typeof(*pos), member))
   
   /**
    * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
    * @pos:        the type * to use as a loop cursor.
    * @n:          another type * to use as temporary storage
    * @head:       the head for your list.
    * @member:     the name of the list_struct within the struct.
    */
   #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))
   
   /**
    * list_for_each_entry_safe_continue - continue list iteration safe against removal
    * @pos:        the type * to use as a loop cursor.
    * @n:          another type * to use as temporary storage
    * @head:       the head for your list.
    * @member:     the name of the list_struct within the struct.
    *
    * Iterate over list of given type, continuing after current point,
    * safe against removal of list entry.
    */
   #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))
   
   /**
    * list_for_each_entry_safe_from - iterate over list from current point safe against removal
    * @pos:        the type * to use as a loop cursor.
    * @n:          another type * to use as temporary storage
    * @head:       the head for your list.
    * @member:     the name of the list_struct within the struct.
    *
    * Iterate over list of given type from current point, safe against
    * removal of list entry.
    */
   #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))
   
   /**
    * list_for_each_entry_safe_reverse - iterate backwards over list safe against removal
    * @pos:        the type * to use as a loop cursor.
    * @n:          another type * to use as temporary storage
    * @head:       the head for your list.
    * @member:     the name of the list_struct within the struct.
    *
    * Iterate backwards over list of given type, safe against removal
    * of list entry.
    */
   #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))
   
   /**
    * list_safe_reset_next - reset a stale list_for_each_entry_safe loop
    * @pos:        the loop cursor used in the list_for_each_entry_safe loop
    * @n:          temporary storage used in list_for_each_entry_safe
    * @member:     the name of the list_struct within the struct.
    *
    * list_safe_reset_next is not safe to use in general if the list may be
    * modified concurrently (eg. the lock is dropped in the loop body). An
    * exception to this is if the cursor element (pos) is pinned in the list,
    * and list_safe_reset_next is called after re-taking the lock and before
    * completing the current iteration of the loop body.
    */
   #define list_safe_reset_next(pos, n, member)                            \
           n = list_entry(pos->member.next, typeof(*pos), 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).
    */
   
   #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 = LIST_POISON1;
           n->pprev = 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;
   }
   
   /* after that we'll appear to be on some hlist and hlist_del will work */
   static inline void hlist_add_fake(struct hlist_node *n)
   {
           n->pprev = &n->next;
   }
   
   /*
    * Move a list from one list head to another. Fixup the pprev
    * reference of the first entry if it exists.
    */
   static inline void hlist_move_list(struct hlist_head *old,
                                      struct hlist_head *new)
   {
           new->first = old->first;
           if (new->first)
                   new->first->pprev = &new->first;
           old->first = NULL;
   }
   
   #define hlist_entry(ptr, type, member) container_of(ptr,type,member)
   
   #define hlist_for_each(pos, head) \
           for (pos = (head)->first; pos ; pos = pos->next)
   
   #define hlist_for_each_safe(pos, n, head) \
           for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \
                pos = n)
   
   /**
    * hlist_for_each_entry - iterate over list of given type
    * @tpos:       the type * to use as a loop cursor.
    * @pos:        the &struct hlist_node to use as a loop cursor.
    * @head:       the head for your list.
    * @member:     the name of the hlist_node within the struct.
    */
   #define hlist_for_each_entry(tpos, pos, head, member)                    \
           for (pos = (head)->first;                                        \
                pos &&                                                      \
                   ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
                pos = pos->next)
   
   /**
    * hlist_for_each_entry_continue - iterate over a hlist continuing after current point
    * @tpos:       the type * to use as a loop cursor.
    * @pos:        the &struct hlist_node to use as a loop cursor.
    * @member:     the name of the hlist_node within the struct.
    */
   #define hlist_for_each_entry_continue(tpos, pos, member)                 \
           for (pos = (pos)->next;                                          \
                pos &&                                                      \
                   ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
                pos = pos->next)
   
   /**
    * hlist_for_each_entry_from - iterate over a hlist continuing from current point
    * @tpos:       the type * to use as a loop cursor.
    * @pos:        the &struct hlist_node to use as a loop cursor.
    * @member:     the name of the hlist_node within the struct.
    */
   #define hlist_for_each_entry_from(tpos, pos, member)                     \
           for (; pos &&                                                    \
                   ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
                pos = pos->next)
   
   /**
    * hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry
    * @tpos:       the type * to use as a loop cursor.
    * @pos:        the &struct hlist_node to use as a loop cursor.
    * @n:          another &struct hlist_node to use as temporary storage
    * @head:       the head for your list.
    * @member:     the name of the hlist_node within the struct.
    */
   #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)
   
   #endif

Cache object: 54e84e940ff2aaa35f7e21d43b1e366a