580 lines
17 KiB
C
580 lines
17 KiB
C
#ifndef _LINUX_LIST_H
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#define _LINUX_LIST_H
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#define LIST_POISON1 ((void *) 0x80000000)
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#define LIST_POISON2 ((void *) 0x80001000)
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#define container_of(ptr, type, member) ({ \
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const __typeof__( ((type *)0)->member ) *__mptr = (ptr); \
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(type *)( (char *)__mptr - __builtin_offsetof(type,member) );})
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struct list_head
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{
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struct list_head *next;
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struct list_head *prev;
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};
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/*
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* Simple doubly linked list implementation.
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*
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* Some of the internal functions ("__xxx") are useful when
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* manipulating whole lists rather than single entries, as
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* sometimes we already know the next/prev entries and we can
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* generate better code by using them directly rather than
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* using the generic single-entry routines.
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*/
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#define LIST_HEAD_INIT(name) { &(name), &(name) }
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#define LIST_HEAD(name) \
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struct list_head name = LIST_HEAD_INIT(name)
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static inline void INIT_LIST_HEAD(struct list_head *list)
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{
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list->next = list;
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list->prev = list;
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}
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static inline void __list_add(struct list_head *new,
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struct list_head *prev,
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struct list_head *next)
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{
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next->prev = new;
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new->next = next;
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new->prev = prev;
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prev->next = new;
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}
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/**
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* list_add - add a new entry
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* @new: new entry to be added
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* @head: list head to add it after
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*
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* Insert a new entry after the specified head.
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* This is good for implementing stacks.
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*/
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static inline void list_add(struct list_head *new, struct list_head *head)
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{
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__list_add(new, head, head->next);
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}
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/**
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* list_add_tail - add a new entry
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* @new: new entry to be added
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* @head: list head to add it before
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*
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* Insert a new entry before the specified head.
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* This is useful for implementing queues.
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*/
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static inline void list_add_tail(struct list_head *new, struct list_head *head)
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{
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__list_add(new, head->prev, head);
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}
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/*
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* Delete a list entry by making the prev/next entries
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* point to each other.
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*
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* This is only for internal list manipulation where we know
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* the prev/next entries already!
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*/
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static inline void __list_del(struct list_head * prev, struct list_head * next)
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{
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next->prev = prev;
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prev->next = next;
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}
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/**
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* list_del - deletes entry from list.
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* @entry: the element to delete from the list.
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* Note: list_empty() on entry does not return true after this, the entry is
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* in an undefined state.
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*/
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static inline void __list_del_entry(struct list_head *entry)
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{
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__list_del(entry->prev, entry->next);
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}
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static inline void list_del(struct list_head *entry)
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{
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__list_del(entry->prev, entry->next);
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entry->next = LIST_POISON1;
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entry->prev = LIST_POISON2;
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}
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/**
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* list_replace - replace old entry by new one
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* @old : the element to be replaced
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* @new : the new element to insert
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*
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* If @old was empty, it will be overwritten.
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*/
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static inline void list_replace(struct list_head *old,
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struct list_head *new)
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{
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new->next = old->next;
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new->next->prev = new;
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new->prev = old->prev;
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new->prev->next = new;
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}
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static inline void list_replace_init(struct list_head *old,
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struct list_head *new)
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{
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list_replace(old, new);
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INIT_LIST_HEAD(old);
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}
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/**
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* list_del_init - deletes entry from list and reinitialize it.
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* @entry: the element to delete from the list.
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*/
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static inline void list_del_init(struct list_head *entry)
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{
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__list_del_entry(entry);
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INIT_LIST_HEAD(entry);
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}
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/**
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* list_move - delete from one list and add as another's head
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* @list: the entry to move
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* @head: the head that will precede our entry
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*/
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static inline void list_move(struct list_head *list, struct list_head *head)
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{
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__list_del_entry(list);
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list_add(list, head);
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}
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/**
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* list_move_tail - delete from one list and add as another's tail
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* @list: the entry to move
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* @head: the head that will follow our entry
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*/
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static inline void list_move_tail(struct list_head *list,
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struct list_head *head)
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{
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__list_del_entry(list);
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list_add_tail(list, head);
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}
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/**
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* list_is_last - tests whether @list is the last entry in list @head
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* @list: the entry to test
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* @head: the head of the list
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*/
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static inline int list_is_last(const struct list_head *list,
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const struct list_head *head)
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{
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return list->next == head;
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}
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/**
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* list_empty - tests whether a list is empty
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* @head: the list to test.
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*/
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static inline int list_empty(const struct list_head *head)
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{
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return head->next == head;
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}
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/**
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* list_empty_careful - tests whether a list is empty and not being modified
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* @head: the list to test
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*
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* Description:
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* tests whether a list is empty _and_ checks that no other CPU might be
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* in the process of modifying either member (next or prev)
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*
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* NOTE: using list_empty_careful() without synchronization
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* can only be safe if the only activity that can happen
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* to the list entry is list_del_init(). Eg. it cannot be used
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* if another CPU could re-list_add() it.
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*/
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static inline int list_empty_careful(const struct list_head *head)
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{
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struct list_head *next = head->next;
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return (next == head) && (next == head->prev);
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}
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/**
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* list_rotate_left - rotate the list to the left
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* @head: the head of the list
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*/
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static inline void list_rotate_left(struct list_head *head)
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{
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struct list_head *first;
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if (!list_empty(head)) {
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first = head->next;
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list_move_tail(first, head);
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}
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}
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/**
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* list_is_singular - tests whether a list has just one entry.
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* @head: the list to test.
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*/
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static inline int list_is_singular(const struct list_head *head)
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{
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return !list_empty(head) && (head->next == head->prev);
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}
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static inline void __list_cut_position(struct list_head *list,
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struct list_head *head, struct list_head *entry)
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{
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struct list_head *new_first = entry->next;
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list->next = head->next;
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list->next->prev = list;
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list->prev = entry;
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entry->next = list;
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head->next = new_first;
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new_first->prev = head;
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}
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/**
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* list_cut_position - cut a list into two
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* @list: a new list to add all removed entries
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* @head: a list with entries
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* @entry: an entry within head, could be the head itself
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* and if so we won't cut the list
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*
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* This helper moves the initial part of @head, up to and
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* including @entry, from @head to @list. You should
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* pass on @entry an element you know is on @head. @list
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* should be an empty list or a list you do not care about
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* losing its data.
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*
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*/
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static inline void list_cut_position(struct list_head *list,
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struct list_head *head, struct list_head *entry)
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{
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if (list_empty(head))
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return;
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if (list_is_singular(head) &&
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(head->next != entry && head != entry))
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return;
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if (entry == head)
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INIT_LIST_HEAD(list);
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else
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__list_cut_position(list, head, entry);
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}
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static inline void __list_splice(const struct list_head *list,
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struct list_head *prev,
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struct list_head *next)
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{
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struct list_head *first = list->next;
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struct list_head *last = list->prev;
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first->prev = prev;
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prev->next = first;
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last->next = next;
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next->prev = last;
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}
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/**
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* list_splice - join two lists, this is designed for stacks
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* @list: the new list to add.
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* @head: the place to add it in the first list.
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*/
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static inline void list_splice(const struct list_head *list,
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struct list_head *head)
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{
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if (!list_empty(list))
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__list_splice(list, head, head->next);
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}
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/**
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* list_splice_tail - join two lists, each list being a queue
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* @list: the new list to add.
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* @head: the place to add it in the first list.
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*/
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static inline void list_splice_tail(struct list_head *list,
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struct list_head *head)
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{
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if (!list_empty(list))
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__list_splice(list, head->prev, head);
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}
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/**
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* list_splice_init - join two lists and reinitialise the emptied list.
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* @list: the new list to add.
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* @head: the place to add it in the first list.
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*
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* The list at @list is reinitialised
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*/
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static inline void list_splice_init(struct list_head *list,
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struct list_head *head)
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{
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if (!list_empty(list)) {
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__list_splice(list, head, head->next);
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INIT_LIST_HEAD(list);
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}
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}
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/**
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* list_splice_tail_init - join two lists and reinitialise the emptied list
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* @list: the new list to add.
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* @head: the place to add it in the first list.
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*
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* Each of the lists is a queue.
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* The list at @list is reinitialised
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*/
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static inline void list_splice_tail_init(struct list_head *list,
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struct list_head *head)
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{
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if (!list_empty(list)) {
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__list_splice(list, head->prev, head);
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INIT_LIST_HEAD(list);
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}
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}
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/**
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* list_entry - get the struct for this entry
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* @ptr: the &struct list_head pointer.
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* @type: the type of the struct this is embedded in.
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* @member: the name of the list_head within the struct.
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*/
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#define list_entry(ptr, type, member) \
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container_of(ptr, type, member)
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/**
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* list_first_entry - get the first element from a list
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* @ptr: the list head to take the element from.
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* @type: the type of the struct this is embedded in.
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* @member: the name of the list_head within the struct.
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*
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* Note, that list is expected to be not empty.
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*/
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#define list_first_entry(ptr, type, member) \
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list_entry((ptr)->next, type, member)
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/**
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* list_last_entry - get the last element from a list
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* @ptr: the list head to take the element from.
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* @type: the type of the struct this is embedded in.
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* @member: the name of the list_head within the struct.
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*
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* Note, that list is expected to be not empty.
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*/
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#define list_last_entry(ptr, type, member) \
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list_entry((ptr)->prev, type, member)
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/**
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* list_first_entry_or_null - get the first element from a list
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* @ptr: the list head to take the element from.
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* @type: the type of the struct this is embedded in.
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* @member: the name of the list_head within the struct.
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*
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* Note that if the list is empty, it returns NULL.
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*/
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#define list_first_entry_or_null(ptr, type, member) \
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(!list_empty(ptr) ? list_first_entry(ptr, type, member) : NULL)
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/**
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* list_next_entry - get the next element in list
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* @pos: the type * to cursor
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* @member: the name of the list_head within the struct.
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*/
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#define list_next_entry(pos, member) \
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list_entry((pos)->member.next, __typeof__(*(pos)), member)
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/**
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* list_prev_entry - get the prev element in list
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* @pos: the type * to cursor
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* @member: the name of the list_head within the struct.
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*/
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#define list_prev_entry(pos, member) \
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list_entry((pos)->member.prev, __typeof__(*(pos)), member)
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/**
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* list_for_each - iterate over a list
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* @pos: the &struct list_head to use as a loop cursor.
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* @head: the head for your list.
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*/
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#define list_for_each(pos, head) \
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for (pos = (head)->next; pos != (head); pos = pos->next)
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/**
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* list_for_each_prev - iterate over a list backwards
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* @pos: the &struct list_head to use as a loop cursor.
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* @head: the head for your list.
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*/
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#define list_for_each_prev(pos, head) \
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for (pos = (head)->prev; pos != (head); pos = pos->prev)
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/**
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* list_for_each_safe - iterate over a list safe against removal of list entry
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* @pos: the &struct list_head to use as a loop cursor.
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* @n: another &struct list_head to use as temporary storage
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* @head: the head for your list.
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*/
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#define list_for_each_safe(pos, n, head) \
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for (pos = (head)->next, n = pos->next; pos != (head); \
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pos = n, n = pos->next)
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/**
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* list_for_each_prev_safe - iterate over a list backwards safe against removal of list entry
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* @pos: the &struct list_head to use as a loop cursor.
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* @n: another &struct list_head to use as temporary storage
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* @head: the head for your list.
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*/
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#define list_for_each_prev_safe(pos, n, head) \
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for (pos = (head)->prev, n = pos->prev; \
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pos != (head); \
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pos = n, n = pos->prev)
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/**
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* list_for_each_entry - iterate over list of given type
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* @pos: the type * to use as a loop cursor.
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* @head: the head for your list.
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* @member: the name of the list_head within the struct.
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*/
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#define list_for_each_entry(pos, head, member) \
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for (pos = list_first_entry(head, __typeof__(*pos), member); \
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&pos->member != (head); \
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pos = list_next_entry(pos, member))
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/**
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* list_for_each_entry_reverse - iterate backwards over list of given type.
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* @pos: the type * to use as a loop cursor.
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* @head: the head for your list.
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* @member: the name of the list_head within the struct.
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*/
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#define list_for_each_entry_reverse(pos, head, member) \
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for (pos = list_last_entry(head, __typeof__(*pos), member); \
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&pos->member != (head); \
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pos = list_prev_entry(pos, member))
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/**
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* list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue()
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* @pos: the type * to use as a start point
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* @head: the head of the list
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* @member: the name of the list_head within the struct.
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*
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* Prepares a pos entry for use as a start point in list_for_each_entry_continue().
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*/
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#define list_prepare_entry(pos, head, member) \
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((pos) ? : list_entry(head, __typeof__(*pos), member))
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/**
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* list_for_each_entry_continue - continue iteration over list of given type
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* @pos: the type * to use as a loop cursor.
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* @head: the head for your list.
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* @member: the name of the list_head within the struct.
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*
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* Continue to iterate over list of given type, continuing after
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* the current position.
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*/
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#define list_for_each_entry_continue(pos, head, member) \
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for (pos = list_next_entry(pos, member); \
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&pos->member != (head); \
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pos = list_next_entry(pos, member))
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/**
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* list_for_each_entry_continue_reverse - iterate backwards from the given point
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* @pos: the type * to use as a loop cursor.
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* @head: the head for your list.
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* @member: the name of the list_head within the struct.
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*
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* Start to iterate over list of given type backwards, continuing after
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* the current position.
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*/
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#define list_for_each_entry_continue_reverse(pos, head, member) \
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for (pos = list_prev_entry(pos, member); \
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&pos->member != (head); \
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pos = list_prev_entry(pos, member))
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/**
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* list_for_each_entry_from - iterate over list of given type from the current point
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* @pos: the type * to use as a loop cursor.
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* @head: the head for your list.
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* @member: the name of the list_head within the struct.
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*
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* Iterate over list of given type, continuing from current position.
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*/
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#define list_for_each_entry_from(pos, head, member) \
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for (; &pos->member != (head); \
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pos = list_next_entry(pos, member))
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/**
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* list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
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* @pos: the type * to use as a loop cursor.
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* @n: another type * to use as temporary storage
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* @head: the head for your list.
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* @member: the name of the list_head within the struct.
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*/
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#define list_for_each_entry_safe(pos, n, head, member) \
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for (pos = list_first_entry(head, __typeof__(*pos), member), \
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n = list_next_entry(pos, member); \
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&pos->member != (head); \
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pos = n, n = list_next_entry(n, member))
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/**
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* list_for_each_entry_safe_continue - continue list iteration safe against removal
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* @pos: the type * to use as a loop cursor.
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* @n: another type * to use as temporary storage
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* @head: the head for your list.
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* @member: the name of the list_head within the struct.
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*
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* Iterate over list of given type, continuing after current point,
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* safe against removal of list entry.
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*/
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#define list_for_each_entry_safe_continue(pos, n, head, member) \
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for (pos = list_next_entry(pos, member), \
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n = list_next_entry(pos, member); \
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&pos->member != (head); \
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pos = n, n = list_next_entry(n, member))
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/**
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* list_for_each_entry_safe_from - iterate over list from current point safe against removal
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* @pos: the type * to use as a loop cursor.
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* @n: another type * to use as temporary storage
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* @head: the head for your list.
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* @member: the name of the list_head within the struct.
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*
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* Iterate over list of given type from current point, safe against
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* removal of list entry.
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*/
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#define list_for_each_entry_safe_from(pos, n, head, member) \
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for (n = list_next_entry(pos, member); \
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&pos->member != (head); \
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pos = n, n = list_next_entry(n, member))
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/**
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* list_for_each_entry_safe_reverse - iterate backwards over list safe against removal
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* @pos: the type * to use as a loop cursor.
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* @n: another type * to use as temporary storage
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* @head: the head for your list.
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* @member: the name of the list_head within the struct.
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*
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* Iterate backwards over list of given type, safe against removal
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* of list entry.
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*/
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#define list_for_each_entry_safe_reverse(pos, n, head, member) \
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for (pos = list_last_entry(head, __typeof__(*pos), member), \
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n = list_prev_entry(pos, member); \
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&pos->member != (head); \
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pos = n, n = list_prev_entry(n, member))
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/**
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* list_safe_reset_next - reset a stale list_for_each_entry_safe loop
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* @pos: the loop cursor used in the list_for_each_entry_safe loop
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* @n: temporary storage used in list_for_each_entry_safe
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* @member: the name of the list_head within the struct.
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*
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* list_safe_reset_next is not safe to use in general if the list may be
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* modified concurrently (eg. the lock is dropped in the loop body). An
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* exception to this is if the cursor element (pos) is pinned in the list,
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* and list_safe_reset_next is called after re-taking the lock and before
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* completing the current iteration of the loop body.
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*/
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#define list_safe_reset_next(pos, n, member) \
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n = list_next_entry(pos, member)
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#endif
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