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#ifndef _LINUX_LIST_H |
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#define _LINUX_LIST_H |
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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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struct list_head { |
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struct list_head *next, *prev; |
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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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#define INIT_LIST_HEAD(ptr) do { \ |
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(ptr)->next = (ptr); (ptr)->prev = (ptr); \ |
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} while (0) |
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/* |
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* Insert a new entry between two known consecutive entries. |
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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 |
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__list_add(struct list_head *new, |
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struct list_head *prev, 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 |
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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 |
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__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(struct list_head *entry) |
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{ |
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__list_del(entry->prev, entry->next); |
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entry->next = (void *) 0; |
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entry->prev = (void *) 0; |
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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->prev, entry->next); |
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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 |
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list_move(struct list_head *list, struct list_head *head) |
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{ |
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__list_del(list->prev, list->next); |
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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 |
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list_move_tail(struct list_head *list, struct list_head *head) |
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{ |
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__list_del(list->prev, list->next); |
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list_add_tail(list, head); |
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} |
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/** |
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* list_empty - test 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(struct list_head *head) |
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{ |
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return head->next == head; |
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} |
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static inline void |
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__list_splice(struct list_head *list, struct list_head *head) |
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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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struct list_head *at = head->next; |
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first->prev = head; |
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head->next = first; |
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last->next = at; |
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at->prev = last; |
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} |
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/** |
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* list_splice - join two lists |
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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 |
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list_splice(struct list_head *list, struct list_head *head) |
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{ |
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if (!list_empty(list)) |
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__list_splice(list, 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 |
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list_splice_init(struct list_head *list, struct list_head *head) |
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{ |
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if (!list_empty(list)) { |
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__list_splice(list, 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_struct within the struct. |
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*/ |
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#define list_entry(ptr, type, member) \ |
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((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member))) |
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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 counter. |
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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_entry_safe - iterate over list of given type safe against |
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* removal of list entry |
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* @pos: the type * to use as a loop counter. |
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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_struct 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_entry((head)->next, typeof(*pos), member), \ |
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n = list_entry(pos->member.next, typeof(*pos), member); \ |
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&pos->member != (head); \ |
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pos = n, n = list_entry(n->member.next, typeof(*n), member)) |
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#endif |