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1ddf752f42
Import a few more functions from the kernel's list.h into our imported copy. Signed-off-by: Zach Brown <zab@versity.com>
354 lines
11 KiB
C
354 lines
11 KiB
C
/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
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* vim:expandtab:shiftwidth=8:tabstop=8:
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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* yanked from the linux kernel..
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*/
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#ifndef _LIST_H_
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#define _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 __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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* 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 __list_add_rcu(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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new->next = next;
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new->prev = prev;
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next->prev = new;
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prev->next = new;
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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(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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/**
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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 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 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(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_is_head - tests whether @list is the 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_head(const struct list_head *list, const struct list_head *head)
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{
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return list == 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(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 __list_splice(struct list_head *list,
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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 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 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);
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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 - iterate over a list
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* @pos: the &struct list_head to use as a loop counter.
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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 counter.
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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 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_entry_is_head - test if the entry points to the head of the list
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* @pos: the type * to 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_entry_is_head(pos, head, member) \
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(&pos->member == (head))
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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 counter.
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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(pos, head, member) \
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for (pos = list_entry((head)->next, typeof(*pos), member); \
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&pos->member != (head); \
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pos = list_entry(pos->member.next, typeof(*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_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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/**
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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_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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!list_entry_is_head(pos, head, member); \
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pos = n, n = list_prev_entry(n, member))
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#endif
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