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16ff3f606c
Add more macros used for removing hash table entries. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
379 lines
10 KiB
C
379 lines
10 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef LIST_H
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#define LIST_H
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#include <stddef.h>
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#include "list_types.h"
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/* Are two types/vars the same type (ignoring qualifiers)? */
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#define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
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/**
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* container_of - cast a member of a structure out to the containing structure
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* @ptr: the pointer to the member.
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* @type: the type of the container struct this is embedded in.
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* @member: the name of the member within the struct.
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*
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*/
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#define container_of(ptr, type, member) ({ \
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void *__mptr = (void *)(ptr); \
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_Static_assert(__same_type(*(ptr), ((type *)0)->member) || \
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__same_type(*(ptr), void), \
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"pointer type mismatch in container_of()"); \
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((type *)(__mptr - offsetof(type, member))); })
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#define LIST_POISON1 ((void *) 0x100)
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#define LIST_POISON2 ((void *) 0x122)
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/*
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* Circular 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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/**
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* INIT_LIST_HEAD - Initialize a list_head structure
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* @list: list_head structure to be initialized.
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*
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* Initializes the list_head to point to itself. If it is a list header,
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* the result is an empty list.
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*/
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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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/*
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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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* 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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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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/**
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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(entry);
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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_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_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(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_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_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_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 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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!list_entry_is_head(pos, head, member); \
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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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!list_entry_is_head(pos, head, member); \
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pos = list_prev_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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!list_entry_is_head(pos, head, member); \
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pos = n, n = list_next_entry(n, member))
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/*
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* Double linked lists with a single pointer list head.
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* Mostly useful for hash tables where the two pointer list head is
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* too wasteful.
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* You lose the ability to access the tail in O(1).
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*/
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#define HLIST_HEAD_INIT { .first = NULL }
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#define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL)
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static inline void INIT_HLIST_NODE(struct hlist_node *h)
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{
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h->next = NULL;
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h->pprev = NULL;
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}
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/**
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* hlist_unhashed - Has node been removed from list and reinitialized?
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* @h: Node to be checked
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*
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* Not that not all removal functions will leave a node in unhashed
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* state. For example, hlist_nulls_del_init_rcu() does leave the
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* node in unhashed state, but hlist_nulls_del() does not.
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*/
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static inline int hlist_unhashed(const struct hlist_node *h)
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{
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return !h->pprev;
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}
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static inline void __hlist_del(struct hlist_node *n)
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{
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struct hlist_node *next = n->next;
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struct hlist_node **pprev = n->pprev;
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*pprev = next;
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if (next)
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next->pprev = pprev;
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}
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/**
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* hlist_del - Delete the specified hlist_node from its list
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* @n: Node to delete.
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*
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* Note that this function leaves the node in hashed state. Use
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* hlist_del_init() or similar instead to unhash @n.
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*/
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static inline void hlist_del(struct hlist_node *n)
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{
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__hlist_del(n);
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n->next = LIST_POISON1;
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n->pprev = LIST_POISON2;
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}
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/**
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* hlist_del_init - Delete the specified hlist_node from its list and initialize
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* @n: Node to delete.
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*
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* Note that this function leaves the node in unhashed state.
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*/
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static inline void hlist_del_init(struct hlist_node *n)
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{
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if (!hlist_unhashed(n)) {
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__hlist_del(n);
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INIT_HLIST_NODE(n);
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}
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}
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/**
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* hlist_add_head - add a new entry at the beginning of the hlist
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* @n: new entry to be added
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* @h: hlist 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 hlist_add_head(struct hlist_node *n, struct hlist_head *h)
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{
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struct hlist_node *first = h->first;
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n->next = first;
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if (first)
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first->pprev = &n->next;
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h->first = n;
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n->pprev = &h->first;
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}
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#define hlist_entry(ptr, type, member) container_of(ptr, type, member)
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#define hlist_entry_safe(ptr, type, member) \
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({ typeof(ptr) ____ptr = (ptr); \
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____ptr ? hlist_entry(____ptr, type, member) : NULL; \
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})
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/**
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* hlist_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 hlist_node within the struct.
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*/
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#define hlist_for_each_entry(pos, head, member) \
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for (pos = hlist_entry_safe((head)->first, typeof(*(pos)), member);\
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pos; \
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pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member))
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/**
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* hlist_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: a &struct hlist_node to use as temporary storage
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* @head: the head for your list.
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* @member: the name of the hlist_node within the struct.
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*/
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#define hlist_for_each_entry_safe(pos, n, head, member) \
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for (pos = hlist_entry_safe((head)->first, typeof(*pos), member);\
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pos && ({ n = pos->member.next; 1; }); \
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pos = hlist_entry_safe(n, typeof(*pos), member))
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#endif /* LIST_H */
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