linux内核list.h

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