mirror of
https://github.com/kdave/btrfs-progs
synced 2024-12-26 08:02:21 +00:00
419 lines
12 KiB
C
419 lines
12 KiB
C
#ifndef _LINUX_LIST_H
|
|
#define _LINUX_LIST_H
|
|
|
|
#define LIST_POISON1 ((void *) 0x00100100)
|
|
#define LIST_POISON2 ((void *) 0x00200200)
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
|
|
struct list_head {
|
|
struct list_head *next, *prev;
|
|
};
|
|
|
|
#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_LIST
|
|
static 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;
|
|
}
|
|
#else
|
|
extern 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.
|
|
*/
|
|
#ifndef CONFIG_DEBUG_LIST
|
|
static inline void list_add(struct list_head *new, struct list_head *head)
|
|
{
|
|
__list_add(new, head, head->next);
|
|
}
|
|
#else
|
|
extern void list_add(struct list_head *new, struct list_head *head);
|
|
#endif
|
|
|
|
|
|
/**
|
|
* 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_LIST
|
|
static inline void list_del(struct list_head *entry)
|
|
{
|
|
__list_del(entry->prev, entry->next);
|
|
entry->next = LIST_POISON1;
|
|
entry->prev = LIST_POISON2;
|
|
}
|
|
#else
|
|
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
|
|
* Note: 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->prev, entry->next);
|
|
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(list->prev, list->next);
|
|
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(list->prev, list->next);
|
|
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);
|
|
}
|
|
|
|
static inline void __list_splice(struct list_head *list,
|
|
struct list_head *head)
|
|
{
|
|
struct list_head *first = list->next;
|
|
struct list_head *last = list->prev;
|
|
struct list_head *at = head->next;
|
|
|
|
first->prev = head;
|
|
head->next = first;
|
|
|
|
last->next = at;
|
|
at->prev = last;
|
|
}
|
|
|
|
/**
|
|
* list_splice - join two lists
|
|
* @list: the new list to add.
|
|
* @head: the place to add it in the first list.
|
|
*/
|
|
static inline void list_splice(struct list_head *list, struct list_head *head)
|
|
{
|
|
if (!list_empty(list))
|
|
__list_splice(list, 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);
|
|
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_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; prefetch(pos->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 differs from list_for_each() in that it's the
|
|
* simplest possible list iteration code, no prefetching is done.
|
|
* Use this for code that knows the list to be very short (empty
|
|
* or 1 entry) most of the time.
|
|
*/
|
|
#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; prefetch(pos->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_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); \
|
|
prefetch(pos->member.next), &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); \
|
|
prefetch(pos->member.prev), &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); \
|
|
prefetch(pos->member.next), &pos->member != (head); \
|
|
pos = list_entry(pos->member.next, 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 (; prefetch(pos->member.next), &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
|
|
* @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
|
|
* @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
|
|
* @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))
|
|
|
|
#endif
|