mirror of
git://sourceware.org/git/lvm2.git
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115 lines
2.4 KiB
C
115 lines
2.4 KiB
C
/* stolen from the Linux kernel. */
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#ifndef _LVM_LIST_H
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#define _LVM_LIST_H
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#ifdef __KERNEL__
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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 = { &name, &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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* Insert a new entry after the specified head..
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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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* Insert a new entry at the tail
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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,
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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(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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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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/*
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* Splice in "list" into "head"
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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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struct list_head *first = list->next;
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if (first != list) {
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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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#define list_entry(ptr, type, member) \
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((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member)))
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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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#endif /* __KERNEL__ */
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#endif
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