#ifndef _LINUX_LIST_H

#define _LINUX_LIST_H

#include <stddef.h>

#define prefetch(x)	((void)0)

#define LIST_POISON1	((void *)0x12345678)

#define LIST_POISON2	((void *)0x87654321)

/*

 * 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!

 */

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;

}

/**

 * 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.

 */

static inline void list_del(struct list_head *entry)

{

	__list_del(entry->prev, entry->next);

	entry->next = LIST_POISON1;

	entry->prev = LIST_POISON2;

}

/**

 * 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->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);

}

/**

 * 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_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_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);	\

	     prefetch(pos->member.prev), &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 (; 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))

/*

 * 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).

 */

struct hlist_head {

	struct hlist_node *first;

};

struct hlist_node {

	struct hlist_node *next, **pprev;

};

#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;

}

#define hlist_entry(ptr, type, member) container_of(ptr,type,member)

#define hlist_for_each(pos, head) \

	for (pos = (head)->first; pos && ({ prefetch(pos->next); 1; }); \

	     pos = pos->next)

#define hlist_for_each_safe(pos, n, head) \

	for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \

	     pos = n)

/**

 * hlist_for_each_entry	- iterate over list of given type

 * @tpos:	the type * to use as a loop cursor.

 * @pos:	the &struct hlist_node 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(tpos, pos, head, member)			 \

	for (pos = (head)->first;					 \

	     pos && ({ prefetch(pos->next); 1;}) &&			 \

		({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \

	     pos = pos->next)

/**

 * hlist_for_each_entry_continue - iterate over a hlist continuing after current point

 * @tpos:	the type * to use as a loop cursor.

 * @pos:	the &struct hlist_node to use as a loop cursor.

 * @member:	the name of the hlist_node within the struct.

 */

#define hlist_for_each_entry_continue(tpos, pos, member)		 \

	for (pos = (pos)->next;						 \

	     pos && ({ prefetch(pos->next); 1;}) &&			 \

		({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \

	     pos = pos->next)

/**

 * hlist_for_each_entry_from - iterate over a hlist continuing from current point

 * @tpos:	the type * to use as a loop cursor.

 * @pos:	the &struct hlist_node to use as a loop cursor.

 * @member:	the name of the hlist_node within the struct.

 */

#define hlist_for_each_entry_from(tpos, pos, member)			 \

	for (; pos && ({ prefetch(pos->next); 1;}) &&			 \

		({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \

	     pos = pos->next)

/**

 * hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry

 * @tpos:	the type * to use as a loop cursor.

 * @pos:	the &struct hlist_node 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(tpos, pos, n, head, member) 		 \

	for (pos = (head)->first;					 \

	     pos && ({ n = pos->next; 1; }) && 				 \

		({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \

	     pos = n)

#endif