staging: usbip: userspace: add new list API

#ifndef _LIST_H

#define _LIST_H

/* Stripped down implementation of linked list taken

 * from the Linux Kernel.

 */

/*

 * 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);

}

/*

 * 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;

}

#define POISON_POINTER_DELTA 0

#define LIST_POISON1  ((void *) 0x00100100 + POISON_POINTER_DELTA)

#define LIST_POISON2  ((void *) 0x00200200 + POISON_POINTER_DELTA)

/**

 * 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_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;

}

/**

 * 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; pos != (head); pos = pos->next)

/**

 * 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)

#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)

/**

 * container_of - cast a member of a structure out to the containing structure

 * @ptr:	the pointer to the member.

 * @type:	the type of the container struct this is embedded in.

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

 *

 */

#define container_of(ptr, type, member) ({			\

	const typeof( ((type *)0)->member ) *__mptr = (ptr);	\

	(type *)( (char *)__mptr - offsetof(type,member) );})

#endif