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#ifndef _LINUX_LIST_H

#define _LINUX_LIST_H

#ifdef __KERNEL__

#include <linux/stddef.h>

#include <linux/prefetch.h>

#include <asm/system.h>

/*

 * These are non-NULL pointers that will result in page faults

 * under normal circumstances, used to verify that nobody uses

 * non-initialized list entries.

 */

#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)

#define INIT_LIST_HEAD(ptr) do { \

        (ptr)->next = (ptr); (ptr)->prev = (ptr); \

} while (0)

/*

 * 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);

}

/*

 * 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_rcu(struct list_head * new,

        struct list_head * prev,

        struct list_head * next)

{

        new->next = next;

        new->prev = prev;

        smp_wmb();

        next->prev = new;

        prev->next = new;

}

/**

 * list_add_rcu - add a new entry to rcu-protected list

 * @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_rcu(struct list_head *new, struct list_head *head)

{

        __list_add_rcu(new, head, head->next);

}

/**

 * list_add_tail_rcu - add a new entry to rcu-protected list

 * @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_rcu(struct list_head *new, struct list_head *head)

{

        __list_add_rcu(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_del_rcu - deletes entry from list without re-initialization

 * @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. It is useful for RCU based

 * lockfree traversal.

 *

 * In particular, it means that we can not poison the forward

 * pointers that may still be used for walking the list.

 */

static inline void list_del_rcu(struct list_head *entry)

{

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

        entry->prev = LIST_POISON2;

}

/**

 * 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_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_ checks that no other CPU might be

 * in the process of still modifying either member

 * @head: the list to test.

 */

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 counter.

 * @head:       the head for your list.

 */

#define list_for_each(pos, head) \

        for (pos = (head)->next, prefetch(pos->next); pos != (head); \

                pos = pos->next, prefetch(pos->next))

/**

 * __list_for_each      -       iterate over a list

 * @pos:        the &struct list_head to use as a loop counter.

 * @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 counter.

 * @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, prefetch(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 counter.

 * @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 counter.

 * @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),  \

                     prefetch(pos->member.next))

/**

 * list_for_each_entry_reverse - iterate backwards over list of given type.

 * @pos:        the type * to use as a loop counter.

 * @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),  \

                     prefetch(pos->member.prev))

/**

 * list_for_each_entry_continue -       iterate over list of given type

 *                      continuing after existing point

 * @pos:        the type * to use as a loop counter.

 * @head:       the head for your list.

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

 */

#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),  \

                     prefetch(pos->member.next))

/**

 * 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 counter.

 * @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_rcu    -       iterate over an rcu-protected list

 * @pos:        the &struct list_head to use as a loop counter.

 * @head:       the head for your list.

 */

#define list_for_each_rcu(pos, head) \

        for (pos = (head)->next, prefetch(pos->next); pos != (head); \

                pos = pos->next, ({ smp_read_barrier_depends(); 0;}), prefetch(pos->next))

#define __list_for_each_rcu(pos, head) \

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

                pos = pos->next, ({ smp_read_barrier_depends(); 0;}))

/**

 * list_for_each_safe_rcu       -       iterate over an rcu-protected list safe

 *                                      against removal of list entry

 * @pos:        the &struct list_head to use as a loop counter.

 * @n:          another &struct list_head to use as temporary storage

 * @head:       the head for your list.

 */

#define list_for_each_safe_rcu(pos, n, head) \

        for (pos = (head)->next, n = pos->next; pos != (head); \

                pos = n, ({ smp_read_barrier_depends(); 0;}), n = pos->next)

/**

 * list_for_each_entry_rcu      -       iterate over rcu list of given type

 * @pos:        the type * to use as a loop counter.

 * @head:       the head for your list.

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

 */

#define list_for_each_entry_rcu(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),  \

                     ({ smp_read_barrier_depends(); 0;}),               \

                     prefetch(pos->member.next))

/**

 * list_for_each_continue_rcu   -       iterate over an rcu-protected list

 *                      continuing after existing point.

 * @pos:        the &struct list_head to use as a loop counter.

 * @head:       the head for your list.

 */

#define list_for_each_continue_rcu(pos, head) \

        for ((pos) = (pos)->next, prefetch((pos)->next); (pos) != (head); \

                (pos) = (pos)->next, ({ smp_read_barrier_depends(); 0;}), prefetch((pos)->next))

/*

 * 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) 

#define INIT_HLIST_NODE(ptr) ((ptr)->next = NULL, (ptr)->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;

}

/**

 * hlist_del_rcu - deletes entry from hash list without re-initialization

 * @n: the element to delete from the hash list.

 *

 * Note: list_unhashed() on entry does not return true after this,

 * the entry is in an undefined state. It is useful for RCU based

 * lockfree traversal.

 *

 * In particular, it means that we can not poison the forward

 * pointers that may still be used for walking the hash list.

 */

static inline void hlist_del_rcu(struct hlist_node *n)

{

        __hlist_del(n);

        n->pprev = LIST_POISON2;

}

static __inline__ void hlist_del_init(struct hlist_node *n)

{

        if (n->pprev)  {

                __hlist_del(n);

                INIT_HLIST_NODE(n);

        }

}  

#define hlist_del_rcu_init hlist_del_init

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;

}

static __inline__ void hlist_add_head_rcu(struct hlist_node *n, struct hlist_head *h)

{

        struct hlist_node *first = h->first;

        n->next = first;

        n->pprev = &h->first;

        smp_wmb();

        if (first)

                first->pprev = &n->next;

        h->first = n;

}

/* 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;

        *(next->pprev)  = n;

        n->next         = next;

}

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

/* Cannot easily do prefetch unfortunately */

#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; n = pos ? pos->next : 0, pos; \

             pos = n)

/**

 * hlist_for_each_entry - iterate over list of given type

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

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

 * @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 existing point

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

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

 * @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 existing point

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

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

 * @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 counter.

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

 * @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)

#else

#warning "don't include kernel headers in userspace"

#endif /* __KERNEL__ */

#endif