测试本地代码高亮

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测试本地代码高亮，效果PHP：

[PHP] 纯文本查看 复制代码

<?php
$mystring = 'abc';
$findme   = 'a';
$pos = strpos($mystring, $findme);

// Note our use of ===.  Simply == would not work as expected
// because the position of 'a' was the 0th (first) character.
if ($pos === false) {
    echo "The string '$findme' was not found in the string '$mystring'";
} else {
    echo "The string '$findme' was found in the string '$mystring'";
    echo " and exists at position $pos";
}
?>

beyes

高亮前文本：

[C++] 纯文本查看 复制代码

#include <stdio.h>
#include <stdlib.h>

#define SAFE_FREE(p) free(p); p = NULL;
int main()
{
    int *p = malloc (sizeof(int));
    *p = 10;

    if (p != NULL)
        SAFE_FREE(p);
    else
        ;

    return (0);
}

高亮后文本

beyes

[C++] 纯文本查看 复制代码

#ifndef _LINUX_LIST_H
#define _LINUX_LIST_H


#ifdef __KERNEL__


#include <linux/stddef.h>
#include <linux/poison.h>
#include <linux/prefetch.h>
#include <asm/system.h>


/*
 * 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);
}


/*
 * 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.
 *
 * The caller must take whatever precautions are necessary
 * (such as holding appropriate locks) to avoid racing
 * with another list-mutation primitive, such as list_add_rcu()
 * or list_del_rcu(), running on this same list.
 * However, it is perfectly legal to run concurrently with
 * the _rcu list-traversal primitives, such as
 * list_for_each_entry_rcu().
 */
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.
 *
 * The caller must take whatever precautions are necessary
 * (such as holding appropriate locks) to avoid racing
 * with another list-mutation primitive, such as list_add_tail_rcu()
 * or list_del_rcu(), running on this same list.
 * However, it is perfectly legal to run concurrently with
 * the _rcu list-traversal primitives, such as
 * list_for_each_entry_rcu().
 */
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.
 */
#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_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.
 *
 * The caller must take whatever precautions are necessary
 * (such as holding appropriate locks) to avoid racing
 * with another list-mutation primitive, such as list_del_rcu()
 * or list_add_rcu(), running on this same list.
 * However, it is perfectly legal to run concurrently with
 * the _rcu list-traversal primitives, such as
 * list_for_each_entry_rcu().
 *
 * Note that the caller is not permitted to immediately free
 * the newly deleted entry.  Instead, either synchronize_rcu()
 * or call_rcu() must be used to defer freeing until an RCU
 * grace period has elapsed.
 */
static inline void list_del_rcu(struct list_head *entry)
{
    __list_del(entry->prev, entry->next);
    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_replace_rcu - replace old entry by new one
 * @old : the element to be replaced
 * @new : the new element to insert
 *
 * The @old entry will be replaced with the @new entry atomically.
 * Note: @old should not be empty.
 */
static inline void list_replace_rcu(struct list_head *old,
                struct list_head *new)
{
    new->next = old->next;
    new->prev = old->prev;
    smp_wmb();
    new->next->prev = new;
    new->prev->next = new;
    old->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_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_splice_init_rcu - splice an RCU-protected list into an existing list.
 * @list:    the RCU-protected list to splice
 * @head:    the place in the list to splice the first list into
 * @sync:    function to sync: synchronize_rcu(), synchronize_sched(), ...
 *
 * @head can be RCU-read traversed concurrently with this function.
 *
 * Note that this function blocks.
 *
 * Important note: the caller must take whatever action is necessary to
 *    prevent any other updates to @head.  In principle, it is possible
 *    to modify the list as soon as sync() begins execution.
 *    If this sort of thing becomes necessary, an alternative version
 *    based on call_rcu() could be created.  But only if -really-
 *    needed -- there is no shortage of RCU API members.
 */
static inline void list_splice_init_rcu(struct list_head *list,
                    struct list_head *head,
                    void (*sync)(void))
{
    struct list_head *first = list->next;
    struct list_head *last = list->prev;
    struct list_head *at = head->next;


    if (list_empty(head))
        return;


    /* "first" and "last" tracking list, so initialize it. */


    INIT_LIST_HEAD(list);


    /*
     * At this point, the list body still points to the source list.
     * Wait for any readers to finish using the list before splicing
     * the list body into the new list.  Any new readers will see
     * an empty list.
     */


    sync();


    /*
     * Readers are finished with the source list, so perform splice.
     * The order is important if the new list is global and accessible
     * to concurrent RCU readers.  Note that RCU readers are not
     * permitted to traverse the prev pointers without excluding
     * this function.
     */


    last->next = at;
    smp_wmb();
    head->next = first;
    first->prev = head;
    at->prev = last;
}


/**
 * 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    -    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_prev_safe - iterate over a list backwards 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_prev_safe(pos, n, head) \\
    for (pos = (head)->prev, n = pos->prev; \\
         prefetch(pos->prev), pos != (head); \\
         pos = n, n = pos->prev)


/**
 * 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))


/**
 * list_for_each_rcu    -    iterate over an rcu-protected list
 * @pos:    the &struct list_head to use as a loop cursor.
 * @head:    the head for your list.
 *
 * This list-traversal primitive may safely run concurrently with
 * the _rcu list-mutation primitives such as list_add_rcu()
 * as long as the traversal is guarded by rcu_read_lock().
 */
#define list_for_each_rcu(pos, head) \\
    for (pos = (head)->next; \\
        prefetch(rcu_dereference(pos)->next), pos != (head); \\
            pos = pos->next)


#define __list_for_each_rcu(pos, head) \\
    for (pos = (head)->next; \\
        rcu_dereference(pos) != (head); \\
            pos = pos->next)


/**
 * list_for_each_safe_rcu
 * @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.
 *
 * Iterate over an rcu-protected list, safe against removal of list entry.
 *
 * This list-traversal primitive may safely run concurrently with
 * the _rcu list-mutation primitives such as list_add_rcu()
 * as long as the traversal is guarded by rcu_read_lock().
 */
#define list_for_each_safe_rcu(pos, n, head) \\
    for (pos = (head)->next; \\
        n = rcu_dereference(pos)->next, pos != (head); \\
        pos = n)


/**
 * list_for_each_entry_rcu    -    iterate over rcu 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.
 *
 * This list-traversal primitive may safely run concurrently with
 * the _rcu list-mutation primitives such as list_add_rcu()
 * as long as the traversal is guarded by rcu_read_lock().
 */
#define list_for_each_entry_rcu(pos, head, member) \\
    for (pos = list_entry((head)->next, typeof(*pos), member); \\
        prefetch(rcu_dereference(pos)->member.next), \\
            &pos->member != (head); \\
        pos = list_entry(pos->member.next, typeof(*pos), member))




/**
 * list_for_each_continue_rcu
 * @pos:    the &struct list_head to use as a loop cursor.
 * @head:    the head for your list.
 *
 * Iterate over an rcu-protected list, continuing after current point.
 *
 * This list-traversal primitive may safely run concurrently with
 * the _rcu list-mutation primitives such as list_add_rcu()
 * as long as the traversal is guarded by rcu_read_lock().
 */
#define list_for_each_continue_rcu(pos, head) \\
    for ((pos) = (pos)->next; \\
        prefetch(rcu_dereference((pos))->next), (pos) != (head); \\
            (pos) = (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)
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;
}


/**
 * 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.
 *
 * The caller must take whatever precautions are necessary
 * (such as holding appropriate locks) to avoid racing
 * with another list-mutation primitive, such as hlist_add_head_rcu()
 * or hlist_del_rcu(), running on this same list.
 * However, it is perfectly legal to run concurrently with
 * the _rcu list-traversal primitives, such as
 * hlist_for_each_entry().
 */
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 (!hlist_unhashed(n)) {
        __hlist_del(n);
        INIT_HLIST_NODE(n);
    }
}


/**
 * hlist_replace_rcu - replace old entry by new one
 * @old : the element to be replaced
 * @new : the new element to insert
 *
 * The @old entry will be replaced with the @new entry atomically.
 */
static inline void hlist_replace_rcu(struct hlist_node *old,
                    struct hlist_node *new)
{
    struct hlist_node *next = old->next;


    new->next = next;
    new->pprev = old->pprev;
    smp_wmb();
    if (next)
        new->next->pprev = &new->next;
    *new->pprev = new;
    old->pprev = LIST_POISON2;
}


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;
}




/**
 * hlist_add_head_rcu
 * @n: the element to add to the hash list.
 * @h: the list to add to.
 *
 * Description:
 * Adds the specified element to the specified hlist,
 * while permitting racing traversals.
 *
 * The caller must take whatever precautions are necessary
 * (such as holding appropriate locks) to avoid racing
 * with another list-mutation primitive, such as hlist_add_head_rcu()
 * or hlist_del_rcu(), running on this same list.
 * However, it is perfectly legal to run concurrently with
 * the _rcu list-traversal primitives, such as
 * hlist_for_each_entry_rcu(), used to prevent memory-consistency
 * problems on Alpha CPUs.  Regardless of the type of CPU, the
 * list-traversal primitive must be guarded by rcu_read_lock().
 */
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;
    n->next = next;
    next->pprev = &n->next;


    if(next->next)
        next->next->pprev  = &next->next;
}


/**
 * hlist_add_before_rcu
 * @n: the new element to add to the hash list.
 * @next: the existing element to add the new element before.
 *
 * Description:
 * Adds the specified element to the specified hlist
 * before the specified node while permitting racing traversals.
 *
 * The caller must take whatever precautions are necessary
 * (such as holding appropriate locks) to avoid racing
 * with another list-mutation primitive, such as hlist_add_head_rcu()
 * or hlist_del_rcu(), running on this same list.
 * However, it is perfectly legal to run concurrently with
 * the _rcu list-traversal primitives, such as
 * hlist_for_each_entry_rcu(), used to prevent memory-consistency
 * problems on Alpha CPUs.
 */
static inline void hlist_add_before_rcu(struct hlist_node *n,
                    struct hlist_node *next)
{
    n->pprev = next->pprev;
    n->next = next;
    smp_wmb();
    next->pprev = &n->next;
    *(n->pprev) = n;
}


/**
 * hlist_add_after_rcu
 * @prev: the existing element to add the new element after.
 * @n: the new element to add to the hash list.
 *
 * Description:
 * Adds the specified element to the specified hlist
 * after the specified node while permitting racing traversals.
 *
 * The caller must take whatever precautions are necessary
 * (such as holding appropriate locks) to avoid racing
 * with another list-mutation primitive, such as hlist_add_head_rcu()
 * or hlist_del_rcu(), running on this same list.
 * However, it is perfectly legal to run concurrently with
 * the _rcu list-traversal primitives, such as
 * hlist_for_each_entry_rcu(), used to prevent memory-consistency
 * problems on Alpha CPUs.
 */
static inline void hlist_add_after_rcu(struct hlist_node *prev,
                       struct hlist_node *n)
{
    n->next = prev->next;
    n->pprev = &prev->next;
    smp_wmb();
    prev->next = n;
    if (n->next)
        n->next->pprev = &n->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)


/**
 * hlist_for_each_entry_rcu - iterate over rcu 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.
 *
 * This list-traversal primitive may safely run concurrently with
 * the _rcu list-mutation primitives such as hlist_add_head_rcu()
 * as long as the traversal is guarded by rcu_read_lock().
 */
#define hlist_for_each_entry_rcu(tpos, pos, head, member)         \\
    for (pos = (head)->first;                     \\
         rcu_dereference(pos) && ({ prefetch(pos->next); 1;}) &&     \\
        ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \\
         pos = pos->next)


#else
#warning "don't include kernel headers in userspace"
#endif /* __KERNEL__ */
#endif