list_debug.c

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/*
 * Copyright 2006, Red Hat, Inc., Dave Jones
 * Released under the General Public License (GPL).
 *
 * This file contains the linked list implementations for
 * DEBUG_LIST.
 */

#include <linux/export.h>
#include <linux/list.h>
#include <linux/bug.h>
#include <linux/kernel.h>
#include <linux/rculist.h>

/*
 * Insert a new entry between two known consecutive entries.
 *
 * This is only for internal list manipulation where we know
 * the prev/next entries already!
 */

void __list_add(struct list_head *new,
                  struct list_head *prev,
                  struct list_head *next)
{
    WARN(next->prev != prev,
        "list_add corruption. next->prev should be "
        "prev (%p), but was %p. (next=%p).\n",
        prev, next->prev, next);
    WARN(prev->next != next,
        "list_add corruption. prev->next should be "
        "next (%p), but was %p. (prev=%p).\n",
        next, prev->next, prev);
    WARN(new == prev || new == next,
         "list_add double add: new=%p, prev=%p, next=%p.\n",
         new, prev, next);
    next->prev = new;
    new->next = next;
    new->prev = prev;
    prev->next = new;
}
EXPORT_SYMBOL(__list_add);

void __list_del_entry(struct list_head *entry)
{
    struct list_head *prev, *next;

    prev = entry->prev;
    next = entry->next;

    if (WARN(next == LIST_POISON1,
        "list_del corruption, %p->next is LIST_POISON1 (%p)\n",
        entry, LIST_POISON1) ||
        WARN(prev == LIST_POISON2,
        "list_del corruption, %p->prev is LIST_POISON2 (%p)\n",
        entry, LIST_POISON2) ||
        WARN(prev->next != entry,
        "list_del corruption. prev->next should be %p, "
        "but was %p\n", entry, prev->next) ||
        WARN(next->prev != entry,
        "list_del corruption. next->prev should be %p, "
        "but was %p\n", entry, next->prev))
        return;

    __list_del(prev, next);
}
EXPORT_SYMBOL(__list_del_entry);

void list_del(struct list_head *entry)
{
    __list_del_entry(entry);
    entry->next = LIST_POISON1;
    entry->prev = LIST_POISON2;
}
EXPORT_SYMBOL(list_del);

/*
 * RCU variants.
 */
void __list_add_rcu(struct list_head *new,
            struct list_head *prev, struct list_head *next)
{
    WARN(next->prev != prev,
        "list_add_rcu corruption. next->prev should be prev (%p), but was %p. (next=%p).\n",
        prev, next->prev, next);
    WARN(prev->next != next,
        "list_add_rcu corruption. prev->next should be next (%p), but was %p. (prev=%p).\n",
        next, prev->next, prev);
    new->next = next;
    new->prev = prev;
    rcu_assign_pointer(list_next_rcu(prev), new);
    next->prev = new;
}
EXPORT_SYMBOL(__list_add_rcu);