/*
   * Copyright 2006, Red Hat, Inc., Dave Jones
   * Released under the General Public License (GPL).
   *

   * This file contains the linked list validation for DEBUG_LIST.

   */

  #include <linux/export.h>

  #include <linux/list.h>

  #include <linux/bug.h>

  #include <linux/kernel.h>

  #include <linux/rculist.h>

  
  /*

   * Check that the data structures for the list manipulations are reasonably
   * valid. Failures here indicate memory corruption (and possibly an exploit
   * attempt).

   */

  bool __list_add_valid(struct list_head *new, struct list_head *prev,
  		      struct list_head *next)

  {

  	CHECK_DATA_CORRUPTION(next->prev != prev,
  		"list_add corruption. next->prev should be prev (%p), but was %p. (next=%p).
  ",
  		prev, next->prev, next);
  	CHECK_DATA_CORRUPTION(prev->next != next,
  		"list_add corruption. prev->next should be next (%p), but was %p. (prev=%p).
  ",
  		next, prev->next, prev);
  	CHECK_DATA_CORRUPTION(new == prev || new == next,
  		"list_add double add: new=%p, prev=%p, next=%p.
  ",
  		new, prev, next);

  	return true;

  }

  EXPORT_SYMBOL(__list_add_valid);

  bool __list_del_entry_valid(struct list_head *entry)

  {
  	struct list_head *prev, *next;
  
  	prev = entry->prev;
  	next = entry->next;

  	CHECK_DATA_CORRUPTION(next == LIST_POISON1,
  		"list_del corruption, %p->next is LIST_POISON1 (%p)
  ",
  		entry, LIST_POISON1);
  	CHECK_DATA_CORRUPTION(prev == LIST_POISON2,
  		"list_del corruption, %p->prev is LIST_POISON2 (%p)
  ",
  		entry, LIST_POISON2);
  	CHECK_DATA_CORRUPTION(prev->next != entry,
  		"list_del corruption. prev->next should be %p, but was %p
  ",
  		entry, prev->next);
  	CHECK_DATA_CORRUPTION(next->prev != entry,
  		"list_del corruption. next->prev should be %p, but was %p
  ",
  		entry, next->prev);

  	return true;

  }

  EXPORT_SYMBOL(__list_del_entry_valid);