/*
   * 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)

  {

  	if (CHECK_DATA_CORRUPTION(next->prev != prev,

  			"list_add corruption. next->prev should be prev (%px), but was %px. (next=%px).
  ",

  			prev, next->prev, next) ||
  	    CHECK_DATA_CORRUPTION(prev->next != next,

  			"list_add corruption. prev->next should be next (%px), but was %px. (prev=%px).
  ",

  			next, prev->next, prev) ||
  	    CHECK_DATA_CORRUPTION(new == prev || new == next,

  			"list_add double add: new=%px, prev=%px, next=%px.
  ",

  			new, prev, next))
  		return false;

  	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;

  	if (CHECK_DATA_CORRUPTION(next == LIST_POISON1,

  			"list_del corruption, %px->next is LIST_POISON1 (%px)
  ",

  			entry, LIST_POISON1) ||
  	    CHECK_DATA_CORRUPTION(prev == LIST_POISON2,

  			"list_del corruption, %px->prev is LIST_POISON2 (%px)
  ",

  			entry, LIST_POISON2) ||
  	    CHECK_DATA_CORRUPTION(prev->next != entry,

  			"list_del corruption. prev->next should be %px, but was %px
  ",

  			entry, prev->next) ||
  	    CHECK_DATA_CORRUPTION(next->prev != entry,

  			"list_del corruption. next->prev should be %px, but was %px
  ",

  			entry, next->prev))
  		return false;

  	return true;

  }

  EXPORT_SYMBOL(__list_del_entry_valid);