1/*
2 * Copyright 2006, Red Hat, Inc., Dave Jones
3 * Released under the General Public License (GPL).
4 *
5 * This file contains the linked list implementations for
6 * DEBUG_LIST.
7 */
8
9#include <linux/export.h>
10#include <linux/list.h>
11#include <linux/bug.h>
12#include <linux/kernel.h>
13#include <linux/rculist.h>
14
15/*
16 * Insert a new entry between two known consecutive entries.
17 *
18 * This is only for internal list manipulation where we know
19 * the prev/next entries already!
20 */
21
22void __list_add(struct list_head *new,
23			      struct list_head *prev,
24			      struct list_head *next)
25{
26	WARN(next->prev != prev,
27		"list_add corruption. next->prev should be "
28		"prev (%p), but was %p. (next=%p).\n",
29		prev, next->prev, next);
30	WARN(prev->next != next,
31		"list_add corruption. prev->next should be "
32		"next (%p), but was %p. (prev=%p).\n",
33		next, prev->next, prev);
34	WARN(new == prev || new == next,
35	     "list_add double add: new=%p, prev=%p, next=%p.\n",
36	     new, prev, next);
37	next->prev = new;
38	new->next = next;
39	new->prev = prev;
40	prev->next = new;
41}
42EXPORT_SYMBOL(__list_add);
43
44void __list_del_entry(struct list_head *entry)
45{
46	struct list_head *prev, *next;
47
48	prev = entry->prev;
49	next = entry->next;
50
51	if (WARN(next == LIST_POISON1,
52		"list_del corruption, %p->next is LIST_POISON1 (%p)\n",
53		entry, LIST_POISON1) ||
54	    WARN(prev == LIST_POISON2,
55		"list_del corruption, %p->prev is LIST_POISON2 (%p)\n",
56		entry, LIST_POISON2) ||
57	    WARN(prev->next != entry,
58		"list_del corruption. prev->next should be %p, "
59		"but was %p\n", entry, prev->next) ||
60	    WARN(next->prev != entry,
61		"list_del corruption. next->prev should be %p, "
62		"but was %p\n", entry, next->prev))
63		return;
64
65	__list_del(prev, next);
66}
67EXPORT_SYMBOL(__list_del_entry);
68
69/**
70 * list_del - deletes entry from list.
71 * @entry: the element to delete from the list.
72 * Note: list_empty on entry does not return true after this, the entry is
73 * in an undefined state.
74 */
75void list_del(struct list_head *entry)
76{
77	__list_del_entry(entry);
78	entry->next = LIST_POISON1;
79	entry->prev = LIST_POISON2;
80}
81EXPORT_SYMBOL(list_del);
82
83/*
84 * RCU variants.
85 */
86void __list_add_rcu(struct list_head *new,
87		    struct list_head *prev, struct list_head *next)
88{
89	WARN(next->prev != prev,
90		"list_add_rcu corruption. next->prev should be prev (%p), but was %p. (next=%p).\n",
91		prev, next->prev, next);
92	WARN(prev->next != next,
93		"list_add_rcu corruption. prev->next should be next (%p), but was %p. (prev=%p).\n",
94		next, prev->next, prev);
95	new->next = next;
96	new->prev = prev;
97	rcu_assign_pointer(list_next_rcu(prev), new);
98	next->prev = new;
99}
100EXPORT_SYMBOL(__list_add_rcu);
101