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
__list_add(struct list_head * new,struct list_head * prev,struct list_head * next)22 void __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 }
42 EXPORT_SYMBOL(__list_add);
43
__list_del_entry(struct list_head * entry)44 void __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 }
67 EXPORT_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 */
list_del(struct list_head * entry)75 void list_del(struct list_head *entry)
76 {
77 __list_del_entry(entry);
78 entry->next = LIST_POISON1;
79 entry->prev = LIST_POISON2;
80 }
81 EXPORT_SYMBOL(list_del);
82
83 /*
84 * RCU variants.
85 */
__list_add_rcu(struct list_head * new,struct list_head * prev,struct list_head * next)86 void __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 }
100 EXPORT_SYMBOL(__list_add_rcu);
101