1
2#ifndef _LINUX_LIST_NULLS_H
3#define _LINUX_LIST_NULLS_H
4
5#include <linux/poison.h>
6#include <linux/const.h>
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21struct hlist_nulls_head {
22 struct hlist_nulls_node *first;
23};
24
25struct hlist_nulls_node {
26 struct hlist_nulls_node *next, **pprev;
27};
28#define NULLS_MARKER(value) (1UL | (((long)value) << 1))
29#define INIT_HLIST_NULLS_HEAD(ptr, nulls) \
30 ((ptr)->first = (struct hlist_nulls_node *) NULLS_MARKER(nulls))
31
32#define hlist_nulls_entry(ptr, type, member) container_of(ptr,type,member)
33
34#define hlist_nulls_entry_safe(ptr, type, member) \
35 ({ typeof(ptr) ____ptr = (ptr); \
36 !is_a_nulls(____ptr) ? hlist_nulls_entry(____ptr, type, member) : NULL; \
37 })
38
39
40
41
42
43static inline int is_a_nulls(const struct hlist_nulls_node *ptr)
44{
45 return ((unsigned long)ptr & 1);
46}
47
48
49
50
51
52
53
54static inline unsigned long get_nulls_value(const struct hlist_nulls_node *ptr)
55{
56 return ((unsigned long)ptr) >> 1;
57}
58
59static inline int hlist_nulls_unhashed(const struct hlist_nulls_node *h)
60{
61 return !h->pprev;
62}
63
64static inline int hlist_nulls_empty(const struct hlist_nulls_head *h)
65{
66 return is_a_nulls(READ_ONCE(h->first));
67}
68
69static inline void hlist_nulls_add_head(struct hlist_nulls_node *n,
70 struct hlist_nulls_head *h)
71{
72 struct hlist_nulls_node *first = h->first;
73
74 n->next = first;
75 n->pprev = &h->first;
76 h->first = n;
77 if (!is_a_nulls(first))
78 first->pprev = &n->next;
79}
80
81static inline void __hlist_nulls_del(struct hlist_nulls_node *n)
82{
83 struct hlist_nulls_node *next = n->next;
84 struct hlist_nulls_node **pprev = n->pprev;
85
86 WRITE_ONCE(*pprev, next);
87 if (!is_a_nulls(next))
88 next->pprev = pprev;
89}
90
91static inline void hlist_nulls_del(struct hlist_nulls_node *n)
92{
93 __hlist_nulls_del(n);
94 n->pprev = LIST_POISON2;
95}
96
97
98
99
100
101
102
103
104
105#define hlist_nulls_for_each_entry(tpos, pos, head, member) \
106 for (pos = (head)->first; \
107 (!is_a_nulls(pos)) && \
108 ({ tpos = hlist_nulls_entry(pos, typeof(*tpos), member); 1;}); \
109 pos = pos->next)
110
111
112
113
114
115
116
117
118#define hlist_nulls_for_each_entry_from(tpos, pos, member) \
119 for (; (!is_a_nulls(pos)) && \
120 ({ tpos = hlist_nulls_entry(pos, typeof(*tpos), member); 1;}); \
121 pos = pos->next)
122
123#endif
124