1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
|
#ifndef _LINUX_LIST_BL_H
#define _LINUX_LIST_BL_H
#include <linux/list.h>
#include <linux/bit_spinlock.h>
/*
* Special version of lists, where head of the list has a lock in the lowest
* bit. This is useful for scalable hash tables without increasing memory
* footprint overhead.
*
* For modification operations, the 0 bit of hlist_bl_head->first
* pointer must be set.
*
* With some small modifications, this can easily be adapted to store several
* arbitrary bits (not just a single lock bit), if the need arises to store
* some fast and compact auxiliary data.
*/
#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
#define LIST_BL_LOCKMASK 1UL
#else
#define LIST_BL_LOCKMASK 0UL
#endif
#ifdef CONFIG_DEBUG_LIST
#define LIST_BL_BUG_ON(x) BUG_ON(x)
#else
#define LIST_BL_BUG_ON(x)
#endif
struct hlist_bl_head {
struct hlist_bl_node *first;
};
struct hlist_bl_node {
struct hlist_bl_node *next, **pprev;
};
#define INIT_HLIST_BL_HEAD(ptr) \
((ptr)->first = NULL)
static inline void INIT_HLIST_BL_NODE(struct hlist_bl_node *h)
{
h->next = NULL;
h->pprev = NULL;
}
#define hlist_bl_entry(ptr, type, member) container_of(ptr,type,member)
static inline int hlist_bl_unhashed(const struct hlist_bl_node *h)
{
return !h->pprev;
}
static inline struct hlist_bl_node *hlist_bl_first(struct hlist_bl_head *h)
{
return (struct hlist_bl_node *)
((unsigned long)h->first & ~LIST_BL_LOCKMASK);
}
static inline void hlist_bl_set_first(struct hlist_bl_head *h,
struct hlist_bl_node *n)
{
LIST_BL_BUG_ON((unsigned long)n & LIST_BL_LOCKMASK);
LIST_BL_BUG_ON(((unsigned long)h->first & LIST_BL_LOCKMASK) !=
LIST_BL_LOCKMASK);
h->first = (struct hlist_bl_node *)((unsigned long)n | LIST_BL_LOCKMASK);
}
static inline int hlist_bl_empty(const struct hlist_bl_head *h)
{
return !((unsigned long)h->first & ~LIST_BL_LOCKMASK);
}
static inline void hlist_bl_add_head(struct hlist_bl_node *n,
struct hlist_bl_head *h)
{
struct hlist_bl_node *first = hlist_bl_first(h);
n->next = first;
if (first)
first->pprev = &n->next;
n->pprev = &h->first;
hlist_bl_set_first(h, n);
}
static inline void __hlist_bl_del(struct hlist_bl_node *n)
{
struct hlist_bl_node *next = n->next;
struct hlist_bl_node **pprev = n->pprev;
LIST_BL_BUG_ON((unsigned long)n & LIST_BL_LOCKMASK);
/* pprev may be `first`, so be careful not to lose the lock bit */
WRITE_ONCE(*pprev,
(struct hlist_bl_node *)
((unsigned long)next |
((unsigned long)*pprev & LIST_BL_LOCKMASK)));
if (next)
next->pprev = pprev;
}
static inline void hlist_bl_del(struct hlist_bl_node *n)
{
__hlist_bl_del(n);
n->next = LIST_POISON1;
n->pprev = LIST_POISON2;
}
static inline void hlist_bl_del_init(struct hlist_bl_node *n)
{
if (!hlist_bl_unhashed(n)) {
__hlist_bl_del(n);
INIT_HLIST_BL_NODE(n);
}
}
static inline void hlist_bl_lock(struct hlist_bl_head *b)
{
bit_spin_lock(0, (unsigned long *)b);
}
static inline void hlist_bl_unlock(struct hlist_bl_head *b)
{
__bit_spin_unlock(0, (unsigned long *)b);
}
static inline bool hlist_bl_is_locked(struct hlist_bl_head *b)
{
return bit_spin_is_locked(0, (unsigned long *)b);
}
/**
* hlist_bl_for_each_entry - iterate over list of given type
* @tpos: the type * to use as a loop cursor.
* @pos: the &struct hlist_node to use as a loop cursor.
* @head: the head for your list.
* @member: the name of the hlist_node within the struct.
*
*/
#define hlist_bl_for_each_entry(tpos, pos, head, member) \
for (pos = hlist_bl_first(head); \
pos && \
({ tpos = hlist_bl_entry(pos, typeof(*tpos), member); 1;}); \
pos = pos->next)
/**
* hlist_bl_for_each_entry_safe - iterate over list of given type safe against removal of list entry
* @tpos: the type * to use as a loop cursor.
* @pos: the &struct hlist_node to use as a loop cursor.
* @n: another &struct hlist_node to use as temporary storage
* @head: the head for your list.
* @member: the name of the hlist_node within the struct.
*/
#define hlist_bl_for_each_entry_safe(tpos, pos, n, head, member) \
for (pos = hlist_bl_first(head); \
pos && ({ n = pos->next; 1; }) && \
({ tpos = hlist_bl_entry(pos, typeof(*tpos), member); 1;}); \
pos = n)
#endif
|
