blob: dca733ef67503845267c0a4f4f616190908d1af7 (
plain) (
blame)
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
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
|
/* SPDX-License-Identifier: GPL-2.0-or-later */
/* Private definitions for the generic associative array implementation.
*
* See Documentation/core-api/assoc_array.rst for information.
*
* Copyright (C) 2013 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#ifndef _LINUX_ASSOC_ARRAY_PRIV_H
#define _LINUX_ASSOC_ARRAY_PRIV_H
#ifdef CONFIG_ASSOCIATIVE_ARRAY
#include <linux/assoc_array.h>
#define ASSOC_ARRAY_FAN_OUT 16 /* Number of slots per node */
#define ASSOC_ARRAY_FAN_MASK (ASSOC_ARRAY_FAN_OUT - 1)
#define ASSOC_ARRAY_LEVEL_STEP (ilog2(ASSOC_ARRAY_FAN_OUT))
#define ASSOC_ARRAY_LEVEL_STEP_MASK (ASSOC_ARRAY_LEVEL_STEP - 1)
#define ASSOC_ARRAY_KEY_CHUNK_MASK (ASSOC_ARRAY_KEY_CHUNK_SIZE - 1)
#define ASSOC_ARRAY_KEY_CHUNK_SHIFT (ilog2(BITS_PER_LONG))
/*
* Undefined type representing a pointer with type information in the bottom
* two bits.
*/
struct assoc_array_ptr;
/*
* An N-way node in the tree.
*
* Each slot contains one of four things:
*
* (1) Nothing (NULL).
*
* (2) A leaf object (pointer types 0).
*
* (3) A next-level node (pointer type 1, subtype 0).
*
* (4) A shortcut (pointer type 1, subtype 1).
*
* The tree is optimised for search-by-ID, but permits reasonable iteration
* also.
*
* The tree is navigated by constructing an index key consisting of an array of
* segments, where each segment is ilog2(ASSOC_ARRAY_FAN_OUT) bits in size.
*
* The segments correspond to levels of the tree (the first segment is used at
* level 0, the second at level 1, etc.).
*/
struct assoc_array_node {
struct assoc_array_ptr *back_pointer;
u8 parent_slot;
struct assoc_array_ptr *slots[ASSOC_ARRAY_FAN_OUT];
unsigned long nr_leaves_on_branch;
};
/*
* A shortcut through the index space out to where a collection of nodes/leaves
* with the same IDs live.
*/
struct assoc_array_shortcut {
struct assoc_array_ptr *back_pointer;
int parent_slot;
int skip_to_level;
struct assoc_array_ptr *next_node;
unsigned long index_key[];
};
/*
* Preallocation cache.
*/
struct assoc_array_edit {
struct rcu_head rcu;
struct assoc_array *array;
const struct assoc_array_ops *ops;
const struct assoc_array_ops *ops_for_excised_subtree;
struct assoc_array_ptr *leaf;
struct assoc_array_ptr **leaf_p;
struct assoc_array_ptr *dead_leaf;
struct assoc_array_ptr *new_meta[3];
struct assoc_array_ptr *excised_meta[1];
struct assoc_array_ptr *excised_subtree;
struct assoc_array_ptr **set_backpointers[ASSOC_ARRAY_FAN_OUT];
struct assoc_array_ptr *set_backpointers_to;
struct assoc_array_node *adjust_count_on;
long adjust_count_by;
struct {
struct assoc_array_ptr **ptr;
struct assoc_array_ptr *to;
} set[2];
struct {
u8 *p;
u8 to;
} set_parent_slot[1];
u8 segment_cache[ASSOC_ARRAY_FAN_OUT + 1];
};
/*
* Internal tree member pointers are marked in the bottom one or two bits to
* indicate what type they are so that we don't have to look behind every
* pointer to see what it points to.
*
* We provide functions to test type annotations and to create and translate
* the annotated pointers.
*/
#define ASSOC_ARRAY_PTR_TYPE_MASK 0x1UL
#define ASSOC_ARRAY_PTR_LEAF_TYPE 0x0UL /* Points to leaf (or nowhere) */
#define ASSOC_ARRAY_PTR_META_TYPE 0x1UL /* Points to node or shortcut */
#define ASSOC_ARRAY_PTR_SUBTYPE_MASK 0x2UL
#define ASSOC_ARRAY_PTR_NODE_SUBTYPE 0x0UL
#define ASSOC_ARRAY_PTR_SHORTCUT_SUBTYPE 0x2UL
static inline bool assoc_array_ptr_is_meta(const struct assoc_array_ptr *x)
{
return (unsigned long)x & ASSOC_ARRAY_PTR_TYPE_MASK;
}
static inline bool assoc_array_ptr_is_leaf(const struct assoc_array_ptr *x)
{
return !assoc_array_ptr_is_meta(x);
}
static inline bool assoc_array_ptr_is_shortcut(const struct assoc_array_ptr *x)
{
return (unsigned long)x & ASSOC_ARRAY_PTR_SUBTYPE_MASK;
}
static inline bool assoc_array_ptr_is_node(const struct assoc_array_ptr *x)
{
return !assoc_array_ptr_is_shortcut(x);
}
static inline void *assoc_array_ptr_to_leaf(const struct assoc_array_ptr *x)
{
return (void *)((unsigned long)x & ~ASSOC_ARRAY_PTR_TYPE_MASK);
}
static inline
unsigned long __assoc_array_ptr_to_meta(const struct assoc_array_ptr *x)
{
return (unsigned long)x &
~(ASSOC_ARRAY_PTR_SUBTYPE_MASK | ASSOC_ARRAY_PTR_TYPE_MASK);
}
static inline
struct assoc_array_node *assoc_array_ptr_to_node(const struct assoc_array_ptr *x)
{
return (struct assoc_array_node *)__assoc_array_ptr_to_meta(x);
}
static inline
struct assoc_array_shortcut *assoc_array_ptr_to_shortcut(const struct assoc_array_ptr *x)
{
return (struct assoc_array_shortcut *)__assoc_array_ptr_to_meta(x);
}
static inline
struct assoc_array_ptr *__assoc_array_x_to_ptr(const void *p, unsigned long t)
{
return (struct assoc_array_ptr *)((unsigned long)p | t);
}
static inline
struct assoc_array_ptr *assoc_array_leaf_to_ptr(const void *p)
{
return __assoc_array_x_to_ptr(p, ASSOC_ARRAY_PTR_LEAF_TYPE);
}
static inline
struct assoc_array_ptr *assoc_array_node_to_ptr(const struct assoc_array_node *p)
{
return __assoc_array_x_to_ptr(
p, ASSOC_ARRAY_PTR_META_TYPE | ASSOC_ARRAY_PTR_NODE_SUBTYPE);
}
static inline
struct assoc_array_ptr *assoc_array_shortcut_to_ptr(const struct assoc_array_shortcut *p)
{
return __assoc_array_x_to_ptr(
p, ASSOC_ARRAY_PTR_META_TYPE | ASSOC_ARRAY_PTR_SHORTCUT_SUBTYPE);
}
#endif /* CONFIG_ASSOCIATIVE_ARRAY */
#endif /* _LINUX_ASSOC_ARRAY_PRIV_H */
|
