Line data Source code
1 : /*
2 : * Statically sized hash table implementation
3 : * (C) 2012 Sasha Levin <levinsasha928@gmail.com>
4 : */
5 :
6 : #ifndef _LINUX_HASHTABLE_H
7 : #define _LINUX_HASHTABLE_H
8 :
9 : #include <linux/list.h>
10 : #include <linux/types.h>
11 : #include <linux/kernel.h>
12 : #include <linux/hash.h>
13 : #include <linux/rculist.h>
14 :
15 : #define DEFINE_HASHTABLE(name, bits) \
16 : struct hlist_head name[1 << (bits)] = \
17 : { [0 ... ((1 << (bits)) - 1)] = HLIST_HEAD_INIT }
18 :
19 : #define DECLARE_HASHTABLE(name, bits) \
20 : struct hlist_head name[1 << (bits)]
21 :
22 : #define HASH_SIZE(name) (ARRAY_SIZE(name))
23 : #define HASH_BITS(name) ilog2(HASH_SIZE(name))
24 :
25 : /* Use hash_32 when possible to allow for fast 32bit hashing in 64bit kernels. */
26 : #define hash_min(val, bits) \
27 : (sizeof(val) <= 4 ? hash_32(val, bits) : hash_long(val, bits))
28 :
29 : static inline void __hash_init(struct hlist_head *ht, unsigned int sz)
30 : {
31 : unsigned int i;
32 :
33 0 : for (i = 0; i < sz; i++)
34 0 : INIT_HLIST_HEAD(&ht[i]);
35 : }
36 :
37 : /**
38 : * hash_init - initialize a hash table
39 : * @hashtable: hashtable to be initialized
40 : *
41 : * Calculates the size of the hashtable from the given parameter, otherwise
42 : * same as hash_init_size.
43 : *
44 : * This has to be a macro since HASH_BITS() will not work on pointers since
45 : * it calculates the size during preprocessing.
46 : */
47 : #define hash_init(hashtable) __hash_init(hashtable, HASH_SIZE(hashtable))
48 :
49 : /**
50 : * hash_add - add an object to a hashtable
51 : * @hashtable: hashtable to add to
52 : * @node: the &struct hlist_node of the object to be added
53 : * @key: the key of the object to be added
54 : */
55 : #define hash_add(hashtable, node, key) \
56 : hlist_add_head(node, &hashtable[hash_min(key, HASH_BITS(hashtable))])
57 :
58 : /**
59 : * hash_add_rcu - add an object to a rcu enabled hashtable
60 : * @hashtable: hashtable to add to
61 : * @node: the &struct hlist_node of the object to be added
62 : * @key: the key of the object to be added
63 : */
64 : #define hash_add_rcu(hashtable, node, key) \
65 : hlist_add_head_rcu(node, &hashtable[hash_min(key, HASH_BITS(hashtable))])
66 :
67 : /**
68 : * hash_hashed - check whether an object is in any hashtable
69 : * @node: the &struct hlist_node of the object to be checked
70 : */
71 : static inline bool hash_hashed(struct hlist_node *node)
72 : {
73 : return !hlist_unhashed(node);
74 : }
75 :
76 : static inline bool __hash_empty(struct hlist_head *ht, unsigned int sz)
77 : {
78 : unsigned int i;
79 :
80 : for (i = 0; i < sz; i++)
81 : if (!hlist_empty(&ht[i]))
82 : return false;
83 :
84 : return true;
85 : }
86 :
87 : /**
88 : * hash_empty - check whether a hashtable is empty
89 : * @hashtable: hashtable to check
90 : *
91 : * This has to be a macro since HASH_BITS() will not work on pointers since
92 : * it calculates the size during preprocessing.
93 : */
94 : #define hash_empty(hashtable) __hash_empty(hashtable, HASH_SIZE(hashtable))
95 :
96 : /**
97 : * hash_del - remove an object from a hashtable
98 : * @node: &struct hlist_node of the object to remove
99 : */
100 : static inline void hash_del(struct hlist_node *node)
101 : {
102 : hlist_del_init(node);
103 : }
104 :
105 : /**
106 : * hash_del_rcu - remove an object from a rcu enabled hashtable
107 : * @node: &struct hlist_node of the object to remove
108 : */
109 : static inline void hash_del_rcu(struct hlist_node *node)
110 : {
111 : hlist_del_init_rcu(node);
112 : }
113 :
114 : /**
115 : * hash_for_each - iterate over a hashtable
116 : * @name: hashtable to iterate
117 : * @bkt: integer to use as bucket loop cursor
118 : * @obj: the type * to use as a loop cursor for each entry
119 : * @member: the name of the hlist_node within the struct
120 : */
121 : #define hash_for_each(name, bkt, obj, member) \
122 : for ((bkt) = 0, obj = NULL; obj == NULL && (bkt) < HASH_SIZE(name);\
123 : (bkt)++)\
124 : hlist_for_each_entry(obj, &name[bkt], member)
125 :
126 : /**
127 : * hash_for_each_rcu - iterate over a rcu enabled hashtable
128 : * @name: hashtable to iterate
129 : * @bkt: integer to use as bucket loop cursor
130 : * @obj: the type * to use as a loop cursor for each entry
131 : * @member: the name of the hlist_node within the struct
132 : */
133 : #define hash_for_each_rcu(name, bkt, obj, member) \
134 : for ((bkt) = 0, obj = NULL; obj == NULL && (bkt) < HASH_SIZE(name);\
135 : (bkt)++)\
136 : hlist_for_each_entry_rcu(obj, &name[bkt], member)
137 :
138 : /**
139 : * hash_for_each_safe - iterate over a hashtable safe against removal of
140 : * hash entry
141 : * @name: hashtable to iterate
142 : * @bkt: integer to use as bucket loop cursor
143 : * @tmp: a &struct used for temporary storage
144 : * @obj: the type * to use as a loop cursor for each entry
145 : * @member: the name of the hlist_node within the struct
146 : */
147 : #define hash_for_each_safe(name, bkt, tmp, obj, member) \
148 : for ((bkt) = 0, obj = NULL; obj == NULL && (bkt) < HASH_SIZE(name);\
149 : (bkt)++)\
150 : hlist_for_each_entry_safe(obj, tmp, &name[bkt], member)
151 :
152 : /**
153 : * hash_for_each_possible - iterate over all possible objects hashing to the
154 : * same bucket
155 : * @name: hashtable to iterate
156 : * @obj: the type * to use as a loop cursor for each entry
157 : * @member: the name of the hlist_node within the struct
158 : * @key: the key of the objects to iterate over
159 : */
160 : #define hash_for_each_possible(name, obj, member, key) \
161 : hlist_for_each_entry(obj, &name[hash_min(key, HASH_BITS(name))], member)
162 :
163 : /**
164 : * hash_for_each_possible_rcu - iterate over all possible objects hashing to the
165 : * same bucket in an rcu enabled hashtable
166 : * in a rcu enabled hashtable
167 : * @name: hashtable to iterate
168 : * @obj: the type * to use as a loop cursor for each entry
169 : * @member: the name of the hlist_node within the struct
170 : * @key: the key of the objects to iterate over
171 : */
172 : #define hash_for_each_possible_rcu(name, obj, member, key) \
173 : hlist_for_each_entry_rcu(obj, &name[hash_min(key, HASH_BITS(name))],\
174 : member)
175 :
176 : /**
177 : * hash_for_each_possible_rcu_notrace - iterate over all possible objects hashing
178 : * to the same bucket in an rcu enabled hashtable in a rcu enabled hashtable
179 : * @name: hashtable to iterate
180 : * @obj: the type * to use as a loop cursor for each entry
181 : * @member: the name of the hlist_node within the struct
182 : * @key: the key of the objects to iterate over
183 : *
184 : * This is the same as hash_for_each_possible_rcu() except that it does
185 : * not do any RCU debugging or tracing.
186 : */
187 : #define hash_for_each_possible_rcu_notrace(name, obj, member, key) \
188 : hlist_for_each_entry_rcu_notrace(obj, \
189 : &name[hash_min(key, HASH_BITS(name))], member)
190 :
191 : /**
192 : * hash_for_each_possible_safe - iterate over all possible objects hashing to the
193 : * same bucket safe against removals
194 : * @name: hashtable to iterate
195 : * @obj: the type * to use as a loop cursor for each entry
196 : * @tmp: a &struct used for temporary storage
197 : * @member: the name of the hlist_node within the struct
198 : * @key: the key of the objects to iterate over
199 : */
200 : #define hash_for_each_possible_safe(name, obj, tmp, member, key) \
201 : hlist_for_each_entry_safe(obj, tmp,\
202 : &name[hash_min(key, HASH_BITS(name))], member)
203 :
204 :
205 : #endif
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