1 /* SPDX-License-Identifier: GPL-2.0-only */
2 #ifndef HASHTABLE_H
3 #define HASHTABLE_H
4
5 #include "array_size.h"
6 #include "list.h"
7
8 #define HASH_SIZE(name) (ARRAY_SIZE(name))
9
10 #define HASHTABLE_DECLARE(name, size) struct hlist_head name[size]
11
12 #define HASHTABLE_DEFINE(name, size) \
13 HASHTABLE_DECLARE(name, size) = \
14 { [0 ... ((size) - 1)] = HLIST_HEAD_INIT }
15
16 #define hash_head(table, key) (&(table)[(key) % HASH_SIZE(table)])
17
__hash_init(struct hlist_head * ht,unsigned int sz)18 static inline void __hash_init(struct hlist_head *ht, unsigned int sz)
19 {
20 unsigned int i;
21
22 for (i = 0; i < sz; i++)
23 INIT_HLIST_HEAD(&ht[i]);
24 }
25
26 /**
27 * hash_init - initialize a hash table
28 * @table: hashtable to be initialized
29 *
30 * This has to be a macro since HASH_SIZE() will not work on pointers since
31 * it calculates the size during preprocessing.
32 */
33 #define hash_init(table) __hash_init(table, HASH_SIZE(table))
34
35 /**
36 * hash_add - add an object to a hashtable
37 * @table: hashtable to add to
38 * @node: the &struct hlist_node of the object to be added
39 * @key: the key of the object to be added
40 */
41 #define hash_add(table, node, key) \
42 hlist_add_head(node, hash_head(table, key))
43
44 /**
45 * hash_del - remove an object from a hashtable
46 * @node: &struct hlist_node of the object to remove
47 */
hash_del(struct hlist_node * node)48 static inline void hash_del(struct hlist_node *node)
49 {
50 hlist_del_init(node);
51 }
52
53 /**
54 * hash_for_each - iterate over a hashtable
55 * @table: hashtable to iterate
56 * @obj: the type * to use as a loop cursor for each entry
57 * @member: the name of the hlist_node within the struct
58 */
59 #define hash_for_each(table, obj, member) \
60 for (int _bkt = 0; _bkt < HASH_SIZE(table); _bkt++) \
61 hlist_for_each_entry(obj, &table[_bkt], member)
62
63 /**
64 * hash_for_each_safe - iterate over a hashtable safe against removal of
65 * hash entry
66 * @table: hashtable to iterate
67 * @obj: the type * to use as a loop cursor for each entry
68 * @tmp: a &struct hlist_node used for temporary storage
69 * @member: the name of the hlist_node within the struct
70 */
71 #define hash_for_each_safe(table, obj, tmp, member) \
72 for (int _bkt = 0; _bkt < HASH_SIZE(table); _bkt++) \
73 hlist_for_each_entry_safe(obj, tmp, &table[_bkt], member)
74
75 /**
76 * hash_for_each_possible - iterate over all possible objects hashing to the
77 * same bucket
78 * @table: hashtable to iterate
79 * @obj: the type * to use as a loop cursor for each entry
80 * @member: the name of the hlist_node within the struct
81 * @key: the key of the objects to iterate over
82 */
83 #define hash_for_each_possible(table, obj, member, key) \
84 hlist_for_each_entry(obj, hash_head(table, key), member)
85
86 /**
87 * hash_for_each_possible_safe - iterate over all possible objects hashing to the
88 * same bucket safe against removals
89 * @table: hashtable to iterate
90 * @obj: the type * to use as a loop cursor for each entry
91 * @tmp: a &struct hlist_node used for temporary storage
92 * @member: the name of the hlist_node within the struct
93 * @key: the key of the objects to iterate over
94 */
95 #define hash_for_each_possible_safe(table, obj, tmp, member, key) \
96 hlist_for_each_entry_safe(obj, tmp, hash_head(table, key), member)
97
98 #endif /* HASHTABLE_H */
99