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
18static 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 */
48static 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 */