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0eb71a9d N |
1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | /* | |
3 | * Resizable, Scalable, Concurrent Hash Table | |
4 | * | |
5 | * Simple structures that might be needed in include | |
6 | * files. | |
7 | */ | |
8 | ||
9 | #ifndef _LINUX_RHASHTABLE_TYPES_H | |
10 | #define _LINUX_RHASHTABLE_TYPES_H | |
11 | ||
12 | #include <linux/atomic.h> | |
13 | #include <linux/compiler.h> | |
14 | #include <linux/mutex.h> | |
15 | #include <linux/workqueue.h> | |
16 | ||
17 | struct rhash_head { | |
18 | struct rhash_head __rcu *next; | |
19 | }; | |
20 | ||
21 | struct rhlist_head { | |
22 | struct rhash_head rhead; | |
23 | struct rhlist_head __rcu *next; | |
24 | }; | |
25 | ||
26 | struct bucket_table; | |
27 | ||
28 | /** | |
29 | * struct rhashtable_compare_arg - Key for the function rhashtable_compare | |
30 | * @ht: Hash table | |
31 | * @key: Key to compare against | |
32 | */ | |
33 | struct rhashtable_compare_arg { | |
34 | struct rhashtable *ht; | |
35 | const void *key; | |
36 | }; | |
37 | ||
38 | typedef u32 (*rht_hashfn_t)(const void *data, u32 len, u32 seed); | |
39 | typedef u32 (*rht_obj_hashfn_t)(const void *data, u32 len, u32 seed); | |
40 | typedef int (*rht_obj_cmpfn_t)(struct rhashtable_compare_arg *arg, | |
41 | const void *obj); | |
42 | ||
43 | /** | |
44 | * struct rhashtable_params - Hash table construction parameters | |
45 | * @nelem_hint: Hint on number of elements, should be 75% of desired size | |
46 | * @key_len: Length of key | |
47 | * @key_offset: Offset of key in struct to be hashed | |
48 | * @head_offset: Offset of rhash_head in struct to be hashed | |
49 | * @max_size: Maximum size while expanding | |
50 | * @min_size: Minimum size while shrinking | |
0eb71a9d | 51 | * @automatic_shrinking: Enable automatic shrinking of tables |
0eb71a9d N |
52 | * @hashfn: Hash function (default: jhash2 if !(key_len % 4), or jhash) |
53 | * @obj_hashfn: Function to hash object | |
54 | * @obj_cmpfn: Function to compare key with object | |
55 | */ | |
56 | struct rhashtable_params { | |
57 | u16 nelem_hint; | |
58 | u16 key_len; | |
59 | u16 key_offset; | |
60 | u16 head_offset; | |
61 | unsigned int max_size; | |
62 | u16 min_size; | |
63 | bool automatic_shrinking; | |
0eb71a9d N |
64 | rht_hashfn_t hashfn; |
65 | rht_obj_hashfn_t obj_hashfn; | |
66 | rht_obj_cmpfn_t obj_cmpfn; | |
67 | }; | |
68 | ||
69 | /** | |
70 | * struct rhashtable - Hash table handle | |
71 | * @tbl: Bucket table | |
72 | * @key_len: Key length for hashfn | |
73 | * @max_elems: Maximum number of elements in table | |
74 | * @p: Configuration parameters | |
75 | * @rhlist: True if this is an rhltable | |
76 | * @run_work: Deferred worker to expand/shrink asynchronously | |
77 | * @mutex: Mutex to protect current/future table swapping | |
78 | * @lock: Spin lock to protect walker list | |
79 | * @nelems: Number of elements in table | |
80 | */ | |
81 | struct rhashtable { | |
82 | struct bucket_table __rcu *tbl; | |
83 | unsigned int key_len; | |
84 | unsigned int max_elems; | |
85 | struct rhashtable_params p; | |
86 | bool rhlist; | |
87 | struct work_struct run_work; | |
88 | struct mutex mutex; | |
89 | spinlock_t lock; | |
90 | atomic_t nelems; | |
91 | }; | |
92 | ||
93 | /** | |
94 | * struct rhltable - Hash table with duplicate objects in a list | |
95 | * @ht: Underlying rhtable | |
96 | */ | |
97 | struct rhltable { | |
98 | struct rhashtable ht; | |
99 | }; | |
100 | ||
101 | /** | |
102 | * struct rhashtable_walker - Hash table walker | |
103 | * @list: List entry on list of walkers | |
104 | * @tbl: The table that we were walking over | |
105 | */ | |
106 | struct rhashtable_walker { | |
107 | struct list_head list; | |
108 | struct bucket_table *tbl; | |
109 | }; | |
110 | ||
111 | /** | |
112 | * struct rhashtable_iter - Hash table iterator | |
113 | * @ht: Table to iterate through | |
114 | * @p: Current pointer | |
115 | * @list: Current hash list pointer | |
116 | * @walker: Associated rhashtable walker | |
117 | * @slot: Current slot | |
118 | * @skip: Number of entries to skip in slot | |
119 | */ | |
120 | struct rhashtable_iter { | |
121 | struct rhashtable *ht; | |
122 | struct rhash_head *p; | |
123 | struct rhlist_head *list; | |
124 | struct rhashtable_walker walker; | |
125 | unsigned int slot; | |
126 | unsigned int skip; | |
127 | bool end_of_table; | |
128 | }; | |
129 | ||
130 | int rhashtable_init(struct rhashtable *ht, | |
131 | const struct rhashtable_params *params); | |
132 | int rhltable_init(struct rhltable *hlt, | |
133 | const struct rhashtable_params *params); | |
134 | ||
135 | #endif /* _LINUX_RHASHTABLE_TYPES_H */ |