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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * include/linux/idr.h | |
3 | * | |
4 | * 2002-10-18 written by Jim Houston jim.houston@ccur.com | |
5 | * Copyright (C) 2002 by Concurrent Computer Corporation | |
6 | * Distributed under the GNU GPL license version 2. | |
7 | * | |
8 | * Small id to pointer translation service avoiding fixed sized | |
9 | * tables. | |
10 | */ | |
f668ab1a LT |
11 | |
12 | #ifndef __IDR_H__ | |
13 | #define __IDR_H__ | |
14 | ||
1da177e4 LT |
15 | #include <linux/types.h> |
16 | #include <linux/bitops.h> | |
199f0ca5 | 17 | #include <linux/init.h> |
2027d1ab | 18 | #include <linux/rcupdate.h> |
1da177e4 LT |
19 | |
20 | #if BITS_PER_LONG == 32 | |
21 | # define IDR_BITS 5 | |
22 | # define IDR_FULL 0xfffffffful | |
23 | /* We can only use two of the bits in the top level because there is | |
24 | only one possible bit in the top level (5 bits * 7 levels = 35 | |
25 | bits, but you only use 31 bits in the id). */ | |
26 | # define TOP_LEVEL_FULL (IDR_FULL >> 30) | |
27 | #elif BITS_PER_LONG == 64 | |
28 | # define IDR_BITS 6 | |
29 | # define IDR_FULL 0xfffffffffffffffful | |
30 | /* We can only use two of the bits in the top level because there is | |
31 | only one possible bit in the top level (6 bits * 6 levels = 36 | |
32 | bits, but you only use 31 bits in the id). */ | |
33 | # define TOP_LEVEL_FULL (IDR_FULL >> 62) | |
34 | #else | |
35 | # error "BITS_PER_LONG is not 32 or 64" | |
36 | #endif | |
37 | ||
38 | #define IDR_SIZE (1 << IDR_BITS) | |
39 | #define IDR_MASK ((1 << IDR_BITS)-1) | |
40 | ||
125c4c70 FW |
41 | #define MAX_IDR_SHIFT (sizeof(int)*8 - 1) |
42 | #define MAX_IDR_BIT (1U << MAX_IDR_SHIFT) | |
43 | #define MAX_IDR_MASK (MAX_IDR_BIT - 1) | |
1da177e4 LT |
44 | |
45 | /* Leave the possibility of an incomplete final layer */ | |
125c4c70 | 46 | #define MAX_IDR_LEVEL ((MAX_IDR_SHIFT + IDR_BITS - 1) / IDR_BITS) |
1da177e4 LT |
47 | |
48 | /* Number of id_layer structs to leave in free list */ | |
125c4c70 | 49 | #define MAX_IDR_FREE (MAX_IDR_LEVEL * 2) |
1da177e4 LT |
50 | |
51 | struct idr_layer { | |
4106ecaf | 52 | unsigned long bitmap; /* A zero bit means "space here" */ |
d2c2486b | 53 | struct idr_layer __rcu *ary[1<<IDR_BITS]; |
4106ecaf TH |
54 | int count; /* When zero, we can release it */ |
55 | int layer; /* distance from leaf */ | |
56 | struct rcu_head rcu_head; | |
1da177e4 LT |
57 | }; |
58 | ||
59 | struct idr { | |
4106ecaf TH |
60 | struct idr_layer __rcu *top; |
61 | struct idr_layer *id_free; | |
62 | int layers; /* only valid w/o concurrent changes */ | |
63 | int id_free_cnt; | |
64 | spinlock_t lock; | |
1da177e4 LT |
65 | }; |
66 | ||
4106ecaf TH |
67 | #define IDR_INIT(name) \ |
68 | { \ | |
69 | .lock = __SPIN_LOCK_UNLOCKED(name.lock), \ | |
1da177e4 LT |
70 | } |
71 | #define DEFINE_IDR(name) struct idr name = IDR_INIT(name) | |
72 | ||
944ca05c ND |
73 | /* Actions to be taken after a call to _idr_sub_alloc */ |
74 | #define IDR_NEED_TO_GROW -2 | |
75 | #define IDR_NOMORE_SPACE -3 | |
76 | ||
77 | #define _idr_rc_to_errno(rc) ((rc) == -1 ? -EAGAIN : -ENOSPC) | |
78 | ||
f9c46d6e | 79 | /** |
56083ab1 | 80 | * DOC: idr sync |
f9c46d6e ND |
81 | * idr synchronization (stolen from radix-tree.h) |
82 | * | |
83 | * idr_find() is able to be called locklessly, using RCU. The caller must | |
84 | * ensure calls to this function are made within rcu_read_lock() regions. | |
85 | * Other readers (lock-free or otherwise) and modifications may be running | |
86 | * concurrently. | |
87 | * | |
88 | * It is still required that the caller manage the synchronization and | |
89 | * lifetimes of the items. So if RCU lock-free lookups are used, typically | |
90 | * this would mean that the items have their own locks, or are amenable to | |
91 | * lock-free access; and that the items are freed by RCU (or only freed after | |
92 | * having been deleted from the idr tree *and* a synchronize_rcu() grace | |
93 | * period). | |
94 | */ | |
95 | ||
1da177e4 LT |
96 | /* |
97 | * This is what we export. | |
98 | */ | |
99 | ||
100 | void *idr_find(struct idr *idp, int id); | |
fd4f2df2 | 101 | int idr_pre_get(struct idr *idp, gfp_t gfp_mask); |
1da177e4 LT |
102 | int idr_get_new(struct idr *idp, void *ptr, int *id); |
103 | int idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id); | |
96d7fa42 KH |
104 | int idr_for_each(struct idr *idp, |
105 | int (*fn)(int id, void *p, void *data), void *data); | |
38460b48 | 106 | void *idr_get_next(struct idr *idp, int *nextid); |
5806f07c | 107 | void *idr_replace(struct idr *idp, void *ptr, int id); |
1da177e4 | 108 | void idr_remove(struct idr *idp, int id); |
8d3b3591 | 109 | void idr_destroy(struct idr *idp); |
1da177e4 | 110 | void idr_init(struct idr *idp); |
f668ab1a | 111 | |
fe6e24ec TH |
112 | void __idr_remove_all(struct idr *idp); /* don't use */ |
113 | ||
114 | /** | |
115 | * idr_remove_all - remove all ids from the given idr tree | |
116 | * @idp: idr handle | |
117 | * | |
118 | * If you're trying to destroy @idp, calling idr_destroy() is enough. | |
119 | * This is going away. Don't use. | |
120 | */ | |
121 | static inline void __deprecated idr_remove_all(struct idr *idp) | |
122 | { | |
123 | __idr_remove_all(idp); | |
124 | } | |
72dba584 TH |
125 | |
126 | /* | |
127 | * IDA - IDR based id allocator, use when translation from id to | |
128 | * pointer isn't necessary. | |
ed9f524a NK |
129 | * |
130 | * IDA_BITMAP_LONGS is calculated to be one less to accommodate | |
131 | * ida_bitmap->nr_busy so that the whole struct fits in 128 bytes. | |
72dba584 TH |
132 | */ |
133 | #define IDA_CHUNK_SIZE 128 /* 128 bytes per chunk */ | |
ed9f524a NK |
134 | #define IDA_BITMAP_LONGS (IDA_CHUNK_SIZE / sizeof(long) - 1) |
135 | #define IDA_BITMAP_BITS (IDA_BITMAP_LONGS * sizeof(long) * 8) | |
72dba584 TH |
136 | |
137 | struct ida_bitmap { | |
138 | long nr_busy; | |
139 | unsigned long bitmap[IDA_BITMAP_LONGS]; | |
140 | }; | |
141 | ||
142 | struct ida { | |
143 | struct idr idr; | |
144 | struct ida_bitmap *free_bitmap; | |
145 | }; | |
146 | ||
eece09ec | 147 | #define IDA_INIT(name) { .idr = IDR_INIT((name).idr), .free_bitmap = NULL, } |
72dba584 TH |
148 | #define DEFINE_IDA(name) struct ida name = IDA_INIT(name) |
149 | ||
150 | int ida_pre_get(struct ida *ida, gfp_t gfp_mask); | |
151 | int ida_get_new_above(struct ida *ida, int starting_id, int *p_id); | |
152 | int ida_get_new(struct ida *ida, int *p_id); | |
153 | void ida_remove(struct ida *ida, int id); | |
154 | void ida_destroy(struct ida *ida); | |
155 | void ida_init(struct ida *ida); | |
156 | ||
88eca020 RR |
157 | int ida_simple_get(struct ida *ida, unsigned int start, unsigned int end, |
158 | gfp_t gfp_mask); | |
159 | void ida_simple_remove(struct ida *ida, unsigned int id); | |
160 | ||
199f0ca5 AM |
161 | void __init idr_init_cache(void); |
162 | ||
9749f30f PR |
163 | /** |
164 | * idr_for_each_entry - iterate over an idr's elements of a given type | |
165 | * @idp: idr handle | |
166 | * @entry: the type * to use as cursor | |
167 | * @id: id entry's key | |
168 | */ | |
169 | #define idr_for_each_entry(idp, entry, id) \ | |
170 | for (id = 0, entry = (typeof(entry))idr_get_next((idp), &(id)); \ | |
171 | entry != NULL; \ | |
172 | ++id, entry = (typeof(entry))idr_get_next((idp), &(id))) | |
173 | ||
f668ab1a | 174 | #endif /* __IDR_H__ */ |