Root/
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 | */ |
11 | |
12 | #ifndef __IDR_H__ |
13 | #define __IDR_H__ |
14 | |
15 | #include <linux/types.h> |
16 | #include <linux/bitops.h> |
17 | #include <linux/init.h> |
18 | #include <linux/rcupdate.h> |
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 | |
41 | #define MAX_ID_SHIFT (sizeof(int)*8 - 1) |
42 | #define MAX_ID_BIT (1U << MAX_ID_SHIFT) |
43 | #define MAX_ID_MASK (MAX_ID_BIT - 1) |
44 | |
45 | /* Leave the possibility of an incomplete final layer */ |
46 | #define MAX_LEVEL (MAX_ID_SHIFT + IDR_BITS - 1) / IDR_BITS |
47 | |
48 | /* Number of id_layer structs to leave in free list */ |
49 | #define IDR_FREE_MAX MAX_LEVEL + MAX_LEVEL |
50 | |
51 | struct idr_layer { |
52 | unsigned long bitmap; /* A zero bit means "space here" */ |
53 | struct idr_layer *ary[1<<IDR_BITS]; |
54 | int count; /* When zero, we can release it */ |
55 | int layer; /* distance from leaf */ |
56 | struct rcu_head rcu_head; |
57 | }; |
58 | |
59 | struct idr { |
60 | struct idr_layer *top; |
61 | struct idr_layer *id_free; |
62 | int layers; /* only valid without concurrent changes */ |
63 | int id_free_cnt; |
64 | spinlock_t lock; |
65 | }; |
66 | |
67 | #define IDR_INIT(name) \ |
68 | { \ |
69 | .top = NULL, \ |
70 | .id_free = NULL, \ |
71 | .layers = 0, \ |
72 | .id_free_cnt = 0, \ |
73 | .lock = __SPIN_LOCK_UNLOCKED(name.lock), \ |
74 | } |
75 | #define DEFINE_IDR(name) struct idr name = IDR_INIT(name) |
76 | |
77 | /* Actions to be taken after a call to _idr_sub_alloc */ |
78 | #define IDR_NEED_TO_GROW -2 |
79 | #define IDR_NOMORE_SPACE -3 |
80 | |
81 | #define _idr_rc_to_errno(rc) ((rc) == -1 ? -EAGAIN : -ENOSPC) |
82 | |
83 | /** |
84 | * idr synchronization (stolen from radix-tree.h) |
85 | * |
86 | * idr_find() is able to be called locklessly, using RCU. The caller must |
87 | * ensure calls to this function are made within rcu_read_lock() regions. |
88 | * Other readers (lock-free or otherwise) and modifications may be running |
89 | * concurrently. |
90 | * |
91 | * It is still required that the caller manage the synchronization and |
92 | * lifetimes of the items. So if RCU lock-free lookups are used, typically |
93 | * this would mean that the items have their own locks, or are amenable to |
94 | * lock-free access; and that the items are freed by RCU (or only freed after |
95 | * having been deleted from the idr tree *and* a synchronize_rcu() grace |
96 | * period). |
97 | */ |
98 | |
99 | /* |
100 | * This is what we export. |
101 | */ |
102 | |
103 | void *idr_find(struct idr *idp, int id); |
104 | int idr_pre_get(struct idr *idp, gfp_t gfp_mask); |
105 | int idr_get_new(struct idr *idp, void *ptr, int *id); |
106 | int idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id); |
107 | int idr_for_each(struct idr *idp, |
108 | int (*fn)(int id, void *p, void *data), void *data); |
109 | void *idr_get_next(struct idr *idp, int *nextid); |
110 | void *idr_replace(struct idr *idp, void *ptr, int id); |
111 | void idr_remove(struct idr *idp, int id); |
112 | void idr_remove_all(struct idr *idp); |
113 | void idr_destroy(struct idr *idp); |
114 | void idr_init(struct idr *idp); |
115 | |
116 | |
117 | /* |
118 | * IDA - IDR based id allocator, use when translation from id to |
119 | * pointer isn't necessary. |
120 | */ |
121 | #define IDA_CHUNK_SIZE 128 /* 128 bytes per chunk */ |
122 | #define IDA_BITMAP_LONGS (128 / sizeof(long) - 1) |
123 | #define IDA_BITMAP_BITS (IDA_BITMAP_LONGS * sizeof(long) * 8) |
124 | |
125 | struct ida_bitmap { |
126 | long nr_busy; |
127 | unsigned long bitmap[IDA_BITMAP_LONGS]; |
128 | }; |
129 | |
130 | struct ida { |
131 | struct idr idr; |
132 | struct ida_bitmap *free_bitmap; |
133 | }; |
134 | |
135 | #define IDA_INIT(name) { .idr = IDR_INIT(name), .free_bitmap = NULL, } |
136 | #define DEFINE_IDA(name) struct ida name = IDA_INIT(name) |
137 | |
138 | int ida_pre_get(struct ida *ida, gfp_t gfp_mask); |
139 | int ida_get_new_above(struct ida *ida, int starting_id, int *p_id); |
140 | int ida_get_new(struct ida *ida, int *p_id); |
141 | void ida_remove(struct ida *ida, int id); |
142 | void ida_destroy(struct ida *ida); |
143 | void ida_init(struct ida *ida); |
144 | |
145 | void __init idr_init_cache(void); |
146 | |
147 | #endif /* __IDR_H__ */ |
148 |
Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master
Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9