diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /include/linux/idr.h |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'include/linux/idr.h')
-rw-r--r-- | include/linux/idr.h | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/include/linux/idr.h b/include/linux/idr.h new file mode 100644 index 000000000000..ca3b7e462576 --- /dev/null +++ b/include/linux/idr.h | |||
@@ -0,0 +1,78 @@ | |||
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 | #include <linux/types.h> | ||
12 | #include <linux/bitops.h> | ||
13 | |||
14 | #if BITS_PER_LONG == 32 | ||
15 | # define IDR_BITS 5 | ||
16 | # define IDR_FULL 0xfffffffful | ||
17 | /* We can only use two of the bits in the top level because there is | ||
18 | only one possible bit in the top level (5 bits * 7 levels = 35 | ||
19 | bits, but you only use 31 bits in the id). */ | ||
20 | # define TOP_LEVEL_FULL (IDR_FULL >> 30) | ||
21 | #elif BITS_PER_LONG == 64 | ||
22 | # define IDR_BITS 6 | ||
23 | # define IDR_FULL 0xfffffffffffffffful | ||
24 | /* We can only use two of the bits in the top level because there is | ||
25 | only one possible bit in the top level (6 bits * 6 levels = 36 | ||
26 | bits, but you only use 31 bits in the id). */ | ||
27 | # define TOP_LEVEL_FULL (IDR_FULL >> 62) | ||
28 | #else | ||
29 | # error "BITS_PER_LONG is not 32 or 64" | ||
30 | #endif | ||
31 | |||
32 | #define IDR_SIZE (1 << IDR_BITS) | ||
33 | #define IDR_MASK ((1 << IDR_BITS)-1) | ||
34 | |||
35 | #define MAX_ID_SHIFT (sizeof(int)*8 - 1) | ||
36 | #define MAX_ID_BIT (1U << MAX_ID_SHIFT) | ||
37 | #define MAX_ID_MASK (MAX_ID_BIT - 1) | ||
38 | |||
39 | /* Leave the possibility of an incomplete final layer */ | ||
40 | #define MAX_LEVEL (MAX_ID_SHIFT + IDR_BITS - 1) / IDR_BITS | ||
41 | |||
42 | /* Number of id_layer structs to leave in free list */ | ||
43 | #define IDR_FREE_MAX MAX_LEVEL + MAX_LEVEL | ||
44 | |||
45 | struct idr_layer { | ||
46 | unsigned long bitmap; /* A zero bit means "space here" */ | ||
47 | struct idr_layer *ary[1<<IDR_BITS]; | ||
48 | int count; /* When zero, we can release it */ | ||
49 | }; | ||
50 | |||
51 | struct idr { | ||
52 | struct idr_layer *top; | ||
53 | struct idr_layer *id_free; | ||
54 | int layers; | ||
55 | int id_free_cnt; | ||
56 | spinlock_t lock; | ||
57 | }; | ||
58 | |||
59 | #define IDR_INIT(name) \ | ||
60 | { \ | ||
61 | .top = NULL, \ | ||
62 | .id_free = NULL, \ | ||
63 | .layers = 0, \ | ||
64 | .id_free_cnt = 0, \ | ||
65 | .lock = SPIN_LOCK_UNLOCKED, \ | ||
66 | } | ||
67 | #define DEFINE_IDR(name) struct idr name = IDR_INIT(name) | ||
68 | |||
69 | /* | ||
70 | * This is what we export. | ||
71 | */ | ||
72 | |||
73 | void *idr_find(struct idr *idp, int id); | ||
74 | int idr_pre_get(struct idr *idp, unsigned gfp_mask); | ||
75 | int idr_get_new(struct idr *idp, void *ptr, int *id); | ||
76 | int idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id); | ||
77 | void idr_remove(struct idr *idp, int id); | ||
78 | void idr_init(struct idr *idp); | ||