Rev 6082 | Rev 6336 | Go to most recent revision | Only display areas with differences | Regard whitespace | Details | Blame | Last modification | View Log | RSS feed
Rev 6082 | Rev 6102 | ||
---|---|---|---|
1 | /* |
1 | /* |
2 | * include/linux/idr.h |
2 | * include/linux/idr.h |
3 | * |
3 | * |
4 | * 2002-10-18 written by Jim Houston jim.houston@ccur.com |
4 | * 2002-10-18 written by Jim Houston jim.houston@ccur.com |
5 | * Copyright (C) 2002 by Concurrent Computer Corporation |
5 | * Copyright (C) 2002 by Concurrent Computer Corporation |
6 | * Distributed under the GNU GPL license version 2. |
6 | * Distributed under the GNU GPL license version 2. |
7 | * |
7 | * |
8 | * Small id to pointer translation service avoiding fixed sized |
8 | * Small id to pointer translation service avoiding fixed sized |
9 | * tables. |
9 | * tables. |
10 | */ |
10 | */ |
11 | 11 | ||
12 | #ifndef __IDR_H__ |
12 | #ifndef __IDR_H__ |
13 | #define __IDR_H__ |
13 | #define __IDR_H__ |
14 | 14 | ||
15 | #include |
15 | #include |
16 | #include |
16 | #include |
17 | #include |
17 | #include |
18 | //#include |
18 | #include |
19 | #include |
19 | #include |
20 | 20 | ||
21 | /* |
21 | /* |
22 | * We want shallower trees and thus more bits covered at each layer. 8 |
22 | * We want shallower trees and thus more bits covered at each layer. 8 |
23 | * bits gives us large enough first layer for most use cases and maximum |
23 | * bits gives us large enough first layer for most use cases and maximum |
24 | * tree depth of 4. Each idr_layer is slightly larger than 2k on 64bit and |
24 | * tree depth of 4. Each idr_layer is slightly larger than 2k on 64bit and |
25 | * 1k on 32bit. |
25 | * 1k on 32bit. |
26 | */ |
26 | */ |
27 | #define IDR_BITS 8 |
27 | #define IDR_BITS 8 |
28 | #define IDR_SIZE (1 << IDR_BITS) |
28 | #define IDR_SIZE (1 << IDR_BITS) |
29 | #define IDR_MASK ((1 << IDR_BITS)-1) |
29 | #define IDR_MASK ((1 << IDR_BITS)-1) |
30 | 30 | ||
31 | struct idr_layer { |
31 | struct idr_layer { |
32 | int prefix; /* the ID prefix of this idr_layer */ |
32 | int prefix; /* the ID prefix of this idr_layer */ |
33 | int layer; /* distance from leaf */ |
33 | int layer; /* distance from leaf */ |
34 | struct idr_layer __rcu *ary[1< |
34 | struct idr_layer __rcu *ary[1< |
35 | int count; /* When zero, we can release it */ |
35 | int count; /* When zero, we can release it */ |
36 | union { |
36 | union { |
37 | /* A zero bit means "space here" */ |
37 | /* A zero bit means "space here" */ |
38 | DECLARE_BITMAP(bitmap, IDR_SIZE); |
38 | DECLARE_BITMAP(bitmap, IDR_SIZE); |
39 | struct rcu_head rcu_head; |
39 | struct rcu_head rcu_head; |
40 | }; |
40 | }; |
41 | }; |
41 | }; |
42 | 42 | ||
43 | struct idr { |
43 | struct idr { |
44 | struct idr_layer __rcu *hint; /* the last layer allocated from */ |
44 | struct idr_layer __rcu *hint; /* the last layer allocated from */ |
45 | struct idr_layer __rcu *top; |
45 | struct idr_layer __rcu *top; |
46 | int layers; /* only valid w/o concurrent changes */ |
46 | int layers; /* only valid w/o concurrent changes */ |
47 | int cur; /* current pos for cyclic allocation */ |
47 | int cur; /* current pos for cyclic allocation */ |
48 | spinlock_t lock; |
48 | spinlock_t lock; |
49 | int id_free_cnt; |
49 | int id_free_cnt; |
50 | struct idr_layer *id_free; |
50 | struct idr_layer *id_free; |
51 | }; |
51 | }; |
52 | 52 | ||
53 | #define IDR_INIT(name) \ |
53 | #define IDR_INIT(name) \ |
54 | { \ |
54 | { \ |
55 | .lock = __SPIN_LOCK_UNLOCKED(name.lock), \ |
55 | .lock = __SPIN_LOCK_UNLOCKED(name.lock), \ |
56 | } |
56 | } |
57 | #define DEFINE_IDR(name) struct idr name = IDR_INIT(name) |
57 | #define DEFINE_IDR(name) struct idr name = IDR_INIT(name) |
58 | 58 | ||
59 | /** |
59 | /** |
60 | * DOC: idr sync |
60 | * DOC: idr sync |
61 | * idr synchronization (stolen from radix-tree.h) |
61 | * idr synchronization (stolen from radix-tree.h) |
62 | * |
62 | * |
63 | * idr_find() is able to be called locklessly, using RCU. The caller must |
63 | * idr_find() is able to be called locklessly, using RCU. The caller must |
64 | * ensure calls to this function are made within rcu_read_lock() regions. |
64 | * ensure calls to this function are made within rcu_read_lock() regions. |
65 | * Other readers (lock-free or otherwise) and modifications may be running |
65 | * Other readers (lock-free or otherwise) and modifications may be running |
66 | * concurrently. |
66 | * concurrently. |
67 | * |
67 | * |
68 | * It is still required that the caller manage the synchronization and |
68 | * It is still required that the caller manage the synchronization and |
69 | * lifetimes of the items. So if RCU lock-free lookups are used, typically |
69 | * lifetimes of the items. So if RCU lock-free lookups are used, typically |
70 | * this would mean that the items have their own locks, or are amenable to |
70 | * this would mean that the items have their own locks, or are amenable to |
71 | * lock-free access; and that the items are freed by RCU (or only freed after |
71 | * lock-free access; and that the items are freed by RCU (or only freed after |
72 | * having been deleted from the idr tree *and* a synchronize_rcu() grace |
72 | * having been deleted from the idr tree *and* a synchronize_rcu() grace |
73 | * period). |
73 | * period). |
74 | */ |
74 | */ |
75 | 75 | ||
76 | /* |
76 | /* |
77 | * This is what we export. |
77 | * This is what we export. |
78 | */ |
78 | */ |
79 | 79 | ||
80 | void *idr_find_slowpath(struct idr *idp, int id); |
80 | void *idr_find_slowpath(struct idr *idp, int id); |
81 | void idr_preload(gfp_t gfp_mask); |
81 | void idr_preload(gfp_t gfp_mask); |
82 | int idr_alloc(struct idr *idp, void *ptr, int start, int end, gfp_t gfp_mask); |
82 | int idr_alloc(struct idr *idp, void *ptr, int start, int end, gfp_t gfp_mask); |
83 | int idr_alloc_cyclic(struct idr *idr, void *ptr, int start, int end, gfp_t gfp_mask); |
83 | int idr_alloc_cyclic(struct idr *idr, void *ptr, int start, int end, gfp_t gfp_mask); |
84 | int idr_for_each(struct idr *idp, |
84 | int idr_for_each(struct idr *idp, |
85 | int (*fn)(int id, void *p, void *data), void *data); |
85 | int (*fn)(int id, void *p, void *data), void *data); |
86 | void *idr_get_next(struct idr *idp, int *nextid); |
86 | void *idr_get_next(struct idr *idp, int *nextid); |
87 | void *idr_replace(struct idr *idp, void *ptr, int id); |
87 | void *idr_replace(struct idr *idp, void *ptr, int id); |
88 | void idr_remove(struct idr *idp, int id); |
88 | void idr_remove(struct idr *idp, int id); |
89 | void idr_destroy(struct idr *idp); |
89 | void idr_destroy(struct idr *idp); |
90 | void idr_init(struct idr *idp); |
90 | void idr_init(struct idr *idp); |
91 | bool idr_is_empty(struct idr *idp); |
91 | bool idr_is_empty(struct idr *idp); |
92 | 92 | ||
93 | /** |
93 | /** |
94 | * idr_preload_end - end preload section started with idr_preload() |
94 | * idr_preload_end - end preload section started with idr_preload() |
95 | * |
95 | * |
96 | * Each idr_preload() should be matched with an invocation of this |
96 | * Each idr_preload() should be matched with an invocation of this |
97 | * function. See idr_preload() for details. |
97 | * function. See idr_preload() for details. |
98 | */ |
98 | */ |
99 | static inline void idr_preload_end(void) |
99 | static inline void idr_preload_end(void) |
100 | { |
100 | { |
101 | // preempt_enable(); |
101 | // preempt_enable(); |
102 | } |
102 | } |
103 | 103 | ||
104 | /** |
104 | /** |
105 | * idr_find - return pointer for given id |
105 | * idr_find - return pointer for given id |
106 | * @idr: idr handle |
106 | * @idr: idr handle |
107 | * @id: lookup key |
107 | * @id: lookup key |
108 | * |
108 | * |
109 | * Return the pointer given the id it has been registered with. A %NULL |
109 | * Return the pointer given the id it has been registered with. A %NULL |
110 | * return indicates that @id is not valid or you passed %NULL in |
110 | * return indicates that @id is not valid or you passed %NULL in |
111 | * idr_get_new(). |
111 | * idr_get_new(). |
112 | * |
112 | * |
113 | * This function can be called under rcu_read_lock(), given that the leaf |
113 | * This function can be called under rcu_read_lock(), given that the leaf |
114 | * pointers lifetimes are correctly managed. |
114 | * pointers lifetimes are correctly managed. |
115 | */ |
115 | */ |
116 | static inline void *idr_find(struct idr *idr, int id) |
116 | static inline void *idr_find(struct idr *idr, int id) |
117 | { |
117 | { |
118 | struct idr_layer *hint = rcu_dereference_raw(idr->hint); |
118 | struct idr_layer *hint = rcu_dereference_raw(idr->hint); |
119 | 119 | ||
120 | if (hint && (id & ~IDR_MASK) == hint->prefix) |
120 | if (hint && (id & ~IDR_MASK) == hint->prefix) |
121 | return rcu_dereference_raw(hint->ary[id & IDR_MASK]); |
121 | return rcu_dereference_raw(hint->ary[id & IDR_MASK]); |
122 | 122 | ||
123 | return idr_find_slowpath(idr, id); |
123 | return idr_find_slowpath(idr, id); |
124 | } |
124 | } |
125 | 125 | ||
126 | /** |
126 | /** |
127 | * idr_for_each_entry - iterate over an idr's elements of a given type |
127 | * idr_for_each_entry - iterate over an idr's elements of a given type |
128 | * @idp: idr handle |
128 | * @idp: idr handle |
129 | * @entry: the type * to use as cursor |
129 | * @entry: the type * to use as cursor |
130 | * @id: id entry's key |
130 | * @id: id entry's key |
131 | * |
131 | * |
132 | * @entry and @id do not need to be initialized before the loop, and |
132 | * @entry and @id do not need to be initialized before the loop, and |
133 | * after normal terminatinon @entry is left with the value NULL. This |
133 | * after normal terminatinon @entry is left with the value NULL. This |
134 | * is convenient for a "not found" value. |
134 | * is convenient for a "not found" value. |
135 | */ |
135 | */ |
136 | #define idr_for_each_entry(idp, entry, id) \ |
136 | #define idr_for_each_entry(idp, entry, id) \ |
137 | for (id = 0; ((entry) = idr_get_next(idp, &(id))) != NULL; ++id) |
137 | for (id = 0; ((entry) = idr_get_next(idp, &(id))) != NULL; ++id) |
138 | 138 | ||
139 | /* |
139 | /* |
140 | * IDA - IDR based id allocator, use when translation from id to |
140 | * IDA - IDR based id allocator, use when translation from id to |
141 | * pointer isn't necessary. |
141 | * pointer isn't necessary. |
142 | * |
142 | * |
143 | * IDA_BITMAP_LONGS is calculated to be one less to accommodate |
143 | * IDA_BITMAP_LONGS is calculated to be one less to accommodate |
144 | * ida_bitmap->nr_busy so that the whole struct fits in 128 bytes. |
144 | * ida_bitmap->nr_busy so that the whole struct fits in 128 bytes. |
145 | */ |
145 | */ |
146 | #define IDA_CHUNK_SIZE 128 /* 128 bytes per chunk */ |
146 | #define IDA_CHUNK_SIZE 128 /* 128 bytes per chunk */ |
147 | #define IDA_BITMAP_LONGS (IDA_CHUNK_SIZE / sizeof(long) - 1) |
147 | #define IDA_BITMAP_LONGS (IDA_CHUNK_SIZE / sizeof(long) - 1) |
148 | #define IDA_BITMAP_BITS (IDA_BITMAP_LONGS * sizeof(long) * 8) |
148 | #define IDA_BITMAP_BITS (IDA_BITMAP_LONGS * sizeof(long) * 8) |
149 | 149 | ||
150 | struct ida_bitmap { |
150 | struct ida_bitmap { |
151 | long nr_busy; |
151 | long nr_busy; |
152 | unsigned long bitmap[IDA_BITMAP_LONGS]; |
152 | unsigned long bitmap[IDA_BITMAP_LONGS]; |
153 | }; |
153 | }; |
154 | 154 | ||
155 | struct ida { |
155 | struct ida { |
156 | struct idr idr; |
156 | struct idr idr; |
157 | struct ida_bitmap *free_bitmap; |
157 | struct ida_bitmap *free_bitmap; |
158 | }; |
158 | }; |
159 | 159 | ||
160 | #define IDA_INIT(name) { .idr = IDR_INIT((name).idr), .free_bitmap = NULL, } |
160 | #define IDA_INIT(name) { .idr = IDR_INIT((name).idr), .free_bitmap = NULL, } |
161 | #define DEFINE_IDA(name) struct ida name = IDA_INIT(name) |
161 | #define DEFINE_IDA(name) struct ida name = IDA_INIT(name) |
162 | 162 | ||
163 | int ida_pre_get(struct ida *ida, gfp_t gfp_mask); |
163 | int ida_pre_get(struct ida *ida, gfp_t gfp_mask); |
164 | int ida_get_new_above(struct ida *ida, int starting_id, int *p_id); |
164 | int ida_get_new_above(struct ida *ida, int starting_id, int *p_id); |
165 | void ida_remove(struct ida *ida, int id); |
165 | void ida_remove(struct ida *ida, int id); |
166 | void ida_destroy(struct ida *ida); |
166 | void ida_destroy(struct ida *ida); |
167 | void ida_init(struct ida *ida); |
167 | void ida_init(struct ida *ida); |
168 | 168 | ||
169 | int ida_simple_get(struct ida *ida, unsigned int start, unsigned int end, |
169 | int ida_simple_get(struct ida *ida, unsigned int start, unsigned int end, |
170 | gfp_t gfp_mask); |
170 | gfp_t gfp_mask); |
171 | void ida_simple_remove(struct ida *ida, unsigned int id); |
171 | void ida_simple_remove(struct ida *ida, unsigned int id); |
172 | 172 | ||
173 | /** |
173 | /** |
174 | * ida_get_new - allocate new ID |
174 | * ida_get_new - allocate new ID |
175 | * @ida: idr handle |
175 | * @ida: idr handle |
176 | * @p_id: pointer to the allocated handle |
176 | * @p_id: pointer to the allocated handle |
177 | * |
177 | * |
178 | * Simple wrapper around ida_get_new_above() w/ @starting_id of zero. |
178 | * Simple wrapper around ida_get_new_above() w/ @starting_id of zero. |
179 | */ |
179 | */ |
180 | static inline int ida_get_new(struct ida *ida, int *p_id) |
180 | static inline int ida_get_new(struct ida *ida, int *p_id) |
181 | { |
181 | { |
182 | return ida_get_new_above(ida, 0, p_id); |
182 | return ida_get_new_above(ida, 0, p_id); |
183 | } |
183 | } |
184 | 184 | ||
185 | void __init idr_init_cache(void); |
185 | void __init idr_init_cache(void); |
186 | 186 | ||
187 | #endif /* __IDR_H__ */ |
187 | #endif /* __IDR_H__ */ |
188 | > |
188 | > |
189 | >><>><> |
189 | >><>><> |