Commit | Line | Data |
---|---|---|
ba20ba2e KO |
1 | #ifndef _LINUX_GENERIC_RADIX_TREE_H |
2 | #define _LINUX_GENERIC_RADIX_TREE_H | |
3 | ||
4 | /** | |
590ba22b | 5 | * DOC: Generic radix trees/sparse arrays |
ba20ba2e KO |
6 | * |
7 | * Very simple and minimalistic, supporting arbitrary size entries up to | |
3a319a24 | 8 | * GENRADIX_NODE_SIZE. |
ba20ba2e KO |
9 | * |
10 | * A genradix is defined with the type it will store, like so: | |
11 | * | |
12 | * static GENRADIX(struct foo) foo_genradix; | |
13 | * | |
14 | * The main operations are: | |
15 | * | |
16 | * - genradix_init(radix) - initialize an empty genradix | |
17 | * | |
18 | * - genradix_free(radix) - free all memory owned by the genradix and | |
19 | * reinitialize it | |
20 | * | |
21 | * - genradix_ptr(radix, idx) - gets a pointer to the entry at idx, returning | |
22 | * NULL if that entry does not exist | |
23 | * | |
24 | * - genradix_ptr_alloc(radix, idx, gfp) - gets a pointer to an entry, | |
25 | * allocating it if necessary | |
26 | * | |
27 | * - genradix_for_each(radix, iter, p) - iterate over each entry in a genradix | |
28 | * | |
29 | * The radix tree allocates one page of entries at a time, so entries may exist | |
30 | * that were never explicitly allocated - they will be initialized to all | |
31 | * zeroes. | |
32 | * | |
33 | * Internally, a genradix is just a radix tree of pages, and indexing works in | |
34 | * terms of byte offsets. The wrappers in this header file use sizeof on the | |
35 | * type the radix contains to calculate a byte offset from the index - see | |
36 | * __idx_to_offset. | |
37 | */ | |
38 | ||
39 | #include <asm/page.h> | |
40 | #include <linux/bug.h> | |
9492261f | 41 | #include <linux/limits.h> |
ba20ba2e | 42 | #include <linux/log2.h> |
b4b87651 AS |
43 | #include <linux/math.h> |
44 | #include <linux/types.h> | |
ba20ba2e KO |
45 | |
46 | struct genradix_root; | |
47 | ||
3a319a24 KO |
48 | #define GENRADIX_NODE_SHIFT 9 |
49 | #define GENRADIX_NODE_SIZE (1U << GENRADIX_NODE_SHIFT) | |
50 | ||
ba20ba2e | 51 | struct __genradix { |
0a650e47 | 52 | struct genradix_root *root; |
ba20ba2e KO |
53 | }; |
54 | ||
55 | /* | |
3a319a24 | 56 | * NOTE: currently, sizeof(_type) must not be larger than GENRADIX_NODE_SIZE: |
ba20ba2e KO |
57 | */ |
58 | ||
59 | #define __GENRADIX_INITIALIZER \ | |
60 | { \ | |
61 | .tree = { \ | |
62 | .root = NULL, \ | |
63 | } \ | |
64 | } | |
65 | ||
66 | /* | |
67 | * We use a 0 size array to stash the type we're storing without taking any | |
68 | * space at runtime - then the various accessor macros can use typeof() to get | |
69 | * to it for casts/sizeof - we also force the alignment so that storing a type | |
70 | * with a ridiculous alignment doesn't blow up the alignment or size of the | |
71 | * genradix. | |
72 | */ | |
73 | ||
74 | #define GENRADIX(_type) \ | |
75 | struct { \ | |
76 | struct __genradix tree; \ | |
77 | _type type[0] __aligned(1); \ | |
78 | } | |
79 | ||
80 | #define DEFINE_GENRADIX(_name, _type) \ | |
81 | GENRADIX(_type) _name = __GENRADIX_INITIALIZER | |
82 | ||
83 | /** | |
84 | * genradix_init - initialize a genradix | |
85 | * @_radix: genradix to initialize | |
86 | * | |
87 | * Does not fail | |
88 | */ | |
89 | #define genradix_init(_radix) \ | |
90 | do { \ | |
91 | *(_radix) = (typeof(*_radix)) __GENRADIX_INITIALIZER; \ | |
92 | } while (0) | |
93 | ||
94 | void __genradix_free(struct __genradix *); | |
95 | ||
96 | /** | |
97 | * genradix_free: free all memory owned by a genradix | |
98 | * @_radix: the genradix to free | |
99 | * | |
100 | * After freeing, @_radix will be reinitialized and empty | |
101 | */ | |
102 | #define genradix_free(_radix) __genradix_free(&(_radix)->tree) | |
103 | ||
104 | static inline size_t __idx_to_offset(size_t idx, size_t obj_size) | |
105 | { | |
106 | if (__builtin_constant_p(obj_size)) | |
3a319a24 | 107 | BUILD_BUG_ON(obj_size > GENRADIX_NODE_SIZE); |
ba20ba2e | 108 | else |
3a319a24 | 109 | BUG_ON(obj_size > GENRADIX_NODE_SIZE); |
ba20ba2e KO |
110 | |
111 | if (!is_power_of_2(obj_size)) { | |
3a319a24 | 112 | size_t objs_per_page = GENRADIX_NODE_SIZE / obj_size; |
ba20ba2e | 113 | |
3a319a24 | 114 | return (idx / objs_per_page) * GENRADIX_NODE_SIZE + |
ba20ba2e KO |
115 | (idx % objs_per_page) * obj_size; |
116 | } else { | |
117 | return idx * obj_size; | |
118 | } | |
119 | } | |
120 | ||
121 | #define __genradix_cast(_radix) (typeof((_radix)->type[0]) *) | |
122 | #define __genradix_obj_size(_radix) sizeof((_radix)->type[0]) | |
73badee4 | 123 | #define __genradix_objs_per_page(_radix) \ |
3a319a24 | 124 | (GENRADIX_NODE_SIZE / sizeof((_radix)->type[0])) |
73badee4 | 125 | #define __genradix_page_remainder(_radix) \ |
3a319a24 | 126 | (GENRADIX_NODE_SIZE % sizeof((_radix)->type[0])) |
73badee4 | 127 | |
ba20ba2e KO |
128 | #define __genradix_idx_to_offset(_radix, _idx) \ |
129 | __idx_to_offset(_idx, __genradix_obj_size(_radix)) | |
130 | ||
131 | void *__genradix_ptr(struct __genradix *, size_t); | |
132 | ||
133 | /** | |
134 | * genradix_ptr - get a pointer to a genradix entry | |
135 | * @_radix: genradix to access | |
136 | * @_idx: index to fetch | |
137 | * | |
138 | * Returns a pointer to entry at @_idx, or NULL if that entry does not exist. | |
139 | */ | |
140 | #define genradix_ptr(_radix, _idx) \ | |
141 | (__genradix_cast(_radix) \ | |
142 | __genradix_ptr(&(_radix)->tree, \ | |
143 | __genradix_idx_to_offset(_radix, _idx))) | |
144 | ||
145 | void *__genradix_ptr_alloc(struct __genradix *, size_t, gfp_t); | |
146 | ||
147 | /** | |
148 | * genradix_ptr_alloc - get a pointer to a genradix entry, allocating it | |
149 | * if necessary | |
150 | * @_radix: genradix to access | |
151 | * @_idx: index to fetch | |
152 | * @_gfp: gfp mask | |
153 | * | |
154 | * Returns a pointer to entry at @_idx, or NULL on allocation failure | |
155 | */ | |
156 | #define genradix_ptr_alloc(_radix, _idx, _gfp) \ | |
157 | (__genradix_cast(_radix) \ | |
158 | __genradix_ptr_alloc(&(_radix)->tree, \ | |
159 | __genradix_idx_to_offset(_radix, _idx), \ | |
160 | _gfp)) | |
161 | ||
162 | struct genradix_iter { | |
163 | size_t offset; | |
164 | size_t pos; | |
165 | }; | |
166 | ||
167 | /** | |
168 | * genradix_iter_init - initialize a genradix_iter | |
169 | * @_radix: genradix that will be iterated over | |
170 | * @_idx: index to start iterating from | |
171 | */ | |
172 | #define genradix_iter_init(_radix, _idx) \ | |
173 | ((struct genradix_iter) { \ | |
174 | .pos = (_idx), \ | |
175 | .offset = __genradix_idx_to_offset((_radix), (_idx)),\ | |
176 | }) | |
177 | ||
178 | void *__genradix_iter_peek(struct genradix_iter *, struct __genradix *, size_t); | |
179 | ||
180 | /** | |
181 | * genradix_iter_peek - get first entry at or above iterator's current | |
182 | * position | |
183 | * @_iter: a genradix_iter | |
184 | * @_radix: genradix being iterated over | |
185 | * | |
186 | * If no more entries exist at or above @_iter's current position, returns NULL | |
187 | */ | |
188 | #define genradix_iter_peek(_iter, _radix) \ | |
189 | (__genradix_cast(_radix) \ | |
190 | __genradix_iter_peek(_iter, &(_radix)->tree, \ | |
73badee4 KO |
191 | __genradix_objs_per_page(_radix))) |
192 | ||
193 | void *__genradix_iter_peek_prev(struct genradix_iter *, struct __genradix *, | |
194 | size_t, size_t); | |
195 | ||
196 | /** | |
197 | * genradix_iter_peek_prev - get first entry at or below iterator's current | |
198 | * position | |
199 | * @_iter: a genradix_iter | |
200 | * @_radix: genradix being iterated over | |
201 | * | |
202 | * If no more entries exist at or below @_iter's current position, returns NULL | |
203 | */ | |
204 | #define genradix_iter_peek_prev(_iter, _radix) \ | |
205 | (__genradix_cast(_radix) \ | |
206 | __genradix_iter_peek_prev(_iter, &(_radix)->tree, \ | |
207 | __genradix_objs_per_page(_radix), \ | |
208 | __genradix_obj_size(_radix) + \ | |
209 | __genradix_page_remainder(_radix))) | |
ba20ba2e KO |
210 | |
211 | static inline void __genradix_iter_advance(struct genradix_iter *iter, | |
212 | size_t obj_size) | |
213 | { | |
9492261f KO |
214 | if (iter->offset + obj_size < iter->offset) { |
215 | iter->offset = SIZE_MAX; | |
216 | iter->pos = SIZE_MAX; | |
217 | return; | |
218 | } | |
219 | ||
ba20ba2e KO |
220 | iter->offset += obj_size; |
221 | ||
222 | if (!is_power_of_2(obj_size) && | |
3a319a24 KO |
223 | (iter->offset & (GENRADIX_NODE_SIZE - 1)) + obj_size > GENRADIX_NODE_SIZE) |
224 | iter->offset = round_up(iter->offset, GENRADIX_NODE_SIZE); | |
ba20ba2e KO |
225 | |
226 | iter->pos++; | |
227 | } | |
228 | ||
229 | #define genradix_iter_advance(_iter, _radix) \ | |
230 | __genradix_iter_advance(_iter, __genradix_obj_size(_radix)) | |
231 | ||
73badee4 KO |
232 | static inline void __genradix_iter_rewind(struct genradix_iter *iter, |
233 | size_t obj_size) | |
234 | { | |
235 | if (iter->offset == 0 || | |
236 | iter->offset == SIZE_MAX) { | |
237 | iter->offset = SIZE_MAX; | |
238 | return; | |
239 | } | |
240 | ||
3a319a24 KO |
241 | if ((iter->offset & (GENRADIX_NODE_SIZE - 1)) == 0) |
242 | iter->offset -= GENRADIX_NODE_SIZE % obj_size; | |
73badee4 KO |
243 | |
244 | iter->offset -= obj_size; | |
245 | iter->pos--; | |
246 | } | |
247 | ||
248 | #define genradix_iter_rewind(_iter, _radix) \ | |
249 | __genradix_iter_rewind(_iter, __genradix_obj_size(_radix)) | |
250 | ||
ba20ba2e KO |
251 | #define genradix_for_each_from(_radix, _iter, _p, _start) \ |
252 | for (_iter = genradix_iter_init(_radix, _start); \ | |
253 | (_p = genradix_iter_peek(&_iter, _radix)) != NULL; \ | |
254 | genradix_iter_advance(&_iter, _radix)) | |
255 | ||
256 | /** | |
257 | * genradix_for_each - iterate over entry in a genradix | |
258 | * @_radix: genradix to iterate over | |
259 | * @_iter: a genradix_iter to track current position | |
260 | * @_p: pointer to genradix entry type | |
261 | * | |
262 | * On every iteration, @_p will point to the current entry, and @_iter.pos | |
263 | * will be the current entry's index. | |
264 | */ | |
265 | #define genradix_for_each(_radix, _iter, _p) \ | |
266 | genradix_for_each_from(_radix, _iter, _p, 0) | |
267 | ||
73badee4 | 268 | #define genradix_last_pos(_radix) \ |
3a319a24 | 269 | (SIZE_MAX / GENRADIX_NODE_SIZE * __genradix_objs_per_page(_radix) - 1) |
73badee4 KO |
270 | |
271 | /** | |
272 | * genradix_for_each_reverse - iterate over entry in a genradix, reverse order | |
273 | * @_radix: genradix to iterate over | |
274 | * @_iter: a genradix_iter to track current position | |
275 | * @_p: pointer to genradix entry type | |
276 | * | |
277 | * On every iteration, @_p will point to the current entry, and @_iter.pos | |
278 | * will be the current entry's index. | |
279 | */ | |
280 | #define genradix_for_each_reverse(_radix, _iter, _p) \ | |
281 | for (_iter = genradix_iter_init(_radix, genradix_last_pos(_radix));\ | |
282 | (_p = genradix_iter_peek_prev(&_iter, _radix)) != NULL;\ | |
283 | genradix_iter_rewind(&_iter, _radix)) | |
284 | ||
ba20ba2e KO |
285 | int __genradix_prealloc(struct __genradix *, size_t, gfp_t); |
286 | ||
287 | /** | |
288 | * genradix_prealloc - preallocate entries in a generic radix tree | |
289 | * @_radix: genradix to preallocate | |
290 | * @_nr: number of entries to preallocate | |
291 | * @_gfp: gfp mask | |
292 | * | |
293 | * Returns 0 on success, -ENOMEM on failure | |
294 | */ | |
295 | #define genradix_prealloc(_radix, _nr, _gfp) \ | |
296 | __genradix_prealloc(&(_radix)->tree, \ | |
297 | __genradix_idx_to_offset(_radix, _nr + 1),\ | |
298 | _gfp) | |
299 | ||
300 | ||
301 | #endif /* _LINUX_GENERIC_RADIX_TREE_H */ |