Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * Copyright (C) 2001 Momchil Velikov | |
3 | * Portions Copyright (C) 2001 Christoph Hellwig | |
201b6264 | 4 | * Copyright (C) 2005 SGI, Christoph Lameter <clameter@sgi.com> |
1da177e4 LT |
5 | * |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License as | |
8 | * published by the Free Software Foundation; either version 2, or (at | |
9 | * your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, but | |
12 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | * General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License | |
17 | * along with this program; if not, write to the Free Software | |
18 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
19 | */ | |
20 | ||
21 | #include <linux/errno.h> | |
22 | #include <linux/init.h> | |
23 | #include <linux/kernel.h> | |
24 | #include <linux/module.h> | |
25 | #include <linux/radix-tree.h> | |
26 | #include <linux/percpu.h> | |
27 | #include <linux/slab.h> | |
28 | #include <linux/notifier.h> | |
29 | #include <linux/cpu.h> | |
30 | #include <linux/gfp.h> | |
31 | #include <linux/string.h> | |
32 | #include <linux/bitops.h> | |
33 | ||
34 | ||
35 | #ifdef __KERNEL__ | |
36 | #define RADIX_TREE_MAP_SHIFT 6 | |
37 | #else | |
38 | #define RADIX_TREE_MAP_SHIFT 3 /* For more stressful testing */ | |
39 | #endif | |
40 | #define RADIX_TREE_TAGS 2 | |
41 | ||
42 | #define RADIX_TREE_MAP_SIZE (1UL << RADIX_TREE_MAP_SHIFT) | |
43 | #define RADIX_TREE_MAP_MASK (RADIX_TREE_MAP_SIZE-1) | |
44 | ||
45 | #define RADIX_TREE_TAG_LONGS \ | |
46 | ((RADIX_TREE_MAP_SIZE + BITS_PER_LONG - 1) / BITS_PER_LONG) | |
47 | ||
48 | struct radix_tree_node { | |
49 | unsigned int count; | |
50 | void *slots[RADIX_TREE_MAP_SIZE]; | |
51 | unsigned long tags[RADIX_TREE_TAGS][RADIX_TREE_TAG_LONGS]; | |
52 | }; | |
53 | ||
54 | struct radix_tree_path { | |
201b6264 | 55 | struct radix_tree_node *node; |
1da177e4 LT |
56 | int offset; |
57 | }; | |
58 | ||
59 | #define RADIX_TREE_INDEX_BITS (8 /* CHAR_BIT */ * sizeof(unsigned long)) | |
60 | #define RADIX_TREE_MAX_PATH (RADIX_TREE_INDEX_BITS/RADIX_TREE_MAP_SHIFT + 2) | |
61 | ||
6c036527 | 62 | static unsigned long height_to_maxindex[RADIX_TREE_MAX_PATH] __read_mostly; |
1da177e4 LT |
63 | |
64 | /* | |
65 | * Radix tree node cache. | |
66 | */ | |
67 | static kmem_cache_t *radix_tree_node_cachep; | |
68 | ||
69 | /* | |
70 | * Per-cpu pool of preloaded nodes | |
71 | */ | |
72 | struct radix_tree_preload { | |
73 | int nr; | |
74 | struct radix_tree_node *nodes[RADIX_TREE_MAX_PATH]; | |
75 | }; | |
76 | DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, }; | |
77 | ||
78 | /* | |
79 | * This assumes that the caller has performed appropriate preallocation, and | |
80 | * that the caller has pinned this thread of control to the current CPU. | |
81 | */ | |
82 | static struct radix_tree_node * | |
83 | radix_tree_node_alloc(struct radix_tree_root *root) | |
84 | { | |
85 | struct radix_tree_node *ret; | |
86 | ||
87 | ret = kmem_cache_alloc(radix_tree_node_cachep, root->gfp_mask); | |
88 | if (ret == NULL && !(root->gfp_mask & __GFP_WAIT)) { | |
89 | struct radix_tree_preload *rtp; | |
90 | ||
91 | rtp = &__get_cpu_var(radix_tree_preloads); | |
92 | if (rtp->nr) { | |
93 | ret = rtp->nodes[rtp->nr - 1]; | |
94 | rtp->nodes[rtp->nr - 1] = NULL; | |
95 | rtp->nr--; | |
96 | } | |
97 | } | |
98 | return ret; | |
99 | } | |
100 | ||
101 | static inline void | |
102 | radix_tree_node_free(struct radix_tree_node *node) | |
103 | { | |
104 | kmem_cache_free(radix_tree_node_cachep, node); | |
105 | } | |
106 | ||
107 | /* | |
108 | * Load up this CPU's radix_tree_node buffer with sufficient objects to | |
109 | * ensure that the addition of a single element in the tree cannot fail. On | |
110 | * success, return zero, with preemption disabled. On error, return -ENOMEM | |
111 | * with preemption not disabled. | |
112 | */ | |
dd0fc66f | 113 | int radix_tree_preload(gfp_t gfp_mask) |
1da177e4 LT |
114 | { |
115 | struct radix_tree_preload *rtp; | |
116 | struct radix_tree_node *node; | |
117 | int ret = -ENOMEM; | |
118 | ||
119 | preempt_disable(); | |
120 | rtp = &__get_cpu_var(radix_tree_preloads); | |
121 | while (rtp->nr < ARRAY_SIZE(rtp->nodes)) { | |
122 | preempt_enable(); | |
123 | node = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask); | |
124 | if (node == NULL) | |
125 | goto out; | |
126 | preempt_disable(); | |
127 | rtp = &__get_cpu_var(radix_tree_preloads); | |
128 | if (rtp->nr < ARRAY_SIZE(rtp->nodes)) | |
129 | rtp->nodes[rtp->nr++] = node; | |
130 | else | |
131 | kmem_cache_free(radix_tree_node_cachep, node); | |
132 | } | |
133 | ret = 0; | |
134 | out: | |
135 | return ret; | |
136 | } | |
137 | ||
138 | static inline void tag_set(struct radix_tree_node *node, int tag, int offset) | |
139 | { | |
d5274261 | 140 | __set_bit(offset, node->tags[tag]); |
1da177e4 LT |
141 | } |
142 | ||
143 | static inline void tag_clear(struct radix_tree_node *node, int tag, int offset) | |
144 | { | |
d5274261 | 145 | __clear_bit(offset, node->tags[tag]); |
1da177e4 LT |
146 | } |
147 | ||
148 | static inline int tag_get(struct radix_tree_node *node, int tag, int offset) | |
149 | { | |
d5274261 | 150 | return test_bit(offset, node->tags[tag]); |
1da177e4 LT |
151 | } |
152 | ||
6e954b9e NP |
153 | /* |
154 | * Returns 1 if any slot in the node has this tag set. | |
155 | * Otherwise returns 0. | |
156 | */ | |
157 | static inline int any_tag_set(struct radix_tree_node *node, int tag) | |
158 | { | |
159 | int idx; | |
160 | for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) { | |
161 | if (node->tags[tag][idx]) | |
162 | return 1; | |
163 | } | |
164 | return 0; | |
165 | } | |
166 | ||
1da177e4 LT |
167 | /* |
168 | * Return the maximum key which can be store into a | |
169 | * radix tree with height HEIGHT. | |
170 | */ | |
171 | static inline unsigned long radix_tree_maxindex(unsigned int height) | |
172 | { | |
173 | return height_to_maxindex[height]; | |
174 | } | |
175 | ||
176 | /* | |
177 | * Extend a radix tree so it can store key @index. | |
178 | */ | |
179 | static int radix_tree_extend(struct radix_tree_root *root, unsigned long index) | |
180 | { | |
181 | struct radix_tree_node *node; | |
182 | unsigned int height; | |
183 | char tags[RADIX_TREE_TAGS]; | |
184 | int tag; | |
185 | ||
186 | /* Figure out what the height should be. */ | |
187 | height = root->height + 1; | |
188 | while (index > radix_tree_maxindex(height)) | |
189 | height++; | |
190 | ||
191 | if (root->rnode == NULL) { | |
192 | root->height = height; | |
193 | goto out; | |
194 | } | |
195 | ||
196 | /* | |
197 | * Prepare the tag status of the top-level node for propagation | |
198 | * into the newly-pushed top-level node(s) | |
199 | */ | |
200 | for (tag = 0; tag < RADIX_TREE_TAGS; tag++) { | |
1da177e4 | 201 | tags[tag] = 0; |
6e954b9e NP |
202 | if (any_tag_set(root->rnode, tag)) |
203 | tags[tag] = 1; | |
1da177e4 LT |
204 | } |
205 | ||
206 | do { | |
207 | if (!(node = radix_tree_node_alloc(root))) | |
208 | return -ENOMEM; | |
209 | ||
210 | /* Increase the height. */ | |
211 | node->slots[0] = root->rnode; | |
212 | ||
213 | /* Propagate the aggregated tag info into the new root */ | |
214 | for (tag = 0; tag < RADIX_TREE_TAGS; tag++) { | |
215 | if (tags[tag]) | |
216 | tag_set(node, tag, 0); | |
217 | } | |
218 | ||
219 | node->count = 1; | |
220 | root->rnode = node; | |
221 | root->height++; | |
222 | } while (height > root->height); | |
223 | out: | |
224 | return 0; | |
225 | } | |
226 | ||
227 | /** | |
228 | * radix_tree_insert - insert into a radix tree | |
229 | * @root: radix tree root | |
230 | * @index: index key | |
231 | * @item: item to insert | |
232 | * | |
233 | * Insert an item into the radix tree at position @index. | |
234 | */ | |
235 | int radix_tree_insert(struct radix_tree_root *root, | |
236 | unsigned long index, void *item) | |
237 | { | |
201b6264 | 238 | struct radix_tree_node *node = NULL, *slot; |
1da177e4 LT |
239 | unsigned int height, shift; |
240 | int offset; | |
241 | int error; | |
242 | ||
243 | /* Make sure the tree is high enough. */ | |
244 | if ((!index && !root->rnode) || | |
245 | index > radix_tree_maxindex(root->height)) { | |
246 | error = radix_tree_extend(root, index); | |
247 | if (error) | |
248 | return error; | |
249 | } | |
250 | ||
201b6264 | 251 | slot = root->rnode; |
1da177e4 LT |
252 | height = root->height; |
253 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; | |
254 | ||
255 | offset = 0; /* uninitialised var warning */ | |
256 | while (height > 0) { | |
201b6264 | 257 | if (slot == NULL) { |
1da177e4 | 258 | /* Have to add a child node. */ |
201b6264 | 259 | if (!(slot = radix_tree_node_alloc(root))) |
1da177e4 | 260 | return -ENOMEM; |
201b6264 CL |
261 | if (node) { |
262 | node->slots[offset] = slot; | |
1da177e4 | 263 | node->count++; |
201b6264 CL |
264 | } else |
265 | root->rnode = slot; | |
1da177e4 LT |
266 | } |
267 | ||
268 | /* Go a level down */ | |
269 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
201b6264 CL |
270 | node = slot; |
271 | slot = node->slots[offset]; | |
1da177e4 LT |
272 | shift -= RADIX_TREE_MAP_SHIFT; |
273 | height--; | |
274 | } | |
275 | ||
201b6264 | 276 | if (slot != NULL) |
1da177e4 | 277 | return -EEXIST; |
201b6264 | 278 | |
1da177e4 LT |
279 | if (node) { |
280 | node->count++; | |
201b6264 | 281 | node->slots[offset] = item; |
1da177e4 LT |
282 | BUG_ON(tag_get(node, 0, offset)); |
283 | BUG_ON(tag_get(node, 1, offset)); | |
201b6264 CL |
284 | } else |
285 | root->rnode = item; | |
1da177e4 | 286 | |
1da177e4 LT |
287 | return 0; |
288 | } | |
289 | EXPORT_SYMBOL(radix_tree_insert); | |
290 | ||
a4331366 HR |
291 | static inline void **__lookup_slot(struct radix_tree_root *root, |
292 | unsigned long index) | |
1da177e4 LT |
293 | { |
294 | unsigned int height, shift; | |
a4331366 | 295 | struct radix_tree_node **slot; |
1da177e4 LT |
296 | |
297 | height = root->height; | |
298 | if (index > radix_tree_maxindex(height)) | |
299 | return NULL; | |
300 | ||
301 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; | |
a4331366 | 302 | slot = &root->rnode; |
1da177e4 LT |
303 | |
304 | while (height > 0) { | |
a4331366 | 305 | if (*slot == NULL) |
1da177e4 LT |
306 | return NULL; |
307 | ||
a4331366 HR |
308 | slot = (struct radix_tree_node **) |
309 | ((*slot)->slots + | |
310 | ((index >> shift) & RADIX_TREE_MAP_MASK)); | |
1da177e4 LT |
311 | shift -= RADIX_TREE_MAP_SHIFT; |
312 | height--; | |
313 | } | |
314 | ||
a4331366 HR |
315 | return (void **)slot; |
316 | } | |
317 | ||
318 | /** | |
319 | * radix_tree_lookup_slot - lookup a slot in a radix tree | |
320 | * @root: radix tree root | |
321 | * @index: index key | |
322 | * | |
323 | * Lookup the slot corresponding to the position @index in the radix tree | |
324 | * @root. This is useful for update-if-exists operations. | |
325 | */ | |
326 | void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index) | |
327 | { | |
328 | return __lookup_slot(root, index); | |
329 | } | |
330 | EXPORT_SYMBOL(radix_tree_lookup_slot); | |
331 | ||
332 | /** | |
333 | * radix_tree_lookup - perform lookup operation on a radix tree | |
334 | * @root: radix tree root | |
335 | * @index: index key | |
336 | * | |
337 | * Lookup the item at the position @index in the radix tree @root. | |
338 | */ | |
339 | void *radix_tree_lookup(struct radix_tree_root *root, unsigned long index) | |
340 | { | |
341 | void **slot; | |
342 | ||
343 | slot = __lookup_slot(root, index); | |
344 | return slot != NULL ? *slot : NULL; | |
1da177e4 LT |
345 | } |
346 | EXPORT_SYMBOL(radix_tree_lookup); | |
347 | ||
348 | /** | |
349 | * radix_tree_tag_set - set a tag on a radix tree node | |
350 | * @root: radix tree root | |
351 | * @index: index key | |
352 | * @tag: tag index | |
353 | * | |
354 | * Set the search tag corresponging to @index in the radix tree. From | |
355 | * the root all the way down to the leaf node. | |
356 | * | |
357 | * Returns the address of the tagged item. Setting a tag on a not-present | |
358 | * item is a bug. | |
359 | */ | |
360 | void *radix_tree_tag_set(struct radix_tree_root *root, | |
361 | unsigned long index, int tag) | |
362 | { | |
363 | unsigned int height, shift; | |
201b6264 | 364 | struct radix_tree_node *slot; |
1da177e4 LT |
365 | |
366 | height = root->height; | |
367 | if (index > radix_tree_maxindex(height)) | |
368 | return NULL; | |
369 | ||
370 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; | |
201b6264 | 371 | slot = root->rnode; |
1da177e4 LT |
372 | |
373 | while (height > 0) { | |
374 | int offset; | |
375 | ||
376 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
d5274261 NP |
377 | if (!tag_get(slot, tag, offset)) |
378 | tag_set(slot, tag, offset); | |
201b6264 CL |
379 | slot = slot->slots[offset]; |
380 | BUG_ON(slot == NULL); | |
1da177e4 LT |
381 | shift -= RADIX_TREE_MAP_SHIFT; |
382 | height--; | |
383 | } | |
384 | ||
201b6264 | 385 | return slot; |
1da177e4 LT |
386 | } |
387 | EXPORT_SYMBOL(radix_tree_tag_set); | |
388 | ||
389 | /** | |
390 | * radix_tree_tag_clear - clear a tag on a radix tree node | |
391 | * @root: radix tree root | |
392 | * @index: index key | |
393 | * @tag: tag index | |
394 | * | |
395 | * Clear the search tag corresponging to @index in the radix tree. If | |
396 | * this causes the leaf node to have no tags set then clear the tag in the | |
397 | * next-to-leaf node, etc. | |
398 | * | |
399 | * Returns the address of the tagged item on success, else NULL. ie: | |
400 | * has the same return value and semantics as radix_tree_lookup(). | |
401 | */ | |
402 | void *radix_tree_tag_clear(struct radix_tree_root *root, | |
403 | unsigned long index, int tag) | |
404 | { | |
405 | struct radix_tree_path path[RADIX_TREE_MAX_PATH], *pathp = path; | |
201b6264 | 406 | struct radix_tree_node *slot; |
1da177e4 LT |
407 | unsigned int height, shift; |
408 | void *ret = NULL; | |
409 | ||
410 | height = root->height; | |
411 | if (index > radix_tree_maxindex(height)) | |
412 | goto out; | |
413 | ||
414 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; | |
415 | pathp->node = NULL; | |
201b6264 | 416 | slot = root->rnode; |
1da177e4 LT |
417 | |
418 | while (height > 0) { | |
419 | int offset; | |
420 | ||
201b6264 | 421 | if (slot == NULL) |
1da177e4 LT |
422 | goto out; |
423 | ||
424 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
425 | pathp[1].offset = offset; | |
201b6264 CL |
426 | pathp[1].node = slot; |
427 | slot = slot->slots[offset]; | |
1da177e4 LT |
428 | pathp++; |
429 | shift -= RADIX_TREE_MAP_SHIFT; | |
430 | height--; | |
431 | } | |
432 | ||
201b6264 | 433 | ret = slot; |
1da177e4 LT |
434 | if (ret == NULL) |
435 | goto out; | |
436 | ||
437 | do { | |
d5274261 NP |
438 | if (!tag_get(pathp->node, tag, pathp->offset)) |
439 | goto out; | |
201b6264 | 440 | tag_clear(pathp->node, tag, pathp->offset); |
6e954b9e NP |
441 | if (any_tag_set(pathp->node, tag)) |
442 | goto out; | |
1da177e4 | 443 | pathp--; |
201b6264 | 444 | } while (pathp->node); |
1da177e4 LT |
445 | out: |
446 | return ret; | |
447 | } | |
448 | EXPORT_SYMBOL(radix_tree_tag_clear); | |
449 | ||
450 | #ifndef __KERNEL__ /* Only the test harness uses this at present */ | |
451 | /** | |
32605a18 MT |
452 | * radix_tree_tag_get - get a tag on a radix tree node |
453 | * @root: radix tree root | |
454 | * @index: index key | |
455 | * @tag: tag index | |
1da177e4 | 456 | * |
32605a18 | 457 | * Return values: |
1da177e4 | 458 | * |
32605a18 MT |
459 | * 0: tag not present |
460 | * 1: tag present, set | |
461 | * -1: tag present, unset | |
1da177e4 LT |
462 | */ |
463 | int radix_tree_tag_get(struct radix_tree_root *root, | |
464 | unsigned long index, int tag) | |
465 | { | |
466 | unsigned int height, shift; | |
201b6264 | 467 | struct radix_tree_node *slot; |
1da177e4 LT |
468 | int saw_unset_tag = 0; |
469 | ||
470 | height = root->height; | |
471 | if (index > radix_tree_maxindex(height)) | |
472 | return 0; | |
473 | ||
474 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; | |
201b6264 | 475 | slot = root->rnode; |
1da177e4 LT |
476 | |
477 | for ( ; ; ) { | |
478 | int offset; | |
479 | ||
201b6264 | 480 | if (slot == NULL) |
1da177e4 LT |
481 | return 0; |
482 | ||
483 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
484 | ||
485 | /* | |
486 | * This is just a debug check. Later, we can bale as soon as | |
487 | * we see an unset tag. | |
488 | */ | |
201b6264 | 489 | if (!tag_get(slot, tag, offset)) |
1da177e4 LT |
490 | saw_unset_tag = 1; |
491 | if (height == 1) { | |
201b6264 | 492 | int ret = tag_get(slot, tag, offset); |
1da177e4 LT |
493 | |
494 | BUG_ON(ret && saw_unset_tag); | |
32605a18 | 495 | return ret ? 1 : -1; |
1da177e4 | 496 | } |
201b6264 | 497 | slot = slot->slots[offset]; |
1da177e4 LT |
498 | shift -= RADIX_TREE_MAP_SHIFT; |
499 | height--; | |
500 | } | |
501 | } | |
502 | EXPORT_SYMBOL(radix_tree_tag_get); | |
503 | #endif | |
504 | ||
505 | static unsigned int | |
506 | __lookup(struct radix_tree_root *root, void **results, unsigned long index, | |
507 | unsigned int max_items, unsigned long *next_index) | |
508 | { | |
509 | unsigned int nr_found = 0; | |
201b6264 | 510 | unsigned int shift, height; |
1da177e4 | 511 | struct radix_tree_node *slot; |
201b6264 CL |
512 | unsigned long i; |
513 | ||
514 | height = root->height; | |
515 | if (height == 0) | |
516 | goto out; | |
1da177e4 LT |
517 | |
518 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; | |
519 | slot = root->rnode; | |
520 | ||
201b6264 | 521 | for ( ; height > 1; height--) { |
1da177e4 | 522 | |
201b6264 CL |
523 | for (i = (index >> shift) & RADIX_TREE_MAP_MASK ; |
524 | i < RADIX_TREE_MAP_SIZE; i++) { | |
1da177e4 LT |
525 | if (slot->slots[i] != NULL) |
526 | break; | |
527 | index &= ~((1UL << shift) - 1); | |
528 | index += 1UL << shift; | |
529 | if (index == 0) | |
530 | goto out; /* 32-bit wraparound */ | |
531 | } | |
532 | if (i == RADIX_TREE_MAP_SIZE) | |
533 | goto out; | |
1da177e4 | 534 | |
1da177e4 LT |
535 | shift -= RADIX_TREE_MAP_SHIFT; |
536 | slot = slot->slots[i]; | |
537 | } | |
201b6264 CL |
538 | |
539 | /* Bottom level: grab some items */ | |
540 | for (i = index & RADIX_TREE_MAP_MASK; i < RADIX_TREE_MAP_SIZE; i++) { | |
541 | index++; | |
542 | if (slot->slots[i]) { | |
543 | results[nr_found++] = slot->slots[i]; | |
544 | if (nr_found == max_items) | |
545 | goto out; | |
546 | } | |
547 | } | |
1da177e4 LT |
548 | out: |
549 | *next_index = index; | |
550 | return nr_found; | |
551 | } | |
552 | ||
553 | /** | |
554 | * radix_tree_gang_lookup - perform multiple lookup on a radix tree | |
555 | * @root: radix tree root | |
556 | * @results: where the results of the lookup are placed | |
557 | * @first_index: start the lookup from this key | |
558 | * @max_items: place up to this many items at *results | |
559 | * | |
560 | * Performs an index-ascending scan of the tree for present items. Places | |
561 | * them at *@results and returns the number of items which were placed at | |
562 | * *@results. | |
563 | * | |
564 | * The implementation is naive. | |
565 | */ | |
566 | unsigned int | |
567 | radix_tree_gang_lookup(struct radix_tree_root *root, void **results, | |
568 | unsigned long first_index, unsigned int max_items) | |
569 | { | |
570 | const unsigned long max_index = radix_tree_maxindex(root->height); | |
571 | unsigned long cur_index = first_index; | |
572 | unsigned int ret = 0; | |
573 | ||
574 | while (ret < max_items) { | |
575 | unsigned int nr_found; | |
576 | unsigned long next_index; /* Index of next search */ | |
577 | ||
578 | if (cur_index > max_index) | |
579 | break; | |
580 | nr_found = __lookup(root, results + ret, cur_index, | |
581 | max_items - ret, &next_index); | |
582 | ret += nr_found; | |
583 | if (next_index == 0) | |
584 | break; | |
585 | cur_index = next_index; | |
586 | } | |
587 | return ret; | |
588 | } | |
589 | EXPORT_SYMBOL(radix_tree_gang_lookup); | |
590 | ||
591 | /* | |
592 | * FIXME: the two tag_get()s here should use find_next_bit() instead of | |
593 | * open-coding the search. | |
594 | */ | |
595 | static unsigned int | |
596 | __lookup_tag(struct radix_tree_root *root, void **results, unsigned long index, | |
597 | unsigned int max_items, unsigned long *next_index, int tag) | |
598 | { | |
599 | unsigned int nr_found = 0; | |
600 | unsigned int shift; | |
601 | unsigned int height = root->height; | |
602 | struct radix_tree_node *slot; | |
603 | ||
604 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; | |
605 | slot = root->rnode; | |
606 | ||
607 | while (height > 0) { | |
608 | unsigned long i = (index >> shift) & RADIX_TREE_MAP_MASK; | |
609 | ||
610 | for ( ; i < RADIX_TREE_MAP_SIZE; i++) { | |
611 | if (tag_get(slot, tag, i)) { | |
612 | BUG_ON(slot->slots[i] == NULL); | |
613 | break; | |
614 | } | |
615 | index &= ~((1UL << shift) - 1); | |
616 | index += 1UL << shift; | |
617 | if (index == 0) | |
618 | goto out; /* 32-bit wraparound */ | |
619 | } | |
620 | if (i == RADIX_TREE_MAP_SIZE) | |
621 | goto out; | |
622 | height--; | |
623 | if (height == 0) { /* Bottom level: grab some items */ | |
624 | unsigned long j = index & RADIX_TREE_MAP_MASK; | |
625 | ||
626 | for ( ; j < RADIX_TREE_MAP_SIZE; j++) { | |
627 | index++; | |
628 | if (tag_get(slot, tag, j)) { | |
629 | BUG_ON(slot->slots[j] == NULL); | |
630 | results[nr_found++] = slot->slots[j]; | |
631 | if (nr_found == max_items) | |
632 | goto out; | |
633 | } | |
634 | } | |
635 | } | |
636 | shift -= RADIX_TREE_MAP_SHIFT; | |
637 | slot = slot->slots[i]; | |
638 | } | |
639 | out: | |
640 | *next_index = index; | |
641 | return nr_found; | |
642 | } | |
643 | ||
644 | /** | |
645 | * radix_tree_gang_lookup_tag - perform multiple lookup on a radix tree | |
646 | * based on a tag | |
647 | * @root: radix tree root | |
648 | * @results: where the results of the lookup are placed | |
649 | * @first_index: start the lookup from this key | |
650 | * @max_items: place up to this many items at *results | |
651 | * @tag: the tag index | |
652 | * | |
653 | * Performs an index-ascending scan of the tree for present items which | |
654 | * have the tag indexed by @tag set. Places the items at *@results and | |
655 | * returns the number of items which were placed at *@results. | |
656 | */ | |
657 | unsigned int | |
658 | radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results, | |
659 | unsigned long first_index, unsigned int max_items, int tag) | |
660 | { | |
661 | const unsigned long max_index = radix_tree_maxindex(root->height); | |
662 | unsigned long cur_index = first_index; | |
663 | unsigned int ret = 0; | |
664 | ||
665 | while (ret < max_items) { | |
666 | unsigned int nr_found; | |
667 | unsigned long next_index; /* Index of next search */ | |
668 | ||
669 | if (cur_index > max_index) | |
670 | break; | |
671 | nr_found = __lookup_tag(root, results + ret, cur_index, | |
672 | max_items - ret, &next_index, tag); | |
673 | ret += nr_found; | |
674 | if (next_index == 0) | |
675 | break; | |
676 | cur_index = next_index; | |
677 | } | |
678 | return ret; | |
679 | } | |
680 | EXPORT_SYMBOL(radix_tree_gang_lookup_tag); | |
681 | ||
682 | /** | |
683 | * radix_tree_delete - delete an item from a radix tree | |
684 | * @root: radix tree root | |
685 | * @index: index key | |
686 | * | |
687 | * Remove the item at @index from the radix tree rooted at @root. | |
688 | * | |
689 | * Returns the address of the deleted item, or NULL if it was not present. | |
690 | */ | |
691 | void *radix_tree_delete(struct radix_tree_root *root, unsigned long index) | |
692 | { | |
693 | struct radix_tree_path path[RADIX_TREE_MAX_PATH], *pathp = path; | |
694 | struct radix_tree_path *orig_pathp; | |
201b6264 | 695 | struct radix_tree_node *slot; |
1da177e4 LT |
696 | unsigned int height, shift; |
697 | void *ret = NULL; | |
698 | char tags[RADIX_TREE_TAGS]; | |
699 | int nr_cleared_tags; | |
d5274261 NP |
700 | int tag; |
701 | int offset; | |
1da177e4 LT |
702 | |
703 | height = root->height; | |
704 | if (index > radix_tree_maxindex(height)) | |
705 | goto out; | |
706 | ||
707 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; | |
708 | pathp->node = NULL; | |
201b6264 | 709 | slot = root->rnode; |
1da177e4 | 710 | |
201b6264 | 711 | for ( ; height > 0; height--) { |
201b6264 | 712 | if (slot == NULL) |
1da177e4 LT |
713 | goto out; |
714 | ||
d5274261 | 715 | pathp++; |
1da177e4 | 716 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; |
d5274261 NP |
717 | pathp->offset = offset; |
718 | pathp->node = slot; | |
201b6264 | 719 | slot = slot->slots[offset]; |
1da177e4 | 720 | shift -= RADIX_TREE_MAP_SHIFT; |
1da177e4 LT |
721 | } |
722 | ||
201b6264 | 723 | ret = slot; |
1da177e4 LT |
724 | if (ret == NULL) |
725 | goto out; | |
726 | ||
727 | orig_pathp = pathp; | |
728 | ||
729 | /* | |
730 | * Clear all tags associated with the just-deleted item | |
731 | */ | |
d5274261 NP |
732 | nr_cleared_tags = 0; |
733 | for (tag = 0; tag < RADIX_TREE_TAGS; tag++) { | |
734 | if (tag_get(pathp->node, tag, pathp->offset)) { | |
735 | tag_clear(pathp->node, tag, pathp->offset); | |
736 | tags[tag] = 0; | |
737 | nr_cleared_tags++; | |
738 | } else | |
739 | tags[tag] = 1; | |
740 | } | |
1da177e4 | 741 | |
d5274261 | 742 | for (pathp--; nr_cleared_tags && pathp->node; pathp--) { |
1da177e4 | 743 | for (tag = 0; tag < RADIX_TREE_TAGS; tag++) { |
1da177e4 LT |
744 | if (tags[tag]) |
745 | continue; | |
746 | ||
201b6264 | 747 | tag_clear(pathp->node, tag, pathp->offset); |
6e954b9e NP |
748 | if (any_tag_set(pathp->node, tag)) { |
749 | tags[tag] = 1; | |
750 | nr_cleared_tags--; | |
1da177e4 LT |
751 | } |
752 | } | |
d5274261 | 753 | } |
1da177e4 | 754 | |
201b6264 CL |
755 | /* Now free the nodes we do not need anymore */ |
756 | for (pathp = orig_pathp; pathp->node; pathp--) { | |
757 | pathp->node->slots[pathp->offset] = NULL; | |
758 | if (--pathp->node->count) | |
759 | goto out; | |
760 | ||
761 | /* Node with zero slots in use so free it */ | |
762 | radix_tree_node_free(pathp->node); | |
1da177e4 | 763 | } |
201b6264 CL |
764 | root->rnode = NULL; |
765 | root->height = 0; | |
1da177e4 LT |
766 | out: |
767 | return ret; | |
768 | } | |
769 | EXPORT_SYMBOL(radix_tree_delete); | |
770 | ||
771 | /** | |
772 | * radix_tree_tagged - test whether any items in the tree are tagged | |
773 | * @root: radix tree root | |
774 | * @tag: tag to test | |
775 | */ | |
776 | int radix_tree_tagged(struct radix_tree_root *root, int tag) | |
777 | { | |
6e954b9e NP |
778 | struct radix_tree_node *rnode; |
779 | rnode = root->rnode; | |
780 | if (!rnode) | |
781 | return 0; | |
782 | return any_tag_set(rnode, tag); | |
1da177e4 LT |
783 | } |
784 | EXPORT_SYMBOL(radix_tree_tagged); | |
785 | ||
786 | static void | |
787 | radix_tree_node_ctor(void *node, kmem_cache_t *cachep, unsigned long flags) | |
788 | { | |
789 | memset(node, 0, sizeof(struct radix_tree_node)); | |
790 | } | |
791 | ||
792 | static __init unsigned long __maxindex(unsigned int height) | |
793 | { | |
794 | unsigned int tmp = height * RADIX_TREE_MAP_SHIFT; | |
795 | unsigned long index = (~0UL >> (RADIX_TREE_INDEX_BITS - tmp - 1)) >> 1; | |
796 | ||
797 | if (tmp >= RADIX_TREE_INDEX_BITS) | |
798 | index = ~0UL; | |
799 | return index; | |
800 | } | |
801 | ||
802 | static __init void radix_tree_init_maxindex(void) | |
803 | { | |
804 | unsigned int i; | |
805 | ||
806 | for (i = 0; i < ARRAY_SIZE(height_to_maxindex); i++) | |
807 | height_to_maxindex[i] = __maxindex(i); | |
808 | } | |
809 | ||
810 | #ifdef CONFIG_HOTPLUG_CPU | |
811 | static int radix_tree_callback(struct notifier_block *nfb, | |
812 | unsigned long action, | |
813 | void *hcpu) | |
814 | { | |
815 | int cpu = (long)hcpu; | |
816 | struct radix_tree_preload *rtp; | |
817 | ||
818 | /* Free per-cpu pool of perloaded nodes */ | |
819 | if (action == CPU_DEAD) { | |
820 | rtp = &per_cpu(radix_tree_preloads, cpu); | |
821 | while (rtp->nr) { | |
822 | kmem_cache_free(radix_tree_node_cachep, | |
823 | rtp->nodes[rtp->nr-1]); | |
824 | rtp->nodes[rtp->nr-1] = NULL; | |
825 | rtp->nr--; | |
826 | } | |
827 | } | |
828 | return NOTIFY_OK; | |
829 | } | |
830 | #endif /* CONFIG_HOTPLUG_CPU */ | |
831 | ||
832 | void __init radix_tree_init(void) | |
833 | { | |
834 | radix_tree_node_cachep = kmem_cache_create("radix_tree_node", | |
835 | sizeof(struct radix_tree_node), 0, | |
836 | SLAB_PANIC, radix_tree_node_ctor, NULL); | |
837 | radix_tree_init_maxindex(); | |
838 | hotcpu_notifier(radix_tree_callback, 0); | |
839 | } |