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 */ | |
a5f51c96 | 256 | do { |
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--; | |
a5f51c96 | 274 | } while (height > 0); |
1da177e4 | 275 | |
201b6264 | 276 | if (slot != NULL) |
1da177e4 | 277 | return -EEXIST; |
201b6264 | 278 | |
a5f51c96 NP |
279 | BUG_ON(!node); |
280 | node->count++; | |
281 | node->slots[offset] = item; | |
282 | BUG_ON(tag_get(node, 0, offset)); | |
283 | BUG_ON(tag_get(node, 1, offset)); | |
1da177e4 | 284 | |
1da177e4 LT |
285 | return 0; |
286 | } | |
287 | EXPORT_SYMBOL(radix_tree_insert); | |
288 | ||
a4331366 HR |
289 | static inline void **__lookup_slot(struct radix_tree_root *root, |
290 | unsigned long index) | |
1da177e4 LT |
291 | { |
292 | unsigned int height, shift; | |
a4331366 | 293 | struct radix_tree_node **slot; |
1da177e4 LT |
294 | |
295 | height = root->height; | |
296 | if (index > radix_tree_maxindex(height)) | |
297 | return NULL; | |
298 | ||
299 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; | |
a4331366 | 300 | slot = &root->rnode; |
1da177e4 LT |
301 | |
302 | while (height > 0) { | |
a4331366 | 303 | if (*slot == NULL) |
1da177e4 LT |
304 | return NULL; |
305 | ||
a4331366 HR |
306 | slot = (struct radix_tree_node **) |
307 | ((*slot)->slots + | |
308 | ((index >> shift) & RADIX_TREE_MAP_MASK)); | |
1da177e4 LT |
309 | shift -= RADIX_TREE_MAP_SHIFT; |
310 | height--; | |
311 | } | |
312 | ||
a4331366 HR |
313 | return (void **)slot; |
314 | } | |
315 | ||
316 | /** | |
317 | * radix_tree_lookup_slot - lookup a slot in a radix tree | |
318 | * @root: radix tree root | |
319 | * @index: index key | |
320 | * | |
321 | * Lookup the slot corresponding to the position @index in the radix tree | |
322 | * @root. This is useful for update-if-exists operations. | |
323 | */ | |
324 | void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index) | |
325 | { | |
326 | return __lookup_slot(root, index); | |
327 | } | |
328 | EXPORT_SYMBOL(radix_tree_lookup_slot); | |
329 | ||
330 | /** | |
331 | * radix_tree_lookup - perform lookup operation on a radix tree | |
332 | * @root: radix tree root | |
333 | * @index: index key | |
334 | * | |
335 | * Lookup the item at the position @index in the radix tree @root. | |
336 | */ | |
337 | void *radix_tree_lookup(struct radix_tree_root *root, unsigned long index) | |
338 | { | |
339 | void **slot; | |
340 | ||
341 | slot = __lookup_slot(root, index); | |
342 | return slot != NULL ? *slot : NULL; | |
1da177e4 LT |
343 | } |
344 | EXPORT_SYMBOL(radix_tree_lookup); | |
345 | ||
346 | /** | |
347 | * radix_tree_tag_set - set a tag on a radix tree node | |
348 | * @root: radix tree root | |
349 | * @index: index key | |
350 | * @tag: tag index | |
351 | * | |
352 | * Set the search tag corresponging to @index in the radix tree. From | |
353 | * the root all the way down to the leaf node. | |
354 | * | |
355 | * Returns the address of the tagged item. Setting a tag on a not-present | |
356 | * item is a bug. | |
357 | */ | |
358 | void *radix_tree_tag_set(struct radix_tree_root *root, | |
359 | unsigned long index, int tag) | |
360 | { | |
361 | unsigned int height, shift; | |
201b6264 | 362 | struct radix_tree_node *slot; |
1da177e4 LT |
363 | |
364 | height = root->height; | |
365 | if (index > radix_tree_maxindex(height)) | |
366 | return NULL; | |
367 | ||
368 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; | |
201b6264 | 369 | slot = root->rnode; |
1da177e4 LT |
370 | |
371 | while (height > 0) { | |
372 | int offset; | |
373 | ||
374 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
d5274261 NP |
375 | if (!tag_get(slot, tag, offset)) |
376 | tag_set(slot, tag, offset); | |
201b6264 CL |
377 | slot = slot->slots[offset]; |
378 | BUG_ON(slot == NULL); | |
1da177e4 LT |
379 | shift -= RADIX_TREE_MAP_SHIFT; |
380 | height--; | |
381 | } | |
382 | ||
201b6264 | 383 | return slot; |
1da177e4 LT |
384 | } |
385 | EXPORT_SYMBOL(radix_tree_tag_set); | |
386 | ||
387 | /** | |
388 | * radix_tree_tag_clear - clear a tag on a radix tree node | |
389 | * @root: radix tree root | |
390 | * @index: index key | |
391 | * @tag: tag index | |
392 | * | |
393 | * Clear the search tag corresponging to @index in the radix tree. If | |
394 | * this causes the leaf node to have no tags set then clear the tag in the | |
395 | * next-to-leaf node, etc. | |
396 | * | |
397 | * Returns the address of the tagged item on success, else NULL. ie: | |
398 | * has the same return value and semantics as radix_tree_lookup(). | |
399 | */ | |
400 | void *radix_tree_tag_clear(struct radix_tree_root *root, | |
401 | unsigned long index, int tag) | |
402 | { | |
403 | struct radix_tree_path path[RADIX_TREE_MAX_PATH], *pathp = path; | |
201b6264 | 404 | struct radix_tree_node *slot; |
1da177e4 LT |
405 | unsigned int height, shift; |
406 | void *ret = NULL; | |
407 | ||
408 | height = root->height; | |
409 | if (index > radix_tree_maxindex(height)) | |
410 | goto out; | |
411 | ||
412 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; | |
413 | pathp->node = NULL; | |
201b6264 | 414 | slot = root->rnode; |
1da177e4 LT |
415 | |
416 | while (height > 0) { | |
417 | int offset; | |
418 | ||
201b6264 | 419 | if (slot == NULL) |
1da177e4 LT |
420 | goto out; |
421 | ||
422 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
423 | pathp[1].offset = offset; | |
201b6264 CL |
424 | pathp[1].node = slot; |
425 | slot = slot->slots[offset]; | |
1da177e4 LT |
426 | pathp++; |
427 | shift -= RADIX_TREE_MAP_SHIFT; | |
428 | height--; | |
429 | } | |
430 | ||
201b6264 | 431 | ret = slot; |
1da177e4 LT |
432 | if (ret == NULL) |
433 | goto out; | |
434 | ||
435 | do { | |
d5274261 NP |
436 | if (!tag_get(pathp->node, tag, pathp->offset)) |
437 | goto out; | |
201b6264 | 438 | tag_clear(pathp->node, tag, pathp->offset); |
6e954b9e NP |
439 | if (any_tag_set(pathp->node, tag)) |
440 | goto out; | |
1da177e4 | 441 | pathp--; |
201b6264 | 442 | } while (pathp->node); |
1da177e4 LT |
443 | out: |
444 | return ret; | |
445 | } | |
446 | EXPORT_SYMBOL(radix_tree_tag_clear); | |
447 | ||
448 | #ifndef __KERNEL__ /* Only the test harness uses this at present */ | |
449 | /** | |
32605a18 MT |
450 | * radix_tree_tag_get - get a tag on a radix tree node |
451 | * @root: radix tree root | |
452 | * @index: index key | |
453 | * @tag: tag index | |
1da177e4 | 454 | * |
32605a18 | 455 | * Return values: |
1da177e4 | 456 | * |
32605a18 MT |
457 | * 0: tag not present |
458 | * 1: tag present, set | |
459 | * -1: tag present, unset | |
1da177e4 LT |
460 | */ |
461 | int radix_tree_tag_get(struct radix_tree_root *root, | |
462 | unsigned long index, int tag) | |
463 | { | |
464 | unsigned int height, shift; | |
201b6264 | 465 | struct radix_tree_node *slot; |
1da177e4 LT |
466 | int saw_unset_tag = 0; |
467 | ||
468 | height = root->height; | |
469 | if (index > radix_tree_maxindex(height)) | |
470 | return 0; | |
471 | ||
472 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; | |
201b6264 | 473 | slot = root->rnode; |
1da177e4 LT |
474 | |
475 | for ( ; ; ) { | |
476 | int offset; | |
477 | ||
201b6264 | 478 | if (slot == NULL) |
1da177e4 LT |
479 | return 0; |
480 | ||
481 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
482 | ||
483 | /* | |
484 | * This is just a debug check. Later, we can bale as soon as | |
485 | * we see an unset tag. | |
486 | */ | |
201b6264 | 487 | if (!tag_get(slot, tag, offset)) |
1da177e4 LT |
488 | saw_unset_tag = 1; |
489 | if (height == 1) { | |
201b6264 | 490 | int ret = tag_get(slot, tag, offset); |
1da177e4 LT |
491 | |
492 | BUG_ON(ret && saw_unset_tag); | |
32605a18 | 493 | return ret ? 1 : -1; |
1da177e4 | 494 | } |
201b6264 | 495 | slot = slot->slots[offset]; |
1da177e4 LT |
496 | shift -= RADIX_TREE_MAP_SHIFT; |
497 | height--; | |
498 | } | |
499 | } | |
500 | EXPORT_SYMBOL(radix_tree_tag_get); | |
501 | #endif | |
502 | ||
503 | static unsigned int | |
504 | __lookup(struct radix_tree_root *root, void **results, unsigned long index, | |
505 | unsigned int max_items, unsigned long *next_index) | |
506 | { | |
507 | unsigned int nr_found = 0; | |
201b6264 | 508 | unsigned int shift, height; |
1da177e4 | 509 | struct radix_tree_node *slot; |
201b6264 CL |
510 | unsigned long i; |
511 | ||
512 | height = root->height; | |
513 | if (height == 0) | |
514 | goto out; | |
1da177e4 LT |
515 | |
516 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; | |
517 | slot = root->rnode; | |
518 | ||
201b6264 | 519 | for ( ; height > 1; height--) { |
1da177e4 | 520 | |
201b6264 CL |
521 | for (i = (index >> shift) & RADIX_TREE_MAP_MASK ; |
522 | i < RADIX_TREE_MAP_SIZE; i++) { | |
1da177e4 LT |
523 | if (slot->slots[i] != NULL) |
524 | break; | |
525 | index &= ~((1UL << shift) - 1); | |
526 | index += 1UL << shift; | |
527 | if (index == 0) | |
528 | goto out; /* 32-bit wraparound */ | |
529 | } | |
530 | if (i == RADIX_TREE_MAP_SIZE) | |
531 | goto out; | |
1da177e4 | 532 | |
1da177e4 LT |
533 | shift -= RADIX_TREE_MAP_SHIFT; |
534 | slot = slot->slots[i]; | |
535 | } | |
201b6264 CL |
536 | |
537 | /* Bottom level: grab some items */ | |
538 | for (i = index & RADIX_TREE_MAP_MASK; i < RADIX_TREE_MAP_SIZE; i++) { | |
539 | index++; | |
540 | if (slot->slots[i]) { | |
541 | results[nr_found++] = slot->slots[i]; | |
542 | if (nr_found == max_items) | |
543 | goto out; | |
544 | } | |
545 | } | |
1da177e4 LT |
546 | out: |
547 | *next_index = index; | |
548 | return nr_found; | |
549 | } | |
550 | ||
551 | /** | |
552 | * radix_tree_gang_lookup - perform multiple lookup on a radix tree | |
553 | * @root: radix tree root | |
554 | * @results: where the results of the lookup are placed | |
555 | * @first_index: start the lookup from this key | |
556 | * @max_items: place up to this many items at *results | |
557 | * | |
558 | * Performs an index-ascending scan of the tree for present items. Places | |
559 | * them at *@results and returns the number of items which were placed at | |
560 | * *@results. | |
561 | * | |
562 | * The implementation is naive. | |
563 | */ | |
564 | unsigned int | |
565 | radix_tree_gang_lookup(struct radix_tree_root *root, void **results, | |
566 | unsigned long first_index, unsigned int max_items) | |
567 | { | |
568 | const unsigned long max_index = radix_tree_maxindex(root->height); | |
569 | unsigned long cur_index = first_index; | |
570 | unsigned int ret = 0; | |
571 | ||
572 | while (ret < max_items) { | |
573 | unsigned int nr_found; | |
574 | unsigned long next_index; /* Index of next search */ | |
575 | ||
576 | if (cur_index > max_index) | |
577 | break; | |
578 | nr_found = __lookup(root, results + ret, cur_index, | |
579 | max_items - ret, &next_index); | |
580 | ret += nr_found; | |
581 | if (next_index == 0) | |
582 | break; | |
583 | cur_index = next_index; | |
584 | } | |
585 | return ret; | |
586 | } | |
587 | EXPORT_SYMBOL(radix_tree_gang_lookup); | |
588 | ||
589 | /* | |
590 | * FIXME: the two tag_get()s here should use find_next_bit() instead of | |
591 | * open-coding the search. | |
592 | */ | |
593 | static unsigned int | |
594 | __lookup_tag(struct radix_tree_root *root, void **results, unsigned long index, | |
595 | unsigned int max_items, unsigned long *next_index, int tag) | |
596 | { | |
597 | unsigned int nr_found = 0; | |
598 | unsigned int shift; | |
599 | unsigned int height = root->height; | |
600 | struct radix_tree_node *slot; | |
601 | ||
602 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; | |
603 | slot = root->rnode; | |
604 | ||
605 | while (height > 0) { | |
606 | unsigned long i = (index >> shift) & RADIX_TREE_MAP_MASK; | |
607 | ||
608 | for ( ; i < RADIX_TREE_MAP_SIZE; i++) { | |
609 | if (tag_get(slot, tag, i)) { | |
610 | BUG_ON(slot->slots[i] == NULL); | |
611 | break; | |
612 | } | |
613 | index &= ~((1UL << shift) - 1); | |
614 | index += 1UL << shift; | |
615 | if (index == 0) | |
616 | goto out; /* 32-bit wraparound */ | |
617 | } | |
618 | if (i == RADIX_TREE_MAP_SIZE) | |
619 | goto out; | |
620 | height--; | |
621 | if (height == 0) { /* Bottom level: grab some items */ | |
622 | unsigned long j = index & RADIX_TREE_MAP_MASK; | |
623 | ||
624 | for ( ; j < RADIX_TREE_MAP_SIZE; j++) { | |
625 | index++; | |
626 | if (tag_get(slot, tag, j)) { | |
627 | BUG_ON(slot->slots[j] == NULL); | |
628 | results[nr_found++] = slot->slots[j]; | |
629 | if (nr_found == max_items) | |
630 | goto out; | |
631 | } | |
632 | } | |
633 | } | |
634 | shift -= RADIX_TREE_MAP_SHIFT; | |
635 | slot = slot->slots[i]; | |
636 | } | |
637 | out: | |
638 | *next_index = index; | |
639 | return nr_found; | |
640 | } | |
641 | ||
642 | /** | |
643 | * radix_tree_gang_lookup_tag - perform multiple lookup on a radix tree | |
644 | * based on a tag | |
645 | * @root: radix tree root | |
646 | * @results: where the results of the lookup are placed | |
647 | * @first_index: start the lookup from this key | |
648 | * @max_items: place up to this many items at *results | |
649 | * @tag: the tag index | |
650 | * | |
651 | * Performs an index-ascending scan of the tree for present items which | |
652 | * have the tag indexed by @tag set. Places the items at *@results and | |
653 | * returns the number of items which were placed at *@results. | |
654 | */ | |
655 | unsigned int | |
656 | radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results, | |
657 | unsigned long first_index, unsigned int max_items, int tag) | |
658 | { | |
659 | const unsigned long max_index = radix_tree_maxindex(root->height); | |
660 | unsigned long cur_index = first_index; | |
661 | unsigned int ret = 0; | |
662 | ||
663 | while (ret < max_items) { | |
664 | unsigned int nr_found; | |
665 | unsigned long next_index; /* Index of next search */ | |
666 | ||
667 | if (cur_index > max_index) | |
668 | break; | |
669 | nr_found = __lookup_tag(root, results + ret, cur_index, | |
670 | max_items - ret, &next_index, tag); | |
671 | ret += nr_found; | |
672 | if (next_index == 0) | |
673 | break; | |
674 | cur_index = next_index; | |
675 | } | |
676 | return ret; | |
677 | } | |
678 | EXPORT_SYMBOL(radix_tree_gang_lookup_tag); | |
679 | ||
a5f51c96 NP |
680 | /** |
681 | * radix_tree_shrink - shrink height of a radix tree to minimal | |
682 | * @root radix tree root | |
683 | */ | |
684 | static inline void radix_tree_shrink(struct radix_tree_root *root) | |
685 | { | |
686 | /* try to shrink tree height */ | |
687 | while (root->height > 1 && | |
688 | root->rnode->count == 1 && | |
689 | root->rnode->slots[0]) { | |
690 | struct radix_tree_node *to_free = root->rnode; | |
691 | ||
692 | root->rnode = to_free->slots[0]; | |
693 | root->height--; | |
694 | /* must only free zeroed nodes into the slab */ | |
695 | tag_clear(to_free, 0, 0); | |
696 | tag_clear(to_free, 1, 0); | |
697 | to_free->slots[0] = NULL; | |
698 | to_free->count = 0; | |
699 | radix_tree_node_free(to_free); | |
700 | } | |
701 | } | |
702 | ||
1da177e4 LT |
703 | /** |
704 | * radix_tree_delete - delete an item from a radix tree | |
705 | * @root: radix tree root | |
706 | * @index: index key | |
707 | * | |
708 | * Remove the item at @index from the radix tree rooted at @root. | |
709 | * | |
710 | * Returns the address of the deleted item, or NULL if it was not present. | |
711 | */ | |
712 | void *radix_tree_delete(struct radix_tree_root *root, unsigned long index) | |
713 | { | |
714 | struct radix_tree_path path[RADIX_TREE_MAX_PATH], *pathp = path; | |
715 | struct radix_tree_path *orig_pathp; | |
201b6264 | 716 | struct radix_tree_node *slot; |
1da177e4 LT |
717 | unsigned int height, shift; |
718 | void *ret = NULL; | |
719 | char tags[RADIX_TREE_TAGS]; | |
720 | int nr_cleared_tags; | |
d5274261 NP |
721 | int tag; |
722 | int offset; | |
1da177e4 LT |
723 | |
724 | height = root->height; | |
725 | if (index > radix_tree_maxindex(height)) | |
726 | goto out; | |
727 | ||
728 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; | |
729 | pathp->node = NULL; | |
201b6264 | 730 | slot = root->rnode; |
1da177e4 | 731 | |
201b6264 | 732 | for ( ; height > 0; height--) { |
201b6264 | 733 | if (slot == NULL) |
1da177e4 LT |
734 | goto out; |
735 | ||
d5274261 | 736 | pathp++; |
1da177e4 | 737 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; |
d5274261 NP |
738 | pathp->offset = offset; |
739 | pathp->node = slot; | |
201b6264 | 740 | slot = slot->slots[offset]; |
1da177e4 | 741 | shift -= RADIX_TREE_MAP_SHIFT; |
1da177e4 LT |
742 | } |
743 | ||
201b6264 | 744 | ret = slot; |
1da177e4 LT |
745 | if (ret == NULL) |
746 | goto out; | |
747 | ||
748 | orig_pathp = pathp; | |
749 | ||
750 | /* | |
751 | * Clear all tags associated with the just-deleted item | |
752 | */ | |
d5274261 NP |
753 | nr_cleared_tags = 0; |
754 | for (tag = 0; tag < RADIX_TREE_TAGS; tag++) { | |
90f9dd8f | 755 | tags[tag] = 1; |
d5274261 NP |
756 | if (tag_get(pathp->node, tag, pathp->offset)) { |
757 | tag_clear(pathp->node, tag, pathp->offset); | |
90f9dd8f N |
758 | if (!any_tag_set(pathp->node, tag)) { |
759 | tags[tag] = 0; | |
760 | nr_cleared_tags++; | |
761 | } | |
762 | } | |
d5274261 | 763 | } |
1da177e4 | 764 | |
d5274261 | 765 | for (pathp--; nr_cleared_tags && pathp->node; pathp--) { |
1da177e4 | 766 | for (tag = 0; tag < RADIX_TREE_TAGS; tag++) { |
1da177e4 LT |
767 | if (tags[tag]) |
768 | continue; | |
769 | ||
201b6264 | 770 | tag_clear(pathp->node, tag, pathp->offset); |
6e954b9e NP |
771 | if (any_tag_set(pathp->node, tag)) { |
772 | tags[tag] = 1; | |
773 | nr_cleared_tags--; | |
1da177e4 LT |
774 | } |
775 | } | |
d5274261 | 776 | } |
1da177e4 | 777 | |
201b6264 CL |
778 | /* Now free the nodes we do not need anymore */ |
779 | for (pathp = orig_pathp; pathp->node; pathp--) { | |
780 | pathp->node->slots[pathp->offset] = NULL; | |
a5f51c96 NP |
781 | pathp->node->count--; |
782 | ||
783 | if (pathp->node->count) { | |
784 | if (pathp->node == root->rnode) | |
785 | radix_tree_shrink(root); | |
201b6264 | 786 | goto out; |
a5f51c96 | 787 | } |
201b6264 CL |
788 | |
789 | /* Node with zero slots in use so free it */ | |
790 | radix_tree_node_free(pathp->node); | |
1da177e4 | 791 | } |
201b6264 CL |
792 | root->rnode = NULL; |
793 | root->height = 0; | |
1da177e4 LT |
794 | out: |
795 | return ret; | |
796 | } | |
797 | EXPORT_SYMBOL(radix_tree_delete); | |
798 | ||
799 | /** | |
800 | * radix_tree_tagged - test whether any items in the tree are tagged | |
801 | * @root: radix tree root | |
802 | * @tag: tag to test | |
803 | */ | |
804 | int radix_tree_tagged(struct radix_tree_root *root, int tag) | |
805 | { | |
6e954b9e NP |
806 | struct radix_tree_node *rnode; |
807 | rnode = root->rnode; | |
808 | if (!rnode) | |
809 | return 0; | |
810 | return any_tag_set(rnode, tag); | |
1da177e4 LT |
811 | } |
812 | EXPORT_SYMBOL(radix_tree_tagged); | |
813 | ||
814 | static void | |
815 | radix_tree_node_ctor(void *node, kmem_cache_t *cachep, unsigned long flags) | |
816 | { | |
817 | memset(node, 0, sizeof(struct radix_tree_node)); | |
818 | } | |
819 | ||
820 | static __init unsigned long __maxindex(unsigned int height) | |
821 | { | |
822 | unsigned int tmp = height * RADIX_TREE_MAP_SHIFT; | |
823 | unsigned long index = (~0UL >> (RADIX_TREE_INDEX_BITS - tmp - 1)) >> 1; | |
824 | ||
825 | if (tmp >= RADIX_TREE_INDEX_BITS) | |
826 | index = ~0UL; | |
827 | return index; | |
828 | } | |
829 | ||
830 | static __init void radix_tree_init_maxindex(void) | |
831 | { | |
832 | unsigned int i; | |
833 | ||
834 | for (i = 0; i < ARRAY_SIZE(height_to_maxindex); i++) | |
835 | height_to_maxindex[i] = __maxindex(i); | |
836 | } | |
837 | ||
838 | #ifdef CONFIG_HOTPLUG_CPU | |
839 | static int radix_tree_callback(struct notifier_block *nfb, | |
840 | unsigned long action, | |
841 | void *hcpu) | |
842 | { | |
843 | int cpu = (long)hcpu; | |
844 | struct radix_tree_preload *rtp; | |
845 | ||
846 | /* Free per-cpu pool of perloaded nodes */ | |
847 | if (action == CPU_DEAD) { | |
848 | rtp = &per_cpu(radix_tree_preloads, cpu); | |
849 | while (rtp->nr) { | |
850 | kmem_cache_free(radix_tree_node_cachep, | |
851 | rtp->nodes[rtp->nr-1]); | |
852 | rtp->nodes[rtp->nr-1] = NULL; | |
853 | rtp->nr--; | |
854 | } | |
855 | } | |
856 | return NOTIFY_OK; | |
857 | } | |
858 | #endif /* CONFIG_HOTPLUG_CPU */ | |
859 | ||
860 | void __init radix_tree_init(void) | |
861 | { | |
862 | radix_tree_node_cachep = kmem_cache_create("radix_tree_node", | |
863 | sizeof(struct radix_tree_node), 0, | |
864 | SLAB_PANIC, radix_tree_node_ctor, NULL); | |
865 | radix_tree_init_maxindex(); | |
866 | hotcpu_notifier(radix_tree_callback, 0); | |
867 | } |