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 | |
1da177e4 LT |
40 | |
41 | #define RADIX_TREE_MAP_SIZE (1UL << RADIX_TREE_MAP_SHIFT) | |
42 | #define RADIX_TREE_MAP_MASK (RADIX_TREE_MAP_SIZE-1) | |
43 | ||
44 | #define RADIX_TREE_TAG_LONGS \ | |
45 | ((RADIX_TREE_MAP_SIZE + BITS_PER_LONG - 1) / BITS_PER_LONG) | |
46 | ||
47 | struct radix_tree_node { | |
48 | unsigned int count; | |
49 | void *slots[RADIX_TREE_MAP_SIZE]; | |
daff89f3 | 50 | unsigned long tags[RADIX_TREE_MAX_TAGS][RADIX_TREE_TAG_LONGS]; |
1da177e4 LT |
51 | }; |
52 | ||
53 | struct radix_tree_path { | |
201b6264 | 54 | struct radix_tree_node *node; |
1da177e4 LT |
55 | int offset; |
56 | }; | |
57 | ||
58 | #define RADIX_TREE_INDEX_BITS (8 /* CHAR_BIT */ * sizeof(unsigned long)) | |
59 | #define RADIX_TREE_MAX_PATH (RADIX_TREE_INDEX_BITS/RADIX_TREE_MAP_SHIFT + 2) | |
60 | ||
6c036527 | 61 | static unsigned long height_to_maxindex[RADIX_TREE_MAX_PATH] __read_mostly; |
1da177e4 LT |
62 | |
63 | /* | |
64 | * Radix tree node cache. | |
65 | */ | |
66 | static kmem_cache_t *radix_tree_node_cachep; | |
67 | ||
68 | /* | |
69 | * Per-cpu pool of preloaded nodes | |
70 | */ | |
71 | struct radix_tree_preload { | |
72 | int nr; | |
73 | struct radix_tree_node *nodes[RADIX_TREE_MAX_PATH]; | |
74 | }; | |
75 | DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, }; | |
76 | ||
612d6c19 NP |
77 | static inline gfp_t root_gfp_mask(struct radix_tree_root *root) |
78 | { | |
79 | return root->gfp_mask & __GFP_BITS_MASK; | |
80 | } | |
81 | ||
1da177e4 LT |
82 | /* |
83 | * This assumes that the caller has performed appropriate preallocation, and | |
84 | * that the caller has pinned this thread of control to the current CPU. | |
85 | */ | |
86 | static struct radix_tree_node * | |
87 | radix_tree_node_alloc(struct radix_tree_root *root) | |
88 | { | |
89 | struct radix_tree_node *ret; | |
612d6c19 | 90 | gfp_t gfp_mask = root_gfp_mask(root); |
1da177e4 | 91 | |
612d6c19 NP |
92 | ret = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask); |
93 | if (ret == NULL && !(gfp_mask & __GFP_WAIT)) { | |
1da177e4 LT |
94 | struct radix_tree_preload *rtp; |
95 | ||
96 | rtp = &__get_cpu_var(radix_tree_preloads); | |
97 | if (rtp->nr) { | |
98 | ret = rtp->nodes[rtp->nr - 1]; | |
99 | rtp->nodes[rtp->nr - 1] = NULL; | |
100 | rtp->nr--; | |
101 | } | |
102 | } | |
103 | return ret; | |
104 | } | |
105 | ||
106 | static inline void | |
107 | radix_tree_node_free(struct radix_tree_node *node) | |
108 | { | |
109 | kmem_cache_free(radix_tree_node_cachep, node); | |
110 | } | |
111 | ||
112 | /* | |
113 | * Load up this CPU's radix_tree_node buffer with sufficient objects to | |
114 | * ensure that the addition of a single element in the tree cannot fail. On | |
115 | * success, return zero, with preemption disabled. On error, return -ENOMEM | |
116 | * with preemption not disabled. | |
117 | */ | |
dd0fc66f | 118 | int radix_tree_preload(gfp_t gfp_mask) |
1da177e4 LT |
119 | { |
120 | struct radix_tree_preload *rtp; | |
121 | struct radix_tree_node *node; | |
122 | int ret = -ENOMEM; | |
123 | ||
124 | preempt_disable(); | |
125 | rtp = &__get_cpu_var(radix_tree_preloads); | |
126 | while (rtp->nr < ARRAY_SIZE(rtp->nodes)) { | |
127 | preempt_enable(); | |
128 | node = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask); | |
129 | if (node == NULL) | |
130 | goto out; | |
131 | preempt_disable(); | |
132 | rtp = &__get_cpu_var(radix_tree_preloads); | |
133 | if (rtp->nr < ARRAY_SIZE(rtp->nodes)) | |
134 | rtp->nodes[rtp->nr++] = node; | |
135 | else | |
136 | kmem_cache_free(radix_tree_node_cachep, node); | |
137 | } | |
138 | ret = 0; | |
139 | out: | |
140 | return ret; | |
141 | } | |
142 | ||
daff89f3 JC |
143 | static inline void tag_set(struct radix_tree_node *node, unsigned int tag, |
144 | int offset) | |
1da177e4 | 145 | { |
d5274261 | 146 | __set_bit(offset, node->tags[tag]); |
1da177e4 LT |
147 | } |
148 | ||
daff89f3 JC |
149 | static inline void tag_clear(struct radix_tree_node *node, unsigned int tag, |
150 | int offset) | |
1da177e4 | 151 | { |
d5274261 | 152 | __clear_bit(offset, node->tags[tag]); |
1da177e4 LT |
153 | } |
154 | ||
daff89f3 JC |
155 | static inline int tag_get(struct radix_tree_node *node, unsigned int tag, |
156 | int offset) | |
1da177e4 | 157 | { |
d5274261 | 158 | return test_bit(offset, node->tags[tag]); |
1da177e4 LT |
159 | } |
160 | ||
612d6c19 NP |
161 | static inline void root_tag_set(struct radix_tree_root *root, unsigned int tag) |
162 | { | |
163 | root->gfp_mask |= (1 << (tag + __GFP_BITS_SHIFT)); | |
164 | } | |
165 | ||
166 | ||
167 | static inline void root_tag_clear(struct radix_tree_root *root, unsigned int tag) | |
168 | { | |
169 | root->gfp_mask &= ~(1 << (tag + __GFP_BITS_SHIFT)); | |
170 | } | |
171 | ||
172 | static inline void root_tag_clear_all(struct radix_tree_root *root) | |
173 | { | |
174 | root->gfp_mask &= __GFP_BITS_MASK; | |
175 | } | |
176 | ||
177 | static inline int root_tag_get(struct radix_tree_root *root, unsigned int tag) | |
178 | { | |
179 | return root->gfp_mask & (1 << (tag + __GFP_BITS_SHIFT)); | |
180 | } | |
181 | ||
6e954b9e NP |
182 | /* |
183 | * Returns 1 if any slot in the node has this tag set. | |
184 | * Otherwise returns 0. | |
185 | */ | |
daff89f3 | 186 | static inline int any_tag_set(struct radix_tree_node *node, unsigned int tag) |
6e954b9e NP |
187 | { |
188 | int idx; | |
189 | for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) { | |
190 | if (node->tags[tag][idx]) | |
191 | return 1; | |
192 | } | |
193 | return 0; | |
194 | } | |
195 | ||
1da177e4 LT |
196 | /* |
197 | * Return the maximum key which can be store into a | |
198 | * radix tree with height HEIGHT. | |
199 | */ | |
200 | static inline unsigned long radix_tree_maxindex(unsigned int height) | |
201 | { | |
202 | return height_to_maxindex[height]; | |
203 | } | |
204 | ||
205 | /* | |
206 | * Extend a radix tree so it can store key @index. | |
207 | */ | |
208 | static int radix_tree_extend(struct radix_tree_root *root, unsigned long index) | |
209 | { | |
210 | struct radix_tree_node *node; | |
211 | unsigned int height; | |
1da177e4 LT |
212 | int tag; |
213 | ||
214 | /* Figure out what the height should be. */ | |
215 | height = root->height + 1; | |
216 | while (index > radix_tree_maxindex(height)) | |
217 | height++; | |
218 | ||
219 | if (root->rnode == NULL) { | |
220 | root->height = height; | |
221 | goto out; | |
222 | } | |
223 | ||
1da177e4 LT |
224 | do { |
225 | if (!(node = radix_tree_node_alloc(root))) | |
226 | return -ENOMEM; | |
227 | ||
228 | /* Increase the height. */ | |
229 | node->slots[0] = root->rnode; | |
230 | ||
231 | /* Propagate the aggregated tag info into the new root */ | |
daff89f3 | 232 | for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { |
612d6c19 | 233 | if (root_tag_get(root, tag)) |
1da177e4 LT |
234 | tag_set(node, tag, 0); |
235 | } | |
236 | ||
237 | node->count = 1; | |
238 | root->rnode = node; | |
239 | root->height++; | |
240 | } while (height > root->height); | |
241 | out: | |
242 | return 0; | |
243 | } | |
244 | ||
245 | /** | |
246 | * radix_tree_insert - insert into a radix tree | |
247 | * @root: radix tree root | |
248 | * @index: index key | |
249 | * @item: item to insert | |
250 | * | |
251 | * Insert an item into the radix tree at position @index. | |
252 | */ | |
253 | int radix_tree_insert(struct radix_tree_root *root, | |
254 | unsigned long index, void *item) | |
255 | { | |
201b6264 | 256 | struct radix_tree_node *node = NULL, *slot; |
1da177e4 LT |
257 | unsigned int height, shift; |
258 | int offset; | |
259 | int error; | |
260 | ||
261 | /* Make sure the tree is high enough. */ | |
612d6c19 | 262 | if (index > radix_tree_maxindex(root->height)) { |
1da177e4 LT |
263 | error = radix_tree_extend(root, index); |
264 | if (error) | |
265 | return error; | |
266 | } | |
267 | ||
201b6264 | 268 | slot = root->rnode; |
1da177e4 LT |
269 | height = root->height; |
270 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; | |
271 | ||
272 | offset = 0; /* uninitialised var warning */ | |
612d6c19 | 273 | while (height > 0) { |
201b6264 | 274 | if (slot == NULL) { |
1da177e4 | 275 | /* Have to add a child node. */ |
201b6264 | 276 | if (!(slot = radix_tree_node_alloc(root))) |
1da177e4 | 277 | return -ENOMEM; |
201b6264 CL |
278 | if (node) { |
279 | node->slots[offset] = slot; | |
1da177e4 | 280 | node->count++; |
201b6264 CL |
281 | } else |
282 | root->rnode = slot; | |
1da177e4 LT |
283 | } |
284 | ||
285 | /* Go a level down */ | |
286 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
201b6264 CL |
287 | node = slot; |
288 | slot = node->slots[offset]; | |
1da177e4 LT |
289 | shift -= RADIX_TREE_MAP_SHIFT; |
290 | height--; | |
612d6c19 | 291 | } |
1da177e4 | 292 | |
201b6264 | 293 | if (slot != NULL) |
1da177e4 | 294 | return -EEXIST; |
201b6264 | 295 | |
612d6c19 NP |
296 | if (node) { |
297 | node->count++; | |
298 | node->slots[offset] = item; | |
299 | BUG_ON(tag_get(node, 0, offset)); | |
300 | BUG_ON(tag_get(node, 1, offset)); | |
301 | } else { | |
302 | root->rnode = item; | |
303 | BUG_ON(root_tag_get(root, 0)); | |
304 | BUG_ON(root_tag_get(root, 1)); | |
305 | } | |
1da177e4 | 306 | |
1da177e4 LT |
307 | return 0; |
308 | } | |
309 | EXPORT_SYMBOL(radix_tree_insert); | |
310 | ||
a4331366 HR |
311 | static inline void **__lookup_slot(struct radix_tree_root *root, |
312 | unsigned long index) | |
1da177e4 LT |
313 | { |
314 | unsigned int height, shift; | |
a4331366 | 315 | struct radix_tree_node **slot; |
1da177e4 LT |
316 | |
317 | height = root->height; | |
612d6c19 | 318 | |
1da177e4 LT |
319 | if (index > radix_tree_maxindex(height)) |
320 | return NULL; | |
321 | ||
612d6c19 NP |
322 | if (height == 0 && root->rnode) |
323 | return (void **)&root->rnode; | |
324 | ||
1da177e4 | 325 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; |
a4331366 | 326 | slot = &root->rnode; |
1da177e4 LT |
327 | |
328 | while (height > 0) { | |
a4331366 | 329 | if (*slot == NULL) |
1da177e4 LT |
330 | return NULL; |
331 | ||
a4331366 HR |
332 | slot = (struct radix_tree_node **) |
333 | ((*slot)->slots + | |
334 | ((index >> shift) & RADIX_TREE_MAP_MASK)); | |
1da177e4 LT |
335 | shift -= RADIX_TREE_MAP_SHIFT; |
336 | height--; | |
337 | } | |
338 | ||
a4331366 HR |
339 | return (void **)slot; |
340 | } | |
341 | ||
342 | /** | |
343 | * radix_tree_lookup_slot - lookup a slot in a radix tree | |
344 | * @root: radix tree root | |
345 | * @index: index key | |
346 | * | |
347 | * Lookup the slot corresponding to the position @index in the radix tree | |
348 | * @root. This is useful for update-if-exists operations. | |
349 | */ | |
350 | void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index) | |
351 | { | |
352 | return __lookup_slot(root, index); | |
353 | } | |
354 | EXPORT_SYMBOL(radix_tree_lookup_slot); | |
355 | ||
356 | /** | |
357 | * radix_tree_lookup - perform lookup operation on a radix tree | |
358 | * @root: radix tree root | |
359 | * @index: index key | |
360 | * | |
361 | * Lookup the item at the position @index in the radix tree @root. | |
362 | */ | |
363 | void *radix_tree_lookup(struct radix_tree_root *root, unsigned long index) | |
364 | { | |
365 | void **slot; | |
366 | ||
367 | slot = __lookup_slot(root, index); | |
368 | return slot != NULL ? *slot : NULL; | |
1da177e4 LT |
369 | } |
370 | EXPORT_SYMBOL(radix_tree_lookup); | |
371 | ||
372 | /** | |
373 | * radix_tree_tag_set - set a tag on a radix tree node | |
374 | * @root: radix tree root | |
375 | * @index: index key | |
376 | * @tag: tag index | |
377 | * | |
daff89f3 JC |
378 | * Set the search tag (which must be < RADIX_TREE_MAX_TAGS) |
379 | * corresponding to @index in the radix tree. From | |
1da177e4 LT |
380 | * the root all the way down to the leaf node. |
381 | * | |
382 | * Returns the address of the tagged item. Setting a tag on a not-present | |
383 | * item is a bug. | |
384 | */ | |
385 | void *radix_tree_tag_set(struct radix_tree_root *root, | |
daff89f3 | 386 | unsigned long index, unsigned int tag) |
1da177e4 LT |
387 | { |
388 | unsigned int height, shift; | |
201b6264 | 389 | struct radix_tree_node *slot; |
1da177e4 LT |
390 | |
391 | height = root->height; | |
392 | if (index > radix_tree_maxindex(height)) | |
393 | return NULL; | |
394 | ||
201b6264 | 395 | slot = root->rnode; |
612d6c19 | 396 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; |
1da177e4 LT |
397 | |
398 | while (height > 0) { | |
399 | int offset; | |
400 | ||
401 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
d5274261 NP |
402 | if (!tag_get(slot, tag, offset)) |
403 | tag_set(slot, tag, offset); | |
201b6264 CL |
404 | slot = slot->slots[offset]; |
405 | BUG_ON(slot == NULL); | |
1da177e4 LT |
406 | shift -= RADIX_TREE_MAP_SHIFT; |
407 | height--; | |
408 | } | |
409 | ||
612d6c19 NP |
410 | /* set the root's tag bit */ |
411 | if (slot && !root_tag_get(root, tag)) | |
412 | root_tag_set(root, tag); | |
413 | ||
201b6264 | 414 | return slot; |
1da177e4 LT |
415 | } |
416 | EXPORT_SYMBOL(radix_tree_tag_set); | |
417 | ||
418 | /** | |
419 | * radix_tree_tag_clear - clear a tag on a radix tree node | |
420 | * @root: radix tree root | |
421 | * @index: index key | |
422 | * @tag: tag index | |
423 | * | |
daff89f3 JC |
424 | * Clear the search tag (which must be < RADIX_TREE_MAX_TAGS) |
425 | * corresponding to @index in the radix tree. If | |
1da177e4 LT |
426 | * this causes the leaf node to have no tags set then clear the tag in the |
427 | * next-to-leaf node, etc. | |
428 | * | |
429 | * Returns the address of the tagged item on success, else NULL. ie: | |
430 | * has the same return value and semantics as radix_tree_lookup(). | |
431 | */ | |
432 | void *radix_tree_tag_clear(struct radix_tree_root *root, | |
daff89f3 | 433 | unsigned long index, unsigned int tag) |
1da177e4 LT |
434 | { |
435 | struct radix_tree_path path[RADIX_TREE_MAX_PATH], *pathp = path; | |
612d6c19 | 436 | struct radix_tree_node *slot = NULL; |
1da177e4 | 437 | unsigned int height, shift; |
1da177e4 LT |
438 | |
439 | height = root->height; | |
440 | if (index > radix_tree_maxindex(height)) | |
441 | goto out; | |
442 | ||
443 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; | |
444 | pathp->node = NULL; | |
201b6264 | 445 | slot = root->rnode; |
1da177e4 LT |
446 | |
447 | while (height > 0) { | |
448 | int offset; | |
449 | ||
201b6264 | 450 | if (slot == NULL) |
1da177e4 LT |
451 | goto out; |
452 | ||
453 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
454 | pathp[1].offset = offset; | |
201b6264 CL |
455 | pathp[1].node = slot; |
456 | slot = slot->slots[offset]; | |
1da177e4 LT |
457 | pathp++; |
458 | shift -= RADIX_TREE_MAP_SHIFT; | |
459 | height--; | |
460 | } | |
461 | ||
612d6c19 | 462 | if (slot == NULL) |
1da177e4 LT |
463 | goto out; |
464 | ||
612d6c19 | 465 | while (pathp->node) { |
d5274261 NP |
466 | if (!tag_get(pathp->node, tag, pathp->offset)) |
467 | goto out; | |
201b6264 | 468 | tag_clear(pathp->node, tag, pathp->offset); |
6e954b9e NP |
469 | if (any_tag_set(pathp->node, tag)) |
470 | goto out; | |
1da177e4 | 471 | pathp--; |
612d6c19 NP |
472 | } |
473 | ||
474 | /* clear the root's tag bit */ | |
475 | if (root_tag_get(root, tag)) | |
476 | root_tag_clear(root, tag); | |
477 | ||
1da177e4 | 478 | out: |
612d6c19 | 479 | return slot; |
1da177e4 LT |
480 | } |
481 | EXPORT_SYMBOL(radix_tree_tag_clear); | |
482 | ||
483 | #ifndef __KERNEL__ /* Only the test harness uses this at present */ | |
484 | /** | |
32605a18 MT |
485 | * radix_tree_tag_get - get a tag on a radix tree node |
486 | * @root: radix tree root | |
487 | * @index: index key | |
daff89f3 | 488 | * @tag: tag index (< RADIX_TREE_MAX_TAGS) |
1da177e4 | 489 | * |
32605a18 | 490 | * Return values: |
1da177e4 | 491 | * |
612d6c19 NP |
492 | * 0: tag not present or not set |
493 | * 1: tag set | |
1da177e4 LT |
494 | */ |
495 | int radix_tree_tag_get(struct radix_tree_root *root, | |
daff89f3 | 496 | unsigned long index, unsigned int tag) |
1da177e4 LT |
497 | { |
498 | unsigned int height, shift; | |
201b6264 | 499 | struct radix_tree_node *slot; |
1da177e4 LT |
500 | int saw_unset_tag = 0; |
501 | ||
502 | height = root->height; | |
503 | if (index > radix_tree_maxindex(height)) | |
504 | return 0; | |
505 | ||
612d6c19 NP |
506 | /* check the root's tag bit */ |
507 | if (!root_tag_get(root, tag)) | |
508 | return 0; | |
509 | ||
510 | if (height == 0) | |
511 | return 1; | |
512 | ||
1da177e4 | 513 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; |
201b6264 | 514 | slot = root->rnode; |
1da177e4 LT |
515 | |
516 | for ( ; ; ) { | |
517 | int offset; | |
518 | ||
201b6264 | 519 | if (slot == NULL) |
1da177e4 LT |
520 | return 0; |
521 | ||
522 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
523 | ||
524 | /* | |
525 | * This is just a debug check. Later, we can bale as soon as | |
526 | * we see an unset tag. | |
527 | */ | |
201b6264 | 528 | if (!tag_get(slot, tag, offset)) |
1da177e4 LT |
529 | saw_unset_tag = 1; |
530 | if (height == 1) { | |
201b6264 | 531 | int ret = tag_get(slot, tag, offset); |
1da177e4 LT |
532 | |
533 | BUG_ON(ret && saw_unset_tag); | |
612d6c19 | 534 | return ret; |
1da177e4 | 535 | } |
201b6264 | 536 | slot = slot->slots[offset]; |
1da177e4 LT |
537 | shift -= RADIX_TREE_MAP_SHIFT; |
538 | height--; | |
539 | } | |
540 | } | |
541 | EXPORT_SYMBOL(radix_tree_tag_get); | |
542 | #endif | |
543 | ||
544 | static unsigned int | |
545 | __lookup(struct radix_tree_root *root, void **results, unsigned long index, | |
546 | unsigned int max_items, unsigned long *next_index) | |
547 | { | |
548 | unsigned int nr_found = 0; | |
201b6264 | 549 | unsigned int shift, height; |
1da177e4 | 550 | struct radix_tree_node *slot; |
201b6264 CL |
551 | unsigned long i; |
552 | ||
553 | height = root->height; | |
612d6c19 NP |
554 | if (height == 0) { |
555 | if (root->rnode && index == 0) | |
556 | results[nr_found++] = root->rnode; | |
201b6264 | 557 | goto out; |
612d6c19 | 558 | } |
1da177e4 LT |
559 | |
560 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; | |
561 | slot = root->rnode; | |
562 | ||
201b6264 | 563 | for ( ; height > 1; height--) { |
1da177e4 | 564 | |
201b6264 CL |
565 | for (i = (index >> shift) & RADIX_TREE_MAP_MASK ; |
566 | i < RADIX_TREE_MAP_SIZE; i++) { | |
1da177e4 LT |
567 | if (slot->slots[i] != NULL) |
568 | break; | |
569 | index &= ~((1UL << shift) - 1); | |
570 | index += 1UL << shift; | |
571 | if (index == 0) | |
572 | goto out; /* 32-bit wraparound */ | |
573 | } | |
574 | if (i == RADIX_TREE_MAP_SIZE) | |
575 | goto out; | |
1da177e4 | 576 | |
1da177e4 LT |
577 | shift -= RADIX_TREE_MAP_SHIFT; |
578 | slot = slot->slots[i]; | |
579 | } | |
201b6264 CL |
580 | |
581 | /* Bottom level: grab some items */ | |
582 | for (i = index & RADIX_TREE_MAP_MASK; i < RADIX_TREE_MAP_SIZE; i++) { | |
583 | index++; | |
584 | if (slot->slots[i]) { | |
585 | results[nr_found++] = slot->slots[i]; | |
586 | if (nr_found == max_items) | |
587 | goto out; | |
588 | } | |
589 | } | |
1da177e4 LT |
590 | out: |
591 | *next_index = index; | |
592 | return nr_found; | |
593 | } | |
594 | ||
595 | /** | |
596 | * radix_tree_gang_lookup - perform multiple lookup on a radix tree | |
597 | * @root: radix tree root | |
598 | * @results: where the results of the lookup are placed | |
599 | * @first_index: start the lookup from this key | |
600 | * @max_items: place up to this many items at *results | |
601 | * | |
602 | * Performs an index-ascending scan of the tree for present items. Places | |
603 | * them at *@results and returns the number of items which were placed at | |
604 | * *@results. | |
605 | * | |
606 | * The implementation is naive. | |
607 | */ | |
608 | unsigned int | |
609 | radix_tree_gang_lookup(struct radix_tree_root *root, void **results, | |
610 | unsigned long first_index, unsigned int max_items) | |
611 | { | |
612 | const unsigned long max_index = radix_tree_maxindex(root->height); | |
613 | unsigned long cur_index = first_index; | |
614 | unsigned int ret = 0; | |
615 | ||
616 | while (ret < max_items) { | |
617 | unsigned int nr_found; | |
618 | unsigned long next_index; /* Index of next search */ | |
619 | ||
620 | if (cur_index > max_index) | |
621 | break; | |
622 | nr_found = __lookup(root, results + ret, cur_index, | |
623 | max_items - ret, &next_index); | |
624 | ret += nr_found; | |
625 | if (next_index == 0) | |
626 | break; | |
627 | cur_index = next_index; | |
628 | } | |
629 | return ret; | |
630 | } | |
631 | EXPORT_SYMBOL(radix_tree_gang_lookup); | |
632 | ||
633 | /* | |
634 | * FIXME: the two tag_get()s here should use find_next_bit() instead of | |
635 | * open-coding the search. | |
636 | */ | |
637 | static unsigned int | |
638 | __lookup_tag(struct radix_tree_root *root, void **results, unsigned long index, | |
daff89f3 | 639 | unsigned int max_items, unsigned long *next_index, unsigned int tag) |
1da177e4 LT |
640 | { |
641 | unsigned int nr_found = 0; | |
642 | unsigned int shift; | |
643 | unsigned int height = root->height; | |
644 | struct radix_tree_node *slot; | |
645 | ||
612d6c19 NP |
646 | if (height == 0) { |
647 | if (root->rnode && index == 0) | |
648 | results[nr_found++] = root->rnode; | |
649 | goto out; | |
650 | } | |
651 | ||
1da177e4 LT |
652 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; |
653 | slot = root->rnode; | |
654 | ||
612d6c19 | 655 | do { |
1da177e4 LT |
656 | unsigned long i = (index >> shift) & RADIX_TREE_MAP_MASK; |
657 | ||
658 | for ( ; i < RADIX_TREE_MAP_SIZE; i++) { | |
659 | if (tag_get(slot, tag, i)) { | |
660 | BUG_ON(slot->slots[i] == NULL); | |
661 | break; | |
662 | } | |
663 | index &= ~((1UL << shift) - 1); | |
664 | index += 1UL << shift; | |
665 | if (index == 0) | |
666 | goto out; /* 32-bit wraparound */ | |
667 | } | |
668 | if (i == RADIX_TREE_MAP_SIZE) | |
669 | goto out; | |
670 | height--; | |
671 | if (height == 0) { /* Bottom level: grab some items */ | |
672 | unsigned long j = index & RADIX_TREE_MAP_MASK; | |
673 | ||
674 | for ( ; j < RADIX_TREE_MAP_SIZE; j++) { | |
675 | index++; | |
676 | if (tag_get(slot, tag, j)) { | |
677 | BUG_ON(slot->slots[j] == NULL); | |
678 | results[nr_found++] = slot->slots[j]; | |
679 | if (nr_found == max_items) | |
680 | goto out; | |
681 | } | |
682 | } | |
683 | } | |
684 | shift -= RADIX_TREE_MAP_SHIFT; | |
685 | slot = slot->slots[i]; | |
612d6c19 | 686 | } while (height > 0); |
1da177e4 LT |
687 | out: |
688 | *next_index = index; | |
689 | return nr_found; | |
690 | } | |
691 | ||
692 | /** | |
693 | * radix_tree_gang_lookup_tag - perform multiple lookup on a radix tree | |
694 | * based on a tag | |
695 | * @root: radix tree root | |
696 | * @results: where the results of the lookup are placed | |
697 | * @first_index: start the lookup from this key | |
698 | * @max_items: place up to this many items at *results | |
daff89f3 | 699 | * @tag: the tag index (< RADIX_TREE_MAX_TAGS) |
1da177e4 LT |
700 | * |
701 | * Performs an index-ascending scan of the tree for present items which | |
702 | * have the tag indexed by @tag set. Places the items at *@results and | |
703 | * returns the number of items which were placed at *@results. | |
704 | */ | |
705 | unsigned int | |
706 | radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results, | |
daff89f3 JC |
707 | unsigned long first_index, unsigned int max_items, |
708 | unsigned int tag) | |
1da177e4 LT |
709 | { |
710 | const unsigned long max_index = radix_tree_maxindex(root->height); | |
711 | unsigned long cur_index = first_index; | |
712 | unsigned int ret = 0; | |
713 | ||
612d6c19 NP |
714 | /* check the root's tag bit */ |
715 | if (!root_tag_get(root, tag)) | |
716 | return 0; | |
717 | ||
1da177e4 LT |
718 | while (ret < max_items) { |
719 | unsigned int nr_found; | |
720 | unsigned long next_index; /* Index of next search */ | |
721 | ||
722 | if (cur_index > max_index) | |
723 | break; | |
724 | nr_found = __lookup_tag(root, results + ret, cur_index, | |
725 | max_items - ret, &next_index, tag); | |
726 | ret += nr_found; | |
727 | if (next_index == 0) | |
728 | break; | |
729 | cur_index = next_index; | |
730 | } | |
731 | return ret; | |
732 | } | |
733 | EXPORT_SYMBOL(radix_tree_gang_lookup_tag); | |
734 | ||
a5f51c96 NP |
735 | /** |
736 | * radix_tree_shrink - shrink height of a radix tree to minimal | |
737 | * @root radix tree root | |
738 | */ | |
739 | static inline void radix_tree_shrink(struct radix_tree_root *root) | |
740 | { | |
741 | /* try to shrink tree height */ | |
612d6c19 | 742 | while (root->height > 0 && |
a5f51c96 NP |
743 | root->rnode->count == 1 && |
744 | root->rnode->slots[0]) { | |
745 | struct radix_tree_node *to_free = root->rnode; | |
746 | ||
747 | root->rnode = to_free->slots[0]; | |
748 | root->height--; | |
749 | /* must only free zeroed nodes into the slab */ | |
750 | tag_clear(to_free, 0, 0); | |
751 | tag_clear(to_free, 1, 0); | |
752 | to_free->slots[0] = NULL; | |
753 | to_free->count = 0; | |
754 | radix_tree_node_free(to_free); | |
755 | } | |
756 | } | |
757 | ||
1da177e4 LT |
758 | /** |
759 | * radix_tree_delete - delete an item from a radix tree | |
760 | * @root: radix tree root | |
761 | * @index: index key | |
762 | * | |
763 | * Remove the item at @index from the radix tree rooted at @root. | |
764 | * | |
765 | * Returns the address of the deleted item, or NULL if it was not present. | |
766 | */ | |
767 | void *radix_tree_delete(struct radix_tree_root *root, unsigned long index) | |
768 | { | |
769 | struct radix_tree_path path[RADIX_TREE_MAX_PATH], *pathp = path; | |
612d6c19 | 770 | struct radix_tree_node *slot = NULL; |
1da177e4 | 771 | unsigned int height, shift; |
d5274261 NP |
772 | int tag; |
773 | int offset; | |
1da177e4 LT |
774 | |
775 | height = root->height; | |
776 | if (index > radix_tree_maxindex(height)) | |
777 | goto out; | |
778 | ||
612d6c19 NP |
779 | slot = root->rnode; |
780 | if (height == 0 && root->rnode) { | |
781 | root_tag_clear_all(root); | |
782 | root->rnode = NULL; | |
783 | goto out; | |
784 | } | |
785 | ||
1da177e4 LT |
786 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; |
787 | pathp->node = NULL; | |
1da177e4 | 788 | |
612d6c19 | 789 | do { |
201b6264 | 790 | if (slot == NULL) |
1da177e4 LT |
791 | goto out; |
792 | ||
d5274261 | 793 | pathp++; |
1da177e4 | 794 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; |
d5274261 NP |
795 | pathp->offset = offset; |
796 | pathp->node = slot; | |
201b6264 | 797 | slot = slot->slots[offset]; |
1da177e4 | 798 | shift -= RADIX_TREE_MAP_SHIFT; |
612d6c19 NP |
799 | height--; |
800 | } while (height > 0); | |
1da177e4 | 801 | |
612d6c19 | 802 | if (slot == NULL) |
1da177e4 LT |
803 | goto out; |
804 | ||
1da177e4 LT |
805 | /* |
806 | * Clear all tags associated with the just-deleted item | |
807 | */ | |
daff89f3 | 808 | for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { |
612d6c19 NP |
809 | if (tag_get(pathp->node, tag, pathp->offset)) |
810 | radix_tree_tag_clear(root, index, tag); | |
d5274261 | 811 | } |
1da177e4 | 812 | |
201b6264 | 813 | /* Now free the nodes we do not need anymore */ |
612d6c19 | 814 | while (pathp->node) { |
201b6264 | 815 | pathp->node->slots[pathp->offset] = NULL; |
a5f51c96 NP |
816 | pathp->node->count--; |
817 | ||
818 | if (pathp->node->count) { | |
819 | if (pathp->node == root->rnode) | |
820 | radix_tree_shrink(root); | |
201b6264 | 821 | goto out; |
a5f51c96 | 822 | } |
201b6264 CL |
823 | |
824 | /* Node with zero slots in use so free it */ | |
825 | radix_tree_node_free(pathp->node); | |
612d6c19 NP |
826 | |
827 | pathp--; | |
1da177e4 | 828 | } |
612d6c19 | 829 | root_tag_clear_all(root); |
201b6264 | 830 | root->height = 0; |
612d6c19 NP |
831 | root->rnode = NULL; |
832 | ||
1da177e4 | 833 | out: |
612d6c19 | 834 | return slot; |
1da177e4 LT |
835 | } |
836 | EXPORT_SYMBOL(radix_tree_delete); | |
837 | ||
838 | /** | |
839 | * radix_tree_tagged - test whether any items in the tree are tagged | |
840 | * @root: radix tree root | |
841 | * @tag: tag to test | |
842 | */ | |
daff89f3 | 843 | int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag) |
1da177e4 | 844 | { |
612d6c19 | 845 | return root_tag_get(root, tag); |
1da177e4 LT |
846 | } |
847 | EXPORT_SYMBOL(radix_tree_tagged); | |
848 | ||
849 | static void | |
850 | radix_tree_node_ctor(void *node, kmem_cache_t *cachep, unsigned long flags) | |
851 | { | |
852 | memset(node, 0, sizeof(struct radix_tree_node)); | |
853 | } | |
854 | ||
855 | static __init unsigned long __maxindex(unsigned int height) | |
856 | { | |
857 | unsigned int tmp = height * RADIX_TREE_MAP_SHIFT; | |
858 | unsigned long index = (~0UL >> (RADIX_TREE_INDEX_BITS - tmp - 1)) >> 1; | |
859 | ||
860 | if (tmp >= RADIX_TREE_INDEX_BITS) | |
861 | index = ~0UL; | |
862 | return index; | |
863 | } | |
864 | ||
865 | static __init void radix_tree_init_maxindex(void) | |
866 | { | |
867 | unsigned int i; | |
868 | ||
869 | for (i = 0; i < ARRAY_SIZE(height_to_maxindex); i++) | |
870 | height_to_maxindex[i] = __maxindex(i); | |
871 | } | |
872 | ||
873 | #ifdef CONFIG_HOTPLUG_CPU | |
874 | static int radix_tree_callback(struct notifier_block *nfb, | |
875 | unsigned long action, | |
876 | void *hcpu) | |
877 | { | |
878 | int cpu = (long)hcpu; | |
879 | struct radix_tree_preload *rtp; | |
880 | ||
881 | /* Free per-cpu pool of perloaded nodes */ | |
882 | if (action == CPU_DEAD) { | |
883 | rtp = &per_cpu(radix_tree_preloads, cpu); | |
884 | while (rtp->nr) { | |
885 | kmem_cache_free(radix_tree_node_cachep, | |
886 | rtp->nodes[rtp->nr-1]); | |
887 | rtp->nodes[rtp->nr-1] = NULL; | |
888 | rtp->nr--; | |
889 | } | |
890 | } | |
891 | return NOTIFY_OK; | |
892 | } | |
893 | #endif /* CONFIG_HOTPLUG_CPU */ | |
894 | ||
895 | void __init radix_tree_init(void) | |
896 | { | |
897 | radix_tree_node_cachep = kmem_cache_create("radix_tree_node", | |
898 | sizeof(struct radix_tree_node), 0, | |
899 | SLAB_PANIC, radix_tree_node_ctor, NULL); | |
900 | radix_tree_init_maxindex(); | |
901 | hotcpu_notifier(radix_tree_callback, 0); | |
902 | } |