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> |
7cf9c2c7 | 5 | * Copyright (C) 2006 Nick Piggin |
1da177e4 LT |
6 | * |
7 | * This program is free software; you can redistribute it and/or | |
8 | * modify it under the terms of the GNU General Public License as | |
9 | * published by the Free Software Foundation; either version 2, or (at | |
10 | * your option) any later version. | |
11 | * | |
12 | * This program is distributed in the hope that it will be useful, but | |
13 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
15 | * General Public License for more details. | |
16 | * | |
17 | * You should have received a copy of the GNU General Public License | |
18 | * along with this program; if not, write to the Free Software | |
19 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
20 | */ | |
21 | ||
22 | #include <linux/errno.h> | |
23 | #include <linux/init.h> | |
24 | #include <linux/kernel.h> | |
25 | #include <linux/module.h> | |
26 | #include <linux/radix-tree.h> | |
27 | #include <linux/percpu.h> | |
28 | #include <linux/slab.h> | |
29 | #include <linux/notifier.h> | |
30 | #include <linux/cpu.h> | |
31 | #include <linux/gfp.h> | |
32 | #include <linux/string.h> | |
33 | #include <linux/bitops.h> | |
7cf9c2c7 | 34 | #include <linux/rcupdate.h> |
1da177e4 LT |
35 | |
36 | ||
37 | #ifdef __KERNEL__ | |
cfd9b7df | 38 | #define RADIX_TREE_MAP_SHIFT (CONFIG_BASE_SMALL ? 4 : 6) |
1da177e4 LT |
39 | #else |
40 | #define RADIX_TREE_MAP_SHIFT 3 /* For more stressful testing */ | |
41 | #endif | |
1da177e4 LT |
42 | |
43 | #define RADIX_TREE_MAP_SIZE (1UL << RADIX_TREE_MAP_SHIFT) | |
44 | #define RADIX_TREE_MAP_MASK (RADIX_TREE_MAP_SIZE-1) | |
45 | ||
46 | #define RADIX_TREE_TAG_LONGS \ | |
47 | ((RADIX_TREE_MAP_SIZE + BITS_PER_LONG - 1) / BITS_PER_LONG) | |
48 | ||
49 | struct radix_tree_node { | |
7cf9c2c7 | 50 | unsigned int height; /* Height from the bottom */ |
1da177e4 | 51 | unsigned int count; |
7cf9c2c7 | 52 | struct rcu_head rcu_head; |
1da177e4 | 53 | void *slots[RADIX_TREE_MAP_SIZE]; |
daff89f3 | 54 | unsigned long tags[RADIX_TREE_MAX_TAGS][RADIX_TREE_TAG_LONGS]; |
1da177e4 LT |
55 | }; |
56 | ||
57 | struct radix_tree_path { | |
201b6264 | 58 | struct radix_tree_node *node; |
1da177e4 LT |
59 | int offset; |
60 | }; | |
61 | ||
62 | #define RADIX_TREE_INDEX_BITS (8 /* CHAR_BIT */ * sizeof(unsigned long)) | |
63 | #define RADIX_TREE_MAX_PATH (RADIX_TREE_INDEX_BITS/RADIX_TREE_MAP_SHIFT + 2) | |
64 | ||
6c036527 | 65 | static unsigned long height_to_maxindex[RADIX_TREE_MAX_PATH] __read_mostly; |
1da177e4 LT |
66 | |
67 | /* | |
68 | * Radix tree node cache. | |
69 | */ | |
e18b890b | 70 | static struct kmem_cache *radix_tree_node_cachep; |
1da177e4 LT |
71 | |
72 | /* | |
73 | * Per-cpu pool of preloaded nodes | |
74 | */ | |
75 | struct radix_tree_preload { | |
76 | int nr; | |
77 | struct radix_tree_node *nodes[RADIX_TREE_MAX_PATH]; | |
78 | }; | |
79 | DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, }; | |
80 | ||
612d6c19 NP |
81 | static inline gfp_t root_gfp_mask(struct radix_tree_root *root) |
82 | { | |
83 | return root->gfp_mask & __GFP_BITS_MASK; | |
84 | } | |
85 | ||
1da177e4 LT |
86 | /* |
87 | * This assumes that the caller has performed appropriate preallocation, and | |
88 | * that the caller has pinned this thread of control to the current CPU. | |
89 | */ | |
90 | static struct radix_tree_node * | |
91 | radix_tree_node_alloc(struct radix_tree_root *root) | |
92 | { | |
93 | struct radix_tree_node *ret; | |
612d6c19 | 94 | gfp_t gfp_mask = root_gfp_mask(root); |
1da177e4 | 95 | |
612d6c19 NP |
96 | ret = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask); |
97 | if (ret == NULL && !(gfp_mask & __GFP_WAIT)) { | |
1da177e4 LT |
98 | struct radix_tree_preload *rtp; |
99 | ||
100 | rtp = &__get_cpu_var(radix_tree_preloads); | |
101 | if (rtp->nr) { | |
102 | ret = rtp->nodes[rtp->nr - 1]; | |
103 | rtp->nodes[rtp->nr - 1] = NULL; | |
104 | rtp->nr--; | |
105 | } | |
106 | } | |
c0bc9875 | 107 | BUG_ON(radix_tree_is_indirect_ptr(ret)); |
1da177e4 LT |
108 | return ret; |
109 | } | |
110 | ||
7cf9c2c7 NP |
111 | static void radix_tree_node_rcu_free(struct rcu_head *head) |
112 | { | |
113 | struct radix_tree_node *node = | |
114 | container_of(head, struct radix_tree_node, rcu_head); | |
115 | kmem_cache_free(radix_tree_node_cachep, node); | |
116 | } | |
117 | ||
1da177e4 LT |
118 | static inline void |
119 | radix_tree_node_free(struct radix_tree_node *node) | |
120 | { | |
7cf9c2c7 | 121 | call_rcu(&node->rcu_head, radix_tree_node_rcu_free); |
1da177e4 LT |
122 | } |
123 | ||
124 | /* | |
125 | * Load up this CPU's radix_tree_node buffer with sufficient objects to | |
126 | * ensure that the addition of a single element in the tree cannot fail. On | |
127 | * success, return zero, with preemption disabled. On error, return -ENOMEM | |
128 | * with preemption not disabled. | |
129 | */ | |
dd0fc66f | 130 | int radix_tree_preload(gfp_t gfp_mask) |
1da177e4 LT |
131 | { |
132 | struct radix_tree_preload *rtp; | |
133 | struct radix_tree_node *node; | |
134 | int ret = -ENOMEM; | |
135 | ||
136 | preempt_disable(); | |
137 | rtp = &__get_cpu_var(radix_tree_preloads); | |
138 | while (rtp->nr < ARRAY_SIZE(rtp->nodes)) { | |
139 | preempt_enable(); | |
140 | node = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask); | |
141 | if (node == NULL) | |
142 | goto out; | |
143 | preempt_disable(); | |
144 | rtp = &__get_cpu_var(radix_tree_preloads); | |
145 | if (rtp->nr < ARRAY_SIZE(rtp->nodes)) | |
146 | rtp->nodes[rtp->nr++] = node; | |
147 | else | |
148 | kmem_cache_free(radix_tree_node_cachep, node); | |
149 | } | |
150 | ret = 0; | |
151 | out: | |
152 | return ret; | |
153 | } | |
d7f0923d | 154 | EXPORT_SYMBOL(radix_tree_preload); |
1da177e4 | 155 | |
daff89f3 JC |
156 | static inline void tag_set(struct radix_tree_node *node, unsigned int tag, |
157 | int offset) | |
1da177e4 | 158 | { |
d5274261 | 159 | __set_bit(offset, node->tags[tag]); |
1da177e4 LT |
160 | } |
161 | ||
daff89f3 JC |
162 | static inline void tag_clear(struct radix_tree_node *node, unsigned int tag, |
163 | int offset) | |
1da177e4 | 164 | { |
d5274261 | 165 | __clear_bit(offset, node->tags[tag]); |
1da177e4 LT |
166 | } |
167 | ||
daff89f3 JC |
168 | static inline int tag_get(struct radix_tree_node *node, unsigned int tag, |
169 | int offset) | |
1da177e4 | 170 | { |
d5274261 | 171 | return test_bit(offset, node->tags[tag]); |
1da177e4 LT |
172 | } |
173 | ||
612d6c19 NP |
174 | static inline void root_tag_set(struct radix_tree_root *root, unsigned int tag) |
175 | { | |
20241ad4 | 176 | root->gfp_mask |= (__force gfp_t)(1 << (tag + __GFP_BITS_SHIFT)); |
612d6c19 NP |
177 | } |
178 | ||
179 | ||
180 | static inline void root_tag_clear(struct radix_tree_root *root, unsigned int tag) | |
181 | { | |
20241ad4 | 182 | root->gfp_mask &= (__force gfp_t)~(1 << (tag + __GFP_BITS_SHIFT)); |
612d6c19 NP |
183 | } |
184 | ||
185 | static inline void root_tag_clear_all(struct radix_tree_root *root) | |
186 | { | |
187 | root->gfp_mask &= __GFP_BITS_MASK; | |
188 | } | |
189 | ||
190 | static inline int root_tag_get(struct radix_tree_root *root, unsigned int tag) | |
191 | { | |
20241ad4 | 192 | return (__force unsigned)root->gfp_mask & (1 << (tag + __GFP_BITS_SHIFT)); |
612d6c19 NP |
193 | } |
194 | ||
6e954b9e NP |
195 | /* |
196 | * Returns 1 if any slot in the node has this tag set. | |
197 | * Otherwise returns 0. | |
198 | */ | |
daff89f3 | 199 | static inline int any_tag_set(struct radix_tree_node *node, unsigned int tag) |
6e954b9e NP |
200 | { |
201 | int idx; | |
202 | for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) { | |
203 | if (node->tags[tag][idx]) | |
204 | return 1; | |
205 | } | |
206 | return 0; | |
207 | } | |
208 | ||
1da177e4 LT |
209 | /* |
210 | * Return the maximum key which can be store into a | |
211 | * radix tree with height HEIGHT. | |
212 | */ | |
213 | static inline unsigned long radix_tree_maxindex(unsigned int height) | |
214 | { | |
215 | return height_to_maxindex[height]; | |
216 | } | |
217 | ||
218 | /* | |
219 | * Extend a radix tree so it can store key @index. | |
220 | */ | |
221 | static int radix_tree_extend(struct radix_tree_root *root, unsigned long index) | |
222 | { | |
223 | struct radix_tree_node *node; | |
224 | unsigned int height; | |
1da177e4 LT |
225 | int tag; |
226 | ||
227 | /* Figure out what the height should be. */ | |
228 | height = root->height + 1; | |
229 | while (index > radix_tree_maxindex(height)) | |
230 | height++; | |
231 | ||
232 | if (root->rnode == NULL) { | |
233 | root->height = height; | |
234 | goto out; | |
235 | } | |
236 | ||
1da177e4 | 237 | do { |
7cf9c2c7 | 238 | unsigned int newheight; |
1da177e4 LT |
239 | if (!(node = radix_tree_node_alloc(root))) |
240 | return -ENOMEM; | |
241 | ||
242 | /* Increase the height. */ | |
c0bc9875 | 243 | node->slots[0] = radix_tree_indirect_to_ptr(root->rnode); |
1da177e4 LT |
244 | |
245 | /* Propagate the aggregated tag info into the new root */ | |
daff89f3 | 246 | for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { |
612d6c19 | 247 | if (root_tag_get(root, tag)) |
1da177e4 LT |
248 | tag_set(node, tag, 0); |
249 | } | |
250 | ||
7cf9c2c7 NP |
251 | newheight = root->height+1; |
252 | node->height = newheight; | |
1da177e4 | 253 | node->count = 1; |
c0bc9875 | 254 | node = radix_tree_ptr_to_indirect(node); |
7cf9c2c7 NP |
255 | rcu_assign_pointer(root->rnode, node); |
256 | root->height = newheight; | |
1da177e4 LT |
257 | } while (height > root->height); |
258 | out: | |
259 | return 0; | |
260 | } | |
261 | ||
262 | /** | |
263 | * radix_tree_insert - insert into a radix tree | |
264 | * @root: radix tree root | |
265 | * @index: index key | |
266 | * @item: item to insert | |
267 | * | |
268 | * Insert an item into the radix tree at position @index. | |
269 | */ | |
270 | int radix_tree_insert(struct radix_tree_root *root, | |
271 | unsigned long index, void *item) | |
272 | { | |
201b6264 | 273 | struct radix_tree_node *node = NULL, *slot; |
1da177e4 LT |
274 | unsigned int height, shift; |
275 | int offset; | |
276 | int error; | |
277 | ||
c0bc9875 | 278 | BUG_ON(radix_tree_is_indirect_ptr(item)); |
7cf9c2c7 | 279 | |
1da177e4 | 280 | /* Make sure the tree is high enough. */ |
612d6c19 | 281 | if (index > radix_tree_maxindex(root->height)) { |
1da177e4 LT |
282 | error = radix_tree_extend(root, index); |
283 | if (error) | |
284 | return error; | |
285 | } | |
286 | ||
c0bc9875 NP |
287 | slot = radix_tree_indirect_to_ptr(root->rnode); |
288 | ||
1da177e4 LT |
289 | height = root->height; |
290 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; | |
291 | ||
292 | offset = 0; /* uninitialised var warning */ | |
612d6c19 | 293 | while (height > 0) { |
201b6264 | 294 | if (slot == NULL) { |
1da177e4 | 295 | /* Have to add a child node. */ |
201b6264 | 296 | if (!(slot = radix_tree_node_alloc(root))) |
1da177e4 | 297 | return -ENOMEM; |
7cf9c2c7 | 298 | slot->height = height; |
201b6264 | 299 | if (node) { |
7cf9c2c7 | 300 | rcu_assign_pointer(node->slots[offset], slot); |
1da177e4 | 301 | node->count++; |
201b6264 | 302 | } else |
c0bc9875 NP |
303 | rcu_assign_pointer(root->rnode, |
304 | radix_tree_ptr_to_indirect(slot)); | |
1da177e4 LT |
305 | } |
306 | ||
307 | /* Go a level down */ | |
308 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
201b6264 CL |
309 | node = slot; |
310 | slot = node->slots[offset]; | |
1da177e4 LT |
311 | shift -= RADIX_TREE_MAP_SHIFT; |
312 | height--; | |
612d6c19 | 313 | } |
1da177e4 | 314 | |
201b6264 | 315 | if (slot != NULL) |
1da177e4 | 316 | return -EEXIST; |
201b6264 | 317 | |
612d6c19 NP |
318 | if (node) { |
319 | node->count++; | |
7cf9c2c7 | 320 | rcu_assign_pointer(node->slots[offset], item); |
612d6c19 NP |
321 | BUG_ON(tag_get(node, 0, offset)); |
322 | BUG_ON(tag_get(node, 1, offset)); | |
323 | } else { | |
c0bc9875 | 324 | rcu_assign_pointer(root->rnode, item); |
612d6c19 NP |
325 | BUG_ON(root_tag_get(root, 0)); |
326 | BUG_ON(root_tag_get(root, 1)); | |
327 | } | |
1da177e4 | 328 | |
1da177e4 LT |
329 | return 0; |
330 | } | |
331 | EXPORT_SYMBOL(radix_tree_insert); | |
332 | ||
7cf9c2c7 NP |
333 | /** |
334 | * radix_tree_lookup_slot - lookup a slot in a radix tree | |
335 | * @root: radix tree root | |
336 | * @index: index key | |
337 | * | |
338 | * Returns: the slot corresponding to the position @index in the | |
339 | * radix tree @root. This is useful for update-if-exists operations. | |
340 | * | |
341 | * This function cannot be called under rcu_read_lock, it must be | |
342 | * excluded from writers, as must the returned slot for subsequent | |
343 | * use by radix_tree_deref_slot() and radix_tree_replace slot. | |
344 | * Caller must hold tree write locked across slot lookup and | |
345 | * replace. | |
346 | */ | |
347 | void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index) | |
1da177e4 LT |
348 | { |
349 | unsigned int height, shift; | |
7cf9c2c7 | 350 | struct radix_tree_node *node, **slot; |
612d6c19 | 351 | |
7cf9c2c7 NP |
352 | node = root->rnode; |
353 | if (node == NULL) | |
1da177e4 LT |
354 | return NULL; |
355 | ||
c0bc9875 | 356 | if (!radix_tree_is_indirect_ptr(node)) { |
7cf9c2c7 NP |
357 | if (index > 0) |
358 | return NULL; | |
612d6c19 | 359 | return (void **)&root->rnode; |
7cf9c2c7 | 360 | } |
c0bc9875 | 361 | node = radix_tree_indirect_to_ptr(node); |
7cf9c2c7 NP |
362 | |
363 | height = node->height; | |
364 | if (index > radix_tree_maxindex(height)) | |
365 | return NULL; | |
612d6c19 | 366 | |
1da177e4 | 367 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; |
1da177e4 | 368 | |
7cf9c2c7 NP |
369 | do { |
370 | slot = (struct radix_tree_node **) | |
371 | (node->slots + ((index>>shift) & RADIX_TREE_MAP_MASK)); | |
372 | node = *slot; | |
373 | if (node == NULL) | |
1da177e4 LT |
374 | return NULL; |
375 | ||
1da177e4 LT |
376 | shift -= RADIX_TREE_MAP_SHIFT; |
377 | height--; | |
7cf9c2c7 | 378 | } while (height > 0); |
1da177e4 | 379 | |
a4331366 HR |
380 | return (void **)slot; |
381 | } | |
a4331366 HR |
382 | EXPORT_SYMBOL(radix_tree_lookup_slot); |
383 | ||
384 | /** | |
385 | * radix_tree_lookup - perform lookup operation on a radix tree | |
386 | * @root: radix tree root | |
387 | * @index: index key | |
388 | * | |
389 | * Lookup the item at the position @index in the radix tree @root. | |
7cf9c2c7 NP |
390 | * |
391 | * This function can be called under rcu_read_lock, however the caller | |
392 | * must manage lifetimes of leaf nodes (eg. RCU may also be used to free | |
393 | * them safely). No RCU barriers are required to access or modify the | |
394 | * returned item, however. | |
a4331366 HR |
395 | */ |
396 | void *radix_tree_lookup(struct radix_tree_root *root, unsigned long index) | |
397 | { | |
7cf9c2c7 NP |
398 | unsigned int height, shift; |
399 | struct radix_tree_node *node, **slot; | |
400 | ||
401 | node = rcu_dereference(root->rnode); | |
402 | if (node == NULL) | |
403 | return NULL; | |
404 | ||
c0bc9875 | 405 | if (!radix_tree_is_indirect_ptr(node)) { |
7cf9c2c7 NP |
406 | if (index > 0) |
407 | return NULL; | |
c0bc9875 | 408 | return node; |
7cf9c2c7 | 409 | } |
c0bc9875 | 410 | node = radix_tree_indirect_to_ptr(node); |
7cf9c2c7 NP |
411 | |
412 | height = node->height; | |
413 | if (index > radix_tree_maxindex(height)) | |
414 | return NULL; | |
415 | ||
416 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; | |
a4331366 | 417 | |
7cf9c2c7 NP |
418 | do { |
419 | slot = (struct radix_tree_node **) | |
420 | (node->slots + ((index>>shift) & RADIX_TREE_MAP_MASK)); | |
421 | node = rcu_dereference(*slot); | |
422 | if (node == NULL) | |
423 | return NULL; | |
424 | ||
425 | shift -= RADIX_TREE_MAP_SHIFT; | |
426 | height--; | |
427 | } while (height > 0); | |
428 | ||
429 | return node; | |
1da177e4 LT |
430 | } |
431 | EXPORT_SYMBOL(radix_tree_lookup); | |
432 | ||
433 | /** | |
434 | * radix_tree_tag_set - set a tag on a radix tree node | |
435 | * @root: radix tree root | |
436 | * @index: index key | |
437 | * @tag: tag index | |
438 | * | |
daff89f3 JC |
439 | * Set the search tag (which must be < RADIX_TREE_MAX_TAGS) |
440 | * corresponding to @index in the radix tree. From | |
1da177e4 LT |
441 | * the root all the way down to the leaf node. |
442 | * | |
443 | * Returns the address of the tagged item. Setting a tag on a not-present | |
444 | * item is a bug. | |
445 | */ | |
446 | void *radix_tree_tag_set(struct radix_tree_root *root, | |
daff89f3 | 447 | unsigned long index, unsigned int tag) |
1da177e4 LT |
448 | { |
449 | unsigned int height, shift; | |
201b6264 | 450 | struct radix_tree_node *slot; |
1da177e4 LT |
451 | |
452 | height = root->height; | |
4c91c364 | 453 | BUG_ON(index > radix_tree_maxindex(height)); |
1da177e4 | 454 | |
c0bc9875 | 455 | slot = radix_tree_indirect_to_ptr(root->rnode); |
612d6c19 | 456 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; |
1da177e4 LT |
457 | |
458 | while (height > 0) { | |
459 | int offset; | |
460 | ||
461 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
d5274261 NP |
462 | if (!tag_get(slot, tag, offset)) |
463 | tag_set(slot, tag, offset); | |
201b6264 CL |
464 | slot = slot->slots[offset]; |
465 | BUG_ON(slot == NULL); | |
1da177e4 LT |
466 | shift -= RADIX_TREE_MAP_SHIFT; |
467 | height--; | |
468 | } | |
469 | ||
612d6c19 NP |
470 | /* set the root's tag bit */ |
471 | if (slot && !root_tag_get(root, tag)) | |
472 | root_tag_set(root, tag); | |
473 | ||
201b6264 | 474 | return slot; |
1da177e4 LT |
475 | } |
476 | EXPORT_SYMBOL(radix_tree_tag_set); | |
477 | ||
478 | /** | |
479 | * radix_tree_tag_clear - clear a tag on a radix tree node | |
480 | * @root: radix tree root | |
481 | * @index: index key | |
482 | * @tag: tag index | |
483 | * | |
daff89f3 JC |
484 | * Clear the search tag (which must be < RADIX_TREE_MAX_TAGS) |
485 | * corresponding to @index in the radix tree. If | |
1da177e4 LT |
486 | * this causes the leaf node to have no tags set then clear the tag in the |
487 | * next-to-leaf node, etc. | |
488 | * | |
489 | * Returns the address of the tagged item on success, else NULL. ie: | |
490 | * has the same return value and semantics as radix_tree_lookup(). | |
491 | */ | |
492 | void *radix_tree_tag_clear(struct radix_tree_root *root, | |
daff89f3 | 493 | unsigned long index, unsigned int tag) |
1da177e4 LT |
494 | { |
495 | struct radix_tree_path path[RADIX_TREE_MAX_PATH], *pathp = path; | |
612d6c19 | 496 | struct radix_tree_node *slot = NULL; |
1da177e4 | 497 | unsigned int height, shift; |
1da177e4 LT |
498 | |
499 | height = root->height; | |
500 | if (index > radix_tree_maxindex(height)) | |
501 | goto out; | |
502 | ||
503 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; | |
504 | pathp->node = NULL; | |
c0bc9875 | 505 | slot = radix_tree_indirect_to_ptr(root->rnode); |
1da177e4 LT |
506 | |
507 | while (height > 0) { | |
508 | int offset; | |
509 | ||
201b6264 | 510 | if (slot == NULL) |
1da177e4 LT |
511 | goto out; |
512 | ||
513 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
514 | pathp[1].offset = offset; | |
201b6264 CL |
515 | pathp[1].node = slot; |
516 | slot = slot->slots[offset]; | |
1da177e4 LT |
517 | pathp++; |
518 | shift -= RADIX_TREE_MAP_SHIFT; | |
519 | height--; | |
520 | } | |
521 | ||
612d6c19 | 522 | if (slot == NULL) |
1da177e4 LT |
523 | goto out; |
524 | ||
612d6c19 | 525 | while (pathp->node) { |
d5274261 NP |
526 | if (!tag_get(pathp->node, tag, pathp->offset)) |
527 | goto out; | |
201b6264 | 528 | tag_clear(pathp->node, tag, pathp->offset); |
6e954b9e NP |
529 | if (any_tag_set(pathp->node, tag)) |
530 | goto out; | |
1da177e4 | 531 | pathp--; |
612d6c19 NP |
532 | } |
533 | ||
534 | /* clear the root's tag bit */ | |
535 | if (root_tag_get(root, tag)) | |
536 | root_tag_clear(root, tag); | |
537 | ||
1da177e4 | 538 | out: |
612d6c19 | 539 | return slot; |
1da177e4 LT |
540 | } |
541 | EXPORT_SYMBOL(radix_tree_tag_clear); | |
542 | ||
543 | #ifndef __KERNEL__ /* Only the test harness uses this at present */ | |
544 | /** | |
32605a18 MT |
545 | * radix_tree_tag_get - get a tag on a radix tree node |
546 | * @root: radix tree root | |
547 | * @index: index key | |
daff89f3 | 548 | * @tag: tag index (< RADIX_TREE_MAX_TAGS) |
1da177e4 | 549 | * |
32605a18 | 550 | * Return values: |
1da177e4 | 551 | * |
612d6c19 NP |
552 | * 0: tag not present or not set |
553 | * 1: tag set | |
1da177e4 LT |
554 | */ |
555 | int radix_tree_tag_get(struct radix_tree_root *root, | |
daff89f3 | 556 | unsigned long index, unsigned int tag) |
1da177e4 LT |
557 | { |
558 | unsigned int height, shift; | |
7cf9c2c7 | 559 | struct radix_tree_node *node; |
1da177e4 LT |
560 | int saw_unset_tag = 0; |
561 | ||
612d6c19 NP |
562 | /* check the root's tag bit */ |
563 | if (!root_tag_get(root, tag)) | |
564 | return 0; | |
565 | ||
7cf9c2c7 NP |
566 | node = rcu_dereference(root->rnode); |
567 | if (node == NULL) | |
568 | return 0; | |
569 | ||
c0bc9875 | 570 | if (!radix_tree_is_indirect_ptr(node)) |
7cf9c2c7 | 571 | return (index == 0); |
c0bc9875 | 572 | node = radix_tree_indirect_to_ptr(node); |
7cf9c2c7 NP |
573 | |
574 | height = node->height; | |
575 | if (index > radix_tree_maxindex(height)) | |
576 | return 0; | |
612d6c19 | 577 | |
1da177e4 | 578 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; |
1da177e4 LT |
579 | |
580 | for ( ; ; ) { | |
581 | int offset; | |
582 | ||
7cf9c2c7 | 583 | if (node == NULL) |
1da177e4 LT |
584 | return 0; |
585 | ||
586 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
587 | ||
588 | /* | |
589 | * This is just a debug check. Later, we can bale as soon as | |
590 | * we see an unset tag. | |
591 | */ | |
7cf9c2c7 | 592 | if (!tag_get(node, tag, offset)) |
1da177e4 LT |
593 | saw_unset_tag = 1; |
594 | if (height == 1) { | |
7cf9c2c7 | 595 | int ret = tag_get(node, tag, offset); |
1da177e4 LT |
596 | |
597 | BUG_ON(ret && saw_unset_tag); | |
e5dcd90b | 598 | return !!ret; |
1da177e4 | 599 | } |
7cf9c2c7 | 600 | node = rcu_dereference(node->slots[offset]); |
1da177e4 LT |
601 | shift -= RADIX_TREE_MAP_SHIFT; |
602 | height--; | |
603 | } | |
604 | } | |
605 | EXPORT_SYMBOL(radix_tree_tag_get); | |
606 | #endif | |
607 | ||
6df8ba4f FW |
608 | /** |
609 | * radix_tree_next_hole - find the next hole (not-present entry) | |
610 | * @root: tree root | |
611 | * @index: index key | |
612 | * @max_scan: maximum range to search | |
613 | * | |
614 | * Search the set [index, min(index+max_scan-1, MAX_INDEX)] for the lowest | |
615 | * indexed hole. | |
616 | * | |
617 | * Returns: the index of the hole if found, otherwise returns an index | |
618 | * outside of the set specified (in which case 'return - index >= max_scan' | |
619 | * will be true). | |
620 | * | |
621 | * radix_tree_next_hole may be called under rcu_read_lock. However, like | |
622 | * radix_tree_gang_lookup, this will not atomically search a snapshot of the | |
623 | * tree at a single point in time. For example, if a hole is created at index | |
624 | * 5, then subsequently a hole is created at index 10, radix_tree_next_hole | |
625 | * covering both indexes may return 10 if called under rcu_read_lock. | |
626 | */ | |
627 | unsigned long radix_tree_next_hole(struct radix_tree_root *root, | |
628 | unsigned long index, unsigned long max_scan) | |
629 | { | |
630 | unsigned long i; | |
631 | ||
632 | for (i = 0; i < max_scan; i++) { | |
633 | if (!radix_tree_lookup(root, index)) | |
634 | break; | |
635 | index++; | |
636 | if (index == 0) | |
637 | break; | |
638 | } | |
639 | ||
640 | return index; | |
641 | } | |
642 | EXPORT_SYMBOL(radix_tree_next_hole); | |
643 | ||
1da177e4 | 644 | static unsigned int |
7cf9c2c7 | 645 | __lookup(struct radix_tree_node *slot, void **results, unsigned long index, |
1da177e4 LT |
646 | unsigned int max_items, unsigned long *next_index) |
647 | { | |
648 | unsigned int nr_found = 0; | |
201b6264 | 649 | unsigned int shift, height; |
201b6264 CL |
650 | unsigned long i; |
651 | ||
7cf9c2c7 NP |
652 | height = slot->height; |
653 | if (height == 0) | |
201b6264 | 654 | goto out; |
1da177e4 | 655 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; |
1da177e4 | 656 | |
201b6264 | 657 | for ( ; height > 1; height--) { |
7cf9c2c7 NP |
658 | i = (index >> shift) & RADIX_TREE_MAP_MASK; |
659 | for (;;) { | |
1da177e4 LT |
660 | if (slot->slots[i] != NULL) |
661 | break; | |
662 | index &= ~((1UL << shift) - 1); | |
663 | index += 1UL << shift; | |
664 | if (index == 0) | |
665 | goto out; /* 32-bit wraparound */ | |
7cf9c2c7 NP |
666 | i++; |
667 | if (i == RADIX_TREE_MAP_SIZE) | |
668 | goto out; | |
1da177e4 | 669 | } |
1da177e4 | 670 | |
1da177e4 | 671 | shift -= RADIX_TREE_MAP_SHIFT; |
7cf9c2c7 NP |
672 | slot = rcu_dereference(slot->slots[i]); |
673 | if (slot == NULL) | |
674 | goto out; | |
1da177e4 | 675 | } |
201b6264 CL |
676 | |
677 | /* Bottom level: grab some items */ | |
678 | for (i = index & RADIX_TREE_MAP_MASK; i < RADIX_TREE_MAP_SIZE; i++) { | |
7cf9c2c7 | 679 | struct radix_tree_node *node; |
201b6264 | 680 | index++; |
7cf9c2c7 NP |
681 | node = slot->slots[i]; |
682 | if (node) { | |
683 | results[nr_found++] = rcu_dereference(node); | |
201b6264 CL |
684 | if (nr_found == max_items) |
685 | goto out; | |
686 | } | |
687 | } | |
1da177e4 LT |
688 | out: |
689 | *next_index = index; | |
690 | return nr_found; | |
691 | } | |
692 | ||
693 | /** | |
694 | * radix_tree_gang_lookup - perform multiple lookup on a radix tree | |
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 | |
699 | * | |
700 | * Performs an index-ascending scan of the tree for present items. Places | |
701 | * them at *@results and returns the number of items which were placed at | |
702 | * *@results. | |
703 | * | |
704 | * The implementation is naive. | |
7cf9c2c7 NP |
705 | * |
706 | * Like radix_tree_lookup, radix_tree_gang_lookup may be called under | |
707 | * rcu_read_lock. In this case, rather than the returned results being | |
708 | * an atomic snapshot of the tree at a single point in time, the semantics | |
709 | * of an RCU protected gang lookup are as though multiple radix_tree_lookups | |
710 | * have been issued in individual locks, and results stored in 'results'. | |
1da177e4 LT |
711 | */ |
712 | unsigned int | |
713 | radix_tree_gang_lookup(struct radix_tree_root *root, void **results, | |
714 | unsigned long first_index, unsigned int max_items) | |
715 | { | |
7cf9c2c7 NP |
716 | unsigned long max_index; |
717 | struct radix_tree_node *node; | |
1da177e4 | 718 | unsigned long cur_index = first_index; |
7cf9c2c7 NP |
719 | unsigned int ret; |
720 | ||
721 | node = rcu_dereference(root->rnode); | |
722 | if (!node) | |
723 | return 0; | |
1da177e4 | 724 | |
c0bc9875 | 725 | if (!radix_tree_is_indirect_ptr(node)) { |
7cf9c2c7 NP |
726 | if (first_index > 0) |
727 | return 0; | |
c0bc9875 | 728 | results[0] = node; |
7cf9c2c7 NP |
729 | return 1; |
730 | } | |
c0bc9875 | 731 | node = radix_tree_indirect_to_ptr(node); |
7cf9c2c7 NP |
732 | |
733 | max_index = radix_tree_maxindex(node->height); | |
734 | ||
735 | ret = 0; | |
1da177e4 LT |
736 | while (ret < max_items) { |
737 | unsigned int nr_found; | |
738 | unsigned long next_index; /* Index of next search */ | |
739 | ||
740 | if (cur_index > max_index) | |
741 | break; | |
7cf9c2c7 | 742 | nr_found = __lookup(node, results + ret, cur_index, |
1da177e4 LT |
743 | max_items - ret, &next_index); |
744 | ret += nr_found; | |
745 | if (next_index == 0) | |
746 | break; | |
747 | cur_index = next_index; | |
748 | } | |
7cf9c2c7 | 749 | |
1da177e4 LT |
750 | return ret; |
751 | } | |
752 | EXPORT_SYMBOL(radix_tree_gang_lookup); | |
753 | ||
754 | /* | |
755 | * FIXME: the two tag_get()s here should use find_next_bit() instead of | |
756 | * open-coding the search. | |
757 | */ | |
758 | static unsigned int | |
7cf9c2c7 | 759 | __lookup_tag(struct radix_tree_node *slot, void **results, unsigned long index, |
daff89f3 | 760 | unsigned int max_items, unsigned long *next_index, unsigned int tag) |
1da177e4 LT |
761 | { |
762 | unsigned int nr_found = 0; | |
7cf9c2c7 | 763 | unsigned int shift, height; |
1da177e4 | 764 | |
7cf9c2c7 NP |
765 | height = slot->height; |
766 | if (height == 0) | |
612d6c19 | 767 | goto out; |
7cf9c2c7 | 768 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; |
1da177e4 | 769 | |
7cf9c2c7 NP |
770 | while (height > 0) { |
771 | unsigned long i = (index >> shift) & RADIX_TREE_MAP_MASK ; | |
1da177e4 | 772 | |
7cf9c2c7 NP |
773 | for (;;) { |
774 | if (tag_get(slot, tag, i)) | |
1da177e4 | 775 | break; |
1da177e4 LT |
776 | index &= ~((1UL << shift) - 1); |
777 | index += 1UL << shift; | |
778 | if (index == 0) | |
779 | goto out; /* 32-bit wraparound */ | |
7cf9c2c7 NP |
780 | i++; |
781 | if (i == RADIX_TREE_MAP_SIZE) | |
782 | goto out; | |
1da177e4 | 783 | } |
1da177e4 LT |
784 | height--; |
785 | if (height == 0) { /* Bottom level: grab some items */ | |
786 | unsigned long j = index & RADIX_TREE_MAP_MASK; | |
787 | ||
788 | for ( ; j < RADIX_TREE_MAP_SIZE; j++) { | |
7cf9c2c7 | 789 | struct radix_tree_node *node; |
1da177e4 | 790 | index++; |
7cf9c2c7 NP |
791 | if (!tag_get(slot, tag, j)) |
792 | continue; | |
793 | node = slot->slots[j]; | |
794 | /* | |
795 | * Even though the tag was found set, we need to | |
796 | * recheck that we have a non-NULL node, because | |
797 | * if this lookup is lockless, it may have been | |
798 | * subsequently deleted. | |
799 | * | |
800 | * Similar care must be taken in any place that | |
801 | * lookup ->slots[x] without a lock (ie. can't | |
802 | * rely on its value remaining the same). | |
803 | */ | |
804 | if (node) { | |
805 | node = rcu_dereference(node); | |
806 | results[nr_found++] = node; | |
1da177e4 LT |
807 | if (nr_found == max_items) |
808 | goto out; | |
809 | } | |
810 | } | |
811 | } | |
812 | shift -= RADIX_TREE_MAP_SHIFT; | |
7cf9c2c7 NP |
813 | slot = rcu_dereference(slot->slots[i]); |
814 | if (slot == NULL) | |
815 | break; | |
816 | } | |
1da177e4 LT |
817 | out: |
818 | *next_index = index; | |
819 | return nr_found; | |
820 | } | |
821 | ||
822 | /** | |
823 | * radix_tree_gang_lookup_tag - perform multiple lookup on a radix tree | |
824 | * based on a tag | |
825 | * @root: radix tree root | |
826 | * @results: where the results of the lookup are placed | |
827 | * @first_index: start the lookup from this key | |
828 | * @max_items: place up to this many items at *results | |
daff89f3 | 829 | * @tag: the tag index (< RADIX_TREE_MAX_TAGS) |
1da177e4 LT |
830 | * |
831 | * Performs an index-ascending scan of the tree for present items which | |
832 | * have the tag indexed by @tag set. Places the items at *@results and | |
833 | * returns the number of items which were placed at *@results. | |
834 | */ | |
835 | unsigned int | |
836 | radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results, | |
daff89f3 JC |
837 | unsigned long first_index, unsigned int max_items, |
838 | unsigned int tag) | |
1da177e4 | 839 | { |
7cf9c2c7 NP |
840 | struct radix_tree_node *node; |
841 | unsigned long max_index; | |
1da177e4 | 842 | unsigned long cur_index = first_index; |
7cf9c2c7 | 843 | unsigned int ret; |
1da177e4 | 844 | |
612d6c19 NP |
845 | /* check the root's tag bit */ |
846 | if (!root_tag_get(root, tag)) | |
847 | return 0; | |
848 | ||
7cf9c2c7 NP |
849 | node = rcu_dereference(root->rnode); |
850 | if (!node) | |
851 | return 0; | |
852 | ||
c0bc9875 | 853 | if (!radix_tree_is_indirect_ptr(node)) { |
7cf9c2c7 NP |
854 | if (first_index > 0) |
855 | return 0; | |
c0bc9875 | 856 | results[0] = node; |
7cf9c2c7 NP |
857 | return 1; |
858 | } | |
c0bc9875 | 859 | node = radix_tree_indirect_to_ptr(node); |
7cf9c2c7 NP |
860 | |
861 | max_index = radix_tree_maxindex(node->height); | |
862 | ||
863 | ret = 0; | |
1da177e4 LT |
864 | while (ret < max_items) { |
865 | unsigned int nr_found; | |
866 | unsigned long next_index; /* Index of next search */ | |
867 | ||
868 | if (cur_index > max_index) | |
869 | break; | |
7cf9c2c7 | 870 | nr_found = __lookup_tag(node, results + ret, cur_index, |
1da177e4 LT |
871 | max_items - ret, &next_index, tag); |
872 | ret += nr_found; | |
873 | if (next_index == 0) | |
874 | break; | |
875 | cur_index = next_index; | |
876 | } | |
7cf9c2c7 | 877 | |
1da177e4 LT |
878 | return ret; |
879 | } | |
880 | EXPORT_SYMBOL(radix_tree_gang_lookup_tag); | |
881 | ||
a5f51c96 NP |
882 | /** |
883 | * radix_tree_shrink - shrink height of a radix tree to minimal | |
884 | * @root radix tree root | |
885 | */ | |
886 | static inline void radix_tree_shrink(struct radix_tree_root *root) | |
887 | { | |
888 | /* try to shrink tree height */ | |
c0bc9875 | 889 | while (root->height > 0) { |
a5f51c96 | 890 | struct radix_tree_node *to_free = root->rnode; |
7cf9c2c7 | 891 | void *newptr; |
a5f51c96 | 892 | |
c0bc9875 NP |
893 | BUG_ON(!radix_tree_is_indirect_ptr(to_free)); |
894 | to_free = radix_tree_indirect_to_ptr(to_free); | |
895 | ||
896 | /* | |
897 | * The candidate node has more than one child, or its child | |
898 | * is not at the leftmost slot, we cannot shrink. | |
899 | */ | |
900 | if (to_free->count != 1) | |
901 | break; | |
902 | if (!to_free->slots[0]) | |
903 | break; | |
904 | ||
7cf9c2c7 NP |
905 | /* |
906 | * We don't need rcu_assign_pointer(), since we are simply | |
907 | * moving the node from one part of the tree to another. If | |
908 | * it was safe to dereference the old pointer to it | |
909 | * (to_free->slots[0]), it will be safe to dereference the new | |
910 | * one (root->rnode). | |
911 | */ | |
912 | newptr = to_free->slots[0]; | |
c0bc9875 NP |
913 | if (root->height > 1) |
914 | newptr = radix_tree_ptr_to_indirect(newptr); | |
7cf9c2c7 | 915 | root->rnode = newptr; |
a5f51c96 NP |
916 | root->height--; |
917 | /* must only free zeroed nodes into the slab */ | |
918 | tag_clear(to_free, 0, 0); | |
919 | tag_clear(to_free, 1, 0); | |
920 | to_free->slots[0] = NULL; | |
921 | to_free->count = 0; | |
922 | radix_tree_node_free(to_free); | |
923 | } | |
924 | } | |
925 | ||
1da177e4 LT |
926 | /** |
927 | * radix_tree_delete - delete an item from a radix tree | |
928 | * @root: radix tree root | |
929 | * @index: index key | |
930 | * | |
931 | * Remove the item at @index from the radix tree rooted at @root. | |
932 | * | |
933 | * Returns the address of the deleted item, or NULL if it was not present. | |
934 | */ | |
935 | void *radix_tree_delete(struct radix_tree_root *root, unsigned long index) | |
936 | { | |
937 | struct radix_tree_path path[RADIX_TREE_MAX_PATH], *pathp = path; | |
612d6c19 | 938 | struct radix_tree_node *slot = NULL; |
7cf9c2c7 | 939 | struct radix_tree_node *to_free; |
1da177e4 | 940 | unsigned int height, shift; |
d5274261 NP |
941 | int tag; |
942 | int offset; | |
1da177e4 LT |
943 | |
944 | height = root->height; | |
945 | if (index > radix_tree_maxindex(height)) | |
946 | goto out; | |
947 | ||
612d6c19 | 948 | slot = root->rnode; |
c0bc9875 | 949 | if (height == 0) { |
612d6c19 NP |
950 | root_tag_clear_all(root); |
951 | root->rnode = NULL; | |
952 | goto out; | |
953 | } | |
c0bc9875 | 954 | slot = radix_tree_indirect_to_ptr(slot); |
612d6c19 | 955 | |
1da177e4 LT |
956 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; |
957 | pathp->node = NULL; | |
1da177e4 | 958 | |
612d6c19 | 959 | do { |
201b6264 | 960 | if (slot == NULL) |
1da177e4 LT |
961 | goto out; |
962 | ||
d5274261 | 963 | pathp++; |
1da177e4 | 964 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; |
d5274261 NP |
965 | pathp->offset = offset; |
966 | pathp->node = slot; | |
201b6264 | 967 | slot = slot->slots[offset]; |
1da177e4 | 968 | shift -= RADIX_TREE_MAP_SHIFT; |
612d6c19 NP |
969 | height--; |
970 | } while (height > 0); | |
1da177e4 | 971 | |
612d6c19 | 972 | if (slot == NULL) |
1da177e4 LT |
973 | goto out; |
974 | ||
1da177e4 LT |
975 | /* |
976 | * Clear all tags associated with the just-deleted item | |
977 | */ | |
daff89f3 | 978 | for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { |
612d6c19 NP |
979 | if (tag_get(pathp->node, tag, pathp->offset)) |
980 | radix_tree_tag_clear(root, index, tag); | |
d5274261 | 981 | } |
1da177e4 | 982 | |
7cf9c2c7 | 983 | to_free = NULL; |
201b6264 | 984 | /* Now free the nodes we do not need anymore */ |
612d6c19 | 985 | while (pathp->node) { |
201b6264 | 986 | pathp->node->slots[pathp->offset] = NULL; |
a5f51c96 | 987 | pathp->node->count--; |
7cf9c2c7 NP |
988 | /* |
989 | * Queue the node for deferred freeing after the | |
990 | * last reference to it disappears (set NULL, above). | |
991 | */ | |
992 | if (to_free) | |
993 | radix_tree_node_free(to_free); | |
a5f51c96 NP |
994 | |
995 | if (pathp->node->count) { | |
c0bc9875 NP |
996 | if (pathp->node == |
997 | radix_tree_indirect_to_ptr(root->rnode)) | |
a5f51c96 | 998 | radix_tree_shrink(root); |
201b6264 | 999 | goto out; |
a5f51c96 | 1000 | } |
201b6264 CL |
1001 | |
1002 | /* Node with zero slots in use so free it */ | |
7cf9c2c7 | 1003 | to_free = pathp->node; |
612d6c19 | 1004 | pathp--; |
7cf9c2c7 | 1005 | |
1da177e4 | 1006 | } |
612d6c19 | 1007 | root_tag_clear_all(root); |
201b6264 | 1008 | root->height = 0; |
612d6c19 | 1009 | root->rnode = NULL; |
7cf9c2c7 NP |
1010 | if (to_free) |
1011 | radix_tree_node_free(to_free); | |
612d6c19 | 1012 | |
1da177e4 | 1013 | out: |
612d6c19 | 1014 | return slot; |
1da177e4 LT |
1015 | } |
1016 | EXPORT_SYMBOL(radix_tree_delete); | |
1017 | ||
1018 | /** | |
1019 | * radix_tree_tagged - test whether any items in the tree are tagged | |
1020 | * @root: radix tree root | |
1021 | * @tag: tag to test | |
1022 | */ | |
daff89f3 | 1023 | int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag) |
1da177e4 | 1024 | { |
612d6c19 | 1025 | return root_tag_get(root, tag); |
1da177e4 LT |
1026 | } |
1027 | EXPORT_SYMBOL(radix_tree_tagged); | |
1028 | ||
1029 | static void | |
e18b890b | 1030 | radix_tree_node_ctor(void *node, struct kmem_cache *cachep, unsigned long flags) |
1da177e4 LT |
1031 | { |
1032 | memset(node, 0, sizeof(struct radix_tree_node)); | |
1033 | } | |
1034 | ||
1035 | static __init unsigned long __maxindex(unsigned int height) | |
1036 | { | |
1037 | unsigned int tmp = height * RADIX_TREE_MAP_SHIFT; | |
1038 | unsigned long index = (~0UL >> (RADIX_TREE_INDEX_BITS - tmp - 1)) >> 1; | |
1039 | ||
1040 | if (tmp >= RADIX_TREE_INDEX_BITS) | |
1041 | index = ~0UL; | |
1042 | return index; | |
1043 | } | |
1044 | ||
1045 | static __init void radix_tree_init_maxindex(void) | |
1046 | { | |
1047 | unsigned int i; | |
1048 | ||
1049 | for (i = 0; i < ARRAY_SIZE(height_to_maxindex); i++) | |
1050 | height_to_maxindex[i] = __maxindex(i); | |
1051 | } | |
1052 | ||
1da177e4 LT |
1053 | static int radix_tree_callback(struct notifier_block *nfb, |
1054 | unsigned long action, | |
1055 | void *hcpu) | |
1056 | { | |
1057 | int cpu = (long)hcpu; | |
1058 | struct radix_tree_preload *rtp; | |
1059 | ||
1060 | /* Free per-cpu pool of perloaded nodes */ | |
8bb78442 | 1061 | if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) { |
1da177e4 LT |
1062 | rtp = &per_cpu(radix_tree_preloads, cpu); |
1063 | while (rtp->nr) { | |
1064 | kmem_cache_free(radix_tree_node_cachep, | |
1065 | rtp->nodes[rtp->nr-1]); | |
1066 | rtp->nodes[rtp->nr-1] = NULL; | |
1067 | rtp->nr--; | |
1068 | } | |
1069 | } | |
1070 | return NOTIFY_OK; | |
1071 | } | |
1da177e4 LT |
1072 | |
1073 | void __init radix_tree_init(void) | |
1074 | { | |
1075 | radix_tree_node_cachep = kmem_cache_create("radix_tree_node", | |
1076 | sizeof(struct radix_tree_node), 0, | |
20c2df83 | 1077 | SLAB_PANIC, radix_tree_node_ctor); |
1da177e4 LT |
1078 | radix_tree_init_maxindex(); |
1079 | hotcpu_notifier(radix_tree_callback, 0); | |
1080 | } |