Commit | Line | Data |
---|---|---|
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)) | |
26fb1589 JM |
63 | #define RADIX_TREE_MAX_PATH (DIV_ROUND_UP(RADIX_TREE_INDEX_BITS, \ |
64 | RADIX_TREE_MAP_SHIFT)) | |
1da177e4 | 65 | |
26fb1589 JM |
66 | /* |
67 | * The height_to_maxindex array needs to be one deeper than the maximum | |
68 | * path as height 0 holds only 1 entry. | |
69 | */ | |
70 | static unsigned long height_to_maxindex[RADIX_TREE_MAX_PATH + 1] __read_mostly; | |
1da177e4 LT |
71 | |
72 | /* | |
73 | * Radix tree node cache. | |
74 | */ | |
e18b890b | 75 | static struct kmem_cache *radix_tree_node_cachep; |
1da177e4 LT |
76 | |
77 | /* | |
78 | * Per-cpu pool of preloaded nodes | |
79 | */ | |
80 | struct radix_tree_preload { | |
81 | int nr; | |
82 | struct radix_tree_node *nodes[RADIX_TREE_MAX_PATH]; | |
83 | }; | |
84 | DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, }; | |
85 | ||
612d6c19 NP |
86 | static inline gfp_t root_gfp_mask(struct radix_tree_root *root) |
87 | { | |
88 | return root->gfp_mask & __GFP_BITS_MASK; | |
89 | } | |
90 | ||
1da177e4 LT |
91 | /* |
92 | * This assumes that the caller has performed appropriate preallocation, and | |
93 | * that the caller has pinned this thread of control to the current CPU. | |
94 | */ | |
95 | static struct radix_tree_node * | |
96 | radix_tree_node_alloc(struct radix_tree_root *root) | |
97 | { | |
98 | struct radix_tree_node *ret; | |
612d6c19 | 99 | gfp_t gfp_mask = root_gfp_mask(root); |
1da177e4 | 100 | |
612d6c19 NP |
101 | ret = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask); |
102 | if (ret == NULL && !(gfp_mask & __GFP_WAIT)) { | |
1da177e4 LT |
103 | struct radix_tree_preload *rtp; |
104 | ||
105 | rtp = &__get_cpu_var(radix_tree_preloads); | |
106 | if (rtp->nr) { | |
107 | ret = rtp->nodes[rtp->nr - 1]; | |
108 | rtp->nodes[rtp->nr - 1] = NULL; | |
109 | rtp->nr--; | |
110 | } | |
111 | } | |
c0bc9875 | 112 | BUG_ON(radix_tree_is_indirect_ptr(ret)); |
1da177e4 LT |
113 | return ret; |
114 | } | |
115 | ||
7cf9c2c7 NP |
116 | static void radix_tree_node_rcu_free(struct rcu_head *head) |
117 | { | |
118 | struct radix_tree_node *node = | |
119 | container_of(head, struct radix_tree_node, rcu_head); | |
120 | kmem_cache_free(radix_tree_node_cachep, node); | |
121 | } | |
122 | ||
1da177e4 LT |
123 | static inline void |
124 | radix_tree_node_free(struct radix_tree_node *node) | |
125 | { | |
7cf9c2c7 | 126 | call_rcu(&node->rcu_head, radix_tree_node_rcu_free); |
1da177e4 LT |
127 | } |
128 | ||
129 | /* | |
130 | * Load up this CPU's radix_tree_node buffer with sufficient objects to | |
131 | * ensure that the addition of a single element in the tree cannot fail. On | |
132 | * success, return zero, with preemption disabled. On error, return -ENOMEM | |
133 | * with preemption not disabled. | |
134 | */ | |
dd0fc66f | 135 | int radix_tree_preload(gfp_t gfp_mask) |
1da177e4 LT |
136 | { |
137 | struct radix_tree_preload *rtp; | |
138 | struct radix_tree_node *node; | |
139 | int ret = -ENOMEM; | |
140 | ||
141 | preempt_disable(); | |
142 | rtp = &__get_cpu_var(radix_tree_preloads); | |
143 | while (rtp->nr < ARRAY_SIZE(rtp->nodes)) { | |
144 | preempt_enable(); | |
145 | node = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask); | |
146 | if (node == NULL) | |
147 | goto out; | |
148 | preempt_disable(); | |
149 | rtp = &__get_cpu_var(radix_tree_preloads); | |
150 | if (rtp->nr < ARRAY_SIZE(rtp->nodes)) | |
151 | rtp->nodes[rtp->nr++] = node; | |
152 | else | |
153 | kmem_cache_free(radix_tree_node_cachep, node); | |
154 | } | |
155 | ret = 0; | |
156 | out: | |
157 | return ret; | |
158 | } | |
d7f0923d | 159 | EXPORT_SYMBOL(radix_tree_preload); |
1da177e4 | 160 | |
daff89f3 JC |
161 | static inline void tag_set(struct radix_tree_node *node, unsigned int tag, |
162 | int offset) | |
1da177e4 | 163 | { |
d5274261 | 164 | __set_bit(offset, node->tags[tag]); |
1da177e4 LT |
165 | } |
166 | ||
daff89f3 JC |
167 | static inline void tag_clear(struct radix_tree_node *node, unsigned int tag, |
168 | int offset) | |
1da177e4 | 169 | { |
d5274261 | 170 | __clear_bit(offset, node->tags[tag]); |
1da177e4 LT |
171 | } |
172 | ||
daff89f3 JC |
173 | static inline int tag_get(struct radix_tree_node *node, unsigned int tag, |
174 | int offset) | |
1da177e4 | 175 | { |
d5274261 | 176 | return test_bit(offset, node->tags[tag]); |
1da177e4 LT |
177 | } |
178 | ||
612d6c19 NP |
179 | static inline void root_tag_set(struct radix_tree_root *root, unsigned int tag) |
180 | { | |
20241ad4 | 181 | root->gfp_mask |= (__force gfp_t)(1 << (tag + __GFP_BITS_SHIFT)); |
612d6c19 NP |
182 | } |
183 | ||
184 | ||
185 | static inline void root_tag_clear(struct radix_tree_root *root, unsigned int tag) | |
186 | { | |
20241ad4 | 187 | root->gfp_mask &= (__force gfp_t)~(1 << (tag + __GFP_BITS_SHIFT)); |
612d6c19 NP |
188 | } |
189 | ||
190 | static inline void root_tag_clear_all(struct radix_tree_root *root) | |
191 | { | |
192 | root->gfp_mask &= __GFP_BITS_MASK; | |
193 | } | |
194 | ||
195 | static inline int root_tag_get(struct radix_tree_root *root, unsigned int tag) | |
196 | { | |
20241ad4 | 197 | return (__force unsigned)root->gfp_mask & (1 << (tag + __GFP_BITS_SHIFT)); |
612d6c19 NP |
198 | } |
199 | ||
6e954b9e NP |
200 | /* |
201 | * Returns 1 if any slot in the node has this tag set. | |
202 | * Otherwise returns 0. | |
203 | */ | |
daff89f3 | 204 | static inline int any_tag_set(struct radix_tree_node *node, unsigned int tag) |
6e954b9e NP |
205 | { |
206 | int idx; | |
207 | for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) { | |
208 | if (node->tags[tag][idx]) | |
209 | return 1; | |
210 | } | |
211 | return 0; | |
212 | } | |
213 | ||
1da177e4 LT |
214 | /* |
215 | * Return the maximum key which can be store into a | |
216 | * radix tree with height HEIGHT. | |
217 | */ | |
218 | static inline unsigned long radix_tree_maxindex(unsigned int height) | |
219 | { | |
220 | return height_to_maxindex[height]; | |
221 | } | |
222 | ||
223 | /* | |
224 | * Extend a radix tree so it can store key @index. | |
225 | */ | |
226 | static int radix_tree_extend(struct radix_tree_root *root, unsigned long index) | |
227 | { | |
228 | struct radix_tree_node *node; | |
229 | unsigned int height; | |
1da177e4 LT |
230 | int tag; |
231 | ||
232 | /* Figure out what the height should be. */ | |
233 | height = root->height + 1; | |
234 | while (index > radix_tree_maxindex(height)) | |
235 | height++; | |
236 | ||
237 | if (root->rnode == NULL) { | |
238 | root->height = height; | |
239 | goto out; | |
240 | } | |
241 | ||
1da177e4 | 242 | do { |
7cf9c2c7 | 243 | unsigned int newheight; |
1da177e4 LT |
244 | if (!(node = radix_tree_node_alloc(root))) |
245 | return -ENOMEM; | |
246 | ||
247 | /* Increase the height. */ | |
c0bc9875 | 248 | node->slots[0] = radix_tree_indirect_to_ptr(root->rnode); |
1da177e4 LT |
249 | |
250 | /* Propagate the aggregated tag info into the new root */ | |
daff89f3 | 251 | for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { |
612d6c19 | 252 | if (root_tag_get(root, tag)) |
1da177e4 LT |
253 | tag_set(node, tag, 0); |
254 | } | |
255 | ||
7cf9c2c7 NP |
256 | newheight = root->height+1; |
257 | node->height = newheight; | |
1da177e4 | 258 | node->count = 1; |
c0bc9875 | 259 | node = radix_tree_ptr_to_indirect(node); |
7cf9c2c7 NP |
260 | rcu_assign_pointer(root->rnode, node); |
261 | root->height = newheight; | |
1da177e4 LT |
262 | } while (height > root->height); |
263 | out: | |
264 | return 0; | |
265 | } | |
266 | ||
267 | /** | |
268 | * radix_tree_insert - insert into a radix tree | |
269 | * @root: radix tree root | |
270 | * @index: index key | |
271 | * @item: item to insert | |
272 | * | |
273 | * Insert an item into the radix tree at position @index. | |
274 | */ | |
275 | int radix_tree_insert(struct radix_tree_root *root, | |
276 | unsigned long index, void *item) | |
277 | { | |
201b6264 | 278 | struct radix_tree_node *node = NULL, *slot; |
1da177e4 LT |
279 | unsigned int height, shift; |
280 | int offset; | |
281 | int error; | |
282 | ||
c0bc9875 | 283 | BUG_ON(radix_tree_is_indirect_ptr(item)); |
7cf9c2c7 | 284 | |
1da177e4 | 285 | /* Make sure the tree is high enough. */ |
612d6c19 | 286 | if (index > radix_tree_maxindex(root->height)) { |
1da177e4 LT |
287 | error = radix_tree_extend(root, index); |
288 | if (error) | |
289 | return error; | |
290 | } | |
291 | ||
c0bc9875 NP |
292 | slot = radix_tree_indirect_to_ptr(root->rnode); |
293 | ||
1da177e4 LT |
294 | height = root->height; |
295 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; | |
296 | ||
297 | offset = 0; /* uninitialised var warning */ | |
612d6c19 | 298 | while (height > 0) { |
201b6264 | 299 | if (slot == NULL) { |
1da177e4 | 300 | /* Have to add a child node. */ |
201b6264 | 301 | if (!(slot = radix_tree_node_alloc(root))) |
1da177e4 | 302 | return -ENOMEM; |
7cf9c2c7 | 303 | slot->height = height; |
201b6264 | 304 | if (node) { |
7cf9c2c7 | 305 | rcu_assign_pointer(node->slots[offset], slot); |
1da177e4 | 306 | node->count++; |
201b6264 | 307 | } else |
c0bc9875 NP |
308 | rcu_assign_pointer(root->rnode, |
309 | radix_tree_ptr_to_indirect(slot)); | |
1da177e4 LT |
310 | } |
311 | ||
312 | /* Go a level down */ | |
313 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
201b6264 CL |
314 | node = slot; |
315 | slot = node->slots[offset]; | |
1da177e4 LT |
316 | shift -= RADIX_TREE_MAP_SHIFT; |
317 | height--; | |
612d6c19 | 318 | } |
1da177e4 | 319 | |
201b6264 | 320 | if (slot != NULL) |
1da177e4 | 321 | return -EEXIST; |
201b6264 | 322 | |
612d6c19 NP |
323 | if (node) { |
324 | node->count++; | |
7cf9c2c7 | 325 | rcu_assign_pointer(node->slots[offset], item); |
612d6c19 NP |
326 | BUG_ON(tag_get(node, 0, offset)); |
327 | BUG_ON(tag_get(node, 1, offset)); | |
328 | } else { | |
c0bc9875 | 329 | rcu_assign_pointer(root->rnode, item); |
612d6c19 NP |
330 | BUG_ON(root_tag_get(root, 0)); |
331 | BUG_ON(root_tag_get(root, 1)); | |
332 | } | |
1da177e4 | 333 | |
1da177e4 LT |
334 | return 0; |
335 | } | |
336 | EXPORT_SYMBOL(radix_tree_insert); | |
337 | ||
7cf9c2c7 NP |
338 | /** |
339 | * radix_tree_lookup_slot - lookup a slot in a radix tree | |
340 | * @root: radix tree root | |
341 | * @index: index key | |
342 | * | |
343 | * Returns: the slot corresponding to the position @index in the | |
344 | * radix tree @root. This is useful for update-if-exists operations. | |
345 | * | |
346 | * This function cannot be called under rcu_read_lock, it must be | |
347 | * excluded from writers, as must the returned slot for subsequent | |
348 | * use by radix_tree_deref_slot() and radix_tree_replace slot. | |
349 | * Caller must hold tree write locked across slot lookup and | |
350 | * replace. | |
351 | */ | |
352 | void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index) | |
1da177e4 LT |
353 | { |
354 | unsigned int height, shift; | |
7cf9c2c7 | 355 | struct radix_tree_node *node, **slot; |
612d6c19 | 356 | |
7cf9c2c7 NP |
357 | node = root->rnode; |
358 | if (node == NULL) | |
1da177e4 LT |
359 | return NULL; |
360 | ||
c0bc9875 | 361 | if (!radix_tree_is_indirect_ptr(node)) { |
7cf9c2c7 NP |
362 | if (index > 0) |
363 | return NULL; | |
612d6c19 | 364 | return (void **)&root->rnode; |
7cf9c2c7 | 365 | } |
c0bc9875 | 366 | node = radix_tree_indirect_to_ptr(node); |
7cf9c2c7 NP |
367 | |
368 | height = node->height; | |
369 | if (index > radix_tree_maxindex(height)) | |
370 | return NULL; | |
612d6c19 | 371 | |
1da177e4 | 372 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; |
1da177e4 | 373 | |
7cf9c2c7 NP |
374 | do { |
375 | slot = (struct radix_tree_node **) | |
376 | (node->slots + ((index>>shift) & RADIX_TREE_MAP_MASK)); | |
377 | node = *slot; | |
378 | if (node == NULL) | |
1da177e4 LT |
379 | return NULL; |
380 | ||
1da177e4 LT |
381 | shift -= RADIX_TREE_MAP_SHIFT; |
382 | height--; | |
7cf9c2c7 | 383 | } while (height > 0); |
1da177e4 | 384 | |
a4331366 HR |
385 | return (void **)slot; |
386 | } | |
a4331366 HR |
387 | EXPORT_SYMBOL(radix_tree_lookup_slot); |
388 | ||
389 | /** | |
390 | * radix_tree_lookup - perform lookup operation on a radix tree | |
391 | * @root: radix tree root | |
392 | * @index: index key | |
393 | * | |
394 | * Lookup the item at the position @index in the radix tree @root. | |
7cf9c2c7 NP |
395 | * |
396 | * This function can be called under rcu_read_lock, however the caller | |
397 | * must manage lifetimes of leaf nodes (eg. RCU may also be used to free | |
398 | * them safely). No RCU barriers are required to access or modify the | |
399 | * returned item, however. | |
a4331366 HR |
400 | */ |
401 | void *radix_tree_lookup(struct radix_tree_root *root, unsigned long index) | |
402 | { | |
7cf9c2c7 NP |
403 | unsigned int height, shift; |
404 | struct radix_tree_node *node, **slot; | |
405 | ||
406 | node = rcu_dereference(root->rnode); | |
407 | if (node == NULL) | |
408 | return NULL; | |
409 | ||
c0bc9875 | 410 | if (!radix_tree_is_indirect_ptr(node)) { |
7cf9c2c7 NP |
411 | if (index > 0) |
412 | return NULL; | |
c0bc9875 | 413 | return node; |
7cf9c2c7 | 414 | } |
c0bc9875 | 415 | node = radix_tree_indirect_to_ptr(node); |
7cf9c2c7 NP |
416 | |
417 | height = node->height; | |
418 | if (index > radix_tree_maxindex(height)) | |
419 | return NULL; | |
420 | ||
421 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; | |
a4331366 | 422 | |
7cf9c2c7 NP |
423 | do { |
424 | slot = (struct radix_tree_node **) | |
425 | (node->slots + ((index>>shift) & RADIX_TREE_MAP_MASK)); | |
426 | node = rcu_dereference(*slot); | |
427 | if (node == NULL) | |
428 | return NULL; | |
429 | ||
430 | shift -= RADIX_TREE_MAP_SHIFT; | |
431 | height--; | |
432 | } while (height > 0); | |
433 | ||
434 | return node; | |
1da177e4 LT |
435 | } |
436 | EXPORT_SYMBOL(radix_tree_lookup); | |
437 | ||
438 | /** | |
439 | * radix_tree_tag_set - set a tag on a radix tree node | |
440 | * @root: radix tree root | |
441 | * @index: index key | |
442 | * @tag: tag index | |
443 | * | |
daff89f3 JC |
444 | * Set the search tag (which must be < RADIX_TREE_MAX_TAGS) |
445 | * corresponding to @index in the radix tree. From | |
1da177e4 LT |
446 | * the root all the way down to the leaf node. |
447 | * | |
448 | * Returns the address of the tagged item. Setting a tag on a not-present | |
449 | * item is a bug. | |
450 | */ | |
451 | void *radix_tree_tag_set(struct radix_tree_root *root, | |
daff89f3 | 452 | unsigned long index, unsigned int tag) |
1da177e4 LT |
453 | { |
454 | unsigned int height, shift; | |
201b6264 | 455 | struct radix_tree_node *slot; |
1da177e4 LT |
456 | |
457 | height = root->height; | |
4c91c364 | 458 | BUG_ON(index > radix_tree_maxindex(height)); |
1da177e4 | 459 | |
c0bc9875 | 460 | slot = radix_tree_indirect_to_ptr(root->rnode); |
612d6c19 | 461 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; |
1da177e4 LT |
462 | |
463 | while (height > 0) { | |
464 | int offset; | |
465 | ||
466 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
d5274261 NP |
467 | if (!tag_get(slot, tag, offset)) |
468 | tag_set(slot, tag, offset); | |
201b6264 CL |
469 | slot = slot->slots[offset]; |
470 | BUG_ON(slot == NULL); | |
1da177e4 LT |
471 | shift -= RADIX_TREE_MAP_SHIFT; |
472 | height--; | |
473 | } | |
474 | ||
612d6c19 NP |
475 | /* set the root's tag bit */ |
476 | if (slot && !root_tag_get(root, tag)) | |
477 | root_tag_set(root, tag); | |
478 | ||
201b6264 | 479 | return slot; |
1da177e4 LT |
480 | } |
481 | EXPORT_SYMBOL(radix_tree_tag_set); | |
482 | ||
483 | /** | |
484 | * radix_tree_tag_clear - clear a tag on a radix tree node | |
485 | * @root: radix tree root | |
486 | * @index: index key | |
487 | * @tag: tag index | |
488 | * | |
daff89f3 JC |
489 | * Clear the search tag (which must be < RADIX_TREE_MAX_TAGS) |
490 | * corresponding to @index in the radix tree. If | |
1da177e4 LT |
491 | * this causes the leaf node to have no tags set then clear the tag in the |
492 | * next-to-leaf node, etc. | |
493 | * | |
494 | * Returns the address of the tagged item on success, else NULL. ie: | |
495 | * has the same return value and semantics as radix_tree_lookup(). | |
496 | */ | |
497 | void *radix_tree_tag_clear(struct radix_tree_root *root, | |
daff89f3 | 498 | unsigned long index, unsigned int tag) |
1da177e4 | 499 | { |
26fb1589 JM |
500 | /* |
501 | * The radix tree path needs to be one longer than the maximum path | |
502 | * since the "list" is null terminated. | |
503 | */ | |
504 | struct radix_tree_path path[RADIX_TREE_MAX_PATH + 1], *pathp = path; | |
612d6c19 | 505 | struct radix_tree_node *slot = NULL; |
1da177e4 | 506 | unsigned int height, shift; |
1da177e4 LT |
507 | |
508 | height = root->height; | |
509 | if (index > radix_tree_maxindex(height)) | |
510 | goto out; | |
511 | ||
512 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; | |
513 | pathp->node = NULL; | |
c0bc9875 | 514 | slot = radix_tree_indirect_to_ptr(root->rnode); |
1da177e4 LT |
515 | |
516 | while (height > 0) { | |
517 | int offset; | |
518 | ||
201b6264 | 519 | if (slot == NULL) |
1da177e4 LT |
520 | goto out; |
521 | ||
522 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
523 | pathp[1].offset = offset; | |
201b6264 CL |
524 | pathp[1].node = slot; |
525 | slot = slot->slots[offset]; | |
1da177e4 LT |
526 | pathp++; |
527 | shift -= RADIX_TREE_MAP_SHIFT; | |
528 | height--; | |
529 | } | |
530 | ||
612d6c19 | 531 | if (slot == NULL) |
1da177e4 LT |
532 | goto out; |
533 | ||
612d6c19 | 534 | while (pathp->node) { |
d5274261 NP |
535 | if (!tag_get(pathp->node, tag, pathp->offset)) |
536 | goto out; | |
201b6264 | 537 | tag_clear(pathp->node, tag, pathp->offset); |
6e954b9e NP |
538 | if (any_tag_set(pathp->node, tag)) |
539 | goto out; | |
1da177e4 | 540 | pathp--; |
612d6c19 NP |
541 | } |
542 | ||
543 | /* clear the root's tag bit */ | |
544 | if (root_tag_get(root, tag)) | |
545 | root_tag_clear(root, tag); | |
546 | ||
1da177e4 | 547 | out: |
612d6c19 | 548 | return slot; |
1da177e4 LT |
549 | } |
550 | EXPORT_SYMBOL(radix_tree_tag_clear); | |
551 | ||
552 | #ifndef __KERNEL__ /* Only the test harness uses this at present */ | |
553 | /** | |
32605a18 MT |
554 | * radix_tree_tag_get - get a tag on a radix tree node |
555 | * @root: radix tree root | |
556 | * @index: index key | |
daff89f3 | 557 | * @tag: tag index (< RADIX_TREE_MAX_TAGS) |
1da177e4 | 558 | * |
32605a18 | 559 | * Return values: |
1da177e4 | 560 | * |
612d6c19 NP |
561 | * 0: tag not present or not set |
562 | * 1: tag set | |
1da177e4 LT |
563 | */ |
564 | int radix_tree_tag_get(struct radix_tree_root *root, | |
daff89f3 | 565 | unsigned long index, unsigned int tag) |
1da177e4 LT |
566 | { |
567 | unsigned int height, shift; | |
7cf9c2c7 | 568 | struct radix_tree_node *node; |
1da177e4 LT |
569 | int saw_unset_tag = 0; |
570 | ||
612d6c19 NP |
571 | /* check the root's tag bit */ |
572 | if (!root_tag_get(root, tag)) | |
573 | return 0; | |
574 | ||
7cf9c2c7 NP |
575 | node = rcu_dereference(root->rnode); |
576 | if (node == NULL) | |
577 | return 0; | |
578 | ||
c0bc9875 | 579 | if (!radix_tree_is_indirect_ptr(node)) |
7cf9c2c7 | 580 | return (index == 0); |
c0bc9875 | 581 | node = radix_tree_indirect_to_ptr(node); |
7cf9c2c7 NP |
582 | |
583 | height = node->height; | |
584 | if (index > radix_tree_maxindex(height)) | |
585 | return 0; | |
612d6c19 | 586 | |
1da177e4 | 587 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; |
1da177e4 LT |
588 | |
589 | for ( ; ; ) { | |
590 | int offset; | |
591 | ||
7cf9c2c7 | 592 | if (node == NULL) |
1da177e4 LT |
593 | return 0; |
594 | ||
595 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
596 | ||
597 | /* | |
598 | * This is just a debug check. Later, we can bale as soon as | |
599 | * we see an unset tag. | |
600 | */ | |
7cf9c2c7 | 601 | if (!tag_get(node, tag, offset)) |
1da177e4 LT |
602 | saw_unset_tag = 1; |
603 | if (height == 1) { | |
7cf9c2c7 | 604 | int ret = tag_get(node, tag, offset); |
1da177e4 LT |
605 | |
606 | BUG_ON(ret && saw_unset_tag); | |
e5dcd90b | 607 | return !!ret; |
1da177e4 | 608 | } |
7cf9c2c7 | 609 | node = rcu_dereference(node->slots[offset]); |
1da177e4 LT |
610 | shift -= RADIX_TREE_MAP_SHIFT; |
611 | height--; | |
612 | } | |
613 | } | |
614 | EXPORT_SYMBOL(radix_tree_tag_get); | |
615 | #endif | |
616 | ||
6df8ba4f FW |
617 | /** |
618 | * radix_tree_next_hole - find the next hole (not-present entry) | |
619 | * @root: tree root | |
620 | * @index: index key | |
621 | * @max_scan: maximum range to search | |
622 | * | |
623 | * Search the set [index, min(index+max_scan-1, MAX_INDEX)] for the lowest | |
624 | * indexed hole. | |
625 | * | |
626 | * Returns: the index of the hole if found, otherwise returns an index | |
627 | * outside of the set specified (in which case 'return - index >= max_scan' | |
628 | * will be true). | |
629 | * | |
630 | * radix_tree_next_hole may be called under rcu_read_lock. However, like | |
631 | * radix_tree_gang_lookup, this will not atomically search a snapshot of the | |
632 | * tree at a single point in time. For example, if a hole is created at index | |
633 | * 5, then subsequently a hole is created at index 10, radix_tree_next_hole | |
634 | * covering both indexes may return 10 if called under rcu_read_lock. | |
635 | */ | |
636 | unsigned long radix_tree_next_hole(struct radix_tree_root *root, | |
637 | unsigned long index, unsigned long max_scan) | |
638 | { | |
639 | unsigned long i; | |
640 | ||
641 | for (i = 0; i < max_scan; i++) { | |
642 | if (!radix_tree_lookup(root, index)) | |
643 | break; | |
644 | index++; | |
645 | if (index == 0) | |
646 | break; | |
647 | } | |
648 | ||
649 | return index; | |
650 | } | |
651 | EXPORT_SYMBOL(radix_tree_next_hole); | |
652 | ||
1da177e4 | 653 | static unsigned int |
7cf9c2c7 | 654 | __lookup(struct radix_tree_node *slot, void **results, unsigned long index, |
1da177e4 LT |
655 | unsigned int max_items, unsigned long *next_index) |
656 | { | |
657 | unsigned int nr_found = 0; | |
201b6264 | 658 | unsigned int shift, height; |
201b6264 CL |
659 | unsigned long i; |
660 | ||
7cf9c2c7 NP |
661 | height = slot->height; |
662 | if (height == 0) | |
201b6264 | 663 | goto out; |
1da177e4 | 664 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; |
1da177e4 | 665 | |
201b6264 | 666 | for ( ; height > 1; height--) { |
7cf9c2c7 NP |
667 | i = (index >> shift) & RADIX_TREE_MAP_MASK; |
668 | for (;;) { | |
1da177e4 LT |
669 | if (slot->slots[i] != NULL) |
670 | break; | |
671 | index &= ~((1UL << shift) - 1); | |
672 | index += 1UL << shift; | |
673 | if (index == 0) | |
674 | goto out; /* 32-bit wraparound */ | |
7cf9c2c7 NP |
675 | i++; |
676 | if (i == RADIX_TREE_MAP_SIZE) | |
677 | goto out; | |
1da177e4 | 678 | } |
1da177e4 | 679 | |
1da177e4 | 680 | shift -= RADIX_TREE_MAP_SHIFT; |
7cf9c2c7 NP |
681 | slot = rcu_dereference(slot->slots[i]); |
682 | if (slot == NULL) | |
683 | goto out; | |
1da177e4 | 684 | } |
201b6264 CL |
685 | |
686 | /* Bottom level: grab some items */ | |
687 | for (i = index & RADIX_TREE_MAP_MASK; i < RADIX_TREE_MAP_SIZE; i++) { | |
7cf9c2c7 | 688 | struct radix_tree_node *node; |
201b6264 | 689 | index++; |
7cf9c2c7 NP |
690 | node = slot->slots[i]; |
691 | if (node) { | |
692 | results[nr_found++] = rcu_dereference(node); | |
201b6264 CL |
693 | if (nr_found == max_items) |
694 | goto out; | |
695 | } | |
696 | } | |
1da177e4 LT |
697 | out: |
698 | *next_index = index; | |
699 | return nr_found; | |
700 | } | |
701 | ||
702 | /** | |
703 | * radix_tree_gang_lookup - perform multiple lookup on a radix tree | |
704 | * @root: radix tree root | |
705 | * @results: where the results of the lookup are placed | |
706 | * @first_index: start the lookup from this key | |
707 | * @max_items: place up to this many items at *results | |
708 | * | |
709 | * Performs an index-ascending scan of the tree for present items. Places | |
710 | * them at *@results and returns the number of items which were placed at | |
711 | * *@results. | |
712 | * | |
713 | * The implementation is naive. | |
7cf9c2c7 NP |
714 | * |
715 | * Like radix_tree_lookup, radix_tree_gang_lookup may be called under | |
716 | * rcu_read_lock. In this case, rather than the returned results being | |
717 | * an atomic snapshot of the tree at a single point in time, the semantics | |
718 | * of an RCU protected gang lookup are as though multiple radix_tree_lookups | |
719 | * have been issued in individual locks, and results stored in 'results'. | |
1da177e4 LT |
720 | */ |
721 | unsigned int | |
722 | radix_tree_gang_lookup(struct radix_tree_root *root, void **results, | |
723 | unsigned long first_index, unsigned int max_items) | |
724 | { | |
7cf9c2c7 NP |
725 | unsigned long max_index; |
726 | struct radix_tree_node *node; | |
1da177e4 | 727 | unsigned long cur_index = first_index; |
7cf9c2c7 NP |
728 | unsigned int ret; |
729 | ||
730 | node = rcu_dereference(root->rnode); | |
731 | if (!node) | |
732 | return 0; | |
1da177e4 | 733 | |
c0bc9875 | 734 | if (!radix_tree_is_indirect_ptr(node)) { |
7cf9c2c7 NP |
735 | if (first_index > 0) |
736 | return 0; | |
c0bc9875 | 737 | results[0] = node; |
7cf9c2c7 NP |
738 | return 1; |
739 | } | |
c0bc9875 | 740 | node = radix_tree_indirect_to_ptr(node); |
7cf9c2c7 NP |
741 | |
742 | max_index = radix_tree_maxindex(node->height); | |
743 | ||
744 | ret = 0; | |
1da177e4 LT |
745 | while (ret < max_items) { |
746 | unsigned int nr_found; | |
747 | unsigned long next_index; /* Index of next search */ | |
748 | ||
749 | if (cur_index > max_index) | |
750 | break; | |
7cf9c2c7 | 751 | nr_found = __lookup(node, results + ret, cur_index, |
1da177e4 LT |
752 | max_items - ret, &next_index); |
753 | ret += nr_found; | |
754 | if (next_index == 0) | |
755 | break; | |
756 | cur_index = next_index; | |
757 | } | |
7cf9c2c7 | 758 | |
1da177e4 LT |
759 | return ret; |
760 | } | |
761 | EXPORT_SYMBOL(radix_tree_gang_lookup); | |
762 | ||
763 | /* | |
764 | * FIXME: the two tag_get()s here should use find_next_bit() instead of | |
765 | * open-coding the search. | |
766 | */ | |
767 | static unsigned int | |
7cf9c2c7 | 768 | __lookup_tag(struct radix_tree_node *slot, void **results, unsigned long index, |
daff89f3 | 769 | unsigned int max_items, unsigned long *next_index, unsigned int tag) |
1da177e4 LT |
770 | { |
771 | unsigned int nr_found = 0; | |
7cf9c2c7 | 772 | unsigned int shift, height; |
1da177e4 | 773 | |
7cf9c2c7 NP |
774 | height = slot->height; |
775 | if (height == 0) | |
612d6c19 | 776 | goto out; |
7cf9c2c7 | 777 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; |
1da177e4 | 778 | |
7cf9c2c7 NP |
779 | while (height > 0) { |
780 | unsigned long i = (index >> shift) & RADIX_TREE_MAP_MASK ; | |
1da177e4 | 781 | |
7cf9c2c7 NP |
782 | for (;;) { |
783 | if (tag_get(slot, tag, i)) | |
1da177e4 | 784 | break; |
1da177e4 LT |
785 | index &= ~((1UL << shift) - 1); |
786 | index += 1UL << shift; | |
787 | if (index == 0) | |
788 | goto out; /* 32-bit wraparound */ | |
7cf9c2c7 NP |
789 | i++; |
790 | if (i == RADIX_TREE_MAP_SIZE) | |
791 | goto out; | |
1da177e4 | 792 | } |
1da177e4 LT |
793 | height--; |
794 | if (height == 0) { /* Bottom level: grab some items */ | |
795 | unsigned long j = index & RADIX_TREE_MAP_MASK; | |
796 | ||
797 | for ( ; j < RADIX_TREE_MAP_SIZE; j++) { | |
7cf9c2c7 | 798 | struct radix_tree_node *node; |
1da177e4 | 799 | index++; |
7cf9c2c7 NP |
800 | if (!tag_get(slot, tag, j)) |
801 | continue; | |
802 | node = slot->slots[j]; | |
803 | /* | |
804 | * Even though the tag was found set, we need to | |
805 | * recheck that we have a non-NULL node, because | |
806 | * if this lookup is lockless, it may have been | |
807 | * subsequently deleted. | |
808 | * | |
809 | * Similar care must be taken in any place that | |
810 | * lookup ->slots[x] without a lock (ie. can't | |
811 | * rely on its value remaining the same). | |
812 | */ | |
813 | if (node) { | |
814 | node = rcu_dereference(node); | |
815 | results[nr_found++] = node; | |
1da177e4 LT |
816 | if (nr_found == max_items) |
817 | goto out; | |
818 | } | |
819 | } | |
820 | } | |
821 | shift -= RADIX_TREE_MAP_SHIFT; | |
7cf9c2c7 NP |
822 | slot = rcu_dereference(slot->slots[i]); |
823 | if (slot == NULL) | |
824 | break; | |
825 | } | |
1da177e4 LT |
826 | out: |
827 | *next_index = index; | |
828 | return nr_found; | |
829 | } | |
830 | ||
831 | /** | |
832 | * radix_tree_gang_lookup_tag - perform multiple lookup on a radix tree | |
833 | * based on a tag | |
834 | * @root: radix tree root | |
835 | * @results: where the results of the lookup are placed | |
836 | * @first_index: start the lookup from this key | |
837 | * @max_items: place up to this many items at *results | |
daff89f3 | 838 | * @tag: the tag index (< RADIX_TREE_MAX_TAGS) |
1da177e4 LT |
839 | * |
840 | * Performs an index-ascending scan of the tree for present items which | |
841 | * have the tag indexed by @tag set. Places the items at *@results and | |
842 | * returns the number of items which were placed at *@results. | |
843 | */ | |
844 | unsigned int | |
845 | radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results, | |
daff89f3 JC |
846 | unsigned long first_index, unsigned int max_items, |
847 | unsigned int tag) | |
1da177e4 | 848 | { |
7cf9c2c7 NP |
849 | struct radix_tree_node *node; |
850 | unsigned long max_index; | |
1da177e4 | 851 | unsigned long cur_index = first_index; |
7cf9c2c7 | 852 | unsigned int ret; |
1da177e4 | 853 | |
612d6c19 NP |
854 | /* check the root's tag bit */ |
855 | if (!root_tag_get(root, tag)) | |
856 | return 0; | |
857 | ||
7cf9c2c7 NP |
858 | node = rcu_dereference(root->rnode); |
859 | if (!node) | |
860 | return 0; | |
861 | ||
c0bc9875 | 862 | if (!radix_tree_is_indirect_ptr(node)) { |
7cf9c2c7 NP |
863 | if (first_index > 0) |
864 | return 0; | |
c0bc9875 | 865 | results[0] = node; |
7cf9c2c7 NP |
866 | return 1; |
867 | } | |
c0bc9875 | 868 | node = radix_tree_indirect_to_ptr(node); |
7cf9c2c7 NP |
869 | |
870 | max_index = radix_tree_maxindex(node->height); | |
871 | ||
872 | ret = 0; | |
1da177e4 LT |
873 | while (ret < max_items) { |
874 | unsigned int nr_found; | |
875 | unsigned long next_index; /* Index of next search */ | |
876 | ||
877 | if (cur_index > max_index) | |
878 | break; | |
7cf9c2c7 | 879 | nr_found = __lookup_tag(node, results + ret, cur_index, |
1da177e4 LT |
880 | max_items - ret, &next_index, tag); |
881 | ret += nr_found; | |
882 | if (next_index == 0) | |
883 | break; | |
884 | cur_index = next_index; | |
885 | } | |
7cf9c2c7 | 886 | |
1da177e4 LT |
887 | return ret; |
888 | } | |
889 | EXPORT_SYMBOL(radix_tree_gang_lookup_tag); | |
890 | ||
a5f51c96 NP |
891 | /** |
892 | * radix_tree_shrink - shrink height of a radix tree to minimal | |
893 | * @root radix tree root | |
894 | */ | |
895 | static inline void radix_tree_shrink(struct radix_tree_root *root) | |
896 | { | |
897 | /* try to shrink tree height */ | |
c0bc9875 | 898 | while (root->height > 0) { |
a5f51c96 | 899 | struct radix_tree_node *to_free = root->rnode; |
7cf9c2c7 | 900 | void *newptr; |
a5f51c96 | 901 | |
c0bc9875 NP |
902 | BUG_ON(!radix_tree_is_indirect_ptr(to_free)); |
903 | to_free = radix_tree_indirect_to_ptr(to_free); | |
904 | ||
905 | /* | |
906 | * The candidate node has more than one child, or its child | |
907 | * is not at the leftmost slot, we cannot shrink. | |
908 | */ | |
909 | if (to_free->count != 1) | |
910 | break; | |
911 | if (!to_free->slots[0]) | |
912 | break; | |
913 | ||
7cf9c2c7 NP |
914 | /* |
915 | * We don't need rcu_assign_pointer(), since we are simply | |
916 | * moving the node from one part of the tree to another. If | |
917 | * it was safe to dereference the old pointer to it | |
918 | * (to_free->slots[0]), it will be safe to dereference the new | |
919 | * one (root->rnode). | |
920 | */ | |
921 | newptr = to_free->slots[0]; | |
c0bc9875 NP |
922 | if (root->height > 1) |
923 | newptr = radix_tree_ptr_to_indirect(newptr); | |
7cf9c2c7 | 924 | root->rnode = newptr; |
a5f51c96 NP |
925 | root->height--; |
926 | /* must only free zeroed nodes into the slab */ | |
927 | tag_clear(to_free, 0, 0); | |
928 | tag_clear(to_free, 1, 0); | |
929 | to_free->slots[0] = NULL; | |
930 | to_free->count = 0; | |
931 | radix_tree_node_free(to_free); | |
932 | } | |
933 | } | |
934 | ||
1da177e4 LT |
935 | /** |
936 | * radix_tree_delete - delete an item from a radix tree | |
937 | * @root: radix tree root | |
938 | * @index: index key | |
939 | * | |
940 | * Remove the item at @index from the radix tree rooted at @root. | |
941 | * | |
942 | * Returns the address of the deleted item, or NULL if it was not present. | |
943 | */ | |
944 | void *radix_tree_delete(struct radix_tree_root *root, unsigned long index) | |
945 | { | |
26fb1589 JM |
946 | /* |
947 | * The radix tree path needs to be one longer than the maximum path | |
948 | * since the "list" is null terminated. | |
949 | */ | |
950 | struct radix_tree_path path[RADIX_TREE_MAX_PATH + 1], *pathp = path; | |
612d6c19 | 951 | struct radix_tree_node *slot = NULL; |
7cf9c2c7 | 952 | struct radix_tree_node *to_free; |
1da177e4 | 953 | unsigned int height, shift; |
d5274261 NP |
954 | int tag; |
955 | int offset; | |
1da177e4 LT |
956 | |
957 | height = root->height; | |
958 | if (index > radix_tree_maxindex(height)) | |
959 | goto out; | |
960 | ||
612d6c19 | 961 | slot = root->rnode; |
c0bc9875 | 962 | if (height == 0) { |
612d6c19 NP |
963 | root_tag_clear_all(root); |
964 | root->rnode = NULL; | |
965 | goto out; | |
966 | } | |
c0bc9875 | 967 | slot = radix_tree_indirect_to_ptr(slot); |
612d6c19 | 968 | |
1da177e4 LT |
969 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; |
970 | pathp->node = NULL; | |
1da177e4 | 971 | |
612d6c19 | 972 | do { |
201b6264 | 973 | if (slot == NULL) |
1da177e4 LT |
974 | goto out; |
975 | ||
d5274261 | 976 | pathp++; |
1da177e4 | 977 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; |
d5274261 NP |
978 | pathp->offset = offset; |
979 | pathp->node = slot; | |
201b6264 | 980 | slot = slot->slots[offset]; |
1da177e4 | 981 | shift -= RADIX_TREE_MAP_SHIFT; |
612d6c19 NP |
982 | height--; |
983 | } while (height > 0); | |
1da177e4 | 984 | |
612d6c19 | 985 | if (slot == NULL) |
1da177e4 LT |
986 | goto out; |
987 | ||
1da177e4 LT |
988 | /* |
989 | * Clear all tags associated with the just-deleted item | |
990 | */ | |
daff89f3 | 991 | for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { |
612d6c19 NP |
992 | if (tag_get(pathp->node, tag, pathp->offset)) |
993 | radix_tree_tag_clear(root, index, tag); | |
d5274261 | 994 | } |
1da177e4 | 995 | |
7cf9c2c7 | 996 | to_free = NULL; |
201b6264 | 997 | /* Now free the nodes we do not need anymore */ |
612d6c19 | 998 | while (pathp->node) { |
201b6264 | 999 | pathp->node->slots[pathp->offset] = NULL; |
a5f51c96 | 1000 | pathp->node->count--; |
7cf9c2c7 NP |
1001 | /* |
1002 | * Queue the node for deferred freeing after the | |
1003 | * last reference to it disappears (set NULL, above). | |
1004 | */ | |
1005 | if (to_free) | |
1006 | radix_tree_node_free(to_free); | |
a5f51c96 NP |
1007 | |
1008 | if (pathp->node->count) { | |
c0bc9875 NP |
1009 | if (pathp->node == |
1010 | radix_tree_indirect_to_ptr(root->rnode)) | |
a5f51c96 | 1011 | radix_tree_shrink(root); |
201b6264 | 1012 | goto out; |
a5f51c96 | 1013 | } |
201b6264 CL |
1014 | |
1015 | /* Node with zero slots in use so free it */ | |
7cf9c2c7 | 1016 | to_free = pathp->node; |
612d6c19 | 1017 | pathp--; |
7cf9c2c7 | 1018 | |
1da177e4 | 1019 | } |
612d6c19 | 1020 | root_tag_clear_all(root); |
201b6264 | 1021 | root->height = 0; |
612d6c19 | 1022 | root->rnode = NULL; |
7cf9c2c7 NP |
1023 | if (to_free) |
1024 | radix_tree_node_free(to_free); | |
612d6c19 | 1025 | |
1da177e4 | 1026 | out: |
612d6c19 | 1027 | return slot; |
1da177e4 LT |
1028 | } |
1029 | EXPORT_SYMBOL(radix_tree_delete); | |
1030 | ||
1031 | /** | |
1032 | * radix_tree_tagged - test whether any items in the tree are tagged | |
1033 | * @root: radix tree root | |
1034 | * @tag: tag to test | |
1035 | */ | |
daff89f3 | 1036 | int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag) |
1da177e4 | 1037 | { |
612d6c19 | 1038 | return root_tag_get(root, tag); |
1da177e4 LT |
1039 | } |
1040 | EXPORT_SYMBOL(radix_tree_tagged); | |
1041 | ||
1042 | static void | |
e18b890b | 1043 | radix_tree_node_ctor(void *node, struct kmem_cache *cachep, unsigned long flags) |
1da177e4 LT |
1044 | { |
1045 | memset(node, 0, sizeof(struct radix_tree_node)); | |
1046 | } | |
1047 | ||
1048 | static __init unsigned long __maxindex(unsigned int height) | |
1049 | { | |
1050 | unsigned int tmp = height * RADIX_TREE_MAP_SHIFT; | |
1051 | unsigned long index = (~0UL >> (RADIX_TREE_INDEX_BITS - tmp - 1)) >> 1; | |
1052 | ||
1053 | if (tmp >= RADIX_TREE_INDEX_BITS) | |
1054 | index = ~0UL; | |
1055 | return index; | |
1056 | } | |
1057 | ||
1058 | static __init void radix_tree_init_maxindex(void) | |
1059 | { | |
1060 | unsigned int i; | |
1061 | ||
1062 | for (i = 0; i < ARRAY_SIZE(height_to_maxindex); i++) | |
1063 | height_to_maxindex[i] = __maxindex(i); | |
1064 | } | |
1065 | ||
1da177e4 LT |
1066 | static int radix_tree_callback(struct notifier_block *nfb, |
1067 | unsigned long action, | |
1068 | void *hcpu) | |
1069 | { | |
1070 | int cpu = (long)hcpu; | |
1071 | struct radix_tree_preload *rtp; | |
1072 | ||
1073 | /* Free per-cpu pool of perloaded nodes */ | |
8bb78442 | 1074 | if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) { |
1da177e4 LT |
1075 | rtp = &per_cpu(radix_tree_preloads, cpu); |
1076 | while (rtp->nr) { | |
1077 | kmem_cache_free(radix_tree_node_cachep, | |
1078 | rtp->nodes[rtp->nr-1]); | |
1079 | rtp->nodes[rtp->nr-1] = NULL; | |
1080 | rtp->nr--; | |
1081 | } | |
1082 | } | |
1083 | return NOTIFY_OK; | |
1084 | } | |
1da177e4 LT |
1085 | |
1086 | void __init radix_tree_init(void) | |
1087 | { | |
1088 | radix_tree_node_cachep = kmem_cache_create("radix_tree_node", | |
1089 | sizeof(struct radix_tree_node), 0, | |
20c2df83 | 1090 | SLAB_PANIC, radix_tree_node_ctor); |
1da177e4 LT |
1091 | radix_tree_init_maxindex(); |
1092 | hotcpu_notifier(radix_tree_callback, 0); | |
1093 | } |