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)) | |
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 | { | |
e2848a0e | 98 | struct radix_tree_node *ret = NULL; |
612d6c19 | 99 | gfp_t gfp_mask = root_gfp_mask(root); |
1da177e4 | 100 | |
e2848a0e | 101 | if (!(gfp_mask & __GFP_WAIT)) { |
1da177e4 LT |
102 | struct radix_tree_preload *rtp; |
103 | ||
e2848a0e NP |
104 | /* |
105 | * Provided the caller has preloaded here, we will always | |
106 | * succeed in getting a node here (and never reach | |
107 | * kmem_cache_alloc) | |
108 | */ | |
1da177e4 LT |
109 | rtp = &__get_cpu_var(radix_tree_preloads); |
110 | if (rtp->nr) { | |
111 | ret = rtp->nodes[rtp->nr - 1]; | |
112 | rtp->nodes[rtp->nr - 1] = NULL; | |
113 | rtp->nr--; | |
114 | } | |
115 | } | |
e2848a0e | 116 | if (ret == NULL) |
488514d1 | 117 | ret = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask); |
e2848a0e | 118 | |
c0bc9875 | 119 | BUG_ON(radix_tree_is_indirect_ptr(ret)); |
1da177e4 LT |
120 | return ret; |
121 | } | |
122 | ||
7cf9c2c7 NP |
123 | static void radix_tree_node_rcu_free(struct rcu_head *head) |
124 | { | |
125 | struct radix_tree_node *node = | |
126 | container_of(head, struct radix_tree_node, rcu_head); | |
127 | kmem_cache_free(radix_tree_node_cachep, node); | |
128 | } | |
129 | ||
1da177e4 LT |
130 | static inline void |
131 | radix_tree_node_free(struct radix_tree_node *node) | |
132 | { | |
7cf9c2c7 | 133 | call_rcu(&node->rcu_head, radix_tree_node_rcu_free); |
1da177e4 LT |
134 | } |
135 | ||
136 | /* | |
137 | * Load up this CPU's radix_tree_node buffer with sufficient objects to | |
138 | * ensure that the addition of a single element in the tree cannot fail. On | |
139 | * success, return zero, with preemption disabled. On error, return -ENOMEM | |
140 | * with preemption not disabled. | |
141 | */ | |
dd0fc66f | 142 | int radix_tree_preload(gfp_t gfp_mask) |
1da177e4 LT |
143 | { |
144 | struct radix_tree_preload *rtp; | |
145 | struct radix_tree_node *node; | |
146 | int ret = -ENOMEM; | |
147 | ||
148 | preempt_disable(); | |
149 | rtp = &__get_cpu_var(radix_tree_preloads); | |
150 | while (rtp->nr < ARRAY_SIZE(rtp->nodes)) { | |
151 | preempt_enable(); | |
488514d1 | 152 | node = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask); |
1da177e4 LT |
153 | if (node == NULL) |
154 | goto out; | |
155 | preempt_disable(); | |
156 | rtp = &__get_cpu_var(radix_tree_preloads); | |
157 | if (rtp->nr < ARRAY_SIZE(rtp->nodes)) | |
158 | rtp->nodes[rtp->nr++] = node; | |
159 | else | |
160 | kmem_cache_free(radix_tree_node_cachep, node); | |
161 | } | |
162 | ret = 0; | |
163 | out: | |
164 | return ret; | |
165 | } | |
d7f0923d | 166 | EXPORT_SYMBOL(radix_tree_preload); |
1da177e4 | 167 | |
daff89f3 JC |
168 | static inline void tag_set(struct radix_tree_node *node, unsigned int tag, |
169 | int offset) | |
1da177e4 | 170 | { |
d5274261 | 171 | __set_bit(offset, node->tags[tag]); |
1da177e4 LT |
172 | } |
173 | ||
daff89f3 JC |
174 | static inline void tag_clear(struct radix_tree_node *node, unsigned int tag, |
175 | int offset) | |
1da177e4 | 176 | { |
d5274261 | 177 | __clear_bit(offset, node->tags[tag]); |
1da177e4 LT |
178 | } |
179 | ||
daff89f3 JC |
180 | static inline int tag_get(struct radix_tree_node *node, unsigned int tag, |
181 | int offset) | |
1da177e4 | 182 | { |
d5274261 | 183 | return test_bit(offset, node->tags[tag]); |
1da177e4 LT |
184 | } |
185 | ||
612d6c19 NP |
186 | static inline void root_tag_set(struct radix_tree_root *root, unsigned int tag) |
187 | { | |
20241ad4 | 188 | root->gfp_mask |= (__force gfp_t)(1 << (tag + __GFP_BITS_SHIFT)); |
612d6c19 NP |
189 | } |
190 | ||
191 | ||
192 | static inline void root_tag_clear(struct radix_tree_root *root, unsigned int tag) | |
193 | { | |
20241ad4 | 194 | root->gfp_mask &= (__force gfp_t)~(1 << (tag + __GFP_BITS_SHIFT)); |
612d6c19 NP |
195 | } |
196 | ||
197 | static inline void root_tag_clear_all(struct radix_tree_root *root) | |
198 | { | |
199 | root->gfp_mask &= __GFP_BITS_MASK; | |
200 | } | |
201 | ||
202 | static inline int root_tag_get(struct radix_tree_root *root, unsigned int tag) | |
203 | { | |
20241ad4 | 204 | return (__force unsigned)root->gfp_mask & (1 << (tag + __GFP_BITS_SHIFT)); |
612d6c19 NP |
205 | } |
206 | ||
6e954b9e NP |
207 | /* |
208 | * Returns 1 if any slot in the node has this tag set. | |
209 | * Otherwise returns 0. | |
210 | */ | |
daff89f3 | 211 | static inline int any_tag_set(struct radix_tree_node *node, unsigned int tag) |
6e954b9e NP |
212 | { |
213 | int idx; | |
214 | for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) { | |
215 | if (node->tags[tag][idx]) | |
216 | return 1; | |
217 | } | |
218 | return 0; | |
219 | } | |
220 | ||
1da177e4 LT |
221 | /* |
222 | * Return the maximum key which can be store into a | |
223 | * radix tree with height HEIGHT. | |
224 | */ | |
225 | static inline unsigned long radix_tree_maxindex(unsigned int height) | |
226 | { | |
227 | return height_to_maxindex[height]; | |
228 | } | |
229 | ||
230 | /* | |
231 | * Extend a radix tree so it can store key @index. | |
232 | */ | |
233 | static int radix_tree_extend(struct radix_tree_root *root, unsigned long index) | |
234 | { | |
235 | struct radix_tree_node *node; | |
236 | unsigned int height; | |
1da177e4 LT |
237 | int tag; |
238 | ||
239 | /* Figure out what the height should be. */ | |
240 | height = root->height + 1; | |
241 | while (index > radix_tree_maxindex(height)) | |
242 | height++; | |
243 | ||
244 | if (root->rnode == NULL) { | |
245 | root->height = height; | |
246 | goto out; | |
247 | } | |
248 | ||
1da177e4 | 249 | do { |
7cf9c2c7 | 250 | unsigned int newheight; |
1da177e4 LT |
251 | if (!(node = radix_tree_node_alloc(root))) |
252 | return -ENOMEM; | |
253 | ||
254 | /* Increase the height. */ | |
c0bc9875 | 255 | node->slots[0] = radix_tree_indirect_to_ptr(root->rnode); |
1da177e4 LT |
256 | |
257 | /* Propagate the aggregated tag info into the new root */ | |
daff89f3 | 258 | for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { |
612d6c19 | 259 | if (root_tag_get(root, tag)) |
1da177e4 LT |
260 | tag_set(node, tag, 0); |
261 | } | |
262 | ||
7cf9c2c7 NP |
263 | newheight = root->height+1; |
264 | node->height = newheight; | |
1da177e4 | 265 | node->count = 1; |
c0bc9875 | 266 | node = radix_tree_ptr_to_indirect(node); |
7cf9c2c7 NP |
267 | rcu_assign_pointer(root->rnode, node); |
268 | root->height = newheight; | |
1da177e4 LT |
269 | } while (height > root->height); |
270 | out: | |
271 | return 0; | |
272 | } | |
273 | ||
274 | /** | |
275 | * radix_tree_insert - insert into a radix tree | |
276 | * @root: radix tree root | |
277 | * @index: index key | |
278 | * @item: item to insert | |
279 | * | |
280 | * Insert an item into the radix tree at position @index. | |
281 | */ | |
282 | int radix_tree_insert(struct radix_tree_root *root, | |
283 | unsigned long index, void *item) | |
284 | { | |
201b6264 | 285 | struct radix_tree_node *node = NULL, *slot; |
1da177e4 LT |
286 | unsigned int height, shift; |
287 | int offset; | |
288 | int error; | |
289 | ||
c0bc9875 | 290 | BUG_ON(radix_tree_is_indirect_ptr(item)); |
7cf9c2c7 | 291 | |
1da177e4 | 292 | /* Make sure the tree is high enough. */ |
612d6c19 | 293 | if (index > radix_tree_maxindex(root->height)) { |
1da177e4 LT |
294 | error = radix_tree_extend(root, index); |
295 | if (error) | |
296 | return error; | |
297 | } | |
298 | ||
c0bc9875 NP |
299 | slot = radix_tree_indirect_to_ptr(root->rnode); |
300 | ||
1da177e4 LT |
301 | height = root->height; |
302 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; | |
303 | ||
304 | offset = 0; /* uninitialised var warning */ | |
612d6c19 | 305 | while (height > 0) { |
201b6264 | 306 | if (slot == NULL) { |
1da177e4 | 307 | /* Have to add a child node. */ |
201b6264 | 308 | if (!(slot = radix_tree_node_alloc(root))) |
1da177e4 | 309 | return -ENOMEM; |
7cf9c2c7 | 310 | slot->height = height; |
201b6264 | 311 | if (node) { |
7cf9c2c7 | 312 | rcu_assign_pointer(node->slots[offset], slot); |
1da177e4 | 313 | node->count++; |
201b6264 | 314 | } else |
c0bc9875 NP |
315 | rcu_assign_pointer(root->rnode, |
316 | radix_tree_ptr_to_indirect(slot)); | |
1da177e4 LT |
317 | } |
318 | ||
319 | /* Go a level down */ | |
320 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
201b6264 CL |
321 | node = slot; |
322 | slot = node->slots[offset]; | |
1da177e4 LT |
323 | shift -= RADIX_TREE_MAP_SHIFT; |
324 | height--; | |
612d6c19 | 325 | } |
1da177e4 | 326 | |
201b6264 | 327 | if (slot != NULL) |
1da177e4 | 328 | return -EEXIST; |
201b6264 | 329 | |
612d6c19 NP |
330 | if (node) { |
331 | node->count++; | |
7cf9c2c7 | 332 | rcu_assign_pointer(node->slots[offset], item); |
612d6c19 NP |
333 | BUG_ON(tag_get(node, 0, offset)); |
334 | BUG_ON(tag_get(node, 1, offset)); | |
335 | } else { | |
c0bc9875 | 336 | rcu_assign_pointer(root->rnode, item); |
612d6c19 NP |
337 | BUG_ON(root_tag_get(root, 0)); |
338 | BUG_ON(root_tag_get(root, 1)); | |
339 | } | |
1da177e4 | 340 | |
1da177e4 LT |
341 | return 0; |
342 | } | |
343 | EXPORT_SYMBOL(radix_tree_insert); | |
344 | ||
7cf9c2c7 NP |
345 | /** |
346 | * radix_tree_lookup_slot - lookup a slot in a radix tree | |
347 | * @root: radix tree root | |
348 | * @index: index key | |
349 | * | |
350 | * Returns: the slot corresponding to the position @index in the | |
351 | * radix tree @root. This is useful for update-if-exists operations. | |
352 | * | |
353 | * This function cannot be called under rcu_read_lock, it must be | |
354 | * excluded from writers, as must the returned slot for subsequent | |
355 | * use by radix_tree_deref_slot() and radix_tree_replace slot. | |
356 | * Caller must hold tree write locked across slot lookup and | |
357 | * replace. | |
358 | */ | |
359 | void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index) | |
1da177e4 LT |
360 | { |
361 | unsigned int height, shift; | |
7cf9c2c7 | 362 | struct radix_tree_node *node, **slot; |
612d6c19 | 363 | |
7cf9c2c7 NP |
364 | node = root->rnode; |
365 | if (node == NULL) | |
1da177e4 LT |
366 | return NULL; |
367 | ||
c0bc9875 | 368 | if (!radix_tree_is_indirect_ptr(node)) { |
7cf9c2c7 NP |
369 | if (index > 0) |
370 | return NULL; | |
612d6c19 | 371 | return (void **)&root->rnode; |
7cf9c2c7 | 372 | } |
c0bc9875 | 373 | node = radix_tree_indirect_to_ptr(node); |
7cf9c2c7 NP |
374 | |
375 | height = node->height; | |
376 | if (index > radix_tree_maxindex(height)) | |
377 | return NULL; | |
612d6c19 | 378 | |
1da177e4 | 379 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; |
1da177e4 | 380 | |
7cf9c2c7 NP |
381 | do { |
382 | slot = (struct radix_tree_node **) | |
383 | (node->slots + ((index>>shift) & RADIX_TREE_MAP_MASK)); | |
384 | node = *slot; | |
385 | if (node == NULL) | |
1da177e4 LT |
386 | return NULL; |
387 | ||
1da177e4 LT |
388 | shift -= RADIX_TREE_MAP_SHIFT; |
389 | height--; | |
7cf9c2c7 | 390 | } while (height > 0); |
1da177e4 | 391 | |
a4331366 HR |
392 | return (void **)slot; |
393 | } | |
a4331366 HR |
394 | EXPORT_SYMBOL(radix_tree_lookup_slot); |
395 | ||
396 | /** | |
397 | * radix_tree_lookup - perform lookup operation on a radix tree | |
398 | * @root: radix tree root | |
399 | * @index: index key | |
400 | * | |
401 | * Lookup the item at the position @index in the radix tree @root. | |
7cf9c2c7 NP |
402 | * |
403 | * This function can be called under rcu_read_lock, however the caller | |
404 | * must manage lifetimes of leaf nodes (eg. RCU may also be used to free | |
405 | * them safely). No RCU barriers are required to access or modify the | |
406 | * returned item, however. | |
a4331366 HR |
407 | */ |
408 | void *radix_tree_lookup(struct radix_tree_root *root, unsigned long index) | |
409 | { | |
7cf9c2c7 NP |
410 | unsigned int height, shift; |
411 | struct radix_tree_node *node, **slot; | |
412 | ||
413 | node = rcu_dereference(root->rnode); | |
414 | if (node == NULL) | |
415 | return NULL; | |
416 | ||
c0bc9875 | 417 | if (!radix_tree_is_indirect_ptr(node)) { |
7cf9c2c7 NP |
418 | if (index > 0) |
419 | return NULL; | |
c0bc9875 | 420 | return node; |
7cf9c2c7 | 421 | } |
c0bc9875 | 422 | node = radix_tree_indirect_to_ptr(node); |
7cf9c2c7 NP |
423 | |
424 | height = node->height; | |
425 | if (index > radix_tree_maxindex(height)) | |
426 | return NULL; | |
427 | ||
428 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; | |
a4331366 | 429 | |
7cf9c2c7 NP |
430 | do { |
431 | slot = (struct radix_tree_node **) | |
432 | (node->slots + ((index>>shift) & RADIX_TREE_MAP_MASK)); | |
433 | node = rcu_dereference(*slot); | |
434 | if (node == NULL) | |
435 | return NULL; | |
436 | ||
437 | shift -= RADIX_TREE_MAP_SHIFT; | |
438 | height--; | |
439 | } while (height > 0); | |
440 | ||
441 | return node; | |
1da177e4 LT |
442 | } |
443 | EXPORT_SYMBOL(radix_tree_lookup); | |
444 | ||
445 | /** | |
446 | * radix_tree_tag_set - set a tag on a radix tree node | |
447 | * @root: radix tree root | |
448 | * @index: index key | |
449 | * @tag: tag index | |
450 | * | |
daff89f3 JC |
451 | * Set the search tag (which must be < RADIX_TREE_MAX_TAGS) |
452 | * corresponding to @index in the radix tree. From | |
1da177e4 LT |
453 | * the root all the way down to the leaf node. |
454 | * | |
455 | * Returns the address of the tagged item. Setting a tag on a not-present | |
456 | * item is a bug. | |
457 | */ | |
458 | void *radix_tree_tag_set(struct radix_tree_root *root, | |
daff89f3 | 459 | unsigned long index, unsigned int tag) |
1da177e4 LT |
460 | { |
461 | unsigned int height, shift; | |
201b6264 | 462 | struct radix_tree_node *slot; |
1da177e4 LT |
463 | |
464 | height = root->height; | |
4c91c364 | 465 | BUG_ON(index > radix_tree_maxindex(height)); |
1da177e4 | 466 | |
c0bc9875 | 467 | slot = radix_tree_indirect_to_ptr(root->rnode); |
612d6c19 | 468 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; |
1da177e4 LT |
469 | |
470 | while (height > 0) { | |
471 | int offset; | |
472 | ||
473 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
d5274261 NP |
474 | if (!tag_get(slot, tag, offset)) |
475 | tag_set(slot, tag, offset); | |
201b6264 CL |
476 | slot = slot->slots[offset]; |
477 | BUG_ON(slot == NULL); | |
1da177e4 LT |
478 | shift -= RADIX_TREE_MAP_SHIFT; |
479 | height--; | |
480 | } | |
481 | ||
612d6c19 NP |
482 | /* set the root's tag bit */ |
483 | if (slot && !root_tag_get(root, tag)) | |
484 | root_tag_set(root, tag); | |
485 | ||
201b6264 | 486 | return slot; |
1da177e4 LT |
487 | } |
488 | EXPORT_SYMBOL(radix_tree_tag_set); | |
489 | ||
490 | /** | |
491 | * radix_tree_tag_clear - clear a tag on a radix tree node | |
492 | * @root: radix tree root | |
493 | * @index: index key | |
494 | * @tag: tag index | |
495 | * | |
daff89f3 JC |
496 | * Clear the search tag (which must be < RADIX_TREE_MAX_TAGS) |
497 | * corresponding to @index in the radix tree. If | |
1da177e4 LT |
498 | * this causes the leaf node to have no tags set then clear the tag in the |
499 | * next-to-leaf node, etc. | |
500 | * | |
501 | * Returns the address of the tagged item on success, else NULL. ie: | |
502 | * has the same return value and semantics as radix_tree_lookup(). | |
503 | */ | |
504 | void *radix_tree_tag_clear(struct radix_tree_root *root, | |
daff89f3 | 505 | unsigned long index, unsigned int tag) |
1da177e4 | 506 | { |
26fb1589 JM |
507 | /* |
508 | * The radix tree path needs to be one longer than the maximum path | |
509 | * since the "list" is null terminated. | |
510 | */ | |
511 | struct radix_tree_path path[RADIX_TREE_MAX_PATH + 1], *pathp = path; | |
612d6c19 | 512 | struct radix_tree_node *slot = NULL; |
1da177e4 | 513 | unsigned int height, shift; |
1da177e4 LT |
514 | |
515 | height = root->height; | |
516 | if (index > radix_tree_maxindex(height)) | |
517 | goto out; | |
518 | ||
519 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; | |
520 | pathp->node = NULL; | |
c0bc9875 | 521 | slot = radix_tree_indirect_to_ptr(root->rnode); |
1da177e4 LT |
522 | |
523 | while (height > 0) { | |
524 | int offset; | |
525 | ||
201b6264 | 526 | if (slot == NULL) |
1da177e4 LT |
527 | goto out; |
528 | ||
529 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
530 | pathp[1].offset = offset; | |
201b6264 CL |
531 | pathp[1].node = slot; |
532 | slot = slot->slots[offset]; | |
1da177e4 LT |
533 | pathp++; |
534 | shift -= RADIX_TREE_MAP_SHIFT; | |
535 | height--; | |
536 | } | |
537 | ||
612d6c19 | 538 | if (slot == NULL) |
1da177e4 LT |
539 | goto out; |
540 | ||
612d6c19 | 541 | while (pathp->node) { |
d5274261 NP |
542 | if (!tag_get(pathp->node, tag, pathp->offset)) |
543 | goto out; | |
201b6264 | 544 | tag_clear(pathp->node, tag, pathp->offset); |
6e954b9e NP |
545 | if (any_tag_set(pathp->node, tag)) |
546 | goto out; | |
1da177e4 | 547 | pathp--; |
612d6c19 NP |
548 | } |
549 | ||
550 | /* clear the root's tag bit */ | |
551 | if (root_tag_get(root, tag)) | |
552 | root_tag_clear(root, tag); | |
553 | ||
1da177e4 | 554 | out: |
612d6c19 | 555 | return slot; |
1da177e4 LT |
556 | } |
557 | EXPORT_SYMBOL(radix_tree_tag_clear); | |
558 | ||
559 | #ifndef __KERNEL__ /* Only the test harness uses this at present */ | |
560 | /** | |
32605a18 MT |
561 | * radix_tree_tag_get - get a tag on a radix tree node |
562 | * @root: radix tree root | |
563 | * @index: index key | |
daff89f3 | 564 | * @tag: tag index (< RADIX_TREE_MAX_TAGS) |
1da177e4 | 565 | * |
32605a18 | 566 | * Return values: |
1da177e4 | 567 | * |
612d6c19 NP |
568 | * 0: tag not present or not set |
569 | * 1: tag set | |
1da177e4 LT |
570 | */ |
571 | int radix_tree_tag_get(struct radix_tree_root *root, | |
daff89f3 | 572 | unsigned long index, unsigned int tag) |
1da177e4 LT |
573 | { |
574 | unsigned int height, shift; | |
7cf9c2c7 | 575 | struct radix_tree_node *node; |
1da177e4 LT |
576 | int saw_unset_tag = 0; |
577 | ||
612d6c19 NP |
578 | /* check the root's tag bit */ |
579 | if (!root_tag_get(root, tag)) | |
580 | return 0; | |
581 | ||
7cf9c2c7 NP |
582 | node = rcu_dereference(root->rnode); |
583 | if (node == NULL) | |
584 | return 0; | |
585 | ||
c0bc9875 | 586 | if (!radix_tree_is_indirect_ptr(node)) |
7cf9c2c7 | 587 | return (index == 0); |
c0bc9875 | 588 | node = radix_tree_indirect_to_ptr(node); |
7cf9c2c7 NP |
589 | |
590 | height = node->height; | |
591 | if (index > radix_tree_maxindex(height)) | |
592 | return 0; | |
612d6c19 | 593 | |
1da177e4 | 594 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; |
1da177e4 LT |
595 | |
596 | for ( ; ; ) { | |
597 | int offset; | |
598 | ||
7cf9c2c7 | 599 | if (node == NULL) |
1da177e4 LT |
600 | return 0; |
601 | ||
602 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
603 | ||
604 | /* | |
605 | * This is just a debug check. Later, we can bale as soon as | |
606 | * we see an unset tag. | |
607 | */ | |
7cf9c2c7 | 608 | if (!tag_get(node, tag, offset)) |
1da177e4 LT |
609 | saw_unset_tag = 1; |
610 | if (height == 1) { | |
7cf9c2c7 | 611 | int ret = tag_get(node, tag, offset); |
1da177e4 LT |
612 | |
613 | BUG_ON(ret && saw_unset_tag); | |
e5dcd90b | 614 | return !!ret; |
1da177e4 | 615 | } |
7cf9c2c7 | 616 | node = rcu_dereference(node->slots[offset]); |
1da177e4 LT |
617 | shift -= RADIX_TREE_MAP_SHIFT; |
618 | height--; | |
619 | } | |
620 | } | |
621 | EXPORT_SYMBOL(radix_tree_tag_get); | |
622 | #endif | |
623 | ||
6df8ba4f FW |
624 | /** |
625 | * radix_tree_next_hole - find the next hole (not-present entry) | |
626 | * @root: tree root | |
627 | * @index: index key | |
628 | * @max_scan: maximum range to search | |
629 | * | |
630 | * Search the set [index, min(index+max_scan-1, MAX_INDEX)] for the lowest | |
631 | * indexed hole. | |
632 | * | |
633 | * Returns: the index of the hole if found, otherwise returns an index | |
634 | * outside of the set specified (in which case 'return - index >= max_scan' | |
635 | * will be true). | |
636 | * | |
637 | * radix_tree_next_hole may be called under rcu_read_lock. However, like | |
638 | * radix_tree_gang_lookup, this will not atomically search a snapshot of the | |
639 | * tree at a single point in time. For example, if a hole is created at index | |
640 | * 5, then subsequently a hole is created at index 10, radix_tree_next_hole | |
641 | * covering both indexes may return 10 if called under rcu_read_lock. | |
642 | */ | |
643 | unsigned long radix_tree_next_hole(struct radix_tree_root *root, | |
644 | unsigned long index, unsigned long max_scan) | |
645 | { | |
646 | unsigned long i; | |
647 | ||
648 | for (i = 0; i < max_scan; i++) { | |
649 | if (!radix_tree_lookup(root, index)) | |
650 | break; | |
651 | index++; | |
652 | if (index == 0) | |
653 | break; | |
654 | } | |
655 | ||
656 | return index; | |
657 | } | |
658 | EXPORT_SYMBOL(radix_tree_next_hole); | |
659 | ||
1da177e4 | 660 | static unsigned int |
7cf9c2c7 | 661 | __lookup(struct radix_tree_node *slot, void **results, unsigned long index, |
1da177e4 LT |
662 | unsigned int max_items, unsigned long *next_index) |
663 | { | |
664 | unsigned int nr_found = 0; | |
201b6264 | 665 | unsigned int shift, height; |
201b6264 CL |
666 | unsigned long i; |
667 | ||
7cf9c2c7 NP |
668 | height = slot->height; |
669 | if (height == 0) | |
201b6264 | 670 | goto out; |
1da177e4 | 671 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; |
1da177e4 | 672 | |
201b6264 | 673 | for ( ; height > 1; height--) { |
7cf9c2c7 NP |
674 | i = (index >> shift) & RADIX_TREE_MAP_MASK; |
675 | for (;;) { | |
1da177e4 LT |
676 | if (slot->slots[i] != NULL) |
677 | break; | |
678 | index &= ~((1UL << shift) - 1); | |
679 | index += 1UL << shift; | |
680 | if (index == 0) | |
681 | goto out; /* 32-bit wraparound */ | |
7cf9c2c7 NP |
682 | i++; |
683 | if (i == RADIX_TREE_MAP_SIZE) | |
684 | goto out; | |
1da177e4 | 685 | } |
1da177e4 | 686 | |
1da177e4 | 687 | shift -= RADIX_TREE_MAP_SHIFT; |
7cf9c2c7 NP |
688 | slot = rcu_dereference(slot->slots[i]); |
689 | if (slot == NULL) | |
690 | goto out; | |
1da177e4 | 691 | } |
201b6264 CL |
692 | |
693 | /* Bottom level: grab some items */ | |
694 | for (i = index & RADIX_TREE_MAP_MASK; i < RADIX_TREE_MAP_SIZE; i++) { | |
7cf9c2c7 | 695 | struct radix_tree_node *node; |
201b6264 | 696 | index++; |
7cf9c2c7 NP |
697 | node = slot->slots[i]; |
698 | if (node) { | |
699 | results[nr_found++] = rcu_dereference(node); | |
201b6264 CL |
700 | if (nr_found == max_items) |
701 | goto out; | |
702 | } | |
703 | } | |
1da177e4 LT |
704 | out: |
705 | *next_index = index; | |
706 | return nr_found; | |
707 | } | |
708 | ||
709 | /** | |
710 | * radix_tree_gang_lookup - perform multiple lookup on a radix tree | |
711 | * @root: radix tree root | |
712 | * @results: where the results of the lookup are placed | |
713 | * @first_index: start the lookup from this key | |
714 | * @max_items: place up to this many items at *results | |
715 | * | |
716 | * Performs an index-ascending scan of the tree for present items. Places | |
717 | * them at *@results and returns the number of items which were placed at | |
718 | * *@results. | |
719 | * | |
720 | * The implementation is naive. | |
7cf9c2c7 NP |
721 | * |
722 | * Like radix_tree_lookup, radix_tree_gang_lookup may be called under | |
723 | * rcu_read_lock. In this case, rather than the returned results being | |
724 | * an atomic snapshot of the tree at a single point in time, the semantics | |
725 | * of an RCU protected gang lookup are as though multiple radix_tree_lookups | |
726 | * have been issued in individual locks, and results stored in 'results'. | |
1da177e4 LT |
727 | */ |
728 | unsigned int | |
729 | radix_tree_gang_lookup(struct radix_tree_root *root, void **results, | |
730 | unsigned long first_index, unsigned int max_items) | |
731 | { | |
7cf9c2c7 NP |
732 | unsigned long max_index; |
733 | struct radix_tree_node *node; | |
1da177e4 | 734 | unsigned long cur_index = first_index; |
7cf9c2c7 NP |
735 | unsigned int ret; |
736 | ||
737 | node = rcu_dereference(root->rnode); | |
738 | if (!node) | |
739 | return 0; | |
1da177e4 | 740 | |
c0bc9875 | 741 | if (!radix_tree_is_indirect_ptr(node)) { |
7cf9c2c7 NP |
742 | if (first_index > 0) |
743 | return 0; | |
c0bc9875 | 744 | results[0] = node; |
7cf9c2c7 NP |
745 | return 1; |
746 | } | |
c0bc9875 | 747 | node = radix_tree_indirect_to_ptr(node); |
7cf9c2c7 NP |
748 | |
749 | max_index = radix_tree_maxindex(node->height); | |
750 | ||
751 | ret = 0; | |
1da177e4 LT |
752 | while (ret < max_items) { |
753 | unsigned int nr_found; | |
754 | unsigned long next_index; /* Index of next search */ | |
755 | ||
756 | if (cur_index > max_index) | |
757 | break; | |
7cf9c2c7 | 758 | nr_found = __lookup(node, results + ret, cur_index, |
1da177e4 LT |
759 | max_items - ret, &next_index); |
760 | ret += nr_found; | |
761 | if (next_index == 0) | |
762 | break; | |
763 | cur_index = next_index; | |
764 | } | |
7cf9c2c7 | 765 | |
1da177e4 LT |
766 | return ret; |
767 | } | |
768 | EXPORT_SYMBOL(radix_tree_gang_lookup); | |
769 | ||
770 | /* | |
771 | * FIXME: the two tag_get()s here should use find_next_bit() instead of | |
772 | * open-coding the search. | |
773 | */ | |
774 | static unsigned int | |
7cf9c2c7 | 775 | __lookup_tag(struct radix_tree_node *slot, void **results, unsigned long index, |
daff89f3 | 776 | unsigned int max_items, unsigned long *next_index, unsigned int tag) |
1da177e4 LT |
777 | { |
778 | unsigned int nr_found = 0; | |
7cf9c2c7 | 779 | unsigned int shift, height; |
1da177e4 | 780 | |
7cf9c2c7 NP |
781 | height = slot->height; |
782 | if (height == 0) | |
612d6c19 | 783 | goto out; |
7cf9c2c7 | 784 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; |
1da177e4 | 785 | |
7cf9c2c7 NP |
786 | while (height > 0) { |
787 | unsigned long i = (index >> shift) & RADIX_TREE_MAP_MASK ; | |
1da177e4 | 788 | |
7cf9c2c7 NP |
789 | for (;;) { |
790 | if (tag_get(slot, tag, i)) | |
1da177e4 | 791 | break; |
1da177e4 LT |
792 | index &= ~((1UL << shift) - 1); |
793 | index += 1UL << shift; | |
794 | if (index == 0) | |
795 | goto out; /* 32-bit wraparound */ | |
7cf9c2c7 NP |
796 | i++; |
797 | if (i == RADIX_TREE_MAP_SIZE) | |
798 | goto out; | |
1da177e4 | 799 | } |
1da177e4 LT |
800 | height--; |
801 | if (height == 0) { /* Bottom level: grab some items */ | |
802 | unsigned long j = index & RADIX_TREE_MAP_MASK; | |
803 | ||
804 | for ( ; j < RADIX_TREE_MAP_SIZE; j++) { | |
7cf9c2c7 | 805 | struct radix_tree_node *node; |
1da177e4 | 806 | index++; |
7cf9c2c7 NP |
807 | if (!tag_get(slot, tag, j)) |
808 | continue; | |
809 | node = slot->slots[j]; | |
810 | /* | |
811 | * Even though the tag was found set, we need to | |
812 | * recheck that we have a non-NULL node, because | |
813 | * if this lookup is lockless, it may have been | |
814 | * subsequently deleted. | |
815 | * | |
816 | * Similar care must be taken in any place that | |
817 | * lookup ->slots[x] without a lock (ie. can't | |
818 | * rely on its value remaining the same). | |
819 | */ | |
820 | if (node) { | |
821 | node = rcu_dereference(node); | |
822 | results[nr_found++] = node; | |
1da177e4 LT |
823 | if (nr_found == max_items) |
824 | goto out; | |
825 | } | |
826 | } | |
827 | } | |
828 | shift -= RADIX_TREE_MAP_SHIFT; | |
7cf9c2c7 NP |
829 | slot = rcu_dereference(slot->slots[i]); |
830 | if (slot == NULL) | |
831 | break; | |
832 | } | |
1da177e4 LT |
833 | out: |
834 | *next_index = index; | |
835 | return nr_found; | |
836 | } | |
837 | ||
838 | /** | |
839 | * radix_tree_gang_lookup_tag - perform multiple lookup on a radix tree | |
840 | * based on a tag | |
841 | * @root: radix tree root | |
842 | * @results: where the results of the lookup are placed | |
843 | * @first_index: start the lookup from this key | |
844 | * @max_items: place up to this many items at *results | |
daff89f3 | 845 | * @tag: the tag index (< RADIX_TREE_MAX_TAGS) |
1da177e4 LT |
846 | * |
847 | * Performs an index-ascending scan of the tree for present items which | |
848 | * have the tag indexed by @tag set. Places the items at *@results and | |
849 | * returns the number of items which were placed at *@results. | |
850 | */ | |
851 | unsigned int | |
852 | radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results, | |
daff89f3 JC |
853 | unsigned long first_index, unsigned int max_items, |
854 | unsigned int tag) | |
1da177e4 | 855 | { |
7cf9c2c7 NP |
856 | struct radix_tree_node *node; |
857 | unsigned long max_index; | |
1da177e4 | 858 | unsigned long cur_index = first_index; |
7cf9c2c7 | 859 | unsigned int ret; |
1da177e4 | 860 | |
612d6c19 NP |
861 | /* check the root's tag bit */ |
862 | if (!root_tag_get(root, tag)) | |
863 | return 0; | |
864 | ||
7cf9c2c7 NP |
865 | node = rcu_dereference(root->rnode); |
866 | if (!node) | |
867 | return 0; | |
868 | ||
c0bc9875 | 869 | if (!radix_tree_is_indirect_ptr(node)) { |
7cf9c2c7 NP |
870 | if (first_index > 0) |
871 | return 0; | |
c0bc9875 | 872 | results[0] = node; |
7cf9c2c7 NP |
873 | return 1; |
874 | } | |
c0bc9875 | 875 | node = radix_tree_indirect_to_ptr(node); |
7cf9c2c7 NP |
876 | |
877 | max_index = radix_tree_maxindex(node->height); | |
878 | ||
879 | ret = 0; | |
1da177e4 LT |
880 | while (ret < max_items) { |
881 | unsigned int nr_found; | |
882 | unsigned long next_index; /* Index of next search */ | |
883 | ||
884 | if (cur_index > max_index) | |
885 | break; | |
7cf9c2c7 | 886 | nr_found = __lookup_tag(node, results + ret, cur_index, |
1da177e4 LT |
887 | max_items - ret, &next_index, tag); |
888 | ret += nr_found; | |
889 | if (next_index == 0) | |
890 | break; | |
891 | cur_index = next_index; | |
892 | } | |
7cf9c2c7 | 893 | |
1da177e4 LT |
894 | return ret; |
895 | } | |
896 | EXPORT_SYMBOL(radix_tree_gang_lookup_tag); | |
897 | ||
a5f51c96 NP |
898 | /** |
899 | * radix_tree_shrink - shrink height of a radix tree to minimal | |
900 | * @root radix tree root | |
901 | */ | |
902 | static inline void radix_tree_shrink(struct radix_tree_root *root) | |
903 | { | |
904 | /* try to shrink tree height */ | |
c0bc9875 | 905 | while (root->height > 0) { |
a5f51c96 | 906 | struct radix_tree_node *to_free = root->rnode; |
7cf9c2c7 | 907 | void *newptr; |
a5f51c96 | 908 | |
c0bc9875 NP |
909 | BUG_ON(!radix_tree_is_indirect_ptr(to_free)); |
910 | to_free = radix_tree_indirect_to_ptr(to_free); | |
911 | ||
912 | /* | |
913 | * The candidate node has more than one child, or its child | |
914 | * is not at the leftmost slot, we cannot shrink. | |
915 | */ | |
916 | if (to_free->count != 1) | |
917 | break; | |
918 | if (!to_free->slots[0]) | |
919 | break; | |
920 | ||
7cf9c2c7 NP |
921 | /* |
922 | * We don't need rcu_assign_pointer(), since we are simply | |
923 | * moving the node from one part of the tree to another. If | |
924 | * it was safe to dereference the old pointer to it | |
925 | * (to_free->slots[0]), it will be safe to dereference the new | |
926 | * one (root->rnode). | |
927 | */ | |
928 | newptr = to_free->slots[0]; | |
c0bc9875 NP |
929 | if (root->height > 1) |
930 | newptr = radix_tree_ptr_to_indirect(newptr); | |
7cf9c2c7 | 931 | root->rnode = newptr; |
a5f51c96 NP |
932 | root->height--; |
933 | /* must only free zeroed nodes into the slab */ | |
934 | tag_clear(to_free, 0, 0); | |
935 | tag_clear(to_free, 1, 0); | |
936 | to_free->slots[0] = NULL; | |
937 | to_free->count = 0; | |
938 | radix_tree_node_free(to_free); | |
939 | } | |
940 | } | |
941 | ||
1da177e4 LT |
942 | /** |
943 | * radix_tree_delete - delete an item from a radix tree | |
944 | * @root: radix tree root | |
945 | * @index: index key | |
946 | * | |
947 | * Remove the item at @index from the radix tree rooted at @root. | |
948 | * | |
949 | * Returns the address of the deleted item, or NULL if it was not present. | |
950 | */ | |
951 | void *radix_tree_delete(struct radix_tree_root *root, unsigned long index) | |
952 | { | |
26fb1589 JM |
953 | /* |
954 | * The radix tree path needs to be one longer than the maximum path | |
955 | * since the "list" is null terminated. | |
956 | */ | |
957 | struct radix_tree_path path[RADIX_TREE_MAX_PATH + 1], *pathp = path; | |
612d6c19 | 958 | struct radix_tree_node *slot = NULL; |
7cf9c2c7 | 959 | struct radix_tree_node *to_free; |
1da177e4 | 960 | unsigned int height, shift; |
d5274261 NP |
961 | int tag; |
962 | int offset; | |
1da177e4 LT |
963 | |
964 | height = root->height; | |
965 | if (index > radix_tree_maxindex(height)) | |
966 | goto out; | |
967 | ||
612d6c19 | 968 | slot = root->rnode; |
c0bc9875 | 969 | if (height == 0) { |
612d6c19 NP |
970 | root_tag_clear_all(root); |
971 | root->rnode = NULL; | |
972 | goto out; | |
973 | } | |
c0bc9875 | 974 | slot = radix_tree_indirect_to_ptr(slot); |
612d6c19 | 975 | |
1da177e4 LT |
976 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; |
977 | pathp->node = NULL; | |
1da177e4 | 978 | |
612d6c19 | 979 | do { |
201b6264 | 980 | if (slot == NULL) |
1da177e4 LT |
981 | goto out; |
982 | ||
d5274261 | 983 | pathp++; |
1da177e4 | 984 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; |
d5274261 NP |
985 | pathp->offset = offset; |
986 | pathp->node = slot; | |
201b6264 | 987 | slot = slot->slots[offset]; |
1da177e4 | 988 | shift -= RADIX_TREE_MAP_SHIFT; |
612d6c19 NP |
989 | height--; |
990 | } while (height > 0); | |
1da177e4 | 991 | |
612d6c19 | 992 | if (slot == NULL) |
1da177e4 LT |
993 | goto out; |
994 | ||
1da177e4 LT |
995 | /* |
996 | * Clear all tags associated with the just-deleted item | |
997 | */ | |
daff89f3 | 998 | for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { |
612d6c19 NP |
999 | if (tag_get(pathp->node, tag, pathp->offset)) |
1000 | radix_tree_tag_clear(root, index, tag); | |
d5274261 | 1001 | } |
1da177e4 | 1002 | |
7cf9c2c7 | 1003 | to_free = NULL; |
201b6264 | 1004 | /* Now free the nodes we do not need anymore */ |
612d6c19 | 1005 | while (pathp->node) { |
201b6264 | 1006 | pathp->node->slots[pathp->offset] = NULL; |
a5f51c96 | 1007 | pathp->node->count--; |
7cf9c2c7 NP |
1008 | /* |
1009 | * Queue the node for deferred freeing after the | |
1010 | * last reference to it disappears (set NULL, above). | |
1011 | */ | |
1012 | if (to_free) | |
1013 | radix_tree_node_free(to_free); | |
a5f51c96 NP |
1014 | |
1015 | if (pathp->node->count) { | |
c0bc9875 NP |
1016 | if (pathp->node == |
1017 | radix_tree_indirect_to_ptr(root->rnode)) | |
a5f51c96 | 1018 | radix_tree_shrink(root); |
201b6264 | 1019 | goto out; |
a5f51c96 | 1020 | } |
201b6264 CL |
1021 | |
1022 | /* Node with zero slots in use so free it */ | |
7cf9c2c7 | 1023 | to_free = pathp->node; |
612d6c19 | 1024 | pathp--; |
7cf9c2c7 | 1025 | |
1da177e4 | 1026 | } |
612d6c19 | 1027 | root_tag_clear_all(root); |
201b6264 | 1028 | root->height = 0; |
612d6c19 | 1029 | root->rnode = NULL; |
7cf9c2c7 NP |
1030 | if (to_free) |
1031 | radix_tree_node_free(to_free); | |
612d6c19 | 1032 | |
1da177e4 | 1033 | out: |
612d6c19 | 1034 | return slot; |
1da177e4 LT |
1035 | } |
1036 | EXPORT_SYMBOL(radix_tree_delete); | |
1037 | ||
1038 | /** | |
1039 | * radix_tree_tagged - test whether any items in the tree are tagged | |
1040 | * @root: radix tree root | |
1041 | * @tag: tag to test | |
1042 | */ | |
daff89f3 | 1043 | int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag) |
1da177e4 | 1044 | { |
612d6c19 | 1045 | return root_tag_get(root, tag); |
1da177e4 LT |
1046 | } |
1047 | EXPORT_SYMBOL(radix_tree_tagged); | |
1048 | ||
1049 | static void | |
4ba9b9d0 | 1050 | radix_tree_node_ctor(struct kmem_cache *cachep, void *node) |
1da177e4 LT |
1051 | { |
1052 | memset(node, 0, sizeof(struct radix_tree_node)); | |
1053 | } | |
1054 | ||
1055 | static __init unsigned long __maxindex(unsigned int height) | |
1056 | { | |
430d275a PL |
1057 | unsigned int width = height * RADIX_TREE_MAP_SHIFT; |
1058 | int shift = RADIX_TREE_INDEX_BITS - width; | |
1059 | ||
1060 | if (shift < 0) | |
1061 | return ~0UL; | |
1062 | if (shift >= BITS_PER_LONG) | |
1063 | return 0UL; | |
1064 | return ~0UL >> shift; | |
1da177e4 LT |
1065 | } |
1066 | ||
1067 | static __init void radix_tree_init_maxindex(void) | |
1068 | { | |
1069 | unsigned int i; | |
1070 | ||
1071 | for (i = 0; i < ARRAY_SIZE(height_to_maxindex); i++) | |
1072 | height_to_maxindex[i] = __maxindex(i); | |
1073 | } | |
1074 | ||
1da177e4 LT |
1075 | static int radix_tree_callback(struct notifier_block *nfb, |
1076 | unsigned long action, | |
1077 | void *hcpu) | |
1078 | { | |
1079 | int cpu = (long)hcpu; | |
1080 | struct radix_tree_preload *rtp; | |
1081 | ||
1082 | /* Free per-cpu pool of perloaded nodes */ | |
8bb78442 | 1083 | if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) { |
1da177e4 LT |
1084 | rtp = &per_cpu(radix_tree_preloads, cpu); |
1085 | while (rtp->nr) { | |
1086 | kmem_cache_free(radix_tree_node_cachep, | |
1087 | rtp->nodes[rtp->nr-1]); | |
1088 | rtp->nodes[rtp->nr-1] = NULL; | |
1089 | rtp->nr--; | |
1090 | } | |
1091 | } | |
1092 | return NOTIFY_OK; | |
1093 | } | |
1da177e4 LT |
1094 | |
1095 | void __init radix_tree_init(void) | |
1096 | { | |
1097 | radix_tree_node_cachep = kmem_cache_create("radix_tree_node", | |
1098 | sizeof(struct radix_tree_node), 0, | |
488514d1 CL |
1099 | SLAB_PANIC | SLAB_RECLAIM_ACCOUNT, |
1100 | radix_tree_node_ctor); | |
1da177e4 LT |
1101 | radix_tree_init_maxindex(); |
1102 | hotcpu_notifier(radix_tree_callback, 0); | |
1103 | } |