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 NP |
116 | if (ret == NULL) |
117 | ret = kmem_cache_alloc(radix_tree_node_cachep, | |
118 | set_migrateflags(gfp_mask, __GFP_RECLAIMABLE)); | |
119 | ||
c0bc9875 | 120 | BUG_ON(radix_tree_is_indirect_ptr(ret)); |
1da177e4 LT |
121 | return ret; |
122 | } | |
123 | ||
7cf9c2c7 NP |
124 | static void radix_tree_node_rcu_free(struct rcu_head *head) |
125 | { | |
126 | struct radix_tree_node *node = | |
127 | container_of(head, struct radix_tree_node, rcu_head); | |
128 | kmem_cache_free(radix_tree_node_cachep, node); | |
129 | } | |
130 | ||
1da177e4 LT |
131 | static inline void |
132 | radix_tree_node_free(struct radix_tree_node *node) | |
133 | { | |
7cf9c2c7 | 134 | call_rcu(&node->rcu_head, radix_tree_node_rcu_free); |
1da177e4 LT |
135 | } |
136 | ||
137 | /* | |
138 | * Load up this CPU's radix_tree_node buffer with sufficient objects to | |
139 | * ensure that the addition of a single element in the tree cannot fail. On | |
140 | * success, return zero, with preemption disabled. On error, return -ENOMEM | |
141 | * with preemption not disabled. | |
142 | */ | |
dd0fc66f | 143 | int radix_tree_preload(gfp_t gfp_mask) |
1da177e4 LT |
144 | { |
145 | struct radix_tree_preload *rtp; | |
146 | struct radix_tree_node *node; | |
147 | int ret = -ENOMEM; | |
148 | ||
149 | preempt_disable(); | |
150 | rtp = &__get_cpu_var(radix_tree_preloads); | |
151 | while (rtp->nr < ARRAY_SIZE(rtp->nodes)) { | |
152 | preempt_enable(); | |
e12ba74d MG |
153 | node = kmem_cache_alloc(radix_tree_node_cachep, |
154 | set_migrateflags(gfp_mask, __GFP_RECLAIMABLE)); | |
1da177e4 LT |
155 | if (node == NULL) |
156 | goto out; | |
157 | preempt_disable(); | |
158 | rtp = &__get_cpu_var(radix_tree_preloads); | |
159 | if (rtp->nr < ARRAY_SIZE(rtp->nodes)) | |
160 | rtp->nodes[rtp->nr++] = node; | |
161 | else | |
162 | kmem_cache_free(radix_tree_node_cachep, node); | |
163 | } | |
164 | ret = 0; | |
165 | out: | |
166 | return ret; | |
167 | } | |
d7f0923d | 168 | EXPORT_SYMBOL(radix_tree_preload); |
1da177e4 | 169 | |
daff89f3 JC |
170 | static inline void tag_set(struct radix_tree_node *node, unsigned int tag, |
171 | int offset) | |
1da177e4 | 172 | { |
d5274261 | 173 | __set_bit(offset, node->tags[tag]); |
1da177e4 LT |
174 | } |
175 | ||
daff89f3 JC |
176 | static inline void tag_clear(struct radix_tree_node *node, unsigned int tag, |
177 | int offset) | |
1da177e4 | 178 | { |
d5274261 | 179 | __clear_bit(offset, node->tags[tag]); |
1da177e4 LT |
180 | } |
181 | ||
daff89f3 JC |
182 | static inline int tag_get(struct radix_tree_node *node, unsigned int tag, |
183 | int offset) | |
1da177e4 | 184 | { |
d5274261 | 185 | return test_bit(offset, node->tags[tag]); |
1da177e4 LT |
186 | } |
187 | ||
612d6c19 NP |
188 | static inline void root_tag_set(struct radix_tree_root *root, unsigned int tag) |
189 | { | |
20241ad4 | 190 | root->gfp_mask |= (__force gfp_t)(1 << (tag + __GFP_BITS_SHIFT)); |
612d6c19 NP |
191 | } |
192 | ||
193 | ||
194 | static inline void root_tag_clear(struct radix_tree_root *root, unsigned int tag) | |
195 | { | |
20241ad4 | 196 | root->gfp_mask &= (__force gfp_t)~(1 << (tag + __GFP_BITS_SHIFT)); |
612d6c19 NP |
197 | } |
198 | ||
199 | static inline void root_tag_clear_all(struct radix_tree_root *root) | |
200 | { | |
201 | root->gfp_mask &= __GFP_BITS_MASK; | |
202 | } | |
203 | ||
204 | static inline int root_tag_get(struct radix_tree_root *root, unsigned int tag) | |
205 | { | |
20241ad4 | 206 | return (__force unsigned)root->gfp_mask & (1 << (tag + __GFP_BITS_SHIFT)); |
612d6c19 NP |
207 | } |
208 | ||
6e954b9e NP |
209 | /* |
210 | * Returns 1 if any slot in the node has this tag set. | |
211 | * Otherwise returns 0. | |
212 | */ | |
daff89f3 | 213 | static inline int any_tag_set(struct radix_tree_node *node, unsigned int tag) |
6e954b9e NP |
214 | { |
215 | int idx; | |
216 | for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) { | |
217 | if (node->tags[tag][idx]) | |
218 | return 1; | |
219 | } | |
220 | return 0; | |
221 | } | |
222 | ||
1da177e4 LT |
223 | /* |
224 | * Return the maximum key which can be store into a | |
225 | * radix tree with height HEIGHT. | |
226 | */ | |
227 | static inline unsigned long radix_tree_maxindex(unsigned int height) | |
228 | { | |
229 | return height_to_maxindex[height]; | |
230 | } | |
231 | ||
232 | /* | |
233 | * Extend a radix tree so it can store key @index. | |
234 | */ | |
235 | static int radix_tree_extend(struct radix_tree_root *root, unsigned long index) | |
236 | { | |
237 | struct radix_tree_node *node; | |
238 | unsigned int height; | |
1da177e4 LT |
239 | int tag; |
240 | ||
241 | /* Figure out what the height should be. */ | |
242 | height = root->height + 1; | |
243 | while (index > radix_tree_maxindex(height)) | |
244 | height++; | |
245 | ||
246 | if (root->rnode == NULL) { | |
247 | root->height = height; | |
248 | goto out; | |
249 | } | |
250 | ||
1da177e4 | 251 | do { |
7cf9c2c7 | 252 | unsigned int newheight; |
1da177e4 LT |
253 | if (!(node = radix_tree_node_alloc(root))) |
254 | return -ENOMEM; | |
255 | ||
256 | /* Increase the height. */ | |
c0bc9875 | 257 | node->slots[0] = radix_tree_indirect_to_ptr(root->rnode); |
1da177e4 LT |
258 | |
259 | /* Propagate the aggregated tag info into the new root */ | |
daff89f3 | 260 | for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { |
612d6c19 | 261 | if (root_tag_get(root, tag)) |
1da177e4 LT |
262 | tag_set(node, tag, 0); |
263 | } | |
264 | ||
7cf9c2c7 NP |
265 | newheight = root->height+1; |
266 | node->height = newheight; | |
1da177e4 | 267 | node->count = 1; |
c0bc9875 | 268 | node = radix_tree_ptr_to_indirect(node); |
7cf9c2c7 NP |
269 | rcu_assign_pointer(root->rnode, node); |
270 | root->height = newheight; | |
1da177e4 LT |
271 | } while (height > root->height); |
272 | out: | |
273 | return 0; | |
274 | } | |
275 | ||
276 | /** | |
277 | * radix_tree_insert - insert into a radix tree | |
278 | * @root: radix tree root | |
279 | * @index: index key | |
280 | * @item: item to insert | |
281 | * | |
282 | * Insert an item into the radix tree at position @index. | |
283 | */ | |
284 | int radix_tree_insert(struct radix_tree_root *root, | |
285 | unsigned long index, void *item) | |
286 | { | |
201b6264 | 287 | struct radix_tree_node *node = NULL, *slot; |
1da177e4 LT |
288 | unsigned int height, shift; |
289 | int offset; | |
290 | int error; | |
291 | ||
c0bc9875 | 292 | BUG_ON(radix_tree_is_indirect_ptr(item)); |
7cf9c2c7 | 293 | |
1da177e4 | 294 | /* Make sure the tree is high enough. */ |
612d6c19 | 295 | if (index > radix_tree_maxindex(root->height)) { |
1da177e4 LT |
296 | error = radix_tree_extend(root, index); |
297 | if (error) | |
298 | return error; | |
299 | } | |
300 | ||
c0bc9875 NP |
301 | slot = radix_tree_indirect_to_ptr(root->rnode); |
302 | ||
1da177e4 LT |
303 | height = root->height; |
304 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; | |
305 | ||
306 | offset = 0; /* uninitialised var warning */ | |
612d6c19 | 307 | while (height > 0) { |
201b6264 | 308 | if (slot == NULL) { |
1da177e4 | 309 | /* Have to add a child node. */ |
201b6264 | 310 | if (!(slot = radix_tree_node_alloc(root))) |
1da177e4 | 311 | return -ENOMEM; |
7cf9c2c7 | 312 | slot->height = height; |
201b6264 | 313 | if (node) { |
7cf9c2c7 | 314 | rcu_assign_pointer(node->slots[offset], slot); |
1da177e4 | 315 | node->count++; |
201b6264 | 316 | } else |
c0bc9875 NP |
317 | rcu_assign_pointer(root->rnode, |
318 | radix_tree_ptr_to_indirect(slot)); | |
1da177e4 LT |
319 | } |
320 | ||
321 | /* Go a level down */ | |
322 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
201b6264 CL |
323 | node = slot; |
324 | slot = node->slots[offset]; | |
1da177e4 LT |
325 | shift -= RADIX_TREE_MAP_SHIFT; |
326 | height--; | |
612d6c19 | 327 | } |
1da177e4 | 328 | |
201b6264 | 329 | if (slot != NULL) |
1da177e4 | 330 | return -EEXIST; |
201b6264 | 331 | |
612d6c19 NP |
332 | if (node) { |
333 | node->count++; | |
7cf9c2c7 | 334 | rcu_assign_pointer(node->slots[offset], item); |
612d6c19 NP |
335 | BUG_ON(tag_get(node, 0, offset)); |
336 | BUG_ON(tag_get(node, 1, offset)); | |
337 | } else { | |
c0bc9875 | 338 | rcu_assign_pointer(root->rnode, item); |
612d6c19 NP |
339 | BUG_ON(root_tag_get(root, 0)); |
340 | BUG_ON(root_tag_get(root, 1)); | |
341 | } | |
1da177e4 | 342 | |
1da177e4 LT |
343 | return 0; |
344 | } | |
345 | EXPORT_SYMBOL(radix_tree_insert); | |
346 | ||
7cf9c2c7 NP |
347 | /** |
348 | * radix_tree_lookup_slot - lookup a slot in a radix tree | |
349 | * @root: radix tree root | |
350 | * @index: index key | |
351 | * | |
352 | * Returns: the slot corresponding to the position @index in the | |
353 | * radix tree @root. This is useful for update-if-exists operations. | |
354 | * | |
355 | * This function cannot be called under rcu_read_lock, it must be | |
356 | * excluded from writers, as must the returned slot for subsequent | |
357 | * use by radix_tree_deref_slot() and radix_tree_replace slot. | |
358 | * Caller must hold tree write locked across slot lookup and | |
359 | * replace. | |
360 | */ | |
361 | void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index) | |
1da177e4 LT |
362 | { |
363 | unsigned int height, shift; | |
7cf9c2c7 | 364 | struct radix_tree_node *node, **slot; |
612d6c19 | 365 | |
7cf9c2c7 NP |
366 | node = root->rnode; |
367 | if (node == NULL) | |
1da177e4 LT |
368 | return NULL; |
369 | ||
c0bc9875 | 370 | if (!radix_tree_is_indirect_ptr(node)) { |
7cf9c2c7 NP |
371 | if (index > 0) |
372 | return NULL; | |
612d6c19 | 373 | return (void **)&root->rnode; |
7cf9c2c7 | 374 | } |
c0bc9875 | 375 | node = radix_tree_indirect_to_ptr(node); |
7cf9c2c7 NP |
376 | |
377 | height = node->height; | |
378 | if (index > radix_tree_maxindex(height)) | |
379 | return NULL; | |
612d6c19 | 380 | |
1da177e4 | 381 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; |
1da177e4 | 382 | |
7cf9c2c7 NP |
383 | do { |
384 | slot = (struct radix_tree_node **) | |
385 | (node->slots + ((index>>shift) & RADIX_TREE_MAP_MASK)); | |
386 | node = *slot; | |
387 | if (node == NULL) | |
1da177e4 LT |
388 | return NULL; |
389 | ||
1da177e4 LT |
390 | shift -= RADIX_TREE_MAP_SHIFT; |
391 | height--; | |
7cf9c2c7 | 392 | } while (height > 0); |
1da177e4 | 393 | |
a4331366 HR |
394 | return (void **)slot; |
395 | } | |
a4331366 HR |
396 | EXPORT_SYMBOL(radix_tree_lookup_slot); |
397 | ||
398 | /** | |
399 | * radix_tree_lookup - perform lookup operation on a radix tree | |
400 | * @root: radix tree root | |
401 | * @index: index key | |
402 | * | |
403 | * Lookup the item at the position @index in the radix tree @root. | |
7cf9c2c7 NP |
404 | * |
405 | * This function can be called under rcu_read_lock, however the caller | |
406 | * must manage lifetimes of leaf nodes (eg. RCU may also be used to free | |
407 | * them safely). No RCU barriers are required to access or modify the | |
408 | * returned item, however. | |
a4331366 HR |
409 | */ |
410 | void *radix_tree_lookup(struct radix_tree_root *root, unsigned long index) | |
411 | { | |
7cf9c2c7 NP |
412 | unsigned int height, shift; |
413 | struct radix_tree_node *node, **slot; | |
414 | ||
415 | node = rcu_dereference(root->rnode); | |
416 | if (node == NULL) | |
417 | return NULL; | |
418 | ||
c0bc9875 | 419 | if (!radix_tree_is_indirect_ptr(node)) { |
7cf9c2c7 NP |
420 | if (index > 0) |
421 | return NULL; | |
c0bc9875 | 422 | return node; |
7cf9c2c7 | 423 | } |
c0bc9875 | 424 | node = radix_tree_indirect_to_ptr(node); |
7cf9c2c7 NP |
425 | |
426 | height = node->height; | |
427 | if (index > radix_tree_maxindex(height)) | |
428 | return NULL; | |
429 | ||
430 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; | |
a4331366 | 431 | |
7cf9c2c7 NP |
432 | do { |
433 | slot = (struct radix_tree_node **) | |
434 | (node->slots + ((index>>shift) & RADIX_TREE_MAP_MASK)); | |
435 | node = rcu_dereference(*slot); | |
436 | if (node == NULL) | |
437 | return NULL; | |
438 | ||
439 | shift -= RADIX_TREE_MAP_SHIFT; | |
440 | height--; | |
441 | } while (height > 0); | |
442 | ||
443 | return node; | |
1da177e4 LT |
444 | } |
445 | EXPORT_SYMBOL(radix_tree_lookup); | |
446 | ||
447 | /** | |
448 | * radix_tree_tag_set - set a tag on a radix tree node | |
449 | * @root: radix tree root | |
450 | * @index: index key | |
451 | * @tag: tag index | |
452 | * | |
daff89f3 JC |
453 | * Set the search tag (which must be < RADIX_TREE_MAX_TAGS) |
454 | * corresponding to @index in the radix tree. From | |
1da177e4 LT |
455 | * the root all the way down to the leaf node. |
456 | * | |
457 | * Returns the address of the tagged item. Setting a tag on a not-present | |
458 | * item is a bug. | |
459 | */ | |
460 | void *radix_tree_tag_set(struct radix_tree_root *root, | |
daff89f3 | 461 | unsigned long index, unsigned int tag) |
1da177e4 LT |
462 | { |
463 | unsigned int height, shift; | |
201b6264 | 464 | struct radix_tree_node *slot; |
1da177e4 LT |
465 | |
466 | height = root->height; | |
4c91c364 | 467 | BUG_ON(index > radix_tree_maxindex(height)); |
1da177e4 | 468 | |
c0bc9875 | 469 | slot = radix_tree_indirect_to_ptr(root->rnode); |
612d6c19 | 470 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; |
1da177e4 LT |
471 | |
472 | while (height > 0) { | |
473 | int offset; | |
474 | ||
475 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
d5274261 NP |
476 | if (!tag_get(slot, tag, offset)) |
477 | tag_set(slot, tag, offset); | |
201b6264 CL |
478 | slot = slot->slots[offset]; |
479 | BUG_ON(slot == NULL); | |
1da177e4 LT |
480 | shift -= RADIX_TREE_MAP_SHIFT; |
481 | height--; | |
482 | } | |
483 | ||
612d6c19 NP |
484 | /* set the root's tag bit */ |
485 | if (slot && !root_tag_get(root, tag)) | |
486 | root_tag_set(root, tag); | |
487 | ||
201b6264 | 488 | return slot; |
1da177e4 LT |
489 | } |
490 | EXPORT_SYMBOL(radix_tree_tag_set); | |
491 | ||
492 | /** | |
493 | * radix_tree_tag_clear - clear a tag on a radix tree node | |
494 | * @root: radix tree root | |
495 | * @index: index key | |
496 | * @tag: tag index | |
497 | * | |
daff89f3 JC |
498 | * Clear the search tag (which must be < RADIX_TREE_MAX_TAGS) |
499 | * corresponding to @index in the radix tree. If | |
1da177e4 LT |
500 | * this causes the leaf node to have no tags set then clear the tag in the |
501 | * next-to-leaf node, etc. | |
502 | * | |
503 | * Returns the address of the tagged item on success, else NULL. ie: | |
504 | * has the same return value and semantics as radix_tree_lookup(). | |
505 | */ | |
506 | void *radix_tree_tag_clear(struct radix_tree_root *root, | |
daff89f3 | 507 | unsigned long index, unsigned int tag) |
1da177e4 | 508 | { |
26fb1589 JM |
509 | /* |
510 | * The radix tree path needs to be one longer than the maximum path | |
511 | * since the "list" is null terminated. | |
512 | */ | |
513 | struct radix_tree_path path[RADIX_TREE_MAX_PATH + 1], *pathp = path; | |
612d6c19 | 514 | struct radix_tree_node *slot = NULL; |
1da177e4 | 515 | unsigned int height, shift; |
1da177e4 LT |
516 | |
517 | height = root->height; | |
518 | if (index > radix_tree_maxindex(height)) | |
519 | goto out; | |
520 | ||
521 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; | |
522 | pathp->node = NULL; | |
c0bc9875 | 523 | slot = radix_tree_indirect_to_ptr(root->rnode); |
1da177e4 LT |
524 | |
525 | while (height > 0) { | |
526 | int offset; | |
527 | ||
201b6264 | 528 | if (slot == NULL) |
1da177e4 LT |
529 | goto out; |
530 | ||
531 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
532 | pathp[1].offset = offset; | |
201b6264 CL |
533 | pathp[1].node = slot; |
534 | slot = slot->slots[offset]; | |
1da177e4 LT |
535 | pathp++; |
536 | shift -= RADIX_TREE_MAP_SHIFT; | |
537 | height--; | |
538 | } | |
539 | ||
612d6c19 | 540 | if (slot == NULL) |
1da177e4 LT |
541 | goto out; |
542 | ||
612d6c19 | 543 | while (pathp->node) { |
d5274261 NP |
544 | if (!tag_get(pathp->node, tag, pathp->offset)) |
545 | goto out; | |
201b6264 | 546 | tag_clear(pathp->node, tag, pathp->offset); |
6e954b9e NP |
547 | if (any_tag_set(pathp->node, tag)) |
548 | goto out; | |
1da177e4 | 549 | pathp--; |
612d6c19 NP |
550 | } |
551 | ||
552 | /* clear the root's tag bit */ | |
553 | if (root_tag_get(root, tag)) | |
554 | root_tag_clear(root, tag); | |
555 | ||
1da177e4 | 556 | out: |
612d6c19 | 557 | return slot; |
1da177e4 LT |
558 | } |
559 | EXPORT_SYMBOL(radix_tree_tag_clear); | |
560 | ||
561 | #ifndef __KERNEL__ /* Only the test harness uses this at present */ | |
562 | /** | |
32605a18 MT |
563 | * radix_tree_tag_get - get a tag on a radix tree node |
564 | * @root: radix tree root | |
565 | * @index: index key | |
daff89f3 | 566 | * @tag: tag index (< RADIX_TREE_MAX_TAGS) |
1da177e4 | 567 | * |
32605a18 | 568 | * Return values: |
1da177e4 | 569 | * |
612d6c19 NP |
570 | * 0: tag not present or not set |
571 | * 1: tag set | |
1da177e4 LT |
572 | */ |
573 | int radix_tree_tag_get(struct radix_tree_root *root, | |
daff89f3 | 574 | unsigned long index, unsigned int tag) |
1da177e4 LT |
575 | { |
576 | unsigned int height, shift; | |
7cf9c2c7 | 577 | struct radix_tree_node *node; |
1da177e4 LT |
578 | int saw_unset_tag = 0; |
579 | ||
612d6c19 NP |
580 | /* check the root's tag bit */ |
581 | if (!root_tag_get(root, tag)) | |
582 | return 0; | |
583 | ||
7cf9c2c7 NP |
584 | node = rcu_dereference(root->rnode); |
585 | if (node == NULL) | |
586 | return 0; | |
587 | ||
c0bc9875 | 588 | if (!radix_tree_is_indirect_ptr(node)) |
7cf9c2c7 | 589 | return (index == 0); |
c0bc9875 | 590 | node = radix_tree_indirect_to_ptr(node); |
7cf9c2c7 NP |
591 | |
592 | height = node->height; | |
593 | if (index > radix_tree_maxindex(height)) | |
594 | return 0; | |
612d6c19 | 595 | |
1da177e4 | 596 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; |
1da177e4 LT |
597 | |
598 | for ( ; ; ) { | |
599 | int offset; | |
600 | ||
7cf9c2c7 | 601 | if (node == NULL) |
1da177e4 LT |
602 | return 0; |
603 | ||
604 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
605 | ||
606 | /* | |
607 | * This is just a debug check. Later, we can bale as soon as | |
608 | * we see an unset tag. | |
609 | */ | |
7cf9c2c7 | 610 | if (!tag_get(node, tag, offset)) |
1da177e4 LT |
611 | saw_unset_tag = 1; |
612 | if (height == 1) { | |
7cf9c2c7 | 613 | int ret = tag_get(node, tag, offset); |
1da177e4 LT |
614 | |
615 | BUG_ON(ret && saw_unset_tag); | |
e5dcd90b | 616 | return !!ret; |
1da177e4 | 617 | } |
7cf9c2c7 | 618 | node = rcu_dereference(node->slots[offset]); |
1da177e4 LT |
619 | shift -= RADIX_TREE_MAP_SHIFT; |
620 | height--; | |
621 | } | |
622 | } | |
623 | EXPORT_SYMBOL(radix_tree_tag_get); | |
624 | #endif | |
625 | ||
6df8ba4f FW |
626 | /** |
627 | * radix_tree_next_hole - find the next hole (not-present entry) | |
628 | * @root: tree root | |
629 | * @index: index key | |
630 | * @max_scan: maximum range to search | |
631 | * | |
632 | * Search the set [index, min(index+max_scan-1, MAX_INDEX)] for the lowest | |
633 | * indexed hole. | |
634 | * | |
635 | * Returns: the index of the hole if found, otherwise returns an index | |
636 | * outside of the set specified (in which case 'return - index >= max_scan' | |
637 | * will be true). | |
638 | * | |
639 | * radix_tree_next_hole may be called under rcu_read_lock. However, like | |
640 | * radix_tree_gang_lookup, this will not atomically search a snapshot of the | |
641 | * tree at a single point in time. For example, if a hole is created at index | |
642 | * 5, then subsequently a hole is created at index 10, radix_tree_next_hole | |
643 | * covering both indexes may return 10 if called under rcu_read_lock. | |
644 | */ | |
645 | unsigned long radix_tree_next_hole(struct radix_tree_root *root, | |
646 | unsigned long index, unsigned long max_scan) | |
647 | { | |
648 | unsigned long i; | |
649 | ||
650 | for (i = 0; i < max_scan; i++) { | |
651 | if (!radix_tree_lookup(root, index)) | |
652 | break; | |
653 | index++; | |
654 | if (index == 0) | |
655 | break; | |
656 | } | |
657 | ||
658 | return index; | |
659 | } | |
660 | EXPORT_SYMBOL(radix_tree_next_hole); | |
661 | ||
1da177e4 | 662 | static unsigned int |
7cf9c2c7 | 663 | __lookup(struct radix_tree_node *slot, void **results, unsigned long index, |
1da177e4 LT |
664 | unsigned int max_items, unsigned long *next_index) |
665 | { | |
666 | unsigned int nr_found = 0; | |
201b6264 | 667 | unsigned int shift, height; |
201b6264 CL |
668 | unsigned long i; |
669 | ||
7cf9c2c7 NP |
670 | height = slot->height; |
671 | if (height == 0) | |
201b6264 | 672 | goto out; |
1da177e4 | 673 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; |
1da177e4 | 674 | |
201b6264 | 675 | for ( ; height > 1; height--) { |
7cf9c2c7 NP |
676 | i = (index >> shift) & RADIX_TREE_MAP_MASK; |
677 | for (;;) { | |
1da177e4 LT |
678 | if (slot->slots[i] != NULL) |
679 | break; | |
680 | index &= ~((1UL << shift) - 1); | |
681 | index += 1UL << shift; | |
682 | if (index == 0) | |
683 | goto out; /* 32-bit wraparound */ | |
7cf9c2c7 NP |
684 | i++; |
685 | if (i == RADIX_TREE_MAP_SIZE) | |
686 | goto out; | |
1da177e4 | 687 | } |
1da177e4 | 688 | |
1da177e4 | 689 | shift -= RADIX_TREE_MAP_SHIFT; |
7cf9c2c7 NP |
690 | slot = rcu_dereference(slot->slots[i]); |
691 | if (slot == NULL) | |
692 | goto out; | |
1da177e4 | 693 | } |
201b6264 CL |
694 | |
695 | /* Bottom level: grab some items */ | |
696 | for (i = index & RADIX_TREE_MAP_MASK; i < RADIX_TREE_MAP_SIZE; i++) { | |
7cf9c2c7 | 697 | struct radix_tree_node *node; |
201b6264 | 698 | index++; |
7cf9c2c7 NP |
699 | node = slot->slots[i]; |
700 | if (node) { | |
701 | results[nr_found++] = rcu_dereference(node); | |
201b6264 CL |
702 | if (nr_found == max_items) |
703 | goto out; | |
704 | } | |
705 | } | |
1da177e4 LT |
706 | out: |
707 | *next_index = index; | |
708 | return nr_found; | |
709 | } | |
710 | ||
711 | /** | |
712 | * radix_tree_gang_lookup - perform multiple lookup on a radix tree | |
713 | * @root: radix tree root | |
714 | * @results: where the results of the lookup are placed | |
715 | * @first_index: start the lookup from this key | |
716 | * @max_items: place up to this many items at *results | |
717 | * | |
718 | * Performs an index-ascending scan of the tree for present items. Places | |
719 | * them at *@results and returns the number of items which were placed at | |
720 | * *@results. | |
721 | * | |
722 | * The implementation is naive. | |
7cf9c2c7 NP |
723 | * |
724 | * Like radix_tree_lookup, radix_tree_gang_lookup may be called under | |
725 | * rcu_read_lock. In this case, rather than the returned results being | |
726 | * an atomic snapshot of the tree at a single point in time, the semantics | |
727 | * of an RCU protected gang lookup are as though multiple radix_tree_lookups | |
728 | * have been issued in individual locks, and results stored in 'results'. | |
1da177e4 LT |
729 | */ |
730 | unsigned int | |
731 | radix_tree_gang_lookup(struct radix_tree_root *root, void **results, | |
732 | unsigned long first_index, unsigned int max_items) | |
733 | { | |
7cf9c2c7 NP |
734 | unsigned long max_index; |
735 | struct radix_tree_node *node; | |
1da177e4 | 736 | unsigned long cur_index = first_index; |
7cf9c2c7 NP |
737 | unsigned int ret; |
738 | ||
739 | node = rcu_dereference(root->rnode); | |
740 | if (!node) | |
741 | return 0; | |
1da177e4 | 742 | |
c0bc9875 | 743 | if (!radix_tree_is_indirect_ptr(node)) { |
7cf9c2c7 NP |
744 | if (first_index > 0) |
745 | return 0; | |
c0bc9875 | 746 | results[0] = node; |
7cf9c2c7 NP |
747 | return 1; |
748 | } | |
c0bc9875 | 749 | node = radix_tree_indirect_to_ptr(node); |
7cf9c2c7 NP |
750 | |
751 | max_index = radix_tree_maxindex(node->height); | |
752 | ||
753 | ret = 0; | |
1da177e4 LT |
754 | while (ret < max_items) { |
755 | unsigned int nr_found; | |
756 | unsigned long next_index; /* Index of next search */ | |
757 | ||
758 | if (cur_index > max_index) | |
759 | break; | |
7cf9c2c7 | 760 | nr_found = __lookup(node, results + ret, cur_index, |
1da177e4 LT |
761 | max_items - ret, &next_index); |
762 | ret += nr_found; | |
763 | if (next_index == 0) | |
764 | break; | |
765 | cur_index = next_index; | |
766 | } | |
7cf9c2c7 | 767 | |
1da177e4 LT |
768 | return ret; |
769 | } | |
770 | EXPORT_SYMBOL(radix_tree_gang_lookup); | |
771 | ||
772 | /* | |
773 | * FIXME: the two tag_get()s here should use find_next_bit() instead of | |
774 | * open-coding the search. | |
775 | */ | |
776 | static unsigned int | |
7cf9c2c7 | 777 | __lookup_tag(struct radix_tree_node *slot, void **results, unsigned long index, |
daff89f3 | 778 | unsigned int max_items, unsigned long *next_index, unsigned int tag) |
1da177e4 LT |
779 | { |
780 | unsigned int nr_found = 0; | |
7cf9c2c7 | 781 | unsigned int shift, height; |
1da177e4 | 782 | |
7cf9c2c7 NP |
783 | height = slot->height; |
784 | if (height == 0) | |
612d6c19 | 785 | goto out; |
7cf9c2c7 | 786 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; |
1da177e4 | 787 | |
7cf9c2c7 NP |
788 | while (height > 0) { |
789 | unsigned long i = (index >> shift) & RADIX_TREE_MAP_MASK ; | |
1da177e4 | 790 | |
7cf9c2c7 NP |
791 | for (;;) { |
792 | if (tag_get(slot, tag, i)) | |
1da177e4 | 793 | break; |
1da177e4 LT |
794 | index &= ~((1UL << shift) - 1); |
795 | index += 1UL << shift; | |
796 | if (index == 0) | |
797 | goto out; /* 32-bit wraparound */ | |
7cf9c2c7 NP |
798 | i++; |
799 | if (i == RADIX_TREE_MAP_SIZE) | |
800 | goto out; | |
1da177e4 | 801 | } |
1da177e4 LT |
802 | height--; |
803 | if (height == 0) { /* Bottom level: grab some items */ | |
804 | unsigned long j = index & RADIX_TREE_MAP_MASK; | |
805 | ||
806 | for ( ; j < RADIX_TREE_MAP_SIZE; j++) { | |
7cf9c2c7 | 807 | struct radix_tree_node *node; |
1da177e4 | 808 | index++; |
7cf9c2c7 NP |
809 | if (!tag_get(slot, tag, j)) |
810 | continue; | |
811 | node = slot->slots[j]; | |
812 | /* | |
813 | * Even though the tag was found set, we need to | |
814 | * recheck that we have a non-NULL node, because | |
815 | * if this lookup is lockless, it may have been | |
816 | * subsequently deleted. | |
817 | * | |
818 | * Similar care must be taken in any place that | |
819 | * lookup ->slots[x] without a lock (ie. can't | |
820 | * rely on its value remaining the same). | |
821 | */ | |
822 | if (node) { | |
823 | node = rcu_dereference(node); | |
824 | results[nr_found++] = node; | |
1da177e4 LT |
825 | if (nr_found == max_items) |
826 | goto out; | |
827 | } | |
828 | } | |
829 | } | |
830 | shift -= RADIX_TREE_MAP_SHIFT; | |
7cf9c2c7 NP |
831 | slot = rcu_dereference(slot->slots[i]); |
832 | if (slot == NULL) | |
833 | break; | |
834 | } | |
1da177e4 LT |
835 | out: |
836 | *next_index = index; | |
837 | return nr_found; | |
838 | } | |
839 | ||
840 | /** | |
841 | * radix_tree_gang_lookup_tag - perform multiple lookup on a radix tree | |
842 | * based on a tag | |
843 | * @root: radix tree root | |
844 | * @results: where the results of the lookup are placed | |
845 | * @first_index: start the lookup from this key | |
846 | * @max_items: place up to this many items at *results | |
daff89f3 | 847 | * @tag: the tag index (< RADIX_TREE_MAX_TAGS) |
1da177e4 LT |
848 | * |
849 | * Performs an index-ascending scan of the tree for present items which | |
850 | * have the tag indexed by @tag set. Places the items at *@results and | |
851 | * returns the number of items which were placed at *@results. | |
852 | */ | |
853 | unsigned int | |
854 | radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results, | |
daff89f3 JC |
855 | unsigned long first_index, unsigned int max_items, |
856 | unsigned int tag) | |
1da177e4 | 857 | { |
7cf9c2c7 NP |
858 | struct radix_tree_node *node; |
859 | unsigned long max_index; | |
1da177e4 | 860 | unsigned long cur_index = first_index; |
7cf9c2c7 | 861 | unsigned int ret; |
1da177e4 | 862 | |
612d6c19 NP |
863 | /* check the root's tag bit */ |
864 | if (!root_tag_get(root, tag)) | |
865 | return 0; | |
866 | ||
7cf9c2c7 NP |
867 | node = rcu_dereference(root->rnode); |
868 | if (!node) | |
869 | return 0; | |
870 | ||
c0bc9875 | 871 | if (!radix_tree_is_indirect_ptr(node)) { |
7cf9c2c7 NP |
872 | if (first_index > 0) |
873 | return 0; | |
c0bc9875 | 874 | results[0] = node; |
7cf9c2c7 NP |
875 | return 1; |
876 | } | |
c0bc9875 | 877 | node = radix_tree_indirect_to_ptr(node); |
7cf9c2c7 NP |
878 | |
879 | max_index = radix_tree_maxindex(node->height); | |
880 | ||
881 | ret = 0; | |
1da177e4 LT |
882 | while (ret < max_items) { |
883 | unsigned int nr_found; | |
884 | unsigned long next_index; /* Index of next search */ | |
885 | ||
886 | if (cur_index > max_index) | |
887 | break; | |
7cf9c2c7 | 888 | nr_found = __lookup_tag(node, results + ret, cur_index, |
1da177e4 LT |
889 | max_items - ret, &next_index, tag); |
890 | ret += nr_found; | |
891 | if (next_index == 0) | |
892 | break; | |
893 | cur_index = next_index; | |
894 | } | |
7cf9c2c7 | 895 | |
1da177e4 LT |
896 | return ret; |
897 | } | |
898 | EXPORT_SYMBOL(radix_tree_gang_lookup_tag); | |
899 | ||
a5f51c96 NP |
900 | /** |
901 | * radix_tree_shrink - shrink height of a radix tree to minimal | |
902 | * @root radix tree root | |
903 | */ | |
904 | static inline void radix_tree_shrink(struct radix_tree_root *root) | |
905 | { | |
906 | /* try to shrink tree height */ | |
c0bc9875 | 907 | while (root->height > 0) { |
a5f51c96 | 908 | struct radix_tree_node *to_free = root->rnode; |
7cf9c2c7 | 909 | void *newptr; |
a5f51c96 | 910 | |
c0bc9875 NP |
911 | BUG_ON(!radix_tree_is_indirect_ptr(to_free)); |
912 | to_free = radix_tree_indirect_to_ptr(to_free); | |
913 | ||
914 | /* | |
915 | * The candidate node has more than one child, or its child | |
916 | * is not at the leftmost slot, we cannot shrink. | |
917 | */ | |
918 | if (to_free->count != 1) | |
919 | break; | |
920 | if (!to_free->slots[0]) | |
921 | break; | |
922 | ||
7cf9c2c7 NP |
923 | /* |
924 | * We don't need rcu_assign_pointer(), since we are simply | |
925 | * moving the node from one part of the tree to another. If | |
926 | * it was safe to dereference the old pointer to it | |
927 | * (to_free->slots[0]), it will be safe to dereference the new | |
928 | * one (root->rnode). | |
929 | */ | |
930 | newptr = to_free->slots[0]; | |
c0bc9875 NP |
931 | if (root->height > 1) |
932 | newptr = radix_tree_ptr_to_indirect(newptr); | |
7cf9c2c7 | 933 | root->rnode = newptr; |
a5f51c96 NP |
934 | root->height--; |
935 | /* must only free zeroed nodes into the slab */ | |
936 | tag_clear(to_free, 0, 0); | |
937 | tag_clear(to_free, 1, 0); | |
938 | to_free->slots[0] = NULL; | |
939 | to_free->count = 0; | |
940 | radix_tree_node_free(to_free); | |
941 | } | |
942 | } | |
943 | ||
1da177e4 LT |
944 | /** |
945 | * radix_tree_delete - delete an item from a radix tree | |
946 | * @root: radix tree root | |
947 | * @index: index key | |
948 | * | |
949 | * Remove the item at @index from the radix tree rooted at @root. | |
950 | * | |
951 | * Returns the address of the deleted item, or NULL if it was not present. | |
952 | */ | |
953 | void *radix_tree_delete(struct radix_tree_root *root, unsigned long index) | |
954 | { | |
26fb1589 JM |
955 | /* |
956 | * The radix tree path needs to be one longer than the maximum path | |
957 | * since the "list" is null terminated. | |
958 | */ | |
959 | struct radix_tree_path path[RADIX_TREE_MAX_PATH + 1], *pathp = path; | |
612d6c19 | 960 | struct radix_tree_node *slot = NULL; |
7cf9c2c7 | 961 | struct radix_tree_node *to_free; |
1da177e4 | 962 | unsigned int height, shift; |
d5274261 NP |
963 | int tag; |
964 | int offset; | |
1da177e4 LT |
965 | |
966 | height = root->height; | |
967 | if (index > radix_tree_maxindex(height)) | |
968 | goto out; | |
969 | ||
612d6c19 | 970 | slot = root->rnode; |
c0bc9875 | 971 | if (height == 0) { |
612d6c19 NP |
972 | root_tag_clear_all(root); |
973 | root->rnode = NULL; | |
974 | goto out; | |
975 | } | |
c0bc9875 | 976 | slot = radix_tree_indirect_to_ptr(slot); |
612d6c19 | 977 | |
1da177e4 LT |
978 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; |
979 | pathp->node = NULL; | |
1da177e4 | 980 | |
612d6c19 | 981 | do { |
201b6264 | 982 | if (slot == NULL) |
1da177e4 LT |
983 | goto out; |
984 | ||
d5274261 | 985 | pathp++; |
1da177e4 | 986 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; |
d5274261 NP |
987 | pathp->offset = offset; |
988 | pathp->node = slot; | |
201b6264 | 989 | slot = slot->slots[offset]; |
1da177e4 | 990 | shift -= RADIX_TREE_MAP_SHIFT; |
612d6c19 NP |
991 | height--; |
992 | } while (height > 0); | |
1da177e4 | 993 | |
612d6c19 | 994 | if (slot == NULL) |
1da177e4 LT |
995 | goto out; |
996 | ||
1da177e4 LT |
997 | /* |
998 | * Clear all tags associated with the just-deleted item | |
999 | */ | |
daff89f3 | 1000 | for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { |
612d6c19 NP |
1001 | if (tag_get(pathp->node, tag, pathp->offset)) |
1002 | radix_tree_tag_clear(root, index, tag); | |
d5274261 | 1003 | } |
1da177e4 | 1004 | |
7cf9c2c7 | 1005 | to_free = NULL; |
201b6264 | 1006 | /* Now free the nodes we do not need anymore */ |
612d6c19 | 1007 | while (pathp->node) { |
201b6264 | 1008 | pathp->node->slots[pathp->offset] = NULL; |
a5f51c96 | 1009 | pathp->node->count--; |
7cf9c2c7 NP |
1010 | /* |
1011 | * Queue the node for deferred freeing after the | |
1012 | * last reference to it disappears (set NULL, above). | |
1013 | */ | |
1014 | if (to_free) | |
1015 | radix_tree_node_free(to_free); | |
a5f51c96 NP |
1016 | |
1017 | if (pathp->node->count) { | |
c0bc9875 NP |
1018 | if (pathp->node == |
1019 | radix_tree_indirect_to_ptr(root->rnode)) | |
a5f51c96 | 1020 | radix_tree_shrink(root); |
201b6264 | 1021 | goto out; |
a5f51c96 | 1022 | } |
201b6264 CL |
1023 | |
1024 | /* Node with zero slots in use so free it */ | |
7cf9c2c7 | 1025 | to_free = pathp->node; |
612d6c19 | 1026 | pathp--; |
7cf9c2c7 | 1027 | |
1da177e4 | 1028 | } |
612d6c19 | 1029 | root_tag_clear_all(root); |
201b6264 | 1030 | root->height = 0; |
612d6c19 | 1031 | root->rnode = NULL; |
7cf9c2c7 NP |
1032 | if (to_free) |
1033 | radix_tree_node_free(to_free); | |
612d6c19 | 1034 | |
1da177e4 | 1035 | out: |
612d6c19 | 1036 | return slot; |
1da177e4 LT |
1037 | } |
1038 | EXPORT_SYMBOL(radix_tree_delete); | |
1039 | ||
1040 | /** | |
1041 | * radix_tree_tagged - test whether any items in the tree are tagged | |
1042 | * @root: radix tree root | |
1043 | * @tag: tag to test | |
1044 | */ | |
daff89f3 | 1045 | int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag) |
1da177e4 | 1046 | { |
612d6c19 | 1047 | return root_tag_get(root, tag); |
1da177e4 LT |
1048 | } |
1049 | EXPORT_SYMBOL(radix_tree_tagged); | |
1050 | ||
1051 | static void | |
4ba9b9d0 | 1052 | radix_tree_node_ctor(struct kmem_cache *cachep, void *node) |
1da177e4 LT |
1053 | { |
1054 | memset(node, 0, sizeof(struct radix_tree_node)); | |
1055 | } | |
1056 | ||
1057 | static __init unsigned long __maxindex(unsigned int height) | |
1058 | { | |
430d275a PL |
1059 | unsigned int width = height * RADIX_TREE_MAP_SHIFT; |
1060 | int shift = RADIX_TREE_INDEX_BITS - width; | |
1061 | ||
1062 | if (shift < 0) | |
1063 | return ~0UL; | |
1064 | if (shift >= BITS_PER_LONG) | |
1065 | return 0UL; | |
1066 | return ~0UL >> shift; | |
1da177e4 LT |
1067 | } |
1068 | ||
1069 | static __init void radix_tree_init_maxindex(void) | |
1070 | { | |
1071 | unsigned int i; | |
1072 | ||
1073 | for (i = 0; i < ARRAY_SIZE(height_to_maxindex); i++) | |
1074 | height_to_maxindex[i] = __maxindex(i); | |
1075 | } | |
1076 | ||
1da177e4 LT |
1077 | static int radix_tree_callback(struct notifier_block *nfb, |
1078 | unsigned long action, | |
1079 | void *hcpu) | |
1080 | { | |
1081 | int cpu = (long)hcpu; | |
1082 | struct radix_tree_preload *rtp; | |
1083 | ||
1084 | /* Free per-cpu pool of perloaded nodes */ | |
8bb78442 | 1085 | if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) { |
1da177e4 LT |
1086 | rtp = &per_cpu(radix_tree_preloads, cpu); |
1087 | while (rtp->nr) { | |
1088 | kmem_cache_free(radix_tree_node_cachep, | |
1089 | rtp->nodes[rtp->nr-1]); | |
1090 | rtp->nodes[rtp->nr-1] = NULL; | |
1091 | rtp->nr--; | |
1092 | } | |
1093 | } | |
1094 | return NOTIFY_OK; | |
1095 | } | |
1da177e4 LT |
1096 | |
1097 | void __init radix_tree_init(void) | |
1098 | { | |
1099 | radix_tree_node_cachep = kmem_cache_create("radix_tree_node", | |
1100 | sizeof(struct radix_tree_node), 0, | |
20c2df83 | 1101 | SLAB_PANIC, radix_tree_node_ctor); |
1da177e4 LT |
1102 | radix_tree_init_maxindex(); |
1103 | hotcpu_notifier(radix_tree_callback, 0); | |
1104 | } |