Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * Copyright (C) 2001 Momchil Velikov | |
3 | * Portions Copyright (C) 2001 Christoph Hellwig | |
cde53535 | 4 | * Copyright (C) 2005 SGI, Christoph Lameter |
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> | |
1da177e4 LT |
31 | #include <linux/string.h> |
32 | #include <linux/bitops.h> | |
7cf9c2c7 | 33 | #include <linux/rcupdate.h> |
1da177e4 LT |
34 | |
35 | ||
36 | #ifdef __KERNEL__ | |
cfd9b7df | 37 | #define RADIX_TREE_MAP_SHIFT (CONFIG_BASE_SMALL ? 4 : 6) |
1da177e4 LT |
38 | #else |
39 | #define RADIX_TREE_MAP_SHIFT 3 /* For more stressful testing */ | |
40 | #endif | |
1da177e4 LT |
41 | |
42 | #define RADIX_TREE_MAP_SIZE (1UL << RADIX_TREE_MAP_SHIFT) | |
43 | #define RADIX_TREE_MAP_MASK (RADIX_TREE_MAP_SIZE-1) | |
44 | ||
45 | #define RADIX_TREE_TAG_LONGS \ | |
46 | ((RADIX_TREE_MAP_SIZE + BITS_PER_LONG - 1) / BITS_PER_LONG) | |
47 | ||
48 | struct radix_tree_node { | |
7cf9c2c7 | 49 | unsigned int height; /* Height from the bottom */ |
1da177e4 | 50 | unsigned int count; |
7cf9c2c7 | 51 | struct rcu_head rcu_head; |
1da177e4 | 52 | void *slots[RADIX_TREE_MAP_SIZE]; |
daff89f3 | 53 | unsigned long tags[RADIX_TREE_MAX_TAGS][RADIX_TREE_TAG_LONGS]; |
1da177e4 LT |
54 | }; |
55 | ||
56 | struct radix_tree_path { | |
201b6264 | 57 | struct radix_tree_node *node; |
1da177e4 LT |
58 | int offset; |
59 | }; | |
60 | ||
61 | #define RADIX_TREE_INDEX_BITS (8 /* CHAR_BIT */ * sizeof(unsigned long)) | |
26fb1589 JM |
62 | #define RADIX_TREE_MAX_PATH (DIV_ROUND_UP(RADIX_TREE_INDEX_BITS, \ |
63 | RADIX_TREE_MAP_SHIFT)) | |
1da177e4 | 64 | |
26fb1589 JM |
65 | /* |
66 | * The height_to_maxindex array needs to be one deeper than the maximum | |
67 | * path as height 0 holds only 1 entry. | |
68 | */ | |
69 | static unsigned long height_to_maxindex[RADIX_TREE_MAX_PATH + 1] __read_mostly; | |
1da177e4 LT |
70 | |
71 | /* | |
72 | * Radix tree node cache. | |
73 | */ | |
e18b890b | 74 | static struct kmem_cache *radix_tree_node_cachep; |
1da177e4 LT |
75 | |
76 | /* | |
77 | * Per-cpu pool of preloaded nodes | |
78 | */ | |
79 | struct radix_tree_preload { | |
80 | int nr; | |
81 | struct radix_tree_node *nodes[RADIX_TREE_MAX_PATH]; | |
82 | }; | |
8cef7d57 | 83 | static DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, }; |
1da177e4 | 84 | |
612d6c19 NP |
85 | static inline gfp_t root_gfp_mask(struct radix_tree_root *root) |
86 | { | |
87 | return root->gfp_mask & __GFP_BITS_MASK; | |
88 | } | |
89 | ||
643b52b9 NP |
90 | static inline void tag_set(struct radix_tree_node *node, unsigned int tag, |
91 | int offset) | |
92 | { | |
93 | __set_bit(offset, node->tags[tag]); | |
94 | } | |
95 | ||
96 | static inline void tag_clear(struct radix_tree_node *node, unsigned int tag, | |
97 | int offset) | |
98 | { | |
99 | __clear_bit(offset, node->tags[tag]); | |
100 | } | |
101 | ||
102 | static inline int tag_get(struct radix_tree_node *node, unsigned int tag, | |
103 | int offset) | |
104 | { | |
105 | return test_bit(offset, node->tags[tag]); | |
106 | } | |
107 | ||
108 | static inline void root_tag_set(struct radix_tree_root *root, unsigned int tag) | |
109 | { | |
110 | root->gfp_mask |= (__force gfp_t)(1 << (tag + __GFP_BITS_SHIFT)); | |
111 | } | |
112 | ||
113 | static inline void root_tag_clear(struct radix_tree_root *root, unsigned int tag) | |
114 | { | |
115 | root->gfp_mask &= (__force gfp_t)~(1 << (tag + __GFP_BITS_SHIFT)); | |
116 | } | |
117 | ||
118 | static inline void root_tag_clear_all(struct radix_tree_root *root) | |
119 | { | |
120 | root->gfp_mask &= __GFP_BITS_MASK; | |
121 | } | |
122 | ||
123 | static inline int root_tag_get(struct radix_tree_root *root, unsigned int tag) | |
124 | { | |
125 | return (__force unsigned)root->gfp_mask & (1 << (tag + __GFP_BITS_SHIFT)); | |
126 | } | |
127 | ||
128 | /* | |
129 | * Returns 1 if any slot in the node has this tag set. | |
130 | * Otherwise returns 0. | |
131 | */ | |
132 | static inline int any_tag_set(struct radix_tree_node *node, unsigned int tag) | |
133 | { | |
134 | int idx; | |
135 | for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) { | |
136 | if (node->tags[tag][idx]) | |
137 | return 1; | |
138 | } | |
139 | return 0; | |
140 | } | |
1da177e4 LT |
141 | /* |
142 | * This assumes that the caller has performed appropriate preallocation, and | |
143 | * that the caller has pinned this thread of control to the current CPU. | |
144 | */ | |
145 | static struct radix_tree_node * | |
146 | radix_tree_node_alloc(struct radix_tree_root *root) | |
147 | { | |
e2848a0e | 148 | struct radix_tree_node *ret = NULL; |
612d6c19 | 149 | gfp_t gfp_mask = root_gfp_mask(root); |
1da177e4 | 150 | |
e2848a0e | 151 | if (!(gfp_mask & __GFP_WAIT)) { |
1da177e4 LT |
152 | struct radix_tree_preload *rtp; |
153 | ||
e2848a0e NP |
154 | /* |
155 | * Provided the caller has preloaded here, we will always | |
156 | * succeed in getting a node here (and never reach | |
157 | * kmem_cache_alloc) | |
158 | */ | |
1da177e4 LT |
159 | rtp = &__get_cpu_var(radix_tree_preloads); |
160 | if (rtp->nr) { | |
161 | ret = rtp->nodes[rtp->nr - 1]; | |
162 | rtp->nodes[rtp->nr - 1] = NULL; | |
163 | rtp->nr--; | |
164 | } | |
165 | } | |
e2848a0e | 166 | if (ret == NULL) |
488514d1 | 167 | ret = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask); |
e2848a0e | 168 | |
c0bc9875 | 169 | BUG_ON(radix_tree_is_indirect_ptr(ret)); |
1da177e4 LT |
170 | return ret; |
171 | } | |
172 | ||
7cf9c2c7 NP |
173 | static void radix_tree_node_rcu_free(struct rcu_head *head) |
174 | { | |
175 | struct radix_tree_node *node = | |
176 | container_of(head, struct radix_tree_node, rcu_head); | |
643b52b9 NP |
177 | |
178 | /* | |
179 | * must only free zeroed nodes into the slab. radix_tree_shrink | |
180 | * can leave us with a non-NULL entry in the first slot, so clear | |
181 | * that here to make sure. | |
182 | */ | |
183 | tag_clear(node, 0, 0); | |
184 | tag_clear(node, 1, 0); | |
185 | node->slots[0] = NULL; | |
186 | node->count = 0; | |
187 | ||
7cf9c2c7 NP |
188 | kmem_cache_free(radix_tree_node_cachep, node); |
189 | } | |
190 | ||
1da177e4 LT |
191 | static inline void |
192 | radix_tree_node_free(struct radix_tree_node *node) | |
193 | { | |
7cf9c2c7 | 194 | call_rcu(&node->rcu_head, radix_tree_node_rcu_free); |
1da177e4 LT |
195 | } |
196 | ||
197 | /* | |
198 | * Load up this CPU's radix_tree_node buffer with sufficient objects to | |
199 | * ensure that the addition of a single element in the tree cannot fail. On | |
200 | * success, return zero, with preemption disabled. On error, return -ENOMEM | |
201 | * with preemption not disabled. | |
b34df792 DH |
202 | * |
203 | * To make use of this facility, the radix tree must be initialised without | |
204 | * __GFP_WAIT being passed to INIT_RADIX_TREE(). | |
1da177e4 | 205 | */ |
dd0fc66f | 206 | int radix_tree_preload(gfp_t gfp_mask) |
1da177e4 LT |
207 | { |
208 | struct radix_tree_preload *rtp; | |
209 | struct radix_tree_node *node; | |
210 | int ret = -ENOMEM; | |
211 | ||
212 | preempt_disable(); | |
213 | rtp = &__get_cpu_var(radix_tree_preloads); | |
214 | while (rtp->nr < ARRAY_SIZE(rtp->nodes)) { | |
215 | preempt_enable(); | |
488514d1 | 216 | node = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask); |
1da177e4 LT |
217 | if (node == NULL) |
218 | goto out; | |
219 | preempt_disable(); | |
220 | rtp = &__get_cpu_var(radix_tree_preloads); | |
221 | if (rtp->nr < ARRAY_SIZE(rtp->nodes)) | |
222 | rtp->nodes[rtp->nr++] = node; | |
223 | else | |
224 | kmem_cache_free(radix_tree_node_cachep, node); | |
225 | } | |
226 | ret = 0; | |
227 | out: | |
228 | return ret; | |
229 | } | |
d7f0923d | 230 | EXPORT_SYMBOL(radix_tree_preload); |
1da177e4 | 231 | |
1da177e4 LT |
232 | /* |
233 | * Return the maximum key which can be store into a | |
234 | * radix tree with height HEIGHT. | |
235 | */ | |
236 | static inline unsigned long radix_tree_maxindex(unsigned int height) | |
237 | { | |
238 | return height_to_maxindex[height]; | |
239 | } | |
240 | ||
241 | /* | |
242 | * Extend a radix tree so it can store key @index. | |
243 | */ | |
244 | static int radix_tree_extend(struct radix_tree_root *root, unsigned long index) | |
245 | { | |
246 | struct radix_tree_node *node; | |
247 | unsigned int height; | |
1da177e4 LT |
248 | int tag; |
249 | ||
250 | /* Figure out what the height should be. */ | |
251 | height = root->height + 1; | |
252 | while (index > radix_tree_maxindex(height)) | |
253 | height++; | |
254 | ||
255 | if (root->rnode == NULL) { | |
256 | root->height = height; | |
257 | goto out; | |
258 | } | |
259 | ||
1da177e4 | 260 | do { |
7cf9c2c7 | 261 | unsigned int newheight; |
1da177e4 LT |
262 | if (!(node = radix_tree_node_alloc(root))) |
263 | return -ENOMEM; | |
264 | ||
265 | /* Increase the height. */ | |
c0bc9875 | 266 | node->slots[0] = radix_tree_indirect_to_ptr(root->rnode); |
1da177e4 LT |
267 | |
268 | /* Propagate the aggregated tag info into the new root */ | |
daff89f3 | 269 | for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { |
612d6c19 | 270 | if (root_tag_get(root, tag)) |
1da177e4 LT |
271 | tag_set(node, tag, 0); |
272 | } | |
273 | ||
7cf9c2c7 NP |
274 | newheight = root->height+1; |
275 | node->height = newheight; | |
1da177e4 | 276 | node->count = 1; |
c0bc9875 | 277 | node = radix_tree_ptr_to_indirect(node); |
7cf9c2c7 NP |
278 | rcu_assign_pointer(root->rnode, node); |
279 | root->height = newheight; | |
1da177e4 LT |
280 | } while (height > root->height); |
281 | out: | |
282 | return 0; | |
283 | } | |
284 | ||
285 | /** | |
286 | * radix_tree_insert - insert into a radix tree | |
287 | * @root: radix tree root | |
288 | * @index: index key | |
289 | * @item: item to insert | |
290 | * | |
291 | * Insert an item into the radix tree at position @index. | |
292 | */ | |
293 | int radix_tree_insert(struct radix_tree_root *root, | |
294 | unsigned long index, void *item) | |
295 | { | |
201b6264 | 296 | struct radix_tree_node *node = NULL, *slot; |
1da177e4 LT |
297 | unsigned int height, shift; |
298 | int offset; | |
299 | int error; | |
300 | ||
c0bc9875 | 301 | BUG_ON(radix_tree_is_indirect_ptr(item)); |
7cf9c2c7 | 302 | |
1da177e4 | 303 | /* Make sure the tree is high enough. */ |
612d6c19 | 304 | if (index > radix_tree_maxindex(root->height)) { |
1da177e4 LT |
305 | error = radix_tree_extend(root, index); |
306 | if (error) | |
307 | return error; | |
308 | } | |
309 | ||
c0bc9875 NP |
310 | slot = radix_tree_indirect_to_ptr(root->rnode); |
311 | ||
1da177e4 LT |
312 | height = root->height; |
313 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; | |
314 | ||
315 | offset = 0; /* uninitialised var warning */ | |
612d6c19 | 316 | while (height > 0) { |
201b6264 | 317 | if (slot == NULL) { |
1da177e4 | 318 | /* Have to add a child node. */ |
201b6264 | 319 | if (!(slot = radix_tree_node_alloc(root))) |
1da177e4 | 320 | return -ENOMEM; |
7cf9c2c7 | 321 | slot->height = height; |
201b6264 | 322 | if (node) { |
7cf9c2c7 | 323 | rcu_assign_pointer(node->slots[offset], slot); |
1da177e4 | 324 | node->count++; |
201b6264 | 325 | } else |
c0bc9875 NP |
326 | rcu_assign_pointer(root->rnode, |
327 | radix_tree_ptr_to_indirect(slot)); | |
1da177e4 LT |
328 | } |
329 | ||
330 | /* Go a level down */ | |
331 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
201b6264 CL |
332 | node = slot; |
333 | slot = node->slots[offset]; | |
1da177e4 LT |
334 | shift -= RADIX_TREE_MAP_SHIFT; |
335 | height--; | |
612d6c19 | 336 | } |
1da177e4 | 337 | |
201b6264 | 338 | if (slot != NULL) |
1da177e4 | 339 | return -EEXIST; |
201b6264 | 340 | |
612d6c19 NP |
341 | if (node) { |
342 | node->count++; | |
7cf9c2c7 | 343 | rcu_assign_pointer(node->slots[offset], item); |
612d6c19 NP |
344 | BUG_ON(tag_get(node, 0, offset)); |
345 | BUG_ON(tag_get(node, 1, offset)); | |
346 | } else { | |
c0bc9875 | 347 | rcu_assign_pointer(root->rnode, item); |
612d6c19 NP |
348 | BUG_ON(root_tag_get(root, 0)); |
349 | BUG_ON(root_tag_get(root, 1)); | |
350 | } | |
1da177e4 | 351 | |
1da177e4 LT |
352 | return 0; |
353 | } | |
354 | EXPORT_SYMBOL(radix_tree_insert); | |
355 | ||
b72b71c6 HS |
356 | /* |
357 | * is_slot == 1 : search for the slot. | |
358 | * is_slot == 0 : search for the node. | |
7cf9c2c7 | 359 | */ |
b72b71c6 HS |
360 | static void *radix_tree_lookup_element(struct radix_tree_root *root, |
361 | unsigned long index, int is_slot) | |
1da177e4 LT |
362 | { |
363 | unsigned int height, shift; | |
7cf9c2c7 | 364 | struct radix_tree_node *node, **slot; |
612d6c19 | 365 | |
2676a58c | 366 | node = rcu_dereference_raw(root->rnode); |
7cf9c2c7 | 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; | |
b72b71c6 | 373 | return is_slot ? (void *)&root->rnode : node; |
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)); | |
2676a58c | 386 | node = rcu_dereference_raw(*slot); |
7cf9c2c7 | 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 | |
b72b71c6 HS |
394 | return is_slot ? (void *)slot:node; |
395 | } | |
396 | ||
397 | /** | |
398 | * radix_tree_lookup_slot - lookup a slot in a radix tree | |
399 | * @root: radix tree root | |
400 | * @index: index key | |
401 | * | |
402 | * Returns: the slot corresponding to the position @index in the | |
403 | * radix tree @root. This is useful for update-if-exists operations. | |
404 | * | |
405 | * This function can be called under rcu_read_lock iff the slot is not | |
406 | * modified by radix_tree_replace_slot, otherwise it must be called | |
407 | * exclusive from other writers. Any dereference of the slot must be done | |
408 | * using radix_tree_deref_slot. | |
409 | */ | |
410 | void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index) | |
411 | { | |
412 | return (void **)radix_tree_lookup_element(root, index, 1); | |
a4331366 | 413 | } |
a4331366 HR |
414 | EXPORT_SYMBOL(radix_tree_lookup_slot); |
415 | ||
416 | /** | |
417 | * radix_tree_lookup - perform lookup operation on a radix tree | |
418 | * @root: radix tree root | |
419 | * @index: index key | |
420 | * | |
421 | * Lookup the item at the position @index in the radix tree @root. | |
7cf9c2c7 NP |
422 | * |
423 | * This function can be called under rcu_read_lock, however the caller | |
424 | * must manage lifetimes of leaf nodes (eg. RCU may also be used to free | |
425 | * them safely). No RCU barriers are required to access or modify the | |
426 | * returned item, however. | |
a4331366 HR |
427 | */ |
428 | void *radix_tree_lookup(struct radix_tree_root *root, unsigned long index) | |
429 | { | |
b72b71c6 | 430 | return radix_tree_lookup_element(root, index, 0); |
1da177e4 LT |
431 | } |
432 | EXPORT_SYMBOL(radix_tree_lookup); | |
433 | ||
434 | /** | |
435 | * radix_tree_tag_set - set a tag on a radix tree node | |
436 | * @root: radix tree root | |
437 | * @index: index key | |
438 | * @tag: tag index | |
439 | * | |
daff89f3 JC |
440 | * Set the search tag (which must be < RADIX_TREE_MAX_TAGS) |
441 | * corresponding to @index in the radix tree. From | |
1da177e4 LT |
442 | * the root all the way down to the leaf node. |
443 | * | |
444 | * Returns the address of the tagged item. Setting a tag on a not-present | |
445 | * item is a bug. | |
446 | */ | |
447 | void *radix_tree_tag_set(struct radix_tree_root *root, | |
daff89f3 | 448 | unsigned long index, unsigned int tag) |
1da177e4 LT |
449 | { |
450 | unsigned int height, shift; | |
201b6264 | 451 | struct radix_tree_node *slot; |
1da177e4 LT |
452 | |
453 | height = root->height; | |
4c91c364 | 454 | BUG_ON(index > radix_tree_maxindex(height)); |
1da177e4 | 455 | |
c0bc9875 | 456 | slot = radix_tree_indirect_to_ptr(root->rnode); |
612d6c19 | 457 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; |
1da177e4 LT |
458 | |
459 | while (height > 0) { | |
460 | int offset; | |
461 | ||
462 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
d5274261 NP |
463 | if (!tag_get(slot, tag, offset)) |
464 | tag_set(slot, tag, offset); | |
201b6264 CL |
465 | slot = slot->slots[offset]; |
466 | BUG_ON(slot == NULL); | |
1da177e4 LT |
467 | shift -= RADIX_TREE_MAP_SHIFT; |
468 | height--; | |
469 | } | |
470 | ||
612d6c19 NP |
471 | /* set the root's tag bit */ |
472 | if (slot && !root_tag_get(root, tag)) | |
473 | root_tag_set(root, tag); | |
474 | ||
201b6264 | 475 | return slot; |
1da177e4 LT |
476 | } |
477 | EXPORT_SYMBOL(radix_tree_tag_set); | |
478 | ||
479 | /** | |
480 | * radix_tree_tag_clear - clear a tag on a radix tree node | |
481 | * @root: radix tree root | |
482 | * @index: index key | |
483 | * @tag: tag index | |
484 | * | |
daff89f3 JC |
485 | * Clear the search tag (which must be < RADIX_TREE_MAX_TAGS) |
486 | * corresponding to @index in the radix tree. If | |
1da177e4 LT |
487 | * this causes the leaf node to have no tags set then clear the tag in the |
488 | * next-to-leaf node, etc. | |
489 | * | |
490 | * Returns the address of the tagged item on success, else NULL. ie: | |
491 | * has the same return value and semantics as radix_tree_lookup(). | |
492 | */ | |
493 | void *radix_tree_tag_clear(struct radix_tree_root *root, | |
daff89f3 | 494 | unsigned long index, unsigned int tag) |
1da177e4 | 495 | { |
26fb1589 JM |
496 | /* |
497 | * The radix tree path needs to be one longer than the maximum path | |
498 | * since the "list" is null terminated. | |
499 | */ | |
500 | struct radix_tree_path path[RADIX_TREE_MAX_PATH + 1], *pathp = path; | |
612d6c19 | 501 | struct radix_tree_node *slot = NULL; |
1da177e4 | 502 | unsigned int height, shift; |
1da177e4 LT |
503 | |
504 | height = root->height; | |
505 | if (index > radix_tree_maxindex(height)) | |
506 | goto out; | |
507 | ||
508 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; | |
509 | pathp->node = NULL; | |
c0bc9875 | 510 | slot = radix_tree_indirect_to_ptr(root->rnode); |
1da177e4 LT |
511 | |
512 | while (height > 0) { | |
513 | int offset; | |
514 | ||
201b6264 | 515 | if (slot == NULL) |
1da177e4 LT |
516 | goto out; |
517 | ||
518 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
519 | pathp[1].offset = offset; | |
201b6264 CL |
520 | pathp[1].node = slot; |
521 | slot = slot->slots[offset]; | |
1da177e4 LT |
522 | pathp++; |
523 | shift -= RADIX_TREE_MAP_SHIFT; | |
524 | height--; | |
525 | } | |
526 | ||
612d6c19 | 527 | if (slot == NULL) |
1da177e4 LT |
528 | goto out; |
529 | ||
612d6c19 | 530 | while (pathp->node) { |
d5274261 NP |
531 | if (!tag_get(pathp->node, tag, pathp->offset)) |
532 | goto out; | |
201b6264 | 533 | tag_clear(pathp->node, tag, pathp->offset); |
6e954b9e NP |
534 | if (any_tag_set(pathp->node, tag)) |
535 | goto out; | |
1da177e4 | 536 | pathp--; |
612d6c19 NP |
537 | } |
538 | ||
539 | /* clear the root's tag bit */ | |
540 | if (root_tag_get(root, tag)) | |
541 | root_tag_clear(root, tag); | |
542 | ||
1da177e4 | 543 | out: |
612d6c19 | 544 | return slot; |
1da177e4 LT |
545 | } |
546 | EXPORT_SYMBOL(radix_tree_tag_clear); | |
547 | ||
1da177e4 | 548 | /** |
32605a18 MT |
549 | * radix_tree_tag_get - get a tag on a radix tree node |
550 | * @root: radix tree root | |
551 | * @index: index key | |
daff89f3 | 552 | * @tag: tag index (< RADIX_TREE_MAX_TAGS) |
1da177e4 | 553 | * |
32605a18 | 554 | * Return values: |
1da177e4 | 555 | * |
612d6c19 NP |
556 | * 0: tag not present or not set |
557 | * 1: tag set | |
ce82653d DH |
558 | * |
559 | * Note that the return value of this function may not be relied on, even if | |
560 | * the RCU lock is held, unless tag modification and node deletion are excluded | |
561 | * from concurrency. | |
1da177e4 LT |
562 | */ |
563 | int radix_tree_tag_get(struct radix_tree_root *root, | |
daff89f3 | 564 | unsigned long index, unsigned int tag) |
1da177e4 LT |
565 | { |
566 | unsigned int height, shift; | |
7cf9c2c7 | 567 | struct radix_tree_node *node; |
1da177e4 LT |
568 | int saw_unset_tag = 0; |
569 | ||
612d6c19 NP |
570 | /* check the root's tag bit */ |
571 | if (!root_tag_get(root, tag)) | |
572 | return 0; | |
573 | ||
2676a58c | 574 | node = rcu_dereference_raw(root->rnode); |
7cf9c2c7 NP |
575 | if (node == NULL) |
576 | return 0; | |
577 | ||
c0bc9875 | 578 | if (!radix_tree_is_indirect_ptr(node)) |
7cf9c2c7 | 579 | return (index == 0); |
c0bc9875 | 580 | node = radix_tree_indirect_to_ptr(node); |
7cf9c2c7 NP |
581 | |
582 | height = node->height; | |
583 | if (index > radix_tree_maxindex(height)) | |
584 | return 0; | |
612d6c19 | 585 | |
1da177e4 | 586 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; |
1da177e4 LT |
587 | |
588 | for ( ; ; ) { | |
589 | int offset; | |
590 | ||
7cf9c2c7 | 591 | if (node == NULL) |
1da177e4 LT |
592 | return 0; |
593 | ||
594 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
595 | ||
596 | /* | |
597 | * This is just a debug check. Later, we can bale as soon as | |
598 | * we see an unset tag. | |
599 | */ | |
7cf9c2c7 | 600 | if (!tag_get(node, tag, offset)) |
1da177e4 | 601 | saw_unset_tag = 1; |
ce82653d DH |
602 | if (height == 1) |
603 | return !!tag_get(node, tag, offset); | |
2676a58c | 604 | node = rcu_dereference_raw(node->slots[offset]); |
1da177e4 LT |
605 | shift -= RADIX_TREE_MAP_SHIFT; |
606 | height--; | |
607 | } | |
608 | } | |
609 | EXPORT_SYMBOL(radix_tree_tag_get); | |
1da177e4 | 610 | |
ebf8aa44 JK |
611 | /** |
612 | * radix_tree_range_tag_if_tagged - for each item in given range set given | |
613 | * tag if item has another tag set | |
614 | * @root: radix tree root | |
615 | * @first_indexp: pointer to a starting index of a range to scan | |
616 | * @last_index: last index of a range to scan | |
617 | * @nr_to_tag: maximum number items to tag | |
618 | * @iftag: tag index to test | |
619 | * @settag: tag index to set if tested tag is set | |
620 | * | |
621 | * This function scans range of radix tree from first_index to last_index | |
622 | * (inclusive). For each item in the range if iftag is set, the function sets | |
623 | * also settag. The function stops either after tagging nr_to_tag items or | |
624 | * after reaching last_index. | |
625 | * | |
626 | * The function returns number of leaves where the tag was set and sets | |
627 | * *first_indexp to the first unscanned index. | |
628 | */ | |
629 | unsigned long radix_tree_range_tag_if_tagged(struct radix_tree_root *root, | |
630 | unsigned long *first_indexp, unsigned long last_index, | |
631 | unsigned long nr_to_tag, | |
632 | unsigned int iftag, unsigned int settag) | |
633 | { | |
634 | unsigned int height = root->height, shift; | |
635 | unsigned long tagged = 0, index = *first_indexp; | |
636 | struct radix_tree_node *open_slots[height], *slot; | |
637 | ||
638 | last_index = min(last_index, radix_tree_maxindex(height)); | |
639 | if (index > last_index) | |
640 | return 0; | |
641 | if (!nr_to_tag) | |
642 | return 0; | |
643 | if (!root_tag_get(root, iftag)) { | |
644 | *first_indexp = last_index + 1; | |
645 | return 0; | |
646 | } | |
647 | if (height == 0) { | |
648 | *first_indexp = last_index + 1; | |
649 | root_tag_set(root, settag); | |
650 | return 1; | |
651 | } | |
652 | ||
653 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; | |
654 | slot = radix_tree_indirect_to_ptr(root->rnode); | |
655 | ||
656 | for (;;) { | |
657 | int offset; | |
658 | ||
659 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
660 | if (!slot->slots[offset]) | |
661 | goto next; | |
662 | if (!tag_get(slot, iftag, offset)) | |
663 | goto next; | |
664 | tag_set(slot, settag, offset); | |
665 | if (height == 1) { | |
666 | tagged++; | |
667 | goto next; | |
668 | } | |
669 | /* Go down one level */ | |
670 | height--; | |
671 | shift -= RADIX_TREE_MAP_SHIFT; | |
672 | open_slots[height] = slot; | |
673 | slot = slot->slots[offset]; | |
674 | continue; | |
675 | next: | |
676 | /* Go to next item at level determined by 'shift' */ | |
677 | index = ((index >> shift) + 1) << shift; | |
678 | if (index > last_index) | |
679 | break; | |
680 | if (tagged >= nr_to_tag) | |
681 | break; | |
682 | while (((index >> shift) & RADIX_TREE_MAP_MASK) == 0) { | |
683 | /* | |
684 | * We've fully scanned this node. Go up. Because | |
685 | * last_index is guaranteed to be in the tree, what | |
686 | * we do below cannot wander astray. | |
687 | */ | |
688 | slot = open_slots[height]; | |
689 | height++; | |
690 | shift += RADIX_TREE_MAP_SHIFT; | |
691 | } | |
692 | } | |
693 | /* | |
694 | * The iftag must have been set somewhere because otherwise | |
695 | * we would return immediated at the beginning of the function | |
696 | */ | |
697 | root_tag_set(root, settag); | |
698 | *first_indexp = index; | |
699 | ||
700 | return tagged; | |
701 | } | |
702 | EXPORT_SYMBOL(radix_tree_range_tag_if_tagged); | |
703 | ||
704 | ||
6df8ba4f FW |
705 | /** |
706 | * radix_tree_next_hole - find the next hole (not-present entry) | |
707 | * @root: tree root | |
708 | * @index: index key | |
709 | * @max_scan: maximum range to search | |
710 | * | |
711 | * Search the set [index, min(index+max_scan-1, MAX_INDEX)] for the lowest | |
712 | * indexed hole. | |
713 | * | |
714 | * Returns: the index of the hole if found, otherwise returns an index | |
715 | * outside of the set specified (in which case 'return - index >= max_scan' | |
8e6bdb7f | 716 | * will be true). In rare cases of index wrap-around, 0 will be returned. |
6df8ba4f FW |
717 | * |
718 | * radix_tree_next_hole may be called under rcu_read_lock. However, like | |
8e6bdb7f WF |
719 | * radix_tree_gang_lookup, this will not atomically search a snapshot of |
720 | * the tree at a single point in time. For example, if a hole is created | |
721 | * at index 5, then subsequently a hole is created at index 10, | |
722 | * radix_tree_next_hole covering both indexes may return 10 if called | |
723 | * under rcu_read_lock. | |
6df8ba4f FW |
724 | */ |
725 | unsigned long radix_tree_next_hole(struct radix_tree_root *root, | |
726 | unsigned long index, unsigned long max_scan) | |
727 | { | |
728 | unsigned long i; | |
729 | ||
730 | for (i = 0; i < max_scan; i++) { | |
731 | if (!radix_tree_lookup(root, index)) | |
732 | break; | |
733 | index++; | |
734 | if (index == 0) | |
735 | break; | |
736 | } | |
737 | ||
738 | return index; | |
739 | } | |
740 | EXPORT_SYMBOL(radix_tree_next_hole); | |
741 | ||
dc566127 WF |
742 | /** |
743 | * radix_tree_prev_hole - find the prev hole (not-present entry) | |
744 | * @root: tree root | |
745 | * @index: index key | |
746 | * @max_scan: maximum range to search | |
747 | * | |
748 | * Search backwards in the range [max(index-max_scan+1, 0), index] | |
749 | * for the first hole. | |
750 | * | |
751 | * Returns: the index of the hole if found, otherwise returns an index | |
752 | * outside of the set specified (in which case 'index - return >= max_scan' | |
edcd1d84 | 753 | * will be true). In rare cases of wrap-around, ULONG_MAX will be returned. |
dc566127 WF |
754 | * |
755 | * radix_tree_next_hole may be called under rcu_read_lock. However, like | |
756 | * radix_tree_gang_lookup, this will not atomically search a snapshot of | |
757 | * the tree at a single point in time. For example, if a hole is created | |
758 | * at index 10, then subsequently a hole is created at index 5, | |
759 | * radix_tree_prev_hole covering both indexes may return 5 if called under | |
760 | * rcu_read_lock. | |
761 | */ | |
762 | unsigned long radix_tree_prev_hole(struct radix_tree_root *root, | |
763 | unsigned long index, unsigned long max_scan) | |
764 | { | |
765 | unsigned long i; | |
766 | ||
767 | for (i = 0; i < max_scan; i++) { | |
768 | if (!radix_tree_lookup(root, index)) | |
769 | break; | |
770 | index--; | |
edcd1d84 | 771 | if (index == ULONG_MAX) |
dc566127 WF |
772 | break; |
773 | } | |
774 | ||
775 | return index; | |
776 | } | |
777 | EXPORT_SYMBOL(radix_tree_prev_hole); | |
778 | ||
1da177e4 | 779 | static unsigned int |
47feff2c | 780 | __lookup(struct radix_tree_node *slot, void ***results, unsigned long index, |
1da177e4 LT |
781 | unsigned int max_items, unsigned long *next_index) |
782 | { | |
783 | unsigned int nr_found = 0; | |
201b6264 | 784 | unsigned int shift, height; |
201b6264 CL |
785 | unsigned long i; |
786 | ||
7cf9c2c7 NP |
787 | height = slot->height; |
788 | if (height == 0) | |
201b6264 | 789 | goto out; |
1da177e4 | 790 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; |
1da177e4 | 791 | |
201b6264 | 792 | for ( ; height > 1; height--) { |
7cf9c2c7 NP |
793 | i = (index >> shift) & RADIX_TREE_MAP_MASK; |
794 | for (;;) { | |
1da177e4 LT |
795 | if (slot->slots[i] != NULL) |
796 | break; | |
797 | index &= ~((1UL << shift) - 1); | |
798 | index += 1UL << shift; | |
799 | if (index == 0) | |
800 | goto out; /* 32-bit wraparound */ | |
7cf9c2c7 NP |
801 | i++; |
802 | if (i == RADIX_TREE_MAP_SIZE) | |
803 | goto out; | |
1da177e4 | 804 | } |
1da177e4 | 805 | |
1da177e4 | 806 | shift -= RADIX_TREE_MAP_SHIFT; |
2676a58c | 807 | slot = rcu_dereference_raw(slot->slots[i]); |
7cf9c2c7 NP |
808 | if (slot == NULL) |
809 | goto out; | |
1da177e4 | 810 | } |
201b6264 CL |
811 | |
812 | /* Bottom level: grab some items */ | |
813 | for (i = index & RADIX_TREE_MAP_MASK; i < RADIX_TREE_MAP_SIZE; i++) { | |
814 | index++; | |
47feff2c NP |
815 | if (slot->slots[i]) { |
816 | results[nr_found++] = &(slot->slots[i]); | |
201b6264 CL |
817 | if (nr_found == max_items) |
818 | goto out; | |
819 | } | |
820 | } | |
1da177e4 LT |
821 | out: |
822 | *next_index = index; | |
823 | return nr_found; | |
824 | } | |
825 | ||
826 | /** | |
827 | * radix_tree_gang_lookup - perform multiple lookup on a radix tree | |
828 | * @root: radix tree root | |
829 | * @results: where the results of the lookup are placed | |
830 | * @first_index: start the lookup from this key | |
831 | * @max_items: place up to this many items at *results | |
832 | * | |
833 | * Performs an index-ascending scan of the tree for present items. Places | |
834 | * them at *@results and returns the number of items which were placed at | |
835 | * *@results. | |
836 | * | |
837 | * The implementation is naive. | |
7cf9c2c7 NP |
838 | * |
839 | * Like radix_tree_lookup, radix_tree_gang_lookup may be called under | |
840 | * rcu_read_lock. In this case, rather than the returned results being | |
841 | * an atomic snapshot of the tree at a single point in time, the semantics | |
842 | * of an RCU protected gang lookup are as though multiple radix_tree_lookups | |
843 | * have been issued in individual locks, and results stored in 'results'. | |
1da177e4 LT |
844 | */ |
845 | unsigned int | |
846 | radix_tree_gang_lookup(struct radix_tree_root *root, void **results, | |
847 | unsigned long first_index, unsigned int max_items) | |
848 | { | |
7cf9c2c7 NP |
849 | unsigned long max_index; |
850 | struct radix_tree_node *node; | |
1da177e4 | 851 | unsigned long cur_index = first_index; |
7cf9c2c7 NP |
852 | unsigned int ret; |
853 | ||
2676a58c | 854 | node = rcu_dereference_raw(root->rnode); |
7cf9c2c7 NP |
855 | if (!node) |
856 | return 0; | |
1da177e4 | 857 | |
c0bc9875 | 858 | if (!radix_tree_is_indirect_ptr(node)) { |
7cf9c2c7 NP |
859 | if (first_index > 0) |
860 | return 0; | |
c0bc9875 | 861 | results[0] = node; |
7cf9c2c7 NP |
862 | return 1; |
863 | } | |
c0bc9875 | 864 | node = radix_tree_indirect_to_ptr(node); |
7cf9c2c7 NP |
865 | |
866 | max_index = radix_tree_maxindex(node->height); | |
867 | ||
868 | ret = 0; | |
1da177e4 | 869 | while (ret < max_items) { |
47feff2c | 870 | unsigned int nr_found, slots_found, i; |
1da177e4 LT |
871 | unsigned long next_index; /* Index of next search */ |
872 | ||
873 | if (cur_index > max_index) | |
874 | break; | |
47feff2c | 875 | slots_found = __lookup(node, (void ***)results + ret, cur_index, |
1da177e4 | 876 | max_items - ret, &next_index); |
47feff2c NP |
877 | nr_found = 0; |
878 | for (i = 0; i < slots_found; i++) { | |
879 | struct radix_tree_node *slot; | |
880 | slot = *(((void ***)results)[ret + i]); | |
881 | if (!slot) | |
882 | continue; | |
2676a58c | 883 | results[ret + nr_found] = rcu_dereference_raw(slot); |
47feff2c NP |
884 | nr_found++; |
885 | } | |
1da177e4 LT |
886 | ret += nr_found; |
887 | if (next_index == 0) | |
888 | break; | |
889 | cur_index = next_index; | |
890 | } | |
7cf9c2c7 | 891 | |
1da177e4 LT |
892 | return ret; |
893 | } | |
894 | EXPORT_SYMBOL(radix_tree_gang_lookup); | |
895 | ||
47feff2c NP |
896 | /** |
897 | * radix_tree_gang_lookup_slot - perform multiple slot lookup on radix tree | |
898 | * @root: radix tree root | |
899 | * @results: where the results of the lookup are placed | |
900 | * @first_index: start the lookup from this key | |
901 | * @max_items: place up to this many items at *results | |
902 | * | |
903 | * Performs an index-ascending scan of the tree for present items. Places | |
904 | * their slots at *@results and returns the number of items which were | |
905 | * placed at *@results. | |
906 | * | |
907 | * The implementation is naive. | |
908 | * | |
909 | * Like radix_tree_gang_lookup as far as RCU and locking goes. Slots must | |
910 | * be dereferenced with radix_tree_deref_slot, and if using only RCU | |
911 | * protection, radix_tree_deref_slot may fail requiring a retry. | |
912 | */ | |
913 | unsigned int | |
914 | radix_tree_gang_lookup_slot(struct radix_tree_root *root, void ***results, | |
915 | unsigned long first_index, unsigned int max_items) | |
916 | { | |
917 | unsigned long max_index; | |
918 | struct radix_tree_node *node; | |
919 | unsigned long cur_index = first_index; | |
920 | unsigned int ret; | |
921 | ||
2676a58c | 922 | node = rcu_dereference_raw(root->rnode); |
47feff2c NP |
923 | if (!node) |
924 | return 0; | |
925 | ||
926 | if (!radix_tree_is_indirect_ptr(node)) { | |
927 | if (first_index > 0) | |
928 | return 0; | |
929 | results[0] = (void **)&root->rnode; | |
930 | return 1; | |
931 | } | |
932 | node = radix_tree_indirect_to_ptr(node); | |
933 | ||
934 | max_index = radix_tree_maxindex(node->height); | |
935 | ||
936 | ret = 0; | |
937 | while (ret < max_items) { | |
938 | unsigned int slots_found; | |
939 | unsigned long next_index; /* Index of next search */ | |
940 | ||
941 | if (cur_index > max_index) | |
942 | break; | |
943 | slots_found = __lookup(node, results + ret, cur_index, | |
944 | max_items - ret, &next_index); | |
945 | ret += slots_found; | |
946 | if (next_index == 0) | |
947 | break; | |
948 | cur_index = next_index; | |
949 | } | |
950 | ||
951 | return ret; | |
952 | } | |
953 | EXPORT_SYMBOL(radix_tree_gang_lookup_slot); | |
954 | ||
1da177e4 LT |
955 | /* |
956 | * FIXME: the two tag_get()s here should use find_next_bit() instead of | |
957 | * open-coding the search. | |
958 | */ | |
959 | static unsigned int | |
47feff2c | 960 | __lookup_tag(struct radix_tree_node *slot, void ***results, unsigned long index, |
daff89f3 | 961 | unsigned int max_items, unsigned long *next_index, unsigned int tag) |
1da177e4 LT |
962 | { |
963 | unsigned int nr_found = 0; | |
7cf9c2c7 | 964 | unsigned int shift, height; |
1da177e4 | 965 | |
7cf9c2c7 NP |
966 | height = slot->height; |
967 | if (height == 0) | |
612d6c19 | 968 | goto out; |
7cf9c2c7 | 969 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; |
1da177e4 | 970 | |
7cf9c2c7 NP |
971 | while (height > 0) { |
972 | unsigned long i = (index >> shift) & RADIX_TREE_MAP_MASK ; | |
1da177e4 | 973 | |
7cf9c2c7 NP |
974 | for (;;) { |
975 | if (tag_get(slot, tag, i)) | |
1da177e4 | 976 | break; |
1da177e4 LT |
977 | index &= ~((1UL << shift) - 1); |
978 | index += 1UL << shift; | |
979 | if (index == 0) | |
980 | goto out; /* 32-bit wraparound */ | |
7cf9c2c7 NP |
981 | i++; |
982 | if (i == RADIX_TREE_MAP_SIZE) | |
983 | goto out; | |
1da177e4 | 984 | } |
1da177e4 LT |
985 | height--; |
986 | if (height == 0) { /* Bottom level: grab some items */ | |
987 | unsigned long j = index & RADIX_TREE_MAP_MASK; | |
988 | ||
989 | for ( ; j < RADIX_TREE_MAP_SIZE; j++) { | |
990 | index++; | |
7cf9c2c7 NP |
991 | if (!tag_get(slot, tag, j)) |
992 | continue; | |
7cf9c2c7 NP |
993 | /* |
994 | * Even though the tag was found set, we need to | |
995 | * recheck that we have a non-NULL node, because | |
996 | * if this lookup is lockless, it may have been | |
997 | * subsequently deleted. | |
998 | * | |
999 | * Similar care must be taken in any place that | |
1000 | * lookup ->slots[x] without a lock (ie. can't | |
1001 | * rely on its value remaining the same). | |
1002 | */ | |
47feff2c NP |
1003 | if (slot->slots[j]) { |
1004 | results[nr_found++] = &(slot->slots[j]); | |
1da177e4 LT |
1005 | if (nr_found == max_items) |
1006 | goto out; | |
1007 | } | |
1008 | } | |
1009 | } | |
1010 | shift -= RADIX_TREE_MAP_SHIFT; | |
2676a58c | 1011 | slot = rcu_dereference_raw(slot->slots[i]); |
7cf9c2c7 NP |
1012 | if (slot == NULL) |
1013 | break; | |
1014 | } | |
1da177e4 LT |
1015 | out: |
1016 | *next_index = index; | |
1017 | return nr_found; | |
1018 | } | |
1019 | ||
1020 | /** | |
1021 | * radix_tree_gang_lookup_tag - perform multiple lookup on a radix tree | |
1022 | * based on a tag | |
1023 | * @root: radix tree root | |
1024 | * @results: where the results of the lookup are placed | |
1025 | * @first_index: start the lookup from this key | |
1026 | * @max_items: place up to this many items at *results | |
daff89f3 | 1027 | * @tag: the tag index (< RADIX_TREE_MAX_TAGS) |
1da177e4 LT |
1028 | * |
1029 | * Performs an index-ascending scan of the tree for present items which | |
1030 | * have the tag indexed by @tag set. Places the items at *@results and | |
1031 | * returns the number of items which were placed at *@results. | |
1032 | */ | |
1033 | unsigned int | |
1034 | radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results, | |
daff89f3 JC |
1035 | unsigned long first_index, unsigned int max_items, |
1036 | unsigned int tag) | |
1da177e4 | 1037 | { |
7cf9c2c7 NP |
1038 | struct radix_tree_node *node; |
1039 | unsigned long max_index; | |
1da177e4 | 1040 | unsigned long cur_index = first_index; |
7cf9c2c7 | 1041 | unsigned int ret; |
1da177e4 | 1042 | |
612d6c19 NP |
1043 | /* check the root's tag bit */ |
1044 | if (!root_tag_get(root, tag)) | |
1045 | return 0; | |
1046 | ||
2676a58c | 1047 | node = rcu_dereference_raw(root->rnode); |
7cf9c2c7 NP |
1048 | if (!node) |
1049 | return 0; | |
1050 | ||
c0bc9875 | 1051 | if (!radix_tree_is_indirect_ptr(node)) { |
7cf9c2c7 NP |
1052 | if (first_index > 0) |
1053 | return 0; | |
c0bc9875 | 1054 | results[0] = node; |
7cf9c2c7 NP |
1055 | return 1; |
1056 | } | |
c0bc9875 | 1057 | node = radix_tree_indirect_to_ptr(node); |
7cf9c2c7 NP |
1058 | |
1059 | max_index = radix_tree_maxindex(node->height); | |
1060 | ||
1061 | ret = 0; | |
1da177e4 | 1062 | while (ret < max_items) { |
47feff2c | 1063 | unsigned int nr_found, slots_found, i; |
1da177e4 LT |
1064 | unsigned long next_index; /* Index of next search */ |
1065 | ||
1066 | if (cur_index > max_index) | |
1067 | break; | |
47feff2c NP |
1068 | slots_found = __lookup_tag(node, (void ***)results + ret, |
1069 | cur_index, max_items - ret, &next_index, tag); | |
1070 | nr_found = 0; | |
1071 | for (i = 0; i < slots_found; i++) { | |
1072 | struct radix_tree_node *slot; | |
1073 | slot = *(((void ***)results)[ret + i]); | |
1074 | if (!slot) | |
1075 | continue; | |
2676a58c | 1076 | results[ret + nr_found] = rcu_dereference_raw(slot); |
47feff2c NP |
1077 | nr_found++; |
1078 | } | |
1da177e4 LT |
1079 | ret += nr_found; |
1080 | if (next_index == 0) | |
1081 | break; | |
1082 | cur_index = next_index; | |
1083 | } | |
7cf9c2c7 | 1084 | |
1da177e4 LT |
1085 | return ret; |
1086 | } | |
1087 | EXPORT_SYMBOL(radix_tree_gang_lookup_tag); | |
1088 | ||
47feff2c NP |
1089 | /** |
1090 | * radix_tree_gang_lookup_tag_slot - perform multiple slot lookup on a | |
1091 | * radix tree based on a tag | |
1092 | * @root: radix tree root | |
1093 | * @results: where the results of the lookup are placed | |
1094 | * @first_index: start the lookup from this key | |
1095 | * @max_items: place up to this many items at *results | |
1096 | * @tag: the tag index (< RADIX_TREE_MAX_TAGS) | |
1097 | * | |
1098 | * Performs an index-ascending scan of the tree for present items which | |
1099 | * have the tag indexed by @tag set. Places the slots at *@results and | |
1100 | * returns the number of slots which were placed at *@results. | |
1101 | */ | |
1102 | unsigned int | |
1103 | radix_tree_gang_lookup_tag_slot(struct radix_tree_root *root, void ***results, | |
1104 | unsigned long first_index, unsigned int max_items, | |
1105 | unsigned int tag) | |
1106 | { | |
1107 | struct radix_tree_node *node; | |
1108 | unsigned long max_index; | |
1109 | unsigned long cur_index = first_index; | |
1110 | unsigned int ret; | |
1111 | ||
1112 | /* check the root's tag bit */ | |
1113 | if (!root_tag_get(root, tag)) | |
1114 | return 0; | |
1115 | ||
2676a58c | 1116 | node = rcu_dereference_raw(root->rnode); |
47feff2c NP |
1117 | if (!node) |
1118 | return 0; | |
1119 | ||
1120 | if (!radix_tree_is_indirect_ptr(node)) { | |
1121 | if (first_index > 0) | |
1122 | return 0; | |
1123 | results[0] = (void **)&root->rnode; | |
1124 | return 1; | |
1125 | } | |
1126 | node = radix_tree_indirect_to_ptr(node); | |
1127 | ||
1128 | max_index = radix_tree_maxindex(node->height); | |
1129 | ||
1130 | ret = 0; | |
1131 | while (ret < max_items) { | |
1132 | unsigned int slots_found; | |
1133 | unsigned long next_index; /* Index of next search */ | |
1134 | ||
1135 | if (cur_index > max_index) | |
1136 | break; | |
1137 | slots_found = __lookup_tag(node, results + ret, | |
1138 | cur_index, max_items - ret, &next_index, tag); | |
1139 | ret += slots_found; | |
1140 | if (next_index == 0) | |
1141 | break; | |
1142 | cur_index = next_index; | |
1143 | } | |
1144 | ||
1145 | return ret; | |
1146 | } | |
1147 | EXPORT_SYMBOL(radix_tree_gang_lookup_tag_slot); | |
1148 | ||
1149 | ||
a5f51c96 NP |
1150 | /** |
1151 | * radix_tree_shrink - shrink height of a radix tree to minimal | |
1152 | * @root radix tree root | |
1153 | */ | |
1154 | static inline void radix_tree_shrink(struct radix_tree_root *root) | |
1155 | { | |
1156 | /* try to shrink tree height */ | |
c0bc9875 | 1157 | while (root->height > 0) { |
a5f51c96 | 1158 | struct radix_tree_node *to_free = root->rnode; |
7cf9c2c7 | 1159 | void *newptr; |
a5f51c96 | 1160 | |
c0bc9875 NP |
1161 | BUG_ON(!radix_tree_is_indirect_ptr(to_free)); |
1162 | to_free = radix_tree_indirect_to_ptr(to_free); | |
1163 | ||
1164 | /* | |
1165 | * The candidate node has more than one child, or its child | |
1166 | * is not at the leftmost slot, we cannot shrink. | |
1167 | */ | |
1168 | if (to_free->count != 1) | |
1169 | break; | |
1170 | if (!to_free->slots[0]) | |
1171 | break; | |
1172 | ||
7cf9c2c7 NP |
1173 | /* |
1174 | * We don't need rcu_assign_pointer(), since we are simply | |
1175 | * moving the node from one part of the tree to another. If | |
1176 | * it was safe to dereference the old pointer to it | |
1177 | * (to_free->slots[0]), it will be safe to dereference the new | |
1178 | * one (root->rnode). | |
1179 | */ | |
1180 | newptr = to_free->slots[0]; | |
c0bc9875 NP |
1181 | if (root->height > 1) |
1182 | newptr = radix_tree_ptr_to_indirect(newptr); | |
7cf9c2c7 | 1183 | root->rnode = newptr; |
a5f51c96 | 1184 | root->height--; |
a5f51c96 NP |
1185 | radix_tree_node_free(to_free); |
1186 | } | |
1187 | } | |
1188 | ||
1da177e4 LT |
1189 | /** |
1190 | * radix_tree_delete - delete an item from a radix tree | |
1191 | * @root: radix tree root | |
1192 | * @index: index key | |
1193 | * | |
1194 | * Remove the item at @index from the radix tree rooted at @root. | |
1195 | * | |
1196 | * Returns the address of the deleted item, or NULL if it was not present. | |
1197 | */ | |
1198 | void *radix_tree_delete(struct radix_tree_root *root, unsigned long index) | |
1199 | { | |
26fb1589 JM |
1200 | /* |
1201 | * The radix tree path needs to be one longer than the maximum path | |
1202 | * since the "list" is null terminated. | |
1203 | */ | |
1204 | struct radix_tree_path path[RADIX_TREE_MAX_PATH + 1], *pathp = path; | |
612d6c19 | 1205 | struct radix_tree_node *slot = NULL; |
7cf9c2c7 | 1206 | struct radix_tree_node *to_free; |
1da177e4 | 1207 | unsigned int height, shift; |
d5274261 NP |
1208 | int tag; |
1209 | int offset; | |
1da177e4 LT |
1210 | |
1211 | height = root->height; | |
1212 | if (index > radix_tree_maxindex(height)) | |
1213 | goto out; | |
1214 | ||
612d6c19 | 1215 | slot = root->rnode; |
c0bc9875 | 1216 | if (height == 0) { |
612d6c19 NP |
1217 | root_tag_clear_all(root); |
1218 | root->rnode = NULL; | |
1219 | goto out; | |
1220 | } | |
c0bc9875 | 1221 | slot = radix_tree_indirect_to_ptr(slot); |
612d6c19 | 1222 | |
1da177e4 LT |
1223 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; |
1224 | pathp->node = NULL; | |
1da177e4 | 1225 | |
612d6c19 | 1226 | do { |
201b6264 | 1227 | if (slot == NULL) |
1da177e4 LT |
1228 | goto out; |
1229 | ||
d5274261 | 1230 | pathp++; |
1da177e4 | 1231 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; |
d5274261 NP |
1232 | pathp->offset = offset; |
1233 | pathp->node = slot; | |
201b6264 | 1234 | slot = slot->slots[offset]; |
1da177e4 | 1235 | shift -= RADIX_TREE_MAP_SHIFT; |
612d6c19 NP |
1236 | height--; |
1237 | } while (height > 0); | |
1da177e4 | 1238 | |
612d6c19 | 1239 | if (slot == NULL) |
1da177e4 LT |
1240 | goto out; |
1241 | ||
1da177e4 LT |
1242 | /* |
1243 | * Clear all tags associated with the just-deleted item | |
1244 | */ | |
daff89f3 | 1245 | for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { |
612d6c19 NP |
1246 | if (tag_get(pathp->node, tag, pathp->offset)) |
1247 | radix_tree_tag_clear(root, index, tag); | |
d5274261 | 1248 | } |
1da177e4 | 1249 | |
7cf9c2c7 | 1250 | to_free = NULL; |
201b6264 | 1251 | /* Now free the nodes we do not need anymore */ |
612d6c19 | 1252 | while (pathp->node) { |
201b6264 | 1253 | pathp->node->slots[pathp->offset] = NULL; |
a5f51c96 | 1254 | pathp->node->count--; |
7cf9c2c7 NP |
1255 | /* |
1256 | * Queue the node for deferred freeing after the | |
1257 | * last reference to it disappears (set NULL, above). | |
1258 | */ | |
1259 | if (to_free) | |
1260 | radix_tree_node_free(to_free); | |
a5f51c96 NP |
1261 | |
1262 | if (pathp->node->count) { | |
c0bc9875 NP |
1263 | if (pathp->node == |
1264 | radix_tree_indirect_to_ptr(root->rnode)) | |
a5f51c96 | 1265 | radix_tree_shrink(root); |
201b6264 | 1266 | goto out; |
a5f51c96 | 1267 | } |
201b6264 CL |
1268 | |
1269 | /* Node with zero slots in use so free it */ | |
7cf9c2c7 | 1270 | to_free = pathp->node; |
612d6c19 | 1271 | pathp--; |
7cf9c2c7 | 1272 | |
1da177e4 | 1273 | } |
612d6c19 | 1274 | root_tag_clear_all(root); |
201b6264 | 1275 | root->height = 0; |
612d6c19 | 1276 | root->rnode = NULL; |
7cf9c2c7 NP |
1277 | if (to_free) |
1278 | radix_tree_node_free(to_free); | |
612d6c19 | 1279 | |
1da177e4 | 1280 | out: |
612d6c19 | 1281 | return slot; |
1da177e4 LT |
1282 | } |
1283 | EXPORT_SYMBOL(radix_tree_delete); | |
1284 | ||
1285 | /** | |
1286 | * radix_tree_tagged - test whether any items in the tree are tagged | |
1287 | * @root: radix tree root | |
1288 | * @tag: tag to test | |
1289 | */ | |
daff89f3 | 1290 | int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag) |
1da177e4 | 1291 | { |
612d6c19 | 1292 | return root_tag_get(root, tag); |
1da177e4 LT |
1293 | } |
1294 | EXPORT_SYMBOL(radix_tree_tagged); | |
1295 | ||
1296 | static void | |
51cc5068 | 1297 | radix_tree_node_ctor(void *node) |
1da177e4 LT |
1298 | { |
1299 | memset(node, 0, sizeof(struct radix_tree_node)); | |
1300 | } | |
1301 | ||
1302 | static __init unsigned long __maxindex(unsigned int height) | |
1303 | { | |
430d275a PL |
1304 | unsigned int width = height * RADIX_TREE_MAP_SHIFT; |
1305 | int shift = RADIX_TREE_INDEX_BITS - width; | |
1306 | ||
1307 | if (shift < 0) | |
1308 | return ~0UL; | |
1309 | if (shift >= BITS_PER_LONG) | |
1310 | return 0UL; | |
1311 | return ~0UL >> shift; | |
1da177e4 LT |
1312 | } |
1313 | ||
1314 | static __init void radix_tree_init_maxindex(void) | |
1315 | { | |
1316 | unsigned int i; | |
1317 | ||
1318 | for (i = 0; i < ARRAY_SIZE(height_to_maxindex); i++) | |
1319 | height_to_maxindex[i] = __maxindex(i); | |
1320 | } | |
1321 | ||
1da177e4 LT |
1322 | static int radix_tree_callback(struct notifier_block *nfb, |
1323 | unsigned long action, | |
1324 | void *hcpu) | |
1325 | { | |
1326 | int cpu = (long)hcpu; | |
1327 | struct radix_tree_preload *rtp; | |
1328 | ||
1329 | /* Free per-cpu pool of perloaded nodes */ | |
8bb78442 | 1330 | if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) { |
1da177e4 LT |
1331 | rtp = &per_cpu(radix_tree_preloads, cpu); |
1332 | while (rtp->nr) { | |
1333 | kmem_cache_free(radix_tree_node_cachep, | |
1334 | rtp->nodes[rtp->nr-1]); | |
1335 | rtp->nodes[rtp->nr-1] = NULL; | |
1336 | rtp->nr--; | |
1337 | } | |
1338 | } | |
1339 | return NOTIFY_OK; | |
1340 | } | |
1da177e4 LT |
1341 | |
1342 | void __init radix_tree_init(void) | |
1343 | { | |
1344 | radix_tree_node_cachep = kmem_cache_create("radix_tree_node", | |
1345 | sizeof(struct radix_tree_node), 0, | |
488514d1 CL |
1346 | SLAB_PANIC | SLAB_RECLAIM_ACCOUNT, |
1347 | radix_tree_node_ctor); | |
1da177e4 LT |
1348 | radix_tree_init_maxindex(); |
1349 | hotcpu_notifier(radix_tree_callback, 0); | |
1350 | } |