Commit | Line | Data |
---|---|---|
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 |
78c1d784 | 6 | * Copyright (C) 2012 Konstantin Khlebnikov |
1da177e4 LT |
7 | * |
8 | * This program is free software; you can redistribute it and/or | |
9 | * modify it under the terms of the GNU General Public License as | |
10 | * published by the Free Software Foundation; either version 2, or (at | |
11 | * your option) any later version. | |
12 | * | |
13 | * This program is distributed in the hope that it will be useful, but | |
14 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | * General Public License for more details. | |
17 | * | |
18 | * You should have received a copy of the GNU General Public License | |
19 | * along with this program; if not, write to the Free Software | |
20 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
21 | */ | |
22 | ||
23 | #include <linux/errno.h> | |
24 | #include <linux/init.h> | |
25 | #include <linux/kernel.h> | |
8bc3bcc9 | 26 | #include <linux/export.h> |
1da177e4 LT |
27 | #include <linux/radix-tree.h> |
28 | #include <linux/percpu.h> | |
29 | #include <linux/slab.h> | |
ce80b067 | 30 | #include <linux/kmemleak.h> |
1da177e4 LT |
31 | #include <linux/notifier.h> |
32 | #include <linux/cpu.h> | |
1da177e4 LT |
33 | #include <linux/string.h> |
34 | #include <linux/bitops.h> | |
7cf9c2c7 | 35 | #include <linux/rcupdate.h> |
92cf2118 | 36 | #include <linux/preempt.h> /* in_interrupt() */ |
1da177e4 LT |
37 | |
38 | ||
26fb1589 JM |
39 | /* |
40 | * The height_to_maxindex array needs to be one deeper than the maximum | |
41 | * path as height 0 holds only 1 entry. | |
42 | */ | |
43 | static unsigned long height_to_maxindex[RADIX_TREE_MAX_PATH + 1] __read_mostly; | |
1da177e4 LT |
44 | |
45 | /* | |
46 | * Radix tree node cache. | |
47 | */ | |
e18b890b | 48 | static struct kmem_cache *radix_tree_node_cachep; |
1da177e4 | 49 | |
55368052 NP |
50 | /* |
51 | * The radix tree is variable-height, so an insert operation not only has | |
52 | * to build the branch to its corresponding item, it also has to build the | |
53 | * branch to existing items if the size has to be increased (by | |
54 | * radix_tree_extend). | |
55 | * | |
56 | * The worst case is a zero height tree with just a single item at index 0, | |
57 | * and then inserting an item at index ULONG_MAX. This requires 2 new branches | |
58 | * of RADIX_TREE_MAX_PATH size to be created, with only the root node shared. | |
59 | * Hence: | |
60 | */ | |
61 | #define RADIX_TREE_PRELOAD_SIZE (RADIX_TREE_MAX_PATH * 2 - 1) | |
62 | ||
1da177e4 LT |
63 | /* |
64 | * Per-cpu pool of preloaded nodes | |
65 | */ | |
66 | struct radix_tree_preload { | |
67 | int nr; | |
9d2a8da0 KS |
68 | /* nodes->private_data points to next preallocated node */ |
69 | struct radix_tree_node *nodes; | |
1da177e4 | 70 | }; |
8cef7d57 | 71 | static DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, }; |
1da177e4 | 72 | |
27d20fdd NP |
73 | static inline void *ptr_to_indirect(void *ptr) |
74 | { | |
75 | return (void *)((unsigned long)ptr | RADIX_TREE_INDIRECT_PTR); | |
76 | } | |
77 | ||
78 | static inline void *indirect_to_ptr(void *ptr) | |
79 | { | |
80 | return (void *)((unsigned long)ptr & ~RADIX_TREE_INDIRECT_PTR); | |
81 | } | |
82 | ||
612d6c19 NP |
83 | static inline gfp_t root_gfp_mask(struct radix_tree_root *root) |
84 | { | |
85 | return root->gfp_mask & __GFP_BITS_MASK; | |
86 | } | |
87 | ||
643b52b9 NP |
88 | static inline void tag_set(struct radix_tree_node *node, unsigned int tag, |
89 | int offset) | |
90 | { | |
91 | __set_bit(offset, node->tags[tag]); | |
92 | } | |
93 | ||
94 | static inline void tag_clear(struct radix_tree_node *node, unsigned int tag, | |
95 | int offset) | |
96 | { | |
97 | __clear_bit(offset, node->tags[tag]); | |
98 | } | |
99 | ||
100 | static inline int tag_get(struct radix_tree_node *node, unsigned int tag, | |
101 | int offset) | |
102 | { | |
103 | return test_bit(offset, node->tags[tag]); | |
104 | } | |
105 | ||
106 | static inline void root_tag_set(struct radix_tree_root *root, unsigned int tag) | |
107 | { | |
108 | root->gfp_mask |= (__force gfp_t)(1 << (tag + __GFP_BITS_SHIFT)); | |
109 | } | |
110 | ||
111 | static inline void root_tag_clear(struct radix_tree_root *root, unsigned int tag) | |
112 | { | |
113 | root->gfp_mask &= (__force gfp_t)~(1 << (tag + __GFP_BITS_SHIFT)); | |
114 | } | |
115 | ||
116 | static inline void root_tag_clear_all(struct radix_tree_root *root) | |
117 | { | |
118 | root->gfp_mask &= __GFP_BITS_MASK; | |
119 | } | |
120 | ||
121 | static inline int root_tag_get(struct radix_tree_root *root, unsigned int tag) | |
122 | { | |
123 | return (__force unsigned)root->gfp_mask & (1 << (tag + __GFP_BITS_SHIFT)); | |
124 | } | |
125 | ||
126 | /* | |
127 | * Returns 1 if any slot in the node has this tag set. | |
128 | * Otherwise returns 0. | |
129 | */ | |
130 | static inline int any_tag_set(struct radix_tree_node *node, unsigned int tag) | |
131 | { | |
132 | int idx; | |
133 | for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) { | |
134 | if (node->tags[tag][idx]) | |
135 | return 1; | |
136 | } | |
137 | return 0; | |
138 | } | |
78c1d784 KK |
139 | |
140 | /** | |
141 | * radix_tree_find_next_bit - find the next set bit in a memory region | |
142 | * | |
143 | * @addr: The address to base the search on | |
144 | * @size: The bitmap size in bits | |
145 | * @offset: The bitnumber to start searching at | |
146 | * | |
147 | * Unrollable variant of find_next_bit() for constant size arrays. | |
148 | * Tail bits starting from size to roundup(size, BITS_PER_LONG) must be zero. | |
149 | * Returns next bit offset, or size if nothing found. | |
150 | */ | |
151 | static __always_inline unsigned long | |
152 | radix_tree_find_next_bit(const unsigned long *addr, | |
153 | unsigned long size, unsigned long offset) | |
154 | { | |
155 | if (!__builtin_constant_p(size)) | |
156 | return find_next_bit(addr, size, offset); | |
157 | ||
158 | if (offset < size) { | |
159 | unsigned long tmp; | |
160 | ||
161 | addr += offset / BITS_PER_LONG; | |
162 | tmp = *addr >> (offset % BITS_PER_LONG); | |
163 | if (tmp) | |
164 | return __ffs(tmp) + offset; | |
165 | offset = (offset + BITS_PER_LONG) & ~(BITS_PER_LONG - 1); | |
166 | while (offset < size) { | |
167 | tmp = *++addr; | |
168 | if (tmp) | |
169 | return __ffs(tmp) + offset; | |
170 | offset += BITS_PER_LONG; | |
171 | } | |
172 | } | |
173 | return size; | |
174 | } | |
175 | ||
7cf19af4 MW |
176 | #if 0 |
177 | static void dump_node(void *slot, int height, int offset) | |
178 | { | |
179 | struct radix_tree_node *node; | |
180 | int i; | |
181 | ||
182 | if (!slot) | |
183 | return; | |
184 | ||
185 | if (height == 0) { | |
186 | pr_debug("radix entry %p offset %d\n", slot, offset); | |
187 | return; | |
188 | } | |
189 | ||
190 | node = indirect_to_ptr(slot); | |
191 | pr_debug("radix node: %p offset %d tags %lx %lx %lx path %x count %d parent %p\n", | |
192 | slot, offset, node->tags[0][0], node->tags[1][0], | |
193 | node->tags[2][0], node->path, node->count, node->parent); | |
194 | ||
195 | for (i = 0; i < RADIX_TREE_MAP_SIZE; i++) | |
196 | dump_node(node->slots[i], height - 1, i); | |
197 | } | |
198 | ||
199 | /* For debug */ | |
200 | static void radix_tree_dump(struct radix_tree_root *root) | |
201 | { | |
202 | pr_debug("radix root: %p height %d rnode %p tags %x\n", | |
203 | root, root->height, root->rnode, | |
204 | root->gfp_mask >> __GFP_BITS_SHIFT); | |
205 | if (!radix_tree_is_indirect_ptr(root->rnode)) | |
206 | return; | |
207 | dump_node(root->rnode, root->height, 0); | |
208 | } | |
209 | #endif | |
210 | ||
1da177e4 LT |
211 | /* |
212 | * This assumes that the caller has performed appropriate preallocation, and | |
213 | * that the caller has pinned this thread of control to the current CPU. | |
214 | */ | |
215 | static struct radix_tree_node * | |
216 | radix_tree_node_alloc(struct radix_tree_root *root) | |
217 | { | |
e2848a0e | 218 | struct radix_tree_node *ret = NULL; |
612d6c19 | 219 | gfp_t gfp_mask = root_gfp_mask(root); |
1da177e4 | 220 | |
5e4c0d97 JK |
221 | /* |
222 | * Preload code isn't irq safe and it doesn't make sence to use | |
223 | * preloading in the interrupt anyway as all the allocations have to | |
224 | * be atomic. So just do normal allocation when in interrupt. | |
225 | */ | |
d0164adc | 226 | if (!gfpflags_allow_blocking(gfp_mask) && !in_interrupt()) { |
1da177e4 LT |
227 | struct radix_tree_preload *rtp; |
228 | ||
58e698af VD |
229 | /* |
230 | * Even if the caller has preloaded, try to allocate from the | |
231 | * cache first for the new node to get accounted. | |
232 | */ | |
233 | ret = kmem_cache_alloc(radix_tree_node_cachep, | |
234 | gfp_mask | __GFP_ACCOUNT | __GFP_NOWARN); | |
235 | if (ret) | |
236 | goto out; | |
237 | ||
e2848a0e NP |
238 | /* |
239 | * Provided the caller has preloaded here, we will always | |
240 | * succeed in getting a node here (and never reach | |
241 | * kmem_cache_alloc) | |
242 | */ | |
7c8e0181 | 243 | rtp = this_cpu_ptr(&radix_tree_preloads); |
1da177e4 | 244 | if (rtp->nr) { |
9d2a8da0 KS |
245 | ret = rtp->nodes; |
246 | rtp->nodes = ret->private_data; | |
247 | ret->private_data = NULL; | |
1da177e4 LT |
248 | rtp->nr--; |
249 | } | |
ce80b067 CM |
250 | /* |
251 | * Update the allocation stack trace as this is more useful | |
252 | * for debugging. | |
253 | */ | |
254 | kmemleak_update_trace(ret); | |
58e698af | 255 | goto out; |
1da177e4 | 256 | } |
58e698af VD |
257 | ret = kmem_cache_alloc(radix_tree_node_cachep, |
258 | gfp_mask | __GFP_ACCOUNT); | |
259 | out: | |
c0bc9875 | 260 | BUG_ON(radix_tree_is_indirect_ptr(ret)); |
1da177e4 LT |
261 | return ret; |
262 | } | |
263 | ||
7cf9c2c7 NP |
264 | static void radix_tree_node_rcu_free(struct rcu_head *head) |
265 | { | |
266 | struct radix_tree_node *node = | |
267 | container_of(head, struct radix_tree_node, rcu_head); | |
b6dd0865 | 268 | int i; |
643b52b9 NP |
269 | |
270 | /* | |
271 | * must only free zeroed nodes into the slab. radix_tree_shrink | |
272 | * can leave us with a non-NULL entry in the first slot, so clear | |
273 | * that here to make sure. | |
274 | */ | |
b6dd0865 DC |
275 | for (i = 0; i < RADIX_TREE_MAX_TAGS; i++) |
276 | tag_clear(node, i, 0); | |
277 | ||
643b52b9 NP |
278 | node->slots[0] = NULL; |
279 | node->count = 0; | |
280 | ||
7cf9c2c7 NP |
281 | kmem_cache_free(radix_tree_node_cachep, node); |
282 | } | |
283 | ||
1da177e4 LT |
284 | static inline void |
285 | radix_tree_node_free(struct radix_tree_node *node) | |
286 | { | |
7cf9c2c7 | 287 | call_rcu(&node->rcu_head, radix_tree_node_rcu_free); |
1da177e4 LT |
288 | } |
289 | ||
290 | /* | |
291 | * Load up this CPU's radix_tree_node buffer with sufficient objects to | |
292 | * ensure that the addition of a single element in the tree cannot fail. On | |
293 | * success, return zero, with preemption disabled. On error, return -ENOMEM | |
294 | * with preemption not disabled. | |
b34df792 DH |
295 | * |
296 | * To make use of this facility, the radix tree must be initialised without | |
d0164adc | 297 | * __GFP_DIRECT_RECLAIM being passed to INIT_RADIX_TREE(). |
1da177e4 | 298 | */ |
5e4c0d97 | 299 | static int __radix_tree_preload(gfp_t gfp_mask) |
1da177e4 LT |
300 | { |
301 | struct radix_tree_preload *rtp; | |
302 | struct radix_tree_node *node; | |
303 | int ret = -ENOMEM; | |
304 | ||
305 | preempt_disable(); | |
7c8e0181 | 306 | rtp = this_cpu_ptr(&radix_tree_preloads); |
9d2a8da0 | 307 | while (rtp->nr < RADIX_TREE_PRELOAD_SIZE) { |
1da177e4 | 308 | preempt_enable(); |
488514d1 | 309 | node = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask); |
1da177e4 LT |
310 | if (node == NULL) |
311 | goto out; | |
312 | preempt_disable(); | |
7c8e0181 | 313 | rtp = this_cpu_ptr(&radix_tree_preloads); |
9d2a8da0 KS |
314 | if (rtp->nr < RADIX_TREE_PRELOAD_SIZE) { |
315 | node->private_data = rtp->nodes; | |
316 | rtp->nodes = node; | |
317 | rtp->nr++; | |
318 | } else { | |
1da177e4 | 319 | kmem_cache_free(radix_tree_node_cachep, node); |
9d2a8da0 | 320 | } |
1da177e4 LT |
321 | } |
322 | ret = 0; | |
323 | out: | |
324 | return ret; | |
325 | } | |
5e4c0d97 JK |
326 | |
327 | /* | |
328 | * Load up this CPU's radix_tree_node buffer with sufficient objects to | |
329 | * ensure that the addition of a single element in the tree cannot fail. On | |
330 | * success, return zero, with preemption disabled. On error, return -ENOMEM | |
331 | * with preemption not disabled. | |
332 | * | |
333 | * To make use of this facility, the radix tree must be initialised without | |
d0164adc | 334 | * __GFP_DIRECT_RECLAIM being passed to INIT_RADIX_TREE(). |
5e4c0d97 JK |
335 | */ |
336 | int radix_tree_preload(gfp_t gfp_mask) | |
337 | { | |
338 | /* Warn on non-sensical use... */ | |
d0164adc | 339 | WARN_ON_ONCE(!gfpflags_allow_blocking(gfp_mask)); |
5e4c0d97 JK |
340 | return __radix_tree_preload(gfp_mask); |
341 | } | |
d7f0923d | 342 | EXPORT_SYMBOL(radix_tree_preload); |
1da177e4 | 343 | |
5e4c0d97 JK |
344 | /* |
345 | * The same as above function, except we don't guarantee preloading happens. | |
346 | * We do it, if we decide it helps. On success, return zero with preemption | |
347 | * disabled. On error, return -ENOMEM with preemption not disabled. | |
348 | */ | |
349 | int radix_tree_maybe_preload(gfp_t gfp_mask) | |
350 | { | |
d0164adc | 351 | if (gfpflags_allow_blocking(gfp_mask)) |
5e4c0d97 JK |
352 | return __radix_tree_preload(gfp_mask); |
353 | /* Preloading doesn't help anything with this gfp mask, skip it */ | |
354 | preempt_disable(); | |
355 | return 0; | |
356 | } | |
357 | EXPORT_SYMBOL(radix_tree_maybe_preload); | |
358 | ||
1da177e4 LT |
359 | /* |
360 | * Return the maximum key which can be store into a | |
361 | * radix tree with height HEIGHT. | |
362 | */ | |
363 | static inline unsigned long radix_tree_maxindex(unsigned int height) | |
364 | { | |
365 | return height_to_maxindex[height]; | |
366 | } | |
367 | ||
368 | /* | |
369 | * Extend a radix tree so it can store key @index. | |
370 | */ | |
e6145236 MW |
371 | static int radix_tree_extend(struct radix_tree_root *root, |
372 | unsigned long index, unsigned order) | |
1da177e4 LT |
373 | { |
374 | struct radix_tree_node *node; | |
e2bdb933 | 375 | struct radix_tree_node *slot; |
1da177e4 | 376 | unsigned int height; |
1da177e4 LT |
377 | int tag; |
378 | ||
379 | /* Figure out what the height should be. */ | |
380 | height = root->height + 1; | |
381 | while (index > radix_tree_maxindex(height)) | |
382 | height++; | |
383 | ||
e6145236 | 384 | if ((root->rnode == NULL) && (order == 0)) { |
1da177e4 LT |
385 | root->height = height; |
386 | goto out; | |
387 | } | |
388 | ||
1da177e4 | 389 | do { |
7cf9c2c7 | 390 | unsigned int newheight; |
1da177e4 LT |
391 | if (!(node = radix_tree_node_alloc(root))) |
392 | return -ENOMEM; | |
393 | ||
1da177e4 | 394 | /* Propagate the aggregated tag info into the new root */ |
daff89f3 | 395 | for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { |
612d6c19 | 396 | if (root_tag_get(root, tag)) |
1da177e4 LT |
397 | tag_set(node, tag, 0); |
398 | } | |
399 | ||
e2bdb933 | 400 | /* Increase the height. */ |
7cf9c2c7 | 401 | newheight = root->height+1; |
449dd698 JW |
402 | BUG_ON(newheight & ~RADIX_TREE_HEIGHT_MASK); |
403 | node->path = newheight; | |
1da177e4 | 404 | node->count = 1; |
e2bdb933 HD |
405 | node->parent = NULL; |
406 | slot = root->rnode; | |
339e6353 | 407 | if (radix_tree_is_indirect_ptr(slot) && newheight > 1) { |
e2bdb933 HD |
408 | slot = indirect_to_ptr(slot); |
409 | slot->parent = node; | |
339e6353 | 410 | slot = ptr_to_indirect(slot); |
e2bdb933 HD |
411 | } |
412 | node->slots[0] = slot; | |
27d20fdd | 413 | node = ptr_to_indirect(node); |
7cf9c2c7 NP |
414 | rcu_assign_pointer(root->rnode, node); |
415 | root->height = newheight; | |
1da177e4 LT |
416 | } while (height > root->height); |
417 | out: | |
418 | return 0; | |
419 | } | |
420 | ||
421 | /** | |
139e5616 | 422 | * __radix_tree_create - create a slot in a radix tree |
1da177e4 LT |
423 | * @root: radix tree root |
424 | * @index: index key | |
e6145236 | 425 | * @order: index occupies 2^order aligned slots |
139e5616 JW |
426 | * @nodep: returns node |
427 | * @slotp: returns slot | |
1da177e4 | 428 | * |
139e5616 JW |
429 | * Create, if necessary, and return the node and slot for an item |
430 | * at position @index in the radix tree @root. | |
431 | * | |
432 | * Until there is more than one item in the tree, no nodes are | |
433 | * allocated and @root->rnode is used as a direct slot instead of | |
434 | * pointing to a node, in which case *@nodep will be NULL. | |
435 | * | |
436 | * Returns -ENOMEM, or 0 for success. | |
1da177e4 | 437 | */ |
139e5616 | 438 | int __radix_tree_create(struct radix_tree_root *root, unsigned long index, |
e6145236 MW |
439 | unsigned order, struct radix_tree_node **nodep, |
440 | void ***slotp) | |
1da177e4 | 441 | { |
201b6264 | 442 | struct radix_tree_node *node = NULL, *slot; |
139e5616 | 443 | unsigned int height, shift, offset; |
1da177e4 LT |
444 | int error; |
445 | ||
e6145236 MW |
446 | BUG_ON((0 < order) && (order < RADIX_TREE_MAP_SHIFT)); |
447 | ||
1da177e4 | 448 | /* Make sure the tree is high enough. */ |
612d6c19 | 449 | if (index > radix_tree_maxindex(root->height)) { |
e6145236 | 450 | error = radix_tree_extend(root, index, order); |
1da177e4 LT |
451 | if (error) |
452 | return error; | |
453 | } | |
454 | ||
e6145236 | 455 | slot = root->rnode; |
c0bc9875 | 456 | |
1da177e4 | 457 | height = root->height; |
0070e28d | 458 | shift = height * RADIX_TREE_MAP_SHIFT; |
1da177e4 LT |
459 | |
460 | offset = 0; /* uninitialised var warning */ | |
e6145236 | 461 | while (shift > order) { |
201b6264 | 462 | if (slot == NULL) { |
1da177e4 | 463 | /* Have to add a child node. */ |
201b6264 | 464 | if (!(slot = radix_tree_node_alloc(root))) |
1da177e4 | 465 | return -ENOMEM; |
449dd698 | 466 | slot->path = height; |
e2bdb933 | 467 | slot->parent = node; |
201b6264 | 468 | if (node) { |
339e6353 MW |
469 | rcu_assign_pointer(node->slots[offset], |
470 | ptr_to_indirect(slot)); | |
1da177e4 | 471 | node->count++; |
449dd698 | 472 | slot->path |= offset << RADIX_TREE_HEIGHT_SHIFT; |
201b6264 | 473 | } else |
339e6353 MW |
474 | rcu_assign_pointer(root->rnode, |
475 | ptr_to_indirect(slot)); | |
e6145236 MW |
476 | } else if (!radix_tree_is_indirect_ptr(slot)) |
477 | break; | |
1da177e4 LT |
478 | |
479 | /* Go a level down */ | |
e6145236 | 480 | height--; |
0070e28d | 481 | shift -= RADIX_TREE_MAP_SHIFT; |
1da177e4 | 482 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; |
e6145236 | 483 | node = indirect_to_ptr(slot); |
201b6264 | 484 | slot = node->slots[offset]; |
e6145236 MW |
485 | } |
486 | ||
487 | /* Insert pointers to the canonical entry */ | |
488 | if ((shift - order) > 0) { | |
489 | int i, n = 1 << (shift - order); | |
490 | offset = offset & ~(n - 1); | |
491 | slot = ptr_to_indirect(&node->slots[offset]); | |
492 | for (i = 0; i < n; i++) { | |
493 | if (node->slots[offset + i]) | |
494 | return -EEXIST; | |
495 | } | |
496 | ||
497 | for (i = 1; i < n; i++) { | |
498 | rcu_assign_pointer(node->slots[offset + i], slot); | |
499 | node->count++; | |
500 | } | |
612d6c19 | 501 | } |
1da177e4 | 502 | |
139e5616 JW |
503 | if (nodep) |
504 | *nodep = node; | |
505 | if (slotp) | |
506 | *slotp = node ? node->slots + offset : (void **)&root->rnode; | |
507 | return 0; | |
508 | } | |
509 | ||
510 | /** | |
e6145236 | 511 | * __radix_tree_insert - insert into a radix tree |
139e5616 JW |
512 | * @root: radix tree root |
513 | * @index: index key | |
e6145236 | 514 | * @order: key covers the 2^order indices around index |
139e5616 JW |
515 | * @item: item to insert |
516 | * | |
517 | * Insert an item into the radix tree at position @index. | |
518 | */ | |
e6145236 MW |
519 | int __radix_tree_insert(struct radix_tree_root *root, unsigned long index, |
520 | unsigned order, void *item) | |
139e5616 JW |
521 | { |
522 | struct radix_tree_node *node; | |
523 | void **slot; | |
524 | int error; | |
525 | ||
526 | BUG_ON(radix_tree_is_indirect_ptr(item)); | |
527 | ||
e6145236 | 528 | error = __radix_tree_create(root, index, order, &node, &slot); |
139e5616 JW |
529 | if (error) |
530 | return error; | |
531 | if (*slot != NULL) | |
1da177e4 | 532 | return -EEXIST; |
139e5616 | 533 | rcu_assign_pointer(*slot, item); |
201b6264 | 534 | |
612d6c19 NP |
535 | if (node) { |
536 | node->count++; | |
139e5616 JW |
537 | BUG_ON(tag_get(node, 0, index & RADIX_TREE_MAP_MASK)); |
538 | BUG_ON(tag_get(node, 1, index & RADIX_TREE_MAP_MASK)); | |
612d6c19 | 539 | } else { |
612d6c19 NP |
540 | BUG_ON(root_tag_get(root, 0)); |
541 | BUG_ON(root_tag_get(root, 1)); | |
542 | } | |
1da177e4 | 543 | |
1da177e4 LT |
544 | return 0; |
545 | } | |
e6145236 | 546 | EXPORT_SYMBOL(__radix_tree_insert); |
1da177e4 | 547 | |
139e5616 JW |
548 | /** |
549 | * __radix_tree_lookup - lookup an item in a radix tree | |
550 | * @root: radix tree root | |
551 | * @index: index key | |
552 | * @nodep: returns node | |
553 | * @slotp: returns slot | |
554 | * | |
555 | * Lookup and return the item at position @index in the radix | |
556 | * tree @root. | |
557 | * | |
558 | * Until there is more than one item in the tree, no nodes are | |
559 | * allocated and @root->rnode is used as a direct slot instead of | |
560 | * pointing to a node, in which case *@nodep will be NULL. | |
7cf9c2c7 | 561 | */ |
139e5616 JW |
562 | void *__radix_tree_lookup(struct radix_tree_root *root, unsigned long index, |
563 | struct radix_tree_node **nodep, void ***slotp) | |
1da177e4 | 564 | { |
139e5616 | 565 | struct radix_tree_node *node, *parent; |
1da177e4 | 566 | unsigned int height, shift; |
139e5616 | 567 | void **slot; |
612d6c19 | 568 | |
2676a58c | 569 | node = rcu_dereference_raw(root->rnode); |
7cf9c2c7 | 570 | if (node == NULL) |
1da177e4 LT |
571 | return NULL; |
572 | ||
c0bc9875 | 573 | if (!radix_tree_is_indirect_ptr(node)) { |
7cf9c2c7 NP |
574 | if (index > 0) |
575 | return NULL; | |
139e5616 JW |
576 | |
577 | if (nodep) | |
578 | *nodep = NULL; | |
579 | if (slotp) | |
580 | *slotp = (void **)&root->rnode; | |
581 | return node; | |
7cf9c2c7 | 582 | } |
27d20fdd | 583 | node = indirect_to_ptr(node); |
7cf9c2c7 | 584 | |
449dd698 | 585 | height = node->path & RADIX_TREE_HEIGHT_MASK; |
7cf9c2c7 NP |
586 | if (index > radix_tree_maxindex(height)) |
587 | return NULL; | |
612d6c19 | 588 | |
1da177e4 | 589 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; |
1da177e4 | 590 | |
7cf9c2c7 | 591 | do { |
139e5616 JW |
592 | parent = node; |
593 | slot = node->slots + ((index >> shift) & RADIX_TREE_MAP_MASK); | |
2676a58c | 594 | node = rcu_dereference_raw(*slot); |
7cf9c2c7 | 595 | if (node == NULL) |
1da177e4 | 596 | return NULL; |
e6145236 MW |
597 | if (!radix_tree_is_indirect_ptr(node)) |
598 | break; | |
339e6353 | 599 | node = indirect_to_ptr(node); |
1da177e4 | 600 | |
1da177e4 LT |
601 | shift -= RADIX_TREE_MAP_SHIFT; |
602 | height--; | |
7cf9c2c7 | 603 | } while (height > 0); |
1da177e4 | 604 | |
139e5616 JW |
605 | if (nodep) |
606 | *nodep = parent; | |
607 | if (slotp) | |
608 | *slotp = slot; | |
609 | return node; | |
b72b71c6 HS |
610 | } |
611 | ||
612 | /** | |
613 | * radix_tree_lookup_slot - lookup a slot in a radix tree | |
614 | * @root: radix tree root | |
615 | * @index: index key | |
616 | * | |
617 | * Returns: the slot corresponding to the position @index in the | |
618 | * radix tree @root. This is useful for update-if-exists operations. | |
619 | * | |
620 | * This function can be called under rcu_read_lock iff the slot is not | |
621 | * modified by radix_tree_replace_slot, otherwise it must be called | |
622 | * exclusive from other writers. Any dereference of the slot must be done | |
623 | * using radix_tree_deref_slot. | |
624 | */ | |
625 | void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index) | |
626 | { | |
139e5616 JW |
627 | void **slot; |
628 | ||
629 | if (!__radix_tree_lookup(root, index, NULL, &slot)) | |
630 | return NULL; | |
631 | return slot; | |
a4331366 | 632 | } |
a4331366 HR |
633 | EXPORT_SYMBOL(radix_tree_lookup_slot); |
634 | ||
635 | /** | |
636 | * radix_tree_lookup - perform lookup operation on a radix tree | |
637 | * @root: radix tree root | |
638 | * @index: index key | |
639 | * | |
640 | * Lookup the item at the position @index in the radix tree @root. | |
7cf9c2c7 NP |
641 | * |
642 | * This function can be called under rcu_read_lock, however the caller | |
643 | * must manage lifetimes of leaf nodes (eg. RCU may also be used to free | |
644 | * them safely). No RCU barriers are required to access or modify the | |
645 | * returned item, however. | |
a4331366 HR |
646 | */ |
647 | void *radix_tree_lookup(struct radix_tree_root *root, unsigned long index) | |
648 | { | |
139e5616 | 649 | return __radix_tree_lookup(root, index, NULL, NULL); |
1da177e4 LT |
650 | } |
651 | EXPORT_SYMBOL(radix_tree_lookup); | |
652 | ||
653 | /** | |
654 | * radix_tree_tag_set - set a tag on a radix tree node | |
655 | * @root: radix tree root | |
656 | * @index: index key | |
657 | * @tag: tag index | |
658 | * | |
daff89f3 JC |
659 | * Set the search tag (which must be < RADIX_TREE_MAX_TAGS) |
660 | * corresponding to @index in the radix tree. From | |
1da177e4 LT |
661 | * the root all the way down to the leaf node. |
662 | * | |
663 | * Returns the address of the tagged item. Setting a tag on a not-present | |
664 | * item is a bug. | |
665 | */ | |
666 | void *radix_tree_tag_set(struct radix_tree_root *root, | |
daff89f3 | 667 | unsigned long index, unsigned int tag) |
1da177e4 LT |
668 | { |
669 | unsigned int height, shift; | |
201b6264 | 670 | struct radix_tree_node *slot; |
1da177e4 LT |
671 | |
672 | height = root->height; | |
4c91c364 | 673 | BUG_ON(index > radix_tree_maxindex(height)); |
1da177e4 | 674 | |
27d20fdd | 675 | slot = indirect_to_ptr(root->rnode); |
612d6c19 | 676 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; |
1da177e4 LT |
677 | |
678 | while (height > 0) { | |
679 | int offset; | |
680 | ||
681 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
d5274261 NP |
682 | if (!tag_get(slot, tag, offset)) |
683 | tag_set(slot, tag, offset); | |
201b6264 CL |
684 | slot = slot->slots[offset]; |
685 | BUG_ON(slot == NULL); | |
e6145236 MW |
686 | if (!radix_tree_is_indirect_ptr(slot)) |
687 | break; | |
339e6353 | 688 | slot = indirect_to_ptr(slot); |
1da177e4 LT |
689 | shift -= RADIX_TREE_MAP_SHIFT; |
690 | height--; | |
691 | } | |
692 | ||
612d6c19 NP |
693 | /* set the root's tag bit */ |
694 | if (slot && !root_tag_get(root, tag)) | |
695 | root_tag_set(root, tag); | |
696 | ||
201b6264 | 697 | return slot; |
1da177e4 LT |
698 | } |
699 | EXPORT_SYMBOL(radix_tree_tag_set); | |
700 | ||
701 | /** | |
702 | * radix_tree_tag_clear - clear a tag on a radix tree node | |
703 | * @root: radix tree root | |
704 | * @index: index key | |
705 | * @tag: tag index | |
706 | * | |
daff89f3 JC |
707 | * Clear the search tag (which must be < RADIX_TREE_MAX_TAGS) |
708 | * corresponding to @index in the radix tree. If | |
1da177e4 LT |
709 | * this causes the leaf node to have no tags set then clear the tag in the |
710 | * next-to-leaf node, etc. | |
711 | * | |
712 | * Returns the address of the tagged item on success, else NULL. ie: | |
713 | * has the same return value and semantics as radix_tree_lookup(). | |
714 | */ | |
715 | void *radix_tree_tag_clear(struct radix_tree_root *root, | |
daff89f3 | 716 | unsigned long index, unsigned int tag) |
1da177e4 | 717 | { |
e2bdb933 | 718 | struct radix_tree_node *node = NULL; |
612d6c19 | 719 | struct radix_tree_node *slot = NULL; |
1da177e4 | 720 | unsigned int height, shift; |
e2bdb933 | 721 | int uninitialized_var(offset); |
1da177e4 LT |
722 | |
723 | height = root->height; | |
724 | if (index > radix_tree_maxindex(height)) | |
725 | goto out; | |
726 | ||
e2bdb933 | 727 | shift = height * RADIX_TREE_MAP_SHIFT; |
339e6353 | 728 | slot = root->rnode; |
1da177e4 | 729 | |
e2bdb933 | 730 | while (shift) { |
201b6264 | 731 | if (slot == NULL) |
1da177e4 | 732 | goto out; |
e6145236 MW |
733 | if (!radix_tree_is_indirect_ptr(slot)) |
734 | break; | |
339e6353 | 735 | slot = indirect_to_ptr(slot); |
1da177e4 | 736 | |
e2bdb933 | 737 | shift -= RADIX_TREE_MAP_SHIFT; |
1da177e4 | 738 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; |
e2bdb933 | 739 | node = slot; |
201b6264 | 740 | slot = slot->slots[offset]; |
1da177e4 LT |
741 | } |
742 | ||
612d6c19 | 743 | if (slot == NULL) |
1da177e4 LT |
744 | goto out; |
745 | ||
e2bdb933 HD |
746 | while (node) { |
747 | if (!tag_get(node, tag, offset)) | |
d5274261 | 748 | goto out; |
e2bdb933 HD |
749 | tag_clear(node, tag, offset); |
750 | if (any_tag_set(node, tag)) | |
6e954b9e | 751 | goto out; |
e2bdb933 HD |
752 | |
753 | index >>= RADIX_TREE_MAP_SHIFT; | |
754 | offset = index & RADIX_TREE_MAP_MASK; | |
755 | node = node->parent; | |
612d6c19 NP |
756 | } |
757 | ||
758 | /* clear the root's tag bit */ | |
759 | if (root_tag_get(root, tag)) | |
760 | root_tag_clear(root, tag); | |
761 | ||
1da177e4 | 762 | out: |
612d6c19 | 763 | return slot; |
1da177e4 LT |
764 | } |
765 | EXPORT_SYMBOL(radix_tree_tag_clear); | |
766 | ||
1da177e4 | 767 | /** |
32605a18 MT |
768 | * radix_tree_tag_get - get a tag on a radix tree node |
769 | * @root: radix tree root | |
770 | * @index: index key | |
daff89f3 | 771 | * @tag: tag index (< RADIX_TREE_MAX_TAGS) |
1da177e4 | 772 | * |
32605a18 | 773 | * Return values: |
1da177e4 | 774 | * |
612d6c19 NP |
775 | * 0: tag not present or not set |
776 | * 1: tag set | |
ce82653d DH |
777 | * |
778 | * Note that the return value of this function may not be relied on, even if | |
779 | * the RCU lock is held, unless tag modification and node deletion are excluded | |
780 | * from concurrency. | |
1da177e4 LT |
781 | */ |
782 | int radix_tree_tag_get(struct radix_tree_root *root, | |
daff89f3 | 783 | unsigned long index, unsigned int tag) |
1da177e4 LT |
784 | { |
785 | unsigned int height, shift; | |
7cf9c2c7 | 786 | struct radix_tree_node *node; |
1da177e4 | 787 | |
612d6c19 NP |
788 | /* check the root's tag bit */ |
789 | if (!root_tag_get(root, tag)) | |
790 | return 0; | |
791 | ||
2676a58c | 792 | node = rcu_dereference_raw(root->rnode); |
7cf9c2c7 NP |
793 | if (node == NULL) |
794 | return 0; | |
795 | ||
c0bc9875 | 796 | if (!radix_tree_is_indirect_ptr(node)) |
7cf9c2c7 | 797 | return (index == 0); |
27d20fdd | 798 | node = indirect_to_ptr(node); |
7cf9c2c7 | 799 | |
449dd698 | 800 | height = node->path & RADIX_TREE_HEIGHT_MASK; |
7cf9c2c7 NP |
801 | if (index > radix_tree_maxindex(height)) |
802 | return 0; | |
612d6c19 | 803 | |
1da177e4 | 804 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; |
1da177e4 LT |
805 | |
806 | for ( ; ; ) { | |
807 | int offset; | |
808 | ||
7cf9c2c7 | 809 | if (node == NULL) |
1da177e4 | 810 | return 0; |
339e6353 | 811 | node = indirect_to_ptr(node); |
1da177e4 LT |
812 | |
813 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
7cf9c2c7 | 814 | if (!tag_get(node, tag, offset)) |
3fa36acb | 815 | return 0; |
ce82653d | 816 | if (height == 1) |
3fa36acb | 817 | return 1; |
2676a58c | 818 | node = rcu_dereference_raw(node->slots[offset]); |
e6145236 MW |
819 | if (!radix_tree_is_indirect_ptr(node)) |
820 | return 1; | |
1da177e4 LT |
821 | shift -= RADIX_TREE_MAP_SHIFT; |
822 | height--; | |
823 | } | |
824 | } | |
825 | EXPORT_SYMBOL(radix_tree_tag_get); | |
1da177e4 | 826 | |
78c1d784 KK |
827 | /** |
828 | * radix_tree_next_chunk - find next chunk of slots for iteration | |
829 | * | |
830 | * @root: radix tree root | |
831 | * @iter: iterator state | |
832 | * @flags: RADIX_TREE_ITER_* flags and tag index | |
833 | * Returns: pointer to chunk first slot, or NULL if iteration is over | |
834 | */ | |
835 | void **radix_tree_next_chunk(struct radix_tree_root *root, | |
836 | struct radix_tree_iter *iter, unsigned flags) | |
837 | { | |
838 | unsigned shift, tag = flags & RADIX_TREE_ITER_TAG_MASK; | |
839 | struct radix_tree_node *rnode, *node; | |
449dd698 | 840 | unsigned long index, offset, height; |
78c1d784 KK |
841 | |
842 | if ((flags & RADIX_TREE_ITER_TAGGED) && !root_tag_get(root, tag)) | |
843 | return NULL; | |
844 | ||
845 | /* | |
846 | * Catch next_index overflow after ~0UL. iter->index never overflows | |
847 | * during iterating; it can be zero only at the beginning. | |
848 | * And we cannot overflow iter->next_index in a single step, | |
849 | * because RADIX_TREE_MAP_SHIFT < BITS_PER_LONG. | |
fffaee36 KK |
850 | * |
851 | * This condition also used by radix_tree_next_slot() to stop | |
852 | * contiguous iterating, and forbid swithing to the next chunk. | |
78c1d784 KK |
853 | */ |
854 | index = iter->next_index; | |
855 | if (!index && iter->index) | |
856 | return NULL; | |
857 | ||
858 | rnode = rcu_dereference_raw(root->rnode); | |
859 | if (radix_tree_is_indirect_ptr(rnode)) { | |
860 | rnode = indirect_to_ptr(rnode); | |
861 | } else if (rnode && !index) { | |
862 | /* Single-slot tree */ | |
863 | iter->index = 0; | |
864 | iter->next_index = 1; | |
865 | iter->tags = 1; | |
866 | return (void **)&root->rnode; | |
867 | } else | |
868 | return NULL; | |
869 | ||
870 | restart: | |
449dd698 JW |
871 | height = rnode->path & RADIX_TREE_HEIGHT_MASK; |
872 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; | |
78c1d784 KK |
873 | offset = index >> shift; |
874 | ||
875 | /* Index outside of the tree */ | |
876 | if (offset >= RADIX_TREE_MAP_SIZE) | |
877 | return NULL; | |
878 | ||
879 | node = rnode; | |
880 | while (1) { | |
e6145236 | 881 | struct radix_tree_node *slot; |
78c1d784 KK |
882 | if ((flags & RADIX_TREE_ITER_TAGGED) ? |
883 | !test_bit(offset, node->tags[tag]) : | |
884 | !node->slots[offset]) { | |
885 | /* Hole detected */ | |
886 | if (flags & RADIX_TREE_ITER_CONTIG) | |
887 | return NULL; | |
888 | ||
889 | if (flags & RADIX_TREE_ITER_TAGGED) | |
890 | offset = radix_tree_find_next_bit( | |
891 | node->tags[tag], | |
892 | RADIX_TREE_MAP_SIZE, | |
893 | offset + 1); | |
894 | else | |
895 | while (++offset < RADIX_TREE_MAP_SIZE) { | |
896 | if (node->slots[offset]) | |
897 | break; | |
898 | } | |
899 | index &= ~((RADIX_TREE_MAP_SIZE << shift) - 1); | |
900 | index += offset << shift; | |
901 | /* Overflow after ~0UL */ | |
902 | if (!index) | |
903 | return NULL; | |
904 | if (offset == RADIX_TREE_MAP_SIZE) | |
905 | goto restart; | |
906 | } | |
907 | ||
908 | /* This is leaf-node */ | |
909 | if (!shift) | |
910 | break; | |
911 | ||
e6145236 MW |
912 | slot = rcu_dereference_raw(node->slots[offset]); |
913 | if (slot == NULL) | |
78c1d784 | 914 | goto restart; |
e6145236 MW |
915 | if (!radix_tree_is_indirect_ptr(slot)) |
916 | break; | |
917 | node = indirect_to_ptr(slot); | |
78c1d784 KK |
918 | shift -= RADIX_TREE_MAP_SHIFT; |
919 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
920 | } | |
921 | ||
922 | /* Update the iterator state */ | |
923 | iter->index = index; | |
924 | iter->next_index = (index | RADIX_TREE_MAP_MASK) + 1; | |
925 | ||
926 | /* Construct iter->tags bit-mask from node->tags[tag] array */ | |
927 | if (flags & RADIX_TREE_ITER_TAGGED) { | |
928 | unsigned tag_long, tag_bit; | |
929 | ||
930 | tag_long = offset / BITS_PER_LONG; | |
931 | tag_bit = offset % BITS_PER_LONG; | |
932 | iter->tags = node->tags[tag][tag_long] >> tag_bit; | |
933 | /* This never happens if RADIX_TREE_TAG_LONGS == 1 */ | |
934 | if (tag_long < RADIX_TREE_TAG_LONGS - 1) { | |
935 | /* Pick tags from next element */ | |
936 | if (tag_bit) | |
937 | iter->tags |= node->tags[tag][tag_long + 1] << | |
938 | (BITS_PER_LONG - tag_bit); | |
939 | /* Clip chunk size, here only BITS_PER_LONG tags */ | |
940 | iter->next_index = index + BITS_PER_LONG; | |
941 | } | |
942 | } | |
943 | ||
944 | return node->slots + offset; | |
945 | } | |
946 | EXPORT_SYMBOL(radix_tree_next_chunk); | |
947 | ||
ebf8aa44 JK |
948 | /** |
949 | * radix_tree_range_tag_if_tagged - for each item in given range set given | |
950 | * tag if item has another tag set | |
951 | * @root: radix tree root | |
952 | * @first_indexp: pointer to a starting index of a range to scan | |
953 | * @last_index: last index of a range to scan | |
954 | * @nr_to_tag: maximum number items to tag | |
955 | * @iftag: tag index to test | |
956 | * @settag: tag index to set if tested tag is set | |
957 | * | |
958 | * This function scans range of radix tree from first_index to last_index | |
959 | * (inclusive). For each item in the range if iftag is set, the function sets | |
960 | * also settag. The function stops either after tagging nr_to_tag items or | |
961 | * after reaching last_index. | |
962 | * | |
144dcfc0 DC |
963 | * The tags must be set from the leaf level only and propagated back up the |
964 | * path to the root. We must do this so that we resolve the full path before | |
965 | * setting any tags on intermediate nodes. If we set tags as we descend, then | |
966 | * we can get to the leaf node and find that the index that has the iftag | |
967 | * set is outside the range we are scanning. This reults in dangling tags and | |
968 | * can lead to problems with later tag operations (e.g. livelocks on lookups). | |
969 | * | |
ebf8aa44 JK |
970 | * The function returns number of leaves where the tag was set and sets |
971 | * *first_indexp to the first unscanned index. | |
d5ed3a4a JK |
972 | * WARNING! *first_indexp can wrap if last_index is ULONG_MAX. Caller must |
973 | * be prepared to handle that. | |
ebf8aa44 JK |
974 | */ |
975 | unsigned long radix_tree_range_tag_if_tagged(struct radix_tree_root *root, | |
976 | unsigned long *first_indexp, unsigned long last_index, | |
977 | unsigned long nr_to_tag, | |
978 | unsigned int iftag, unsigned int settag) | |
979 | { | |
144dcfc0 | 980 | unsigned int height = root->height; |
e2bdb933 | 981 | struct radix_tree_node *node = NULL; |
144dcfc0 DC |
982 | struct radix_tree_node *slot; |
983 | unsigned int shift; | |
984 | unsigned long tagged = 0; | |
985 | unsigned long index = *first_indexp; | |
ebf8aa44 JK |
986 | |
987 | last_index = min(last_index, radix_tree_maxindex(height)); | |
988 | if (index > last_index) | |
989 | return 0; | |
990 | if (!nr_to_tag) | |
991 | return 0; | |
992 | if (!root_tag_get(root, iftag)) { | |
993 | *first_indexp = last_index + 1; | |
994 | return 0; | |
995 | } | |
996 | if (height == 0) { | |
997 | *first_indexp = last_index + 1; | |
998 | root_tag_set(root, settag); | |
999 | return 1; | |
1000 | } | |
1001 | ||
1002 | shift = (height - 1) * RADIX_TREE_MAP_SHIFT; | |
27d20fdd | 1003 | slot = indirect_to_ptr(root->rnode); |
ebf8aa44 JK |
1004 | |
1005 | for (;;) { | |
e2bdb933 | 1006 | unsigned long upindex; |
ebf8aa44 JK |
1007 | int offset; |
1008 | ||
1009 | offset = (index >> shift) & RADIX_TREE_MAP_MASK; | |
1010 | if (!slot->slots[offset]) | |
1011 | goto next; | |
1012 | if (!tag_get(slot, iftag, offset)) | |
1013 | goto next; | |
e2bdb933 | 1014 | if (shift) { |
e2bdb933 | 1015 | node = slot; |
144dcfc0 | 1016 | slot = slot->slots[offset]; |
e6145236 MW |
1017 | if (radix_tree_is_indirect_ptr(slot)) { |
1018 | slot = indirect_to_ptr(slot); | |
1019 | shift -= RADIX_TREE_MAP_SHIFT; | |
1020 | continue; | |
1021 | } else { | |
1022 | slot = node; | |
1023 | node = node->parent; | |
1024 | } | |
144dcfc0 DC |
1025 | } |
1026 | ||
1027 | /* tag the leaf */ | |
e6145236 | 1028 | tagged += 1 << shift; |
ebf8aa44 | 1029 | tag_set(slot, settag, offset); |
144dcfc0 DC |
1030 | |
1031 | /* walk back up the path tagging interior nodes */ | |
e2bdb933 HD |
1032 | upindex = index; |
1033 | while (node) { | |
1034 | upindex >>= RADIX_TREE_MAP_SHIFT; | |
1035 | offset = upindex & RADIX_TREE_MAP_MASK; | |
1036 | ||
144dcfc0 | 1037 | /* stop if we find a node with the tag already set */ |
e2bdb933 | 1038 | if (tag_get(node, settag, offset)) |
144dcfc0 | 1039 | break; |
e2bdb933 HD |
1040 | tag_set(node, settag, offset); |
1041 | node = node->parent; | |
ebf8aa44 | 1042 | } |
144dcfc0 | 1043 | |
e2bdb933 HD |
1044 | /* |
1045 | * Small optimization: now clear that node pointer. | |
1046 | * Since all of this slot's ancestors now have the tag set | |
1047 | * from setting it above, we have no further need to walk | |
1048 | * back up the tree setting tags, until we update slot to | |
1049 | * point to another radix_tree_node. | |
1050 | */ | |
1051 | node = NULL; | |
1052 | ||
ebf8aa44 JK |
1053 | next: |
1054 | /* Go to next item at level determined by 'shift' */ | |
1055 | index = ((index >> shift) + 1) << shift; | |
d5ed3a4a JK |
1056 | /* Overflow can happen when last_index is ~0UL... */ |
1057 | if (index > last_index || !index) | |
ebf8aa44 JK |
1058 | break; |
1059 | if (tagged >= nr_to_tag) | |
1060 | break; | |
1061 | while (((index >> shift) & RADIX_TREE_MAP_MASK) == 0) { | |
1062 | /* | |
1063 | * We've fully scanned this node. Go up. Because | |
1064 | * last_index is guaranteed to be in the tree, what | |
1065 | * we do below cannot wander astray. | |
1066 | */ | |
e2bdb933 | 1067 | slot = slot->parent; |
ebf8aa44 JK |
1068 | shift += RADIX_TREE_MAP_SHIFT; |
1069 | } | |
1070 | } | |
1071 | /* | |
ac15ee69 TO |
1072 | * We need not to tag the root tag if there is no tag which is set with |
1073 | * settag within the range from *first_indexp to last_index. | |
ebf8aa44 | 1074 | */ |
ac15ee69 TO |
1075 | if (tagged > 0) |
1076 | root_tag_set(root, settag); | |
ebf8aa44 JK |
1077 | *first_indexp = index; |
1078 | ||
1079 | return tagged; | |
1080 | } | |
1081 | EXPORT_SYMBOL(radix_tree_range_tag_if_tagged); | |
1082 | ||
1da177e4 LT |
1083 | /** |
1084 | * radix_tree_gang_lookup - perform multiple lookup on a radix tree | |
1085 | * @root: radix tree root | |
1086 | * @results: where the results of the lookup are placed | |
1087 | * @first_index: start the lookup from this key | |
1088 | * @max_items: place up to this many items at *results | |
1089 | * | |
1090 | * Performs an index-ascending scan of the tree for present items. Places | |
1091 | * them at *@results and returns the number of items which were placed at | |
1092 | * *@results. | |
1093 | * | |
1094 | * The implementation is naive. | |
7cf9c2c7 NP |
1095 | * |
1096 | * Like radix_tree_lookup, radix_tree_gang_lookup may be called under | |
1097 | * rcu_read_lock. In this case, rather than the returned results being | |
1098 | * an atomic snapshot of the tree at a single point in time, the semantics | |
1099 | * of an RCU protected gang lookup are as though multiple radix_tree_lookups | |
1100 | * have been issued in individual locks, and results stored in 'results'. | |
1da177e4 LT |
1101 | */ |
1102 | unsigned int | |
1103 | radix_tree_gang_lookup(struct radix_tree_root *root, void **results, | |
1104 | unsigned long first_index, unsigned int max_items) | |
1105 | { | |
cebbd29e KK |
1106 | struct radix_tree_iter iter; |
1107 | void **slot; | |
1108 | unsigned int ret = 0; | |
7cf9c2c7 | 1109 | |
cebbd29e | 1110 | if (unlikely(!max_items)) |
7cf9c2c7 | 1111 | return 0; |
1da177e4 | 1112 | |
cebbd29e | 1113 | radix_tree_for_each_slot(slot, root, &iter, first_index) { |
46437f9a | 1114 | results[ret] = rcu_dereference_raw(*slot); |
cebbd29e KK |
1115 | if (!results[ret]) |
1116 | continue; | |
46437f9a MW |
1117 | if (radix_tree_is_indirect_ptr(results[ret])) { |
1118 | slot = radix_tree_iter_retry(&iter); | |
1119 | continue; | |
1120 | } | |
cebbd29e | 1121 | if (++ret == max_items) |
1da177e4 | 1122 | break; |
1da177e4 | 1123 | } |
7cf9c2c7 | 1124 | |
1da177e4 LT |
1125 | return ret; |
1126 | } | |
1127 | EXPORT_SYMBOL(radix_tree_gang_lookup); | |
1128 | ||
47feff2c NP |
1129 | /** |
1130 | * radix_tree_gang_lookup_slot - perform multiple slot lookup on radix tree | |
1131 | * @root: radix tree root | |
1132 | * @results: where the results of the lookup are placed | |
6328650b | 1133 | * @indices: where their indices should be placed (but usually NULL) |
47feff2c NP |
1134 | * @first_index: start the lookup from this key |
1135 | * @max_items: place up to this many items at *results | |
1136 | * | |
1137 | * Performs an index-ascending scan of the tree for present items. Places | |
1138 | * their slots at *@results and returns the number of items which were | |
1139 | * placed at *@results. | |
1140 | * | |
1141 | * The implementation is naive. | |
1142 | * | |
1143 | * Like radix_tree_gang_lookup as far as RCU and locking goes. Slots must | |
1144 | * be dereferenced with radix_tree_deref_slot, and if using only RCU | |
1145 | * protection, radix_tree_deref_slot may fail requiring a retry. | |
1146 | */ | |
1147 | unsigned int | |
6328650b HD |
1148 | radix_tree_gang_lookup_slot(struct radix_tree_root *root, |
1149 | void ***results, unsigned long *indices, | |
47feff2c NP |
1150 | unsigned long first_index, unsigned int max_items) |
1151 | { | |
cebbd29e KK |
1152 | struct radix_tree_iter iter; |
1153 | void **slot; | |
1154 | unsigned int ret = 0; | |
47feff2c | 1155 | |
cebbd29e | 1156 | if (unlikely(!max_items)) |
47feff2c NP |
1157 | return 0; |
1158 | ||
cebbd29e KK |
1159 | radix_tree_for_each_slot(slot, root, &iter, first_index) { |
1160 | results[ret] = slot; | |
6328650b | 1161 | if (indices) |
cebbd29e KK |
1162 | indices[ret] = iter.index; |
1163 | if (++ret == max_items) | |
47feff2c | 1164 | break; |
47feff2c NP |
1165 | } |
1166 | ||
1167 | return ret; | |
1168 | } | |
1169 | EXPORT_SYMBOL(radix_tree_gang_lookup_slot); | |
1170 | ||
1da177e4 LT |
1171 | /** |
1172 | * radix_tree_gang_lookup_tag - perform multiple lookup on a radix tree | |
1173 | * based on a tag | |
1174 | * @root: radix tree root | |
1175 | * @results: where the results of the lookup are placed | |
1176 | * @first_index: start the lookup from this key | |
1177 | * @max_items: place up to this many items at *results | |
daff89f3 | 1178 | * @tag: the tag index (< RADIX_TREE_MAX_TAGS) |
1da177e4 LT |
1179 | * |
1180 | * Performs an index-ascending scan of the tree for present items which | |
1181 | * have the tag indexed by @tag set. Places the items at *@results and | |
1182 | * returns the number of items which were placed at *@results. | |
1183 | */ | |
1184 | unsigned int | |
1185 | radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results, | |
daff89f3 JC |
1186 | unsigned long first_index, unsigned int max_items, |
1187 | unsigned int tag) | |
1da177e4 | 1188 | { |
cebbd29e KK |
1189 | struct radix_tree_iter iter; |
1190 | void **slot; | |
1191 | unsigned int ret = 0; | |
612d6c19 | 1192 | |
cebbd29e | 1193 | if (unlikely(!max_items)) |
7cf9c2c7 NP |
1194 | return 0; |
1195 | ||
cebbd29e | 1196 | radix_tree_for_each_tagged(slot, root, &iter, first_index, tag) { |
46437f9a | 1197 | results[ret] = rcu_dereference_raw(*slot); |
cebbd29e KK |
1198 | if (!results[ret]) |
1199 | continue; | |
46437f9a MW |
1200 | if (radix_tree_is_indirect_ptr(results[ret])) { |
1201 | slot = radix_tree_iter_retry(&iter); | |
1202 | continue; | |
1203 | } | |
cebbd29e | 1204 | if (++ret == max_items) |
1da177e4 | 1205 | break; |
1da177e4 | 1206 | } |
7cf9c2c7 | 1207 | |
1da177e4 LT |
1208 | return ret; |
1209 | } | |
1210 | EXPORT_SYMBOL(radix_tree_gang_lookup_tag); | |
1211 | ||
47feff2c NP |
1212 | /** |
1213 | * radix_tree_gang_lookup_tag_slot - perform multiple slot lookup on a | |
1214 | * radix tree based on a tag | |
1215 | * @root: radix tree root | |
1216 | * @results: where the results of the lookup are placed | |
1217 | * @first_index: start the lookup from this key | |
1218 | * @max_items: place up to this many items at *results | |
1219 | * @tag: the tag index (< RADIX_TREE_MAX_TAGS) | |
1220 | * | |
1221 | * Performs an index-ascending scan of the tree for present items which | |
1222 | * have the tag indexed by @tag set. Places the slots at *@results and | |
1223 | * returns the number of slots which were placed at *@results. | |
1224 | */ | |
1225 | unsigned int | |
1226 | radix_tree_gang_lookup_tag_slot(struct radix_tree_root *root, void ***results, | |
1227 | unsigned long first_index, unsigned int max_items, | |
1228 | unsigned int tag) | |
1229 | { | |
cebbd29e KK |
1230 | struct radix_tree_iter iter; |
1231 | void **slot; | |
1232 | unsigned int ret = 0; | |
47feff2c | 1233 | |
cebbd29e | 1234 | if (unlikely(!max_items)) |
47feff2c NP |
1235 | return 0; |
1236 | ||
cebbd29e KK |
1237 | radix_tree_for_each_tagged(slot, root, &iter, first_index, tag) { |
1238 | results[ret] = slot; | |
1239 | if (++ret == max_items) | |
47feff2c | 1240 | break; |
47feff2c NP |
1241 | } |
1242 | ||
1243 | return ret; | |
1244 | } | |
1245 | EXPORT_SYMBOL(radix_tree_gang_lookup_tag_slot); | |
1246 | ||
e504f3fd HD |
1247 | #if defined(CONFIG_SHMEM) && defined(CONFIG_SWAP) |
1248 | #include <linux/sched.h> /* for cond_resched() */ | |
1249 | ||
1250 | /* | |
1251 | * This linear search is at present only useful to shmem_unuse_inode(). | |
1252 | */ | |
1253 | static unsigned long __locate(struct radix_tree_node *slot, void *item, | |
1254 | unsigned long index, unsigned long *found_index) | |
1255 | { | |
1256 | unsigned int shift, height; | |
1257 | unsigned long i; | |
1258 | ||
449dd698 | 1259 | height = slot->path & RADIX_TREE_HEIGHT_MASK; |
e504f3fd HD |
1260 | shift = (height-1) * RADIX_TREE_MAP_SHIFT; |
1261 | ||
1262 | for ( ; height > 1; height--) { | |
1263 | i = (index >> shift) & RADIX_TREE_MAP_MASK; | |
1264 | for (;;) { | |
1265 | if (slot->slots[i] != NULL) | |
1266 | break; | |
1267 | index &= ~((1UL << shift) - 1); | |
1268 | index += 1UL << shift; | |
1269 | if (index == 0) | |
1270 | goto out; /* 32-bit wraparound */ | |
1271 | i++; | |
1272 | if (i == RADIX_TREE_MAP_SIZE) | |
1273 | goto out; | |
1274 | } | |
1275 | ||
e504f3fd HD |
1276 | slot = rcu_dereference_raw(slot->slots[i]); |
1277 | if (slot == NULL) | |
1278 | goto out; | |
e6145236 MW |
1279 | if (!radix_tree_is_indirect_ptr(slot)) { |
1280 | if (slot == item) { | |
1281 | *found_index = index + i; | |
1282 | index = 0; | |
1283 | } else { | |
1284 | index += shift; | |
1285 | } | |
1286 | goto out; | |
1287 | } | |
339e6353 | 1288 | slot = indirect_to_ptr(slot); |
e6145236 | 1289 | shift -= RADIX_TREE_MAP_SHIFT; |
e504f3fd HD |
1290 | } |
1291 | ||
1292 | /* Bottom level: check items */ | |
1293 | for (i = 0; i < RADIX_TREE_MAP_SIZE; i++) { | |
1294 | if (slot->slots[i] == item) { | |
1295 | *found_index = index + i; | |
1296 | index = 0; | |
1297 | goto out; | |
1298 | } | |
1299 | } | |
1300 | index += RADIX_TREE_MAP_SIZE; | |
1301 | out: | |
1302 | return index; | |
1303 | } | |
1304 | ||
1305 | /** | |
1306 | * radix_tree_locate_item - search through radix tree for item | |
1307 | * @root: radix tree root | |
1308 | * @item: item to be found | |
1309 | * | |
1310 | * Returns index where item was found, or -1 if not found. | |
1311 | * Caller must hold no lock (since this time-consuming function needs | |
1312 | * to be preemptible), and must check afterwards if item is still there. | |
1313 | */ | |
1314 | unsigned long radix_tree_locate_item(struct radix_tree_root *root, void *item) | |
1315 | { | |
1316 | struct radix_tree_node *node; | |
1317 | unsigned long max_index; | |
1318 | unsigned long cur_index = 0; | |
1319 | unsigned long found_index = -1; | |
1320 | ||
1321 | do { | |
1322 | rcu_read_lock(); | |
1323 | node = rcu_dereference_raw(root->rnode); | |
1324 | if (!radix_tree_is_indirect_ptr(node)) { | |
1325 | rcu_read_unlock(); | |
1326 | if (node == item) | |
1327 | found_index = 0; | |
1328 | break; | |
1329 | } | |
1330 | ||
1331 | node = indirect_to_ptr(node); | |
449dd698 JW |
1332 | max_index = radix_tree_maxindex(node->path & |
1333 | RADIX_TREE_HEIGHT_MASK); | |
5f30fc94 HD |
1334 | if (cur_index > max_index) { |
1335 | rcu_read_unlock(); | |
e504f3fd | 1336 | break; |
5f30fc94 | 1337 | } |
e504f3fd HD |
1338 | |
1339 | cur_index = __locate(node, item, cur_index, &found_index); | |
1340 | rcu_read_unlock(); | |
1341 | cond_resched(); | |
1342 | } while (cur_index != 0 && cur_index <= max_index); | |
1343 | ||
1344 | return found_index; | |
1345 | } | |
1346 | #else | |
1347 | unsigned long radix_tree_locate_item(struct radix_tree_root *root, void *item) | |
1348 | { | |
1349 | return -1; | |
1350 | } | |
1351 | #endif /* CONFIG_SHMEM && CONFIG_SWAP */ | |
47feff2c | 1352 | |
a5f51c96 NP |
1353 | /** |
1354 | * radix_tree_shrink - shrink height of a radix tree to minimal | |
1355 | * @root radix tree root | |
1356 | */ | |
1357 | static inline void radix_tree_shrink(struct radix_tree_root *root) | |
1358 | { | |
1359 | /* try to shrink tree height */ | |
c0bc9875 | 1360 | while (root->height > 0) { |
a5f51c96 | 1361 | struct radix_tree_node *to_free = root->rnode; |
e2bdb933 | 1362 | struct radix_tree_node *slot; |
a5f51c96 | 1363 | |
c0bc9875 | 1364 | BUG_ON(!radix_tree_is_indirect_ptr(to_free)); |
27d20fdd | 1365 | to_free = indirect_to_ptr(to_free); |
c0bc9875 NP |
1366 | |
1367 | /* | |
1368 | * The candidate node has more than one child, or its child | |
e6145236 MW |
1369 | * is not at the leftmost slot, or it is a multiorder entry, |
1370 | * we cannot shrink. | |
c0bc9875 NP |
1371 | */ |
1372 | if (to_free->count != 1) | |
1373 | break; | |
339e6353 MW |
1374 | slot = to_free->slots[0]; |
1375 | if (!slot) | |
c0bc9875 NP |
1376 | break; |
1377 | ||
7cf9c2c7 NP |
1378 | /* |
1379 | * We don't need rcu_assign_pointer(), since we are simply | |
27d20fdd NP |
1380 | * moving the node from one part of the tree to another: if it |
1381 | * was safe to dereference the old pointer to it | |
7cf9c2c7 | 1382 | * (to_free->slots[0]), it will be safe to dereference the new |
27d20fdd | 1383 | * one (root->rnode) as far as dependent read barriers go. |
7cf9c2c7 | 1384 | */ |
e2bdb933 | 1385 | if (root->height > 1) { |
e6145236 MW |
1386 | if (!radix_tree_is_indirect_ptr(slot)) |
1387 | break; | |
1388 | ||
339e6353 | 1389 | slot = indirect_to_ptr(slot); |
e2bdb933 HD |
1390 | slot->parent = NULL; |
1391 | slot = ptr_to_indirect(slot); | |
1392 | } | |
1393 | root->rnode = slot; | |
a5f51c96 | 1394 | root->height--; |
27d20fdd NP |
1395 | |
1396 | /* | |
1397 | * We have a dilemma here. The node's slot[0] must not be | |
1398 | * NULLed in case there are concurrent lookups expecting to | |
1399 | * find the item. However if this was a bottom-level node, | |
1400 | * then it may be subject to the slot pointer being visible | |
1401 | * to callers dereferencing it. If item corresponding to | |
1402 | * slot[0] is subsequently deleted, these callers would expect | |
1403 | * their slot to become empty sooner or later. | |
1404 | * | |
1405 | * For example, lockless pagecache will look up a slot, deref | |
1406 | * the page pointer, and if the page is 0 refcount it means it | |
1407 | * was concurrently deleted from pagecache so try the deref | |
1408 | * again. Fortunately there is already a requirement for logic | |
1409 | * to retry the entire slot lookup -- the indirect pointer | |
1410 | * problem (replacing direct root node with an indirect pointer | |
1411 | * also results in a stale slot). So tag the slot as indirect | |
1412 | * to force callers to retry. | |
1413 | */ | |
1414 | if (root->height == 0) | |
1415 | *((unsigned long *)&to_free->slots[0]) |= | |
1416 | RADIX_TREE_INDIRECT_PTR; | |
1417 | ||
a5f51c96 NP |
1418 | radix_tree_node_free(to_free); |
1419 | } | |
1420 | } | |
1421 | ||
139e5616 JW |
1422 | /** |
1423 | * __radix_tree_delete_node - try to free node after clearing a slot | |
1424 | * @root: radix tree root | |
139e5616 JW |
1425 | * @node: node containing @index |
1426 | * | |
1427 | * After clearing the slot at @index in @node from radix tree | |
1428 | * rooted at @root, call this function to attempt freeing the | |
1429 | * node and shrinking the tree. | |
1430 | * | |
1431 | * Returns %true if @node was freed, %false otherwise. | |
1432 | */ | |
449dd698 | 1433 | bool __radix_tree_delete_node(struct radix_tree_root *root, |
139e5616 JW |
1434 | struct radix_tree_node *node) |
1435 | { | |
1436 | bool deleted = false; | |
1437 | ||
1438 | do { | |
1439 | struct radix_tree_node *parent; | |
1440 | ||
1441 | if (node->count) { | |
1442 | if (node == indirect_to_ptr(root->rnode)) { | |
1443 | radix_tree_shrink(root); | |
1444 | if (root->height == 0) | |
1445 | deleted = true; | |
1446 | } | |
1447 | return deleted; | |
1448 | } | |
1449 | ||
1450 | parent = node->parent; | |
1451 | if (parent) { | |
449dd698 | 1452 | unsigned int offset; |
139e5616 | 1453 | |
449dd698 JW |
1454 | offset = node->path >> RADIX_TREE_HEIGHT_SHIFT; |
1455 | parent->slots[offset] = NULL; | |
139e5616 JW |
1456 | parent->count--; |
1457 | } else { | |
1458 | root_tag_clear_all(root); | |
1459 | root->height = 0; | |
1460 | root->rnode = NULL; | |
1461 | } | |
1462 | ||
1463 | radix_tree_node_free(node); | |
1464 | deleted = true; | |
1465 | ||
1466 | node = parent; | |
1467 | } while (node); | |
1468 | ||
1469 | return deleted; | |
1470 | } | |
1471 | ||
1da177e4 | 1472 | /** |
53c59f26 | 1473 | * radix_tree_delete_item - delete an item from a radix tree |
1da177e4 LT |
1474 | * @root: radix tree root |
1475 | * @index: index key | |
53c59f26 | 1476 | * @item: expected item |
1da177e4 | 1477 | * |
53c59f26 | 1478 | * Remove @item at @index from the radix tree rooted at @root. |
1da177e4 | 1479 | * |
53c59f26 JW |
1480 | * Returns the address of the deleted item, or NULL if it was not present |
1481 | * or the entry at the given @index was not @item. | |
1da177e4 | 1482 | */ |
53c59f26 JW |
1483 | void *radix_tree_delete_item(struct radix_tree_root *root, |
1484 | unsigned long index, void *item) | |
1da177e4 | 1485 | { |
139e5616 | 1486 | struct radix_tree_node *node; |
e6145236 | 1487 | unsigned int offset, i; |
139e5616 JW |
1488 | void **slot; |
1489 | void *entry; | |
d5274261 | 1490 | int tag; |
1da177e4 | 1491 | |
139e5616 JW |
1492 | entry = __radix_tree_lookup(root, index, &node, &slot); |
1493 | if (!entry) | |
1494 | return NULL; | |
1da177e4 | 1495 | |
139e5616 JW |
1496 | if (item && entry != item) |
1497 | return NULL; | |
1498 | ||
1499 | if (!node) { | |
612d6c19 NP |
1500 | root_tag_clear_all(root); |
1501 | root->rnode = NULL; | |
139e5616 | 1502 | return entry; |
612d6c19 | 1503 | } |
1da177e4 | 1504 | |
139e5616 | 1505 | offset = index & RADIX_TREE_MAP_MASK; |
53c59f26 | 1506 | |
1da177e4 | 1507 | /* |
e2bdb933 HD |
1508 | * Clear all tags associated with the item to be deleted. |
1509 | * This way of doing it would be inefficient, but seldom is any set. | |
1da177e4 | 1510 | */ |
daff89f3 | 1511 | for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { |
e2bdb933 | 1512 | if (tag_get(node, tag, offset)) |
612d6c19 | 1513 | radix_tree_tag_clear(root, index, tag); |
d5274261 | 1514 | } |
1da177e4 | 1515 | |
e6145236 MW |
1516 | /* Delete any sibling slots pointing to this slot */ |
1517 | for (i = 1; offset + i < RADIX_TREE_MAP_SIZE; i++) { | |
1518 | if (node->slots[offset + i] != ptr_to_indirect(slot)) | |
1519 | break; | |
1520 | node->slots[offset + i] = NULL; | |
1521 | node->count--; | |
1522 | } | |
139e5616 JW |
1523 | node->slots[offset] = NULL; |
1524 | node->count--; | |
e2bdb933 | 1525 | |
449dd698 | 1526 | __radix_tree_delete_node(root, node); |
612d6c19 | 1527 | |
139e5616 | 1528 | return entry; |
1da177e4 | 1529 | } |
53c59f26 JW |
1530 | EXPORT_SYMBOL(radix_tree_delete_item); |
1531 | ||
1532 | /** | |
1533 | * radix_tree_delete - delete an item from a radix tree | |
1534 | * @root: radix tree root | |
1535 | * @index: index key | |
1536 | * | |
1537 | * Remove the item at @index from the radix tree rooted at @root. | |
1538 | * | |
1539 | * Returns the address of the deleted item, or NULL if it was not present. | |
1540 | */ | |
1541 | void *radix_tree_delete(struct radix_tree_root *root, unsigned long index) | |
1542 | { | |
1543 | return radix_tree_delete_item(root, index, NULL); | |
1544 | } | |
1da177e4 LT |
1545 | EXPORT_SYMBOL(radix_tree_delete); |
1546 | ||
1547 | /** | |
1548 | * radix_tree_tagged - test whether any items in the tree are tagged | |
1549 | * @root: radix tree root | |
1550 | * @tag: tag to test | |
1551 | */ | |
daff89f3 | 1552 | int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag) |
1da177e4 | 1553 | { |
612d6c19 | 1554 | return root_tag_get(root, tag); |
1da177e4 LT |
1555 | } |
1556 | EXPORT_SYMBOL(radix_tree_tagged); | |
1557 | ||
1558 | static void | |
449dd698 | 1559 | radix_tree_node_ctor(void *arg) |
1da177e4 | 1560 | { |
449dd698 JW |
1561 | struct radix_tree_node *node = arg; |
1562 | ||
1563 | memset(node, 0, sizeof(*node)); | |
1564 | INIT_LIST_HEAD(&node->private_list); | |
1da177e4 LT |
1565 | } |
1566 | ||
1567 | static __init unsigned long __maxindex(unsigned int height) | |
1568 | { | |
430d275a PL |
1569 | unsigned int width = height * RADIX_TREE_MAP_SHIFT; |
1570 | int shift = RADIX_TREE_INDEX_BITS - width; | |
1571 | ||
1572 | if (shift < 0) | |
1573 | return ~0UL; | |
1574 | if (shift >= BITS_PER_LONG) | |
1575 | return 0UL; | |
1576 | return ~0UL >> shift; | |
1da177e4 LT |
1577 | } |
1578 | ||
1579 | static __init void radix_tree_init_maxindex(void) | |
1580 | { | |
1581 | unsigned int i; | |
1582 | ||
1583 | for (i = 0; i < ARRAY_SIZE(height_to_maxindex); i++) | |
1584 | height_to_maxindex[i] = __maxindex(i); | |
1585 | } | |
1586 | ||
1da177e4 LT |
1587 | static int radix_tree_callback(struct notifier_block *nfb, |
1588 | unsigned long action, | |
1589 | void *hcpu) | |
1590 | { | |
1591 | int cpu = (long)hcpu; | |
1592 | struct radix_tree_preload *rtp; | |
9d2a8da0 | 1593 | struct radix_tree_node *node; |
1da177e4 LT |
1594 | |
1595 | /* Free per-cpu pool of perloaded nodes */ | |
8bb78442 | 1596 | if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) { |
1da177e4 LT |
1597 | rtp = &per_cpu(radix_tree_preloads, cpu); |
1598 | while (rtp->nr) { | |
9d2a8da0 KS |
1599 | node = rtp->nodes; |
1600 | rtp->nodes = node->private_data; | |
1601 | kmem_cache_free(radix_tree_node_cachep, node); | |
1602 | rtp->nr--; | |
1da177e4 LT |
1603 | } |
1604 | } | |
1605 | return NOTIFY_OK; | |
1606 | } | |
1da177e4 LT |
1607 | |
1608 | void __init radix_tree_init(void) | |
1609 | { | |
1610 | radix_tree_node_cachep = kmem_cache_create("radix_tree_node", | |
1611 | sizeof(struct radix_tree_node), 0, | |
488514d1 CL |
1612 | SLAB_PANIC | SLAB_RECLAIM_ACCOUNT, |
1613 | radix_tree_node_ctor); | |
1da177e4 LT |
1614 | radix_tree_init_maxindex(); |
1615 | hotcpu_notifier(radix_tree_callback, 0); | |
1616 | } |