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 |
6b053b8e MW |
7 | * Copyright (C) 2016 Intel, Matthew Wilcox |
8 | * Copyright (C) 2016 Intel, Ross Zwisler | |
1da177e4 LT |
9 | * |
10 | * This program is free software; you can redistribute it and/or | |
11 | * modify it under the terms of the GNU General Public License as | |
12 | * published by the Free Software Foundation; either version 2, or (at | |
13 | * your option) any later version. | |
14 | * | |
15 | * This program is distributed in the hope that it will be useful, but | |
16 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
18 | * General Public License for more details. | |
19 | * | |
20 | * You should have received a copy of the GNU General Public License | |
21 | * along with this program; if not, write to the Free Software | |
22 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
23 | */ | |
24 | ||
0a835c4f MW |
25 | #include <linux/bitmap.h> |
26 | #include <linux/bitops.h> | |
e157b555 | 27 | #include <linux/cpu.h> |
1da177e4 | 28 | #include <linux/errno.h> |
0a835c4f MW |
29 | #include <linux/export.h> |
30 | #include <linux/idr.h> | |
1da177e4 LT |
31 | #include <linux/init.h> |
32 | #include <linux/kernel.h> | |
0a835c4f | 33 | #include <linux/kmemleak.h> |
1da177e4 | 34 | #include <linux/percpu.h> |
0a835c4f MW |
35 | #include <linux/preempt.h> /* in_interrupt() */ |
36 | #include <linux/radix-tree.h> | |
37 | #include <linux/rcupdate.h> | |
1da177e4 | 38 | #include <linux/slab.h> |
1da177e4 | 39 | #include <linux/string.h> |
1da177e4 LT |
40 | |
41 | ||
c78c66d1 KS |
42 | /* Number of nodes in fully populated tree of given height */ |
43 | static unsigned long height_to_maxnodes[RADIX_TREE_MAX_PATH + 1] __read_mostly; | |
44 | ||
1da177e4 LT |
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 | ||
0a835c4f MW |
63 | /* |
64 | * The IDR does not have to be as high as the radix tree since it uses | |
65 | * signed integers, not unsigned longs. | |
66 | */ | |
67 | #define IDR_INDEX_BITS (8 /* CHAR_BIT */ * sizeof(int) - 1) | |
68 | #define IDR_MAX_PATH (DIV_ROUND_UP(IDR_INDEX_BITS, \ | |
69 | RADIX_TREE_MAP_SHIFT)) | |
70 | #define IDR_PRELOAD_SIZE (IDR_MAX_PATH * 2 - 1) | |
71 | ||
7ad3d4d8 MW |
72 | /* |
73 | * The IDA is even shorter since it uses a bitmap at the last level. | |
74 | */ | |
75 | #define IDA_INDEX_BITS (8 * sizeof(int) - 1 - ilog2(IDA_BITMAP_BITS)) | |
76 | #define IDA_MAX_PATH (DIV_ROUND_UP(IDA_INDEX_BITS, \ | |
77 | RADIX_TREE_MAP_SHIFT)) | |
78 | #define IDA_PRELOAD_SIZE (IDA_MAX_PATH * 2 - 1) | |
79 | ||
1da177e4 LT |
80 | /* |
81 | * Per-cpu pool of preloaded nodes | |
82 | */ | |
83 | struct radix_tree_preload { | |
2fcd9005 | 84 | unsigned nr; |
1293d5c5 | 85 | /* nodes->parent points to next preallocated node */ |
9d2a8da0 | 86 | struct radix_tree_node *nodes; |
1da177e4 | 87 | }; |
8cef7d57 | 88 | static DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, }; |
1da177e4 | 89 | |
148deab2 MW |
90 | static inline struct radix_tree_node *entry_to_node(void *ptr) |
91 | { | |
92 | return (void *)((unsigned long)ptr & ~RADIX_TREE_INTERNAL_NODE); | |
93 | } | |
94 | ||
a4db4dce | 95 | static inline void *node_to_entry(void *ptr) |
27d20fdd | 96 | { |
30ff46cc | 97 | return (void *)((unsigned long)ptr | RADIX_TREE_INTERNAL_NODE); |
27d20fdd NP |
98 | } |
99 | ||
a4db4dce | 100 | #define RADIX_TREE_RETRY node_to_entry(NULL) |
afe0e395 | 101 | |
db050f29 MW |
102 | #ifdef CONFIG_RADIX_TREE_MULTIORDER |
103 | /* Sibling slots point directly to another slot in the same node */ | |
35534c86 MW |
104 | static inline |
105 | bool is_sibling_entry(const struct radix_tree_node *parent, void *node) | |
db050f29 | 106 | { |
d7b62727 | 107 | void __rcu **ptr = node; |
db050f29 MW |
108 | return (parent->slots <= ptr) && |
109 | (ptr < parent->slots + RADIX_TREE_MAP_SIZE); | |
110 | } | |
111 | #else | |
35534c86 MW |
112 | static inline |
113 | bool is_sibling_entry(const struct radix_tree_node *parent, void *node) | |
db050f29 MW |
114 | { |
115 | return false; | |
116 | } | |
117 | #endif | |
118 | ||
d7b62727 MW |
119 | static inline unsigned long |
120 | get_slot_offset(const struct radix_tree_node *parent, void __rcu **slot) | |
db050f29 MW |
121 | { |
122 | return slot - parent->slots; | |
123 | } | |
124 | ||
35534c86 | 125 | static unsigned int radix_tree_descend(const struct radix_tree_node *parent, |
9e85d811 | 126 | struct radix_tree_node **nodep, unsigned long index) |
db050f29 | 127 | { |
9e85d811 | 128 | unsigned int offset = (index >> parent->shift) & RADIX_TREE_MAP_MASK; |
d7b62727 | 129 | void __rcu **entry = rcu_dereference_raw(parent->slots[offset]); |
db050f29 MW |
130 | |
131 | #ifdef CONFIG_RADIX_TREE_MULTIORDER | |
b194d16c | 132 | if (radix_tree_is_internal_node(entry)) { |
8d2c0d36 | 133 | if (is_sibling_entry(parent, entry)) { |
d7b62727 MW |
134 | void __rcu **sibentry; |
135 | sibentry = (void __rcu **) entry_to_node(entry); | |
8d2c0d36 LT |
136 | offset = get_slot_offset(parent, sibentry); |
137 | entry = rcu_dereference_raw(*sibentry); | |
db050f29 MW |
138 | } |
139 | } | |
140 | #endif | |
141 | ||
142 | *nodep = (void *)entry; | |
143 | return offset; | |
144 | } | |
145 | ||
35534c86 | 146 | static inline gfp_t root_gfp_mask(const struct radix_tree_root *root) |
612d6c19 NP |
147 | { |
148 | return root->gfp_mask & __GFP_BITS_MASK; | |
149 | } | |
150 | ||
643b52b9 NP |
151 | static inline void tag_set(struct radix_tree_node *node, unsigned int tag, |
152 | int offset) | |
153 | { | |
154 | __set_bit(offset, node->tags[tag]); | |
155 | } | |
156 | ||
157 | static inline void tag_clear(struct radix_tree_node *node, unsigned int tag, | |
158 | int offset) | |
159 | { | |
160 | __clear_bit(offset, node->tags[tag]); | |
161 | } | |
162 | ||
35534c86 | 163 | static inline int tag_get(const struct radix_tree_node *node, unsigned int tag, |
643b52b9 NP |
164 | int offset) |
165 | { | |
166 | return test_bit(offset, node->tags[tag]); | |
167 | } | |
168 | ||
35534c86 | 169 | static inline void root_tag_set(struct radix_tree_root *root, unsigned tag) |
643b52b9 | 170 | { |
0a835c4f | 171 | root->gfp_mask |= (__force gfp_t)(1 << (tag + ROOT_TAG_SHIFT)); |
643b52b9 NP |
172 | } |
173 | ||
2fcd9005 | 174 | static inline void root_tag_clear(struct radix_tree_root *root, unsigned tag) |
643b52b9 | 175 | { |
0a835c4f | 176 | root->gfp_mask &= (__force gfp_t)~(1 << (tag + ROOT_TAG_SHIFT)); |
643b52b9 NP |
177 | } |
178 | ||
179 | static inline void root_tag_clear_all(struct radix_tree_root *root) | |
180 | { | |
0a835c4f | 181 | root->gfp_mask &= (1 << ROOT_TAG_SHIFT) - 1; |
643b52b9 NP |
182 | } |
183 | ||
35534c86 | 184 | static inline int root_tag_get(const struct radix_tree_root *root, unsigned tag) |
643b52b9 | 185 | { |
0a835c4f | 186 | return (__force int)root->gfp_mask & (1 << (tag + ROOT_TAG_SHIFT)); |
643b52b9 NP |
187 | } |
188 | ||
35534c86 | 189 | static inline unsigned root_tags_get(const struct radix_tree_root *root) |
643b52b9 | 190 | { |
0a835c4f | 191 | return (__force unsigned)root->gfp_mask >> ROOT_TAG_SHIFT; |
643b52b9 NP |
192 | } |
193 | ||
0a835c4f | 194 | static inline bool is_idr(const struct radix_tree_root *root) |
7b60e9ad | 195 | { |
0a835c4f | 196 | return !!(root->gfp_mask & ROOT_IS_IDR); |
7b60e9ad MW |
197 | } |
198 | ||
643b52b9 NP |
199 | /* |
200 | * Returns 1 if any slot in the node has this tag set. | |
201 | * Otherwise returns 0. | |
202 | */ | |
35534c86 MW |
203 | static inline int any_tag_set(const struct radix_tree_node *node, |
204 | unsigned int tag) | |
643b52b9 | 205 | { |
2fcd9005 | 206 | unsigned idx; |
643b52b9 NP |
207 | for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) { |
208 | if (node->tags[tag][idx]) | |
209 | return 1; | |
210 | } | |
211 | return 0; | |
212 | } | |
78c1d784 | 213 | |
0a835c4f MW |
214 | static inline void all_tag_set(struct radix_tree_node *node, unsigned int tag) |
215 | { | |
216 | bitmap_fill(node->tags[tag], RADIX_TREE_MAP_SIZE); | |
217 | } | |
218 | ||
78c1d784 KK |
219 | /** |
220 | * radix_tree_find_next_bit - find the next set bit in a memory region | |
221 | * | |
222 | * @addr: The address to base the search on | |
223 | * @size: The bitmap size in bits | |
224 | * @offset: The bitnumber to start searching at | |
225 | * | |
226 | * Unrollable variant of find_next_bit() for constant size arrays. | |
227 | * Tail bits starting from size to roundup(size, BITS_PER_LONG) must be zero. | |
228 | * Returns next bit offset, or size if nothing found. | |
229 | */ | |
230 | static __always_inline unsigned long | |
bc412fca MW |
231 | radix_tree_find_next_bit(struct radix_tree_node *node, unsigned int tag, |
232 | unsigned long offset) | |
78c1d784 | 233 | { |
bc412fca | 234 | const unsigned long *addr = node->tags[tag]; |
78c1d784 | 235 | |
bc412fca | 236 | if (offset < RADIX_TREE_MAP_SIZE) { |
78c1d784 KK |
237 | unsigned long tmp; |
238 | ||
239 | addr += offset / BITS_PER_LONG; | |
240 | tmp = *addr >> (offset % BITS_PER_LONG); | |
241 | if (tmp) | |
242 | return __ffs(tmp) + offset; | |
243 | offset = (offset + BITS_PER_LONG) & ~(BITS_PER_LONG - 1); | |
bc412fca | 244 | while (offset < RADIX_TREE_MAP_SIZE) { |
78c1d784 KK |
245 | tmp = *++addr; |
246 | if (tmp) | |
247 | return __ffs(tmp) + offset; | |
248 | offset += BITS_PER_LONG; | |
249 | } | |
250 | } | |
bc412fca | 251 | return RADIX_TREE_MAP_SIZE; |
78c1d784 KK |
252 | } |
253 | ||
268f42de MW |
254 | static unsigned int iter_offset(const struct radix_tree_iter *iter) |
255 | { | |
256 | return (iter->index >> iter_shift(iter)) & RADIX_TREE_MAP_MASK; | |
257 | } | |
258 | ||
218ed750 MW |
259 | /* |
260 | * The maximum index which can be stored in a radix tree | |
261 | */ | |
262 | static inline unsigned long shift_maxindex(unsigned int shift) | |
263 | { | |
264 | return (RADIX_TREE_MAP_SIZE << shift) - 1; | |
265 | } | |
266 | ||
35534c86 | 267 | static inline unsigned long node_maxindex(const struct radix_tree_node *node) |
218ed750 MW |
268 | { |
269 | return shift_maxindex(node->shift); | |
270 | } | |
271 | ||
0a835c4f MW |
272 | static unsigned long next_index(unsigned long index, |
273 | const struct radix_tree_node *node, | |
274 | unsigned long offset) | |
275 | { | |
276 | return (index & ~node_maxindex(node)) + (offset << node->shift); | |
277 | } | |
278 | ||
0796c583 | 279 | #ifndef __KERNEL__ |
d0891265 | 280 | static void dump_node(struct radix_tree_node *node, unsigned long index) |
7cf19af4 | 281 | { |
0796c583 | 282 | unsigned long i; |
7cf19af4 | 283 | |
218ed750 MW |
284 | pr_debug("radix node: %p offset %d indices %lu-%lu parent %p tags %lx %lx %lx shift %d count %d exceptional %d\n", |
285 | node, node->offset, index, index | node_maxindex(node), | |
286 | node->parent, | |
0796c583 | 287 | node->tags[0][0], node->tags[1][0], node->tags[2][0], |
218ed750 | 288 | node->shift, node->count, node->exceptional); |
0796c583 RZ |
289 | |
290 | for (i = 0; i < RADIX_TREE_MAP_SIZE; i++) { | |
d0891265 MW |
291 | unsigned long first = index | (i << node->shift); |
292 | unsigned long last = first | ((1UL << node->shift) - 1); | |
0796c583 RZ |
293 | void *entry = node->slots[i]; |
294 | if (!entry) | |
295 | continue; | |
218ed750 MW |
296 | if (entry == RADIX_TREE_RETRY) { |
297 | pr_debug("radix retry offset %ld indices %lu-%lu parent %p\n", | |
298 | i, first, last, node); | |
b194d16c | 299 | } else if (!radix_tree_is_internal_node(entry)) { |
218ed750 MW |
300 | pr_debug("radix entry %p offset %ld indices %lu-%lu parent %p\n", |
301 | entry, i, first, last, node); | |
302 | } else if (is_sibling_entry(node, entry)) { | |
303 | pr_debug("radix sblng %p offset %ld indices %lu-%lu parent %p val %p\n", | |
304 | entry, i, first, last, node, | |
305 | *(void **)entry_to_node(entry)); | |
0796c583 | 306 | } else { |
4dd6c098 | 307 | dump_node(entry_to_node(entry), first); |
0796c583 RZ |
308 | } |
309 | } | |
7cf19af4 MW |
310 | } |
311 | ||
312 | /* For debug */ | |
313 | static void radix_tree_dump(struct radix_tree_root *root) | |
314 | { | |
d0891265 MW |
315 | pr_debug("radix root: %p rnode %p tags %x\n", |
316 | root, root->rnode, | |
0a835c4f | 317 | root->gfp_mask >> ROOT_TAG_SHIFT); |
b194d16c | 318 | if (!radix_tree_is_internal_node(root->rnode)) |
7cf19af4 | 319 | return; |
4dd6c098 | 320 | dump_node(entry_to_node(root->rnode), 0); |
7cf19af4 | 321 | } |
0a835c4f MW |
322 | |
323 | static void dump_ida_node(void *entry, unsigned long index) | |
324 | { | |
325 | unsigned long i; | |
326 | ||
327 | if (!entry) | |
328 | return; | |
329 | ||
330 | if (radix_tree_is_internal_node(entry)) { | |
331 | struct radix_tree_node *node = entry_to_node(entry); | |
332 | ||
333 | pr_debug("ida node: %p offset %d indices %lu-%lu parent %p free %lx shift %d count %d\n", | |
334 | node, node->offset, index * IDA_BITMAP_BITS, | |
335 | ((index | node_maxindex(node)) + 1) * | |
336 | IDA_BITMAP_BITS - 1, | |
337 | node->parent, node->tags[0][0], node->shift, | |
338 | node->count); | |
339 | for (i = 0; i < RADIX_TREE_MAP_SIZE; i++) | |
340 | dump_ida_node(node->slots[i], | |
341 | index | (i << node->shift)); | |
d37cacc5 MW |
342 | } else if (radix_tree_exceptional_entry(entry)) { |
343 | pr_debug("ida excp: %p offset %d indices %lu-%lu data %lx\n", | |
344 | entry, (int)(index & RADIX_TREE_MAP_MASK), | |
345 | index * IDA_BITMAP_BITS, | |
346 | index * IDA_BITMAP_BITS + BITS_PER_LONG - | |
347 | RADIX_TREE_EXCEPTIONAL_SHIFT, | |
348 | (unsigned long)entry >> | |
349 | RADIX_TREE_EXCEPTIONAL_SHIFT); | |
0a835c4f MW |
350 | } else { |
351 | struct ida_bitmap *bitmap = entry; | |
352 | ||
353 | pr_debug("ida btmp: %p offset %d indices %lu-%lu data", bitmap, | |
354 | (int)(index & RADIX_TREE_MAP_MASK), | |
355 | index * IDA_BITMAP_BITS, | |
356 | (index + 1) * IDA_BITMAP_BITS - 1); | |
357 | for (i = 0; i < IDA_BITMAP_LONGS; i++) | |
358 | pr_cont(" %lx", bitmap->bitmap[i]); | |
359 | pr_cont("\n"); | |
360 | } | |
361 | } | |
362 | ||
363 | static void ida_dump(struct ida *ida) | |
364 | { | |
365 | struct radix_tree_root *root = &ida->ida_rt; | |
7ad3d4d8 MW |
366 | pr_debug("ida: %p node %p free %d\n", ida, root->rnode, |
367 | root->gfp_mask >> ROOT_TAG_SHIFT); | |
0a835c4f MW |
368 | dump_ida_node(root->rnode, 0); |
369 | } | |
7cf19af4 MW |
370 | #endif |
371 | ||
1da177e4 LT |
372 | /* |
373 | * This assumes that the caller has performed appropriate preallocation, and | |
374 | * that the caller has pinned this thread of control to the current CPU. | |
375 | */ | |
376 | static struct radix_tree_node * | |
0a835c4f | 377 | radix_tree_node_alloc(gfp_t gfp_mask, struct radix_tree_node *parent, |
d58275bc | 378 | struct radix_tree_root *root, |
e8de4340 MW |
379 | unsigned int shift, unsigned int offset, |
380 | unsigned int count, unsigned int exceptional) | |
1da177e4 | 381 | { |
e2848a0e | 382 | struct radix_tree_node *ret = NULL; |
1da177e4 | 383 | |
5e4c0d97 | 384 | /* |
2fcd9005 MW |
385 | * Preload code isn't irq safe and it doesn't make sense to use |
386 | * preloading during an interrupt anyway as all the allocations have | |
387 | * to be atomic. So just do normal allocation when in interrupt. | |
5e4c0d97 | 388 | */ |
d0164adc | 389 | if (!gfpflags_allow_blocking(gfp_mask) && !in_interrupt()) { |
1da177e4 LT |
390 | struct radix_tree_preload *rtp; |
391 | ||
58e698af VD |
392 | /* |
393 | * Even if the caller has preloaded, try to allocate from the | |
05eb6e72 VD |
394 | * cache first for the new node to get accounted to the memory |
395 | * cgroup. | |
58e698af VD |
396 | */ |
397 | ret = kmem_cache_alloc(radix_tree_node_cachep, | |
05eb6e72 | 398 | gfp_mask | __GFP_NOWARN); |
58e698af VD |
399 | if (ret) |
400 | goto out; | |
401 | ||
e2848a0e NP |
402 | /* |
403 | * Provided the caller has preloaded here, we will always | |
404 | * succeed in getting a node here (and never reach | |
405 | * kmem_cache_alloc) | |
406 | */ | |
7c8e0181 | 407 | rtp = this_cpu_ptr(&radix_tree_preloads); |
1da177e4 | 408 | if (rtp->nr) { |
9d2a8da0 | 409 | ret = rtp->nodes; |
1293d5c5 | 410 | rtp->nodes = ret->parent; |
1da177e4 LT |
411 | rtp->nr--; |
412 | } | |
ce80b067 CM |
413 | /* |
414 | * Update the allocation stack trace as this is more useful | |
415 | * for debugging. | |
416 | */ | |
417 | kmemleak_update_trace(ret); | |
58e698af | 418 | goto out; |
1da177e4 | 419 | } |
05eb6e72 | 420 | ret = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask); |
58e698af | 421 | out: |
b194d16c | 422 | BUG_ON(radix_tree_is_internal_node(ret)); |
e8de4340 | 423 | if (ret) { |
e8de4340 MW |
424 | ret->shift = shift; |
425 | ret->offset = offset; | |
426 | ret->count = count; | |
427 | ret->exceptional = exceptional; | |
d58275bc MW |
428 | ret->parent = parent; |
429 | ret->root = root; | |
e8de4340 | 430 | } |
1da177e4 LT |
431 | return ret; |
432 | } | |
433 | ||
7cf9c2c7 NP |
434 | static void radix_tree_node_rcu_free(struct rcu_head *head) |
435 | { | |
436 | struct radix_tree_node *node = | |
437 | container_of(head, struct radix_tree_node, rcu_head); | |
643b52b9 NP |
438 | |
439 | /* | |
175542f5 MW |
440 | * Must only free zeroed nodes into the slab. We can be left with |
441 | * non-NULL entries by radix_tree_free_nodes, so clear the entries | |
442 | * and tags here. | |
643b52b9 | 443 | */ |
175542f5 MW |
444 | memset(node->slots, 0, sizeof(node->slots)); |
445 | memset(node->tags, 0, sizeof(node->tags)); | |
91d9c05a | 446 | INIT_LIST_HEAD(&node->private_list); |
643b52b9 | 447 | |
7cf9c2c7 NP |
448 | kmem_cache_free(radix_tree_node_cachep, node); |
449 | } | |
450 | ||
1da177e4 LT |
451 | static inline void |
452 | radix_tree_node_free(struct radix_tree_node *node) | |
453 | { | |
7cf9c2c7 | 454 | call_rcu(&node->rcu_head, radix_tree_node_rcu_free); |
1da177e4 LT |
455 | } |
456 | ||
457 | /* | |
458 | * Load up this CPU's radix_tree_node buffer with sufficient objects to | |
459 | * ensure that the addition of a single element in the tree cannot fail. On | |
460 | * success, return zero, with preemption disabled. On error, return -ENOMEM | |
461 | * with preemption not disabled. | |
b34df792 DH |
462 | * |
463 | * To make use of this facility, the radix tree must be initialised without | |
d0164adc | 464 | * __GFP_DIRECT_RECLAIM being passed to INIT_RADIX_TREE(). |
1da177e4 | 465 | */ |
2791653a | 466 | static int __radix_tree_preload(gfp_t gfp_mask, unsigned nr) |
1da177e4 LT |
467 | { |
468 | struct radix_tree_preload *rtp; | |
469 | struct radix_tree_node *node; | |
470 | int ret = -ENOMEM; | |
471 | ||
05eb6e72 VD |
472 | /* |
473 | * Nodes preloaded by one cgroup can be be used by another cgroup, so | |
474 | * they should never be accounted to any particular memory cgroup. | |
475 | */ | |
476 | gfp_mask &= ~__GFP_ACCOUNT; | |
477 | ||
1da177e4 | 478 | preempt_disable(); |
7c8e0181 | 479 | rtp = this_cpu_ptr(&radix_tree_preloads); |
c78c66d1 | 480 | while (rtp->nr < nr) { |
1da177e4 | 481 | preempt_enable(); |
488514d1 | 482 | node = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask); |
1da177e4 LT |
483 | if (node == NULL) |
484 | goto out; | |
485 | preempt_disable(); | |
7c8e0181 | 486 | rtp = this_cpu_ptr(&radix_tree_preloads); |
c78c66d1 | 487 | if (rtp->nr < nr) { |
1293d5c5 | 488 | node->parent = rtp->nodes; |
9d2a8da0 KS |
489 | rtp->nodes = node; |
490 | rtp->nr++; | |
491 | } else { | |
1da177e4 | 492 | kmem_cache_free(radix_tree_node_cachep, node); |
9d2a8da0 | 493 | } |
1da177e4 LT |
494 | } |
495 | ret = 0; | |
496 | out: | |
497 | return ret; | |
498 | } | |
5e4c0d97 JK |
499 | |
500 | /* | |
501 | * Load up this CPU's radix_tree_node buffer with sufficient objects to | |
502 | * ensure that the addition of a single element in the tree cannot fail. On | |
503 | * success, return zero, with preemption disabled. On error, return -ENOMEM | |
504 | * with preemption not disabled. | |
505 | * | |
506 | * To make use of this facility, the radix tree must be initialised without | |
d0164adc | 507 | * __GFP_DIRECT_RECLAIM being passed to INIT_RADIX_TREE(). |
5e4c0d97 JK |
508 | */ |
509 | int radix_tree_preload(gfp_t gfp_mask) | |
510 | { | |
511 | /* Warn on non-sensical use... */ | |
d0164adc | 512 | WARN_ON_ONCE(!gfpflags_allow_blocking(gfp_mask)); |
c78c66d1 | 513 | return __radix_tree_preload(gfp_mask, RADIX_TREE_PRELOAD_SIZE); |
5e4c0d97 | 514 | } |
d7f0923d | 515 | EXPORT_SYMBOL(radix_tree_preload); |
1da177e4 | 516 | |
5e4c0d97 JK |
517 | /* |
518 | * The same as above function, except we don't guarantee preloading happens. | |
519 | * We do it, if we decide it helps. On success, return zero with preemption | |
520 | * disabled. On error, return -ENOMEM with preemption not disabled. | |
521 | */ | |
522 | int radix_tree_maybe_preload(gfp_t gfp_mask) | |
523 | { | |
d0164adc | 524 | if (gfpflags_allow_blocking(gfp_mask)) |
c78c66d1 | 525 | return __radix_tree_preload(gfp_mask, RADIX_TREE_PRELOAD_SIZE); |
5e4c0d97 JK |
526 | /* Preloading doesn't help anything with this gfp mask, skip it */ |
527 | preempt_disable(); | |
528 | return 0; | |
529 | } | |
530 | EXPORT_SYMBOL(radix_tree_maybe_preload); | |
531 | ||
2791653a MW |
532 | #ifdef CONFIG_RADIX_TREE_MULTIORDER |
533 | /* | |
534 | * Preload with enough objects to ensure that we can split a single entry | |
535 | * of order @old_order into many entries of size @new_order | |
536 | */ | |
537 | int radix_tree_split_preload(unsigned int old_order, unsigned int new_order, | |
538 | gfp_t gfp_mask) | |
539 | { | |
540 | unsigned top = 1 << (old_order % RADIX_TREE_MAP_SHIFT); | |
541 | unsigned layers = (old_order / RADIX_TREE_MAP_SHIFT) - | |
542 | (new_order / RADIX_TREE_MAP_SHIFT); | |
543 | unsigned nr = 0; | |
544 | ||
545 | WARN_ON_ONCE(!gfpflags_allow_blocking(gfp_mask)); | |
546 | BUG_ON(new_order >= old_order); | |
547 | ||
548 | while (layers--) | |
549 | nr = nr * RADIX_TREE_MAP_SIZE + 1; | |
550 | return __radix_tree_preload(gfp_mask, top * nr); | |
551 | } | |
552 | #endif | |
553 | ||
c78c66d1 KS |
554 | /* |
555 | * The same as function above, but preload number of nodes required to insert | |
556 | * (1 << order) continuous naturally-aligned elements. | |
557 | */ | |
558 | int radix_tree_maybe_preload_order(gfp_t gfp_mask, int order) | |
559 | { | |
560 | unsigned long nr_subtrees; | |
561 | int nr_nodes, subtree_height; | |
562 | ||
563 | /* Preloading doesn't help anything with this gfp mask, skip it */ | |
564 | if (!gfpflags_allow_blocking(gfp_mask)) { | |
565 | preempt_disable(); | |
566 | return 0; | |
567 | } | |
568 | ||
569 | /* | |
570 | * Calculate number and height of fully populated subtrees it takes to | |
571 | * store (1 << order) elements. | |
572 | */ | |
573 | nr_subtrees = 1 << order; | |
574 | for (subtree_height = 0; nr_subtrees > RADIX_TREE_MAP_SIZE; | |
575 | subtree_height++) | |
576 | nr_subtrees >>= RADIX_TREE_MAP_SHIFT; | |
577 | ||
578 | /* | |
579 | * The worst case is zero height tree with a single item at index 0 and | |
580 | * then inserting items starting at ULONG_MAX - (1 << order). | |
581 | * | |
582 | * This requires RADIX_TREE_MAX_PATH nodes to build branch from root to | |
583 | * 0-index item. | |
584 | */ | |
585 | nr_nodes = RADIX_TREE_MAX_PATH; | |
586 | ||
587 | /* Plus branch to fully populated subtrees. */ | |
588 | nr_nodes += RADIX_TREE_MAX_PATH - subtree_height; | |
589 | ||
590 | /* Root node is shared. */ | |
591 | nr_nodes--; | |
592 | ||
593 | /* Plus nodes required to build subtrees. */ | |
594 | nr_nodes += nr_subtrees * height_to_maxnodes[subtree_height]; | |
595 | ||
596 | return __radix_tree_preload(gfp_mask, nr_nodes); | |
597 | } | |
598 | ||
35534c86 | 599 | static unsigned radix_tree_load_root(const struct radix_tree_root *root, |
1456a439 MW |
600 | struct radix_tree_node **nodep, unsigned long *maxindex) |
601 | { | |
602 | struct radix_tree_node *node = rcu_dereference_raw(root->rnode); | |
603 | ||
604 | *nodep = node; | |
605 | ||
b194d16c | 606 | if (likely(radix_tree_is_internal_node(node))) { |
4dd6c098 | 607 | node = entry_to_node(node); |
1456a439 | 608 | *maxindex = node_maxindex(node); |
c12e51b0 | 609 | return node->shift + RADIX_TREE_MAP_SHIFT; |
1456a439 MW |
610 | } |
611 | ||
612 | *maxindex = 0; | |
613 | return 0; | |
614 | } | |
615 | ||
1da177e4 LT |
616 | /* |
617 | * Extend a radix tree so it can store key @index. | |
618 | */ | |
0a835c4f | 619 | static int radix_tree_extend(struct radix_tree_root *root, gfp_t gfp, |
d0891265 | 620 | unsigned long index, unsigned int shift) |
1da177e4 | 621 | { |
d7b62727 | 622 | void *entry; |
d0891265 | 623 | unsigned int maxshift; |
1da177e4 LT |
624 | int tag; |
625 | ||
d0891265 MW |
626 | /* Figure out what the shift should be. */ |
627 | maxshift = shift; | |
628 | while (index > shift_maxindex(maxshift)) | |
629 | maxshift += RADIX_TREE_MAP_SHIFT; | |
1da177e4 | 630 | |
d7b62727 MW |
631 | entry = rcu_dereference_raw(root->rnode); |
632 | if (!entry && (!is_idr(root) || root_tag_get(root, IDR_FREE))) | |
1da177e4 | 633 | goto out; |
1da177e4 | 634 | |
1da177e4 | 635 | do { |
0a835c4f | 636 | struct radix_tree_node *node = radix_tree_node_alloc(gfp, NULL, |
d58275bc | 637 | root, shift, 0, 1, 0); |
2fcd9005 | 638 | if (!node) |
1da177e4 LT |
639 | return -ENOMEM; |
640 | ||
0a835c4f MW |
641 | if (is_idr(root)) { |
642 | all_tag_set(node, IDR_FREE); | |
643 | if (!root_tag_get(root, IDR_FREE)) { | |
644 | tag_clear(node, IDR_FREE, 0); | |
645 | root_tag_set(root, IDR_FREE); | |
646 | } | |
647 | } else { | |
648 | /* Propagate the aggregated tag info to the new child */ | |
649 | for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { | |
650 | if (root_tag_get(root, tag)) | |
651 | tag_set(node, tag, 0); | |
652 | } | |
1da177e4 LT |
653 | } |
654 | ||
d0891265 | 655 | BUG_ON(shift > BITS_PER_LONG); |
d7b62727 MW |
656 | if (radix_tree_is_internal_node(entry)) { |
657 | entry_to_node(entry)->parent = node; | |
658 | } else if (radix_tree_exceptional_entry(entry)) { | |
f7942430 | 659 | /* Moving an exceptional root->rnode to a node */ |
e8de4340 | 660 | node->exceptional = 1; |
f7942430 | 661 | } |
d7b62727 MW |
662 | /* |
663 | * entry was already in the radix tree, so we do not need | |
664 | * rcu_assign_pointer here | |
665 | */ | |
666 | node->slots[0] = (void __rcu *)entry; | |
667 | entry = node_to_entry(node); | |
668 | rcu_assign_pointer(root->rnode, entry); | |
d0891265 | 669 | shift += RADIX_TREE_MAP_SHIFT; |
d0891265 | 670 | } while (shift <= maxshift); |
1da177e4 | 671 | out: |
d0891265 | 672 | return maxshift + RADIX_TREE_MAP_SHIFT; |
1da177e4 LT |
673 | } |
674 | ||
f4b109c6 JW |
675 | /** |
676 | * radix_tree_shrink - shrink radix tree to minimum height | |
677 | * @root radix tree root | |
678 | */ | |
0ac398ef | 679 | static inline bool radix_tree_shrink(struct radix_tree_root *root, |
4d693d08 JW |
680 | radix_tree_update_node_t update_node, |
681 | void *private) | |
f4b109c6 | 682 | { |
0ac398ef MW |
683 | bool shrunk = false; |
684 | ||
f4b109c6 | 685 | for (;;) { |
12320d0f | 686 | struct radix_tree_node *node = rcu_dereference_raw(root->rnode); |
f4b109c6 JW |
687 | struct radix_tree_node *child; |
688 | ||
689 | if (!radix_tree_is_internal_node(node)) | |
690 | break; | |
691 | node = entry_to_node(node); | |
692 | ||
693 | /* | |
694 | * The candidate node has more than one child, or its child | |
695 | * is not at the leftmost slot, or the child is a multiorder | |
696 | * entry, we cannot shrink. | |
697 | */ | |
698 | if (node->count != 1) | |
699 | break; | |
12320d0f | 700 | child = rcu_dereference_raw(node->slots[0]); |
f4b109c6 JW |
701 | if (!child) |
702 | break; | |
703 | if (!radix_tree_is_internal_node(child) && node->shift) | |
704 | break; | |
705 | ||
706 | if (radix_tree_is_internal_node(child)) | |
707 | entry_to_node(child)->parent = NULL; | |
708 | ||
709 | /* | |
710 | * We don't need rcu_assign_pointer(), since we are simply | |
711 | * moving the node from one part of the tree to another: if it | |
712 | * was safe to dereference the old pointer to it | |
713 | * (node->slots[0]), it will be safe to dereference the new | |
714 | * one (root->rnode) as far as dependent read barriers go. | |
715 | */ | |
d7b62727 | 716 | root->rnode = (void __rcu *)child; |
0a835c4f MW |
717 | if (is_idr(root) && !tag_get(node, IDR_FREE, 0)) |
718 | root_tag_clear(root, IDR_FREE); | |
f4b109c6 JW |
719 | |
720 | /* | |
721 | * We have a dilemma here. The node's slot[0] must not be | |
722 | * NULLed in case there are concurrent lookups expecting to | |
723 | * find the item. However if this was a bottom-level node, | |
724 | * then it may be subject to the slot pointer being visible | |
725 | * to callers dereferencing it. If item corresponding to | |
726 | * slot[0] is subsequently deleted, these callers would expect | |
727 | * their slot to become empty sooner or later. | |
728 | * | |
729 | * For example, lockless pagecache will look up a slot, deref | |
730 | * the page pointer, and if the page has 0 refcount it means it | |
731 | * was concurrently deleted from pagecache so try the deref | |
732 | * again. Fortunately there is already a requirement for logic | |
733 | * to retry the entire slot lookup -- the indirect pointer | |
734 | * problem (replacing direct root node with an indirect pointer | |
735 | * also results in a stale slot). So tag the slot as indirect | |
736 | * to force callers to retry. | |
737 | */ | |
4d693d08 JW |
738 | node->count = 0; |
739 | if (!radix_tree_is_internal_node(child)) { | |
d7b62727 | 740 | node->slots[0] = (void __rcu *)RADIX_TREE_RETRY; |
4d693d08 JW |
741 | if (update_node) |
742 | update_node(node, private); | |
743 | } | |
f4b109c6 | 744 | |
ea07b862 | 745 | WARN_ON_ONCE(!list_empty(&node->private_list)); |
f4b109c6 | 746 | radix_tree_node_free(node); |
0ac398ef | 747 | shrunk = true; |
f4b109c6 | 748 | } |
0ac398ef MW |
749 | |
750 | return shrunk; | |
f4b109c6 JW |
751 | } |
752 | ||
0ac398ef | 753 | static bool delete_node(struct radix_tree_root *root, |
4d693d08 JW |
754 | struct radix_tree_node *node, |
755 | radix_tree_update_node_t update_node, void *private) | |
f4b109c6 | 756 | { |
0ac398ef MW |
757 | bool deleted = false; |
758 | ||
f4b109c6 JW |
759 | do { |
760 | struct radix_tree_node *parent; | |
761 | ||
762 | if (node->count) { | |
12320d0f MW |
763 | if (node_to_entry(node) == |
764 | rcu_dereference_raw(root->rnode)) | |
0ac398ef MW |
765 | deleted |= radix_tree_shrink(root, update_node, |
766 | private); | |
767 | return deleted; | |
f4b109c6 JW |
768 | } |
769 | ||
770 | parent = node->parent; | |
771 | if (parent) { | |
772 | parent->slots[node->offset] = NULL; | |
773 | parent->count--; | |
774 | } else { | |
0a835c4f MW |
775 | /* |
776 | * Shouldn't the tags already have all been cleared | |
777 | * by the caller? | |
778 | */ | |
779 | if (!is_idr(root)) | |
780 | root_tag_clear_all(root); | |
f4b109c6 JW |
781 | root->rnode = NULL; |
782 | } | |
783 | ||
ea07b862 | 784 | WARN_ON_ONCE(!list_empty(&node->private_list)); |
f4b109c6 | 785 | radix_tree_node_free(node); |
0ac398ef | 786 | deleted = true; |
f4b109c6 JW |
787 | |
788 | node = parent; | |
789 | } while (node); | |
0ac398ef MW |
790 | |
791 | return deleted; | |
f4b109c6 JW |
792 | } |
793 | ||
1da177e4 | 794 | /** |
139e5616 | 795 | * __radix_tree_create - create a slot in a radix tree |
1da177e4 LT |
796 | * @root: radix tree root |
797 | * @index: index key | |
e6145236 | 798 | * @order: index occupies 2^order aligned slots |
139e5616 JW |
799 | * @nodep: returns node |
800 | * @slotp: returns slot | |
1da177e4 | 801 | * |
139e5616 JW |
802 | * Create, if necessary, and return the node and slot for an item |
803 | * at position @index in the radix tree @root. | |
804 | * | |
805 | * Until there is more than one item in the tree, no nodes are | |
806 | * allocated and @root->rnode is used as a direct slot instead of | |
807 | * pointing to a node, in which case *@nodep will be NULL. | |
808 | * | |
809 | * Returns -ENOMEM, or 0 for success. | |
1da177e4 | 810 | */ |
139e5616 | 811 | int __radix_tree_create(struct radix_tree_root *root, unsigned long index, |
e6145236 | 812 | unsigned order, struct radix_tree_node **nodep, |
d7b62727 | 813 | void __rcu ***slotp) |
1da177e4 | 814 | { |
89148aa4 | 815 | struct radix_tree_node *node = NULL, *child; |
d7b62727 | 816 | void __rcu **slot = (void __rcu **)&root->rnode; |
49ea6ebc | 817 | unsigned long maxindex; |
89148aa4 | 818 | unsigned int shift, offset = 0; |
49ea6ebc | 819 | unsigned long max = index | ((1UL << order) - 1); |
0a835c4f | 820 | gfp_t gfp = root_gfp_mask(root); |
49ea6ebc | 821 | |
89148aa4 | 822 | shift = radix_tree_load_root(root, &child, &maxindex); |
1da177e4 LT |
823 | |
824 | /* Make sure the tree is high enough. */ | |
175542f5 MW |
825 | if (order > 0 && max == ((1UL << order) - 1)) |
826 | max++; | |
49ea6ebc | 827 | if (max > maxindex) { |
0a835c4f | 828 | int error = radix_tree_extend(root, gfp, max, shift); |
49ea6ebc | 829 | if (error < 0) |
1da177e4 | 830 | return error; |
49ea6ebc | 831 | shift = error; |
12320d0f | 832 | child = rcu_dereference_raw(root->rnode); |
1da177e4 LT |
833 | } |
834 | ||
e6145236 | 835 | while (shift > order) { |
c12e51b0 | 836 | shift -= RADIX_TREE_MAP_SHIFT; |
89148aa4 | 837 | if (child == NULL) { |
1da177e4 | 838 | /* Have to add a child node. */ |
d58275bc | 839 | child = radix_tree_node_alloc(gfp, node, root, shift, |
e8de4340 | 840 | offset, 0, 0); |
89148aa4 | 841 | if (!child) |
1da177e4 | 842 | return -ENOMEM; |
89148aa4 MW |
843 | rcu_assign_pointer(*slot, node_to_entry(child)); |
844 | if (node) | |
1da177e4 | 845 | node->count++; |
89148aa4 | 846 | } else if (!radix_tree_is_internal_node(child)) |
e6145236 | 847 | break; |
1da177e4 LT |
848 | |
849 | /* Go a level down */ | |
89148aa4 | 850 | node = entry_to_node(child); |
9e85d811 | 851 | offset = radix_tree_descend(node, &child, index); |
89148aa4 | 852 | slot = &node->slots[offset]; |
e6145236 MW |
853 | } |
854 | ||
175542f5 MW |
855 | if (nodep) |
856 | *nodep = node; | |
857 | if (slotp) | |
858 | *slotp = slot; | |
859 | return 0; | |
860 | } | |
861 | ||
175542f5 MW |
862 | /* |
863 | * Free any nodes below this node. The tree is presumed to not need | |
864 | * shrinking, and any user data in the tree is presumed to not need a | |
865 | * destructor called on it. If we need to add a destructor, we can | |
866 | * add that functionality later. Note that we may not clear tags or | |
867 | * slots from the tree as an RCU walker may still have a pointer into | |
868 | * this subtree. We could replace the entries with RADIX_TREE_RETRY, | |
869 | * but we'll still have to clear those in rcu_free. | |
870 | */ | |
871 | static void radix_tree_free_nodes(struct radix_tree_node *node) | |
872 | { | |
873 | unsigned offset = 0; | |
874 | struct radix_tree_node *child = entry_to_node(node); | |
875 | ||
876 | for (;;) { | |
12320d0f | 877 | void *entry = rcu_dereference_raw(child->slots[offset]); |
175542f5 MW |
878 | if (radix_tree_is_internal_node(entry) && |
879 | !is_sibling_entry(child, entry)) { | |
880 | child = entry_to_node(entry); | |
881 | offset = 0; | |
882 | continue; | |
883 | } | |
884 | offset++; | |
885 | while (offset == RADIX_TREE_MAP_SIZE) { | |
886 | struct radix_tree_node *old = child; | |
887 | offset = child->offset + 1; | |
888 | child = child->parent; | |
dd040b6f | 889 | WARN_ON_ONCE(!list_empty(&old->private_list)); |
175542f5 MW |
890 | radix_tree_node_free(old); |
891 | if (old == entry_to_node(node)) | |
892 | return; | |
893 | } | |
894 | } | |
895 | } | |
896 | ||
0a835c4f | 897 | #ifdef CONFIG_RADIX_TREE_MULTIORDER |
d7b62727 MW |
898 | static inline int insert_entries(struct radix_tree_node *node, |
899 | void __rcu **slot, void *item, unsigned order, bool replace) | |
175542f5 MW |
900 | { |
901 | struct radix_tree_node *child; | |
902 | unsigned i, n, tag, offset, tags = 0; | |
903 | ||
904 | if (node) { | |
e157b555 MW |
905 | if (order > node->shift) |
906 | n = 1 << (order - node->shift); | |
907 | else | |
908 | n = 1; | |
175542f5 MW |
909 | offset = get_slot_offset(node, slot); |
910 | } else { | |
911 | n = 1; | |
912 | offset = 0; | |
913 | } | |
914 | ||
915 | if (n > 1) { | |
e6145236 | 916 | offset = offset & ~(n - 1); |
89148aa4 | 917 | slot = &node->slots[offset]; |
175542f5 MW |
918 | } |
919 | child = node_to_entry(slot); | |
920 | ||
921 | for (i = 0; i < n; i++) { | |
922 | if (slot[i]) { | |
923 | if (replace) { | |
924 | node->count--; | |
925 | for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) | |
926 | if (tag_get(node, tag, offset + i)) | |
927 | tags |= 1 << tag; | |
928 | } else | |
e6145236 MW |
929 | return -EEXIST; |
930 | } | |
175542f5 | 931 | } |
e6145236 | 932 | |
175542f5 | 933 | for (i = 0; i < n; i++) { |
12320d0f | 934 | struct radix_tree_node *old = rcu_dereference_raw(slot[i]); |
175542f5 | 935 | if (i) { |
89148aa4 | 936 | rcu_assign_pointer(slot[i], child); |
175542f5 MW |
937 | for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) |
938 | if (tags & (1 << tag)) | |
939 | tag_clear(node, tag, offset + i); | |
940 | } else { | |
941 | rcu_assign_pointer(slot[i], item); | |
942 | for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) | |
943 | if (tags & (1 << tag)) | |
944 | tag_set(node, tag, offset); | |
e6145236 | 945 | } |
175542f5 | 946 | if (radix_tree_is_internal_node(old) && |
e157b555 MW |
947 | !is_sibling_entry(node, old) && |
948 | (old != RADIX_TREE_RETRY)) | |
175542f5 MW |
949 | radix_tree_free_nodes(old); |
950 | if (radix_tree_exceptional_entry(old)) | |
951 | node->exceptional--; | |
612d6c19 | 952 | } |
175542f5 MW |
953 | if (node) { |
954 | node->count += n; | |
955 | if (radix_tree_exceptional_entry(item)) | |
956 | node->exceptional += n; | |
957 | } | |
958 | return n; | |
139e5616 | 959 | } |
175542f5 | 960 | #else |
d7b62727 MW |
961 | static inline int insert_entries(struct radix_tree_node *node, |
962 | void __rcu **slot, void *item, unsigned order, bool replace) | |
175542f5 MW |
963 | { |
964 | if (*slot) | |
965 | return -EEXIST; | |
966 | rcu_assign_pointer(*slot, item); | |
967 | if (node) { | |
968 | node->count++; | |
969 | if (radix_tree_exceptional_entry(item)) | |
970 | node->exceptional++; | |
971 | } | |
972 | return 1; | |
973 | } | |
974 | #endif | |
139e5616 JW |
975 | |
976 | /** | |
e6145236 | 977 | * __radix_tree_insert - insert into a radix tree |
139e5616 JW |
978 | * @root: radix tree root |
979 | * @index: index key | |
e6145236 | 980 | * @order: key covers the 2^order indices around index |
139e5616 JW |
981 | * @item: item to insert |
982 | * | |
983 | * Insert an item into the radix tree at position @index. | |
984 | */ | |
e6145236 MW |
985 | int __radix_tree_insert(struct radix_tree_root *root, unsigned long index, |
986 | unsigned order, void *item) | |
139e5616 JW |
987 | { |
988 | struct radix_tree_node *node; | |
d7b62727 | 989 | void __rcu **slot; |
139e5616 JW |
990 | int error; |
991 | ||
b194d16c | 992 | BUG_ON(radix_tree_is_internal_node(item)); |
139e5616 | 993 | |
e6145236 | 994 | error = __radix_tree_create(root, index, order, &node, &slot); |
139e5616 JW |
995 | if (error) |
996 | return error; | |
175542f5 MW |
997 | |
998 | error = insert_entries(node, slot, item, order, false); | |
999 | if (error < 0) | |
1000 | return error; | |
201b6264 | 1001 | |
612d6c19 | 1002 | if (node) { |
7b60e9ad | 1003 | unsigned offset = get_slot_offset(node, slot); |
7b60e9ad MW |
1004 | BUG_ON(tag_get(node, 0, offset)); |
1005 | BUG_ON(tag_get(node, 1, offset)); | |
1006 | BUG_ON(tag_get(node, 2, offset)); | |
612d6c19 | 1007 | } else { |
7b60e9ad | 1008 | BUG_ON(root_tags_get(root)); |
612d6c19 | 1009 | } |
1da177e4 | 1010 | |
1da177e4 LT |
1011 | return 0; |
1012 | } | |
e6145236 | 1013 | EXPORT_SYMBOL(__radix_tree_insert); |
1da177e4 | 1014 | |
139e5616 JW |
1015 | /** |
1016 | * __radix_tree_lookup - lookup an item in a radix tree | |
1017 | * @root: radix tree root | |
1018 | * @index: index key | |
1019 | * @nodep: returns node | |
1020 | * @slotp: returns slot | |
1021 | * | |
1022 | * Lookup and return the item at position @index in the radix | |
1023 | * tree @root. | |
1024 | * | |
1025 | * Until there is more than one item in the tree, no nodes are | |
1026 | * allocated and @root->rnode is used as a direct slot instead of | |
1027 | * pointing to a node, in which case *@nodep will be NULL. | |
7cf9c2c7 | 1028 | */ |
35534c86 MW |
1029 | void *__radix_tree_lookup(const struct radix_tree_root *root, |
1030 | unsigned long index, struct radix_tree_node **nodep, | |
d7b62727 | 1031 | void __rcu ***slotp) |
1da177e4 | 1032 | { |
139e5616 | 1033 | struct radix_tree_node *node, *parent; |
85829954 | 1034 | unsigned long maxindex; |
d7b62727 | 1035 | void __rcu **slot; |
612d6c19 | 1036 | |
85829954 MW |
1037 | restart: |
1038 | parent = NULL; | |
d7b62727 | 1039 | slot = (void __rcu **)&root->rnode; |
9e85d811 | 1040 | radix_tree_load_root(root, &node, &maxindex); |
85829954 | 1041 | if (index > maxindex) |
1da177e4 LT |
1042 | return NULL; |
1043 | ||
b194d16c | 1044 | while (radix_tree_is_internal_node(node)) { |
85829954 | 1045 | unsigned offset; |
1da177e4 | 1046 | |
85829954 MW |
1047 | if (node == RADIX_TREE_RETRY) |
1048 | goto restart; | |
4dd6c098 | 1049 | parent = entry_to_node(node); |
9e85d811 | 1050 | offset = radix_tree_descend(parent, &node, index); |
85829954 MW |
1051 | slot = parent->slots + offset; |
1052 | } | |
1da177e4 | 1053 | |
139e5616 JW |
1054 | if (nodep) |
1055 | *nodep = parent; | |
1056 | if (slotp) | |
1057 | *slotp = slot; | |
1058 | return node; | |
b72b71c6 HS |
1059 | } |
1060 | ||
1061 | /** | |
1062 | * radix_tree_lookup_slot - lookup a slot in a radix tree | |
1063 | * @root: radix tree root | |
1064 | * @index: index key | |
1065 | * | |
1066 | * Returns: the slot corresponding to the position @index in the | |
1067 | * radix tree @root. This is useful for update-if-exists operations. | |
1068 | * | |
1069 | * This function can be called under rcu_read_lock iff the slot is not | |
1070 | * modified by radix_tree_replace_slot, otherwise it must be called | |
1071 | * exclusive from other writers. Any dereference of the slot must be done | |
1072 | * using radix_tree_deref_slot. | |
1073 | */ | |
d7b62727 | 1074 | void __rcu **radix_tree_lookup_slot(const struct radix_tree_root *root, |
35534c86 | 1075 | unsigned long index) |
b72b71c6 | 1076 | { |
d7b62727 | 1077 | void __rcu **slot; |
139e5616 JW |
1078 | |
1079 | if (!__radix_tree_lookup(root, index, NULL, &slot)) | |
1080 | return NULL; | |
1081 | return slot; | |
a4331366 | 1082 | } |
a4331366 HR |
1083 | EXPORT_SYMBOL(radix_tree_lookup_slot); |
1084 | ||
1085 | /** | |
1086 | * radix_tree_lookup - perform lookup operation on a radix tree | |
1087 | * @root: radix tree root | |
1088 | * @index: index key | |
1089 | * | |
1090 | * Lookup the item at the position @index in the radix tree @root. | |
7cf9c2c7 NP |
1091 | * |
1092 | * This function can be called under rcu_read_lock, however the caller | |
1093 | * must manage lifetimes of leaf nodes (eg. RCU may also be used to free | |
1094 | * them safely). No RCU barriers are required to access or modify the | |
1095 | * returned item, however. | |
a4331366 | 1096 | */ |
35534c86 | 1097 | void *radix_tree_lookup(const struct radix_tree_root *root, unsigned long index) |
a4331366 | 1098 | { |
139e5616 | 1099 | return __radix_tree_lookup(root, index, NULL, NULL); |
1da177e4 LT |
1100 | } |
1101 | EXPORT_SYMBOL(radix_tree_lookup); | |
1102 | ||
0a835c4f | 1103 | static inline void replace_sibling_entries(struct radix_tree_node *node, |
d7b62727 | 1104 | void __rcu **slot, int count, int exceptional) |
a90eb3a2 | 1105 | { |
a90eb3a2 MW |
1106 | #ifdef CONFIG_RADIX_TREE_MULTIORDER |
1107 | void *ptr = node_to_entry(slot); | |
0a835c4f | 1108 | unsigned offset = get_slot_offset(node, slot) + 1; |
a90eb3a2 | 1109 | |
0a835c4f | 1110 | while (offset < RADIX_TREE_MAP_SIZE) { |
12320d0f | 1111 | if (rcu_dereference_raw(node->slots[offset]) != ptr) |
a90eb3a2 | 1112 | break; |
0a835c4f MW |
1113 | if (count < 0) { |
1114 | node->slots[offset] = NULL; | |
1115 | node->count--; | |
1116 | } | |
1117 | node->exceptional += exceptional; | |
1118 | offset++; | |
a90eb3a2 MW |
1119 | } |
1120 | #endif | |
a90eb3a2 MW |
1121 | } |
1122 | ||
d7b62727 MW |
1123 | static void replace_slot(void __rcu **slot, void *item, |
1124 | struct radix_tree_node *node, int count, int exceptional) | |
f7942430 | 1125 | { |
0a835c4f MW |
1126 | if (WARN_ON_ONCE(radix_tree_is_internal_node(item))) |
1127 | return; | |
f7942430 | 1128 | |
0a835c4f | 1129 | if (node && (count || exceptional)) { |
f4b109c6 | 1130 | node->count += count; |
0a835c4f MW |
1131 | node->exceptional += exceptional; |
1132 | replace_sibling_entries(node, slot, count, exceptional); | |
f4b109c6 | 1133 | } |
f7942430 JW |
1134 | |
1135 | rcu_assign_pointer(*slot, item); | |
1136 | } | |
1137 | ||
0a835c4f MW |
1138 | static bool node_tag_get(const struct radix_tree_root *root, |
1139 | const struct radix_tree_node *node, | |
1140 | unsigned int tag, unsigned int offset) | |
a90eb3a2 | 1141 | { |
0a835c4f MW |
1142 | if (node) |
1143 | return tag_get(node, tag, offset); | |
1144 | return root_tag_get(root, tag); | |
1145 | } | |
a90eb3a2 | 1146 | |
0a835c4f MW |
1147 | /* |
1148 | * IDR users want to be able to store NULL in the tree, so if the slot isn't | |
1149 | * free, don't adjust the count, even if it's transitioning between NULL and | |
1150 | * non-NULL. For the IDA, we mark slots as being IDR_FREE while they still | |
1151 | * have empty bits, but it only stores NULL in slots when they're being | |
1152 | * deleted. | |
1153 | */ | |
1154 | static int calculate_count(struct radix_tree_root *root, | |
d7b62727 | 1155 | struct radix_tree_node *node, void __rcu **slot, |
0a835c4f MW |
1156 | void *item, void *old) |
1157 | { | |
1158 | if (is_idr(root)) { | |
1159 | unsigned offset = get_slot_offset(node, slot); | |
1160 | bool free = node_tag_get(root, node, IDR_FREE, offset); | |
1161 | if (!free) | |
1162 | return 0; | |
1163 | if (!old) | |
1164 | return 1; | |
a90eb3a2 | 1165 | } |
0a835c4f | 1166 | return !!item - !!old; |
a90eb3a2 MW |
1167 | } |
1168 | ||
6d75f366 JW |
1169 | /** |
1170 | * __radix_tree_replace - replace item in a slot | |
4d693d08 JW |
1171 | * @root: radix tree root |
1172 | * @node: pointer to tree node | |
1173 | * @slot: pointer to slot in @node | |
1174 | * @item: new item to store in the slot. | |
1175 | * @update_node: callback for changing leaf nodes | |
1176 | * @private: private data to pass to @update_node | |
6d75f366 JW |
1177 | * |
1178 | * For use with __radix_tree_lookup(). Caller must hold tree write locked | |
1179 | * across slot lookup and replacement. | |
1180 | */ | |
1181 | void __radix_tree_replace(struct radix_tree_root *root, | |
1182 | struct radix_tree_node *node, | |
d7b62727 | 1183 | void __rcu **slot, void *item, |
4d693d08 | 1184 | radix_tree_update_node_t update_node, void *private) |
6d75f366 | 1185 | { |
0a835c4f MW |
1186 | void *old = rcu_dereference_raw(*slot); |
1187 | int exceptional = !!radix_tree_exceptional_entry(item) - | |
1188 | !!radix_tree_exceptional_entry(old); | |
1189 | int count = calculate_count(root, node, slot, item, old); | |
1190 | ||
6d75f366 | 1191 | /* |
f4b109c6 JW |
1192 | * This function supports replacing exceptional entries and |
1193 | * deleting entries, but that needs accounting against the | |
1194 | * node unless the slot is root->rnode. | |
6d75f366 | 1195 | */ |
d7b62727 | 1196 | WARN_ON_ONCE(!node && (slot != (void __rcu **)&root->rnode) && |
0a835c4f MW |
1197 | (count || exceptional)); |
1198 | replace_slot(slot, item, node, count, exceptional); | |
f4b109c6 | 1199 | |
4d693d08 JW |
1200 | if (!node) |
1201 | return; | |
1202 | ||
1203 | if (update_node) | |
1204 | update_node(node, private); | |
1205 | ||
1206 | delete_node(root, node, update_node, private); | |
6d75f366 JW |
1207 | } |
1208 | ||
1209 | /** | |
1210 | * radix_tree_replace_slot - replace item in a slot | |
1211 | * @root: radix tree root | |
1212 | * @slot: pointer to slot | |
1213 | * @item: new item to store in the slot. | |
1214 | * | |
1215 | * For use with radix_tree_lookup_slot(), radix_tree_gang_lookup_slot(), | |
1216 | * radix_tree_gang_lookup_tag_slot(). Caller must hold tree write locked | |
1217 | * across slot lookup and replacement. | |
1218 | * | |
1219 | * NOTE: This cannot be used to switch between non-entries (empty slots), | |
1220 | * regular entries, and exceptional entries, as that requires accounting | |
f4b109c6 | 1221 | * inside the radix tree node. When switching from one type of entry or |
e157b555 MW |
1222 | * deleting, use __radix_tree_lookup() and __radix_tree_replace() or |
1223 | * radix_tree_iter_replace(). | |
6d75f366 JW |
1224 | */ |
1225 | void radix_tree_replace_slot(struct radix_tree_root *root, | |
d7b62727 | 1226 | void __rcu **slot, void *item) |
6d75f366 | 1227 | { |
0a835c4f | 1228 | __radix_tree_replace(root, NULL, slot, item, NULL, NULL); |
6d75f366 | 1229 | } |
10257d71 | 1230 | EXPORT_SYMBOL(radix_tree_replace_slot); |
6d75f366 | 1231 | |
e157b555 MW |
1232 | /** |
1233 | * radix_tree_iter_replace - replace item in a slot | |
1234 | * @root: radix tree root | |
1235 | * @slot: pointer to slot | |
1236 | * @item: new item to store in the slot. | |
1237 | * | |
1238 | * For use with radix_tree_split() and radix_tree_for_each_slot(). | |
1239 | * Caller must hold tree write locked across split and replacement. | |
1240 | */ | |
1241 | void radix_tree_iter_replace(struct radix_tree_root *root, | |
d7b62727 MW |
1242 | const struct radix_tree_iter *iter, |
1243 | void __rcu **slot, void *item) | |
e157b555 MW |
1244 | { |
1245 | __radix_tree_replace(root, iter->node, slot, item, NULL, NULL); | |
1246 | } | |
1247 | ||
175542f5 MW |
1248 | #ifdef CONFIG_RADIX_TREE_MULTIORDER |
1249 | /** | |
1250 | * radix_tree_join - replace multiple entries with one multiorder entry | |
1251 | * @root: radix tree root | |
1252 | * @index: an index inside the new entry | |
1253 | * @order: order of the new entry | |
1254 | * @item: new entry | |
1255 | * | |
1256 | * Call this function to replace several entries with one larger entry. | |
1257 | * The existing entries are presumed to not need freeing as a result of | |
1258 | * this call. | |
1259 | * | |
1260 | * The replacement entry will have all the tags set on it that were set | |
1261 | * on any of the entries it is replacing. | |
1262 | */ | |
1263 | int radix_tree_join(struct radix_tree_root *root, unsigned long index, | |
1264 | unsigned order, void *item) | |
1265 | { | |
1266 | struct radix_tree_node *node; | |
d7b62727 | 1267 | void __rcu **slot; |
175542f5 MW |
1268 | int error; |
1269 | ||
1270 | BUG_ON(radix_tree_is_internal_node(item)); | |
1271 | ||
1272 | error = __radix_tree_create(root, index, order, &node, &slot); | |
1273 | if (!error) | |
1274 | error = insert_entries(node, slot, item, order, true); | |
1275 | if (error > 0) | |
1276 | error = 0; | |
1277 | ||
1278 | return error; | |
1279 | } | |
e157b555 MW |
1280 | |
1281 | /** | |
1282 | * radix_tree_split - Split an entry into smaller entries | |
1283 | * @root: radix tree root | |
1284 | * @index: An index within the large entry | |
1285 | * @order: Order of new entries | |
1286 | * | |
1287 | * Call this function as the first step in replacing a multiorder entry | |
1288 | * with several entries of lower order. After this function returns, | |
1289 | * loop over the relevant portion of the tree using radix_tree_for_each_slot() | |
1290 | * and call radix_tree_iter_replace() to set up each new entry. | |
1291 | * | |
1292 | * The tags from this entry are replicated to all the new entries. | |
1293 | * | |
1294 | * The radix tree should be locked against modification during the entire | |
1295 | * replacement operation. Lock-free lookups will see RADIX_TREE_RETRY which | |
1296 | * should prompt RCU walkers to restart the lookup from the root. | |
1297 | */ | |
1298 | int radix_tree_split(struct radix_tree_root *root, unsigned long index, | |
1299 | unsigned order) | |
1300 | { | |
1301 | struct radix_tree_node *parent, *node, *child; | |
d7b62727 | 1302 | void __rcu **slot; |
e157b555 MW |
1303 | unsigned int offset, end; |
1304 | unsigned n, tag, tags = 0; | |
0a835c4f | 1305 | gfp_t gfp = root_gfp_mask(root); |
e157b555 MW |
1306 | |
1307 | if (!__radix_tree_lookup(root, index, &parent, &slot)) | |
1308 | return -ENOENT; | |
1309 | if (!parent) | |
1310 | return -ENOENT; | |
1311 | ||
1312 | offset = get_slot_offset(parent, slot); | |
1313 | ||
1314 | for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) | |
1315 | if (tag_get(parent, tag, offset)) | |
1316 | tags |= 1 << tag; | |
1317 | ||
1318 | for (end = offset + 1; end < RADIX_TREE_MAP_SIZE; end++) { | |
12320d0f MW |
1319 | if (!is_sibling_entry(parent, |
1320 | rcu_dereference_raw(parent->slots[end]))) | |
e157b555 MW |
1321 | break; |
1322 | for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) | |
1323 | if (tags & (1 << tag)) | |
1324 | tag_set(parent, tag, end); | |
1325 | /* rcu_assign_pointer ensures tags are set before RETRY */ | |
1326 | rcu_assign_pointer(parent->slots[end], RADIX_TREE_RETRY); | |
1327 | } | |
1328 | rcu_assign_pointer(parent->slots[offset], RADIX_TREE_RETRY); | |
1329 | parent->exceptional -= (end - offset); | |
1330 | ||
1331 | if (order == parent->shift) | |
1332 | return 0; | |
1333 | if (order > parent->shift) { | |
1334 | while (offset < end) | |
1335 | offset += insert_entries(parent, &parent->slots[offset], | |
1336 | RADIX_TREE_RETRY, order, true); | |
1337 | return 0; | |
1338 | } | |
1339 | ||
1340 | node = parent; | |
1341 | ||
1342 | for (;;) { | |
1343 | if (node->shift > order) { | |
d58275bc | 1344 | child = radix_tree_node_alloc(gfp, node, root, |
e8de4340 MW |
1345 | node->shift - RADIX_TREE_MAP_SHIFT, |
1346 | offset, 0, 0); | |
e157b555 MW |
1347 | if (!child) |
1348 | goto nomem; | |
e157b555 MW |
1349 | if (node != parent) { |
1350 | node->count++; | |
12320d0f MW |
1351 | rcu_assign_pointer(node->slots[offset], |
1352 | node_to_entry(child)); | |
e157b555 MW |
1353 | for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) |
1354 | if (tags & (1 << tag)) | |
1355 | tag_set(node, tag, offset); | |
1356 | } | |
1357 | ||
1358 | node = child; | |
1359 | offset = 0; | |
1360 | continue; | |
1361 | } | |
1362 | ||
1363 | n = insert_entries(node, &node->slots[offset], | |
1364 | RADIX_TREE_RETRY, order, false); | |
1365 | BUG_ON(n > RADIX_TREE_MAP_SIZE); | |
1366 | ||
1367 | for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) | |
1368 | if (tags & (1 << tag)) | |
1369 | tag_set(node, tag, offset); | |
1370 | offset += n; | |
1371 | ||
1372 | while (offset == RADIX_TREE_MAP_SIZE) { | |
1373 | if (node == parent) | |
1374 | break; | |
1375 | offset = node->offset; | |
1376 | child = node; | |
1377 | node = node->parent; | |
1378 | rcu_assign_pointer(node->slots[offset], | |
1379 | node_to_entry(child)); | |
1380 | offset++; | |
1381 | } | |
1382 | if ((node == parent) && (offset == end)) | |
1383 | return 0; | |
1384 | } | |
1385 | ||
1386 | nomem: | |
1387 | /* Shouldn't happen; did user forget to preload? */ | |
1388 | /* TODO: free all the allocated nodes */ | |
1389 | WARN_ON(1); | |
1390 | return -ENOMEM; | |
1391 | } | |
175542f5 MW |
1392 | #endif |
1393 | ||
30b888ba MW |
1394 | static void node_tag_set(struct radix_tree_root *root, |
1395 | struct radix_tree_node *node, | |
1396 | unsigned int tag, unsigned int offset) | |
1397 | { | |
1398 | while (node) { | |
1399 | if (tag_get(node, tag, offset)) | |
1400 | return; | |
1401 | tag_set(node, tag, offset); | |
1402 | offset = node->offset; | |
1403 | node = node->parent; | |
1404 | } | |
1405 | ||
1406 | if (!root_tag_get(root, tag)) | |
1407 | root_tag_set(root, tag); | |
1408 | } | |
1409 | ||
1da177e4 LT |
1410 | /** |
1411 | * radix_tree_tag_set - set a tag on a radix tree node | |
1412 | * @root: radix tree root | |
1413 | * @index: index key | |
2fcd9005 | 1414 | * @tag: tag index |
1da177e4 | 1415 | * |
daff89f3 JC |
1416 | * Set the search tag (which must be < RADIX_TREE_MAX_TAGS) |
1417 | * corresponding to @index in the radix tree. From | |
1da177e4 LT |
1418 | * the root all the way down to the leaf node. |
1419 | * | |
2fcd9005 | 1420 | * Returns the address of the tagged item. Setting a tag on a not-present |
1da177e4 LT |
1421 | * item is a bug. |
1422 | */ | |
1423 | void *radix_tree_tag_set(struct radix_tree_root *root, | |
daff89f3 | 1424 | unsigned long index, unsigned int tag) |
1da177e4 | 1425 | { |
fb969909 RZ |
1426 | struct radix_tree_node *node, *parent; |
1427 | unsigned long maxindex; | |
1da177e4 | 1428 | |
9e85d811 | 1429 | radix_tree_load_root(root, &node, &maxindex); |
fb969909 | 1430 | BUG_ON(index > maxindex); |
1da177e4 | 1431 | |
b194d16c | 1432 | while (radix_tree_is_internal_node(node)) { |
fb969909 | 1433 | unsigned offset; |
1da177e4 | 1434 | |
4dd6c098 | 1435 | parent = entry_to_node(node); |
9e85d811 | 1436 | offset = radix_tree_descend(parent, &node, index); |
fb969909 RZ |
1437 | BUG_ON(!node); |
1438 | ||
1439 | if (!tag_get(parent, tag, offset)) | |
1440 | tag_set(parent, tag, offset); | |
1da177e4 LT |
1441 | } |
1442 | ||
612d6c19 | 1443 | /* set the root's tag bit */ |
fb969909 | 1444 | if (!root_tag_get(root, tag)) |
612d6c19 NP |
1445 | root_tag_set(root, tag); |
1446 | ||
fb969909 | 1447 | return node; |
1da177e4 LT |
1448 | } |
1449 | EXPORT_SYMBOL(radix_tree_tag_set); | |
1450 | ||
30b888ba MW |
1451 | /** |
1452 | * radix_tree_iter_tag_set - set a tag on the current iterator entry | |
1453 | * @root: radix tree root | |
1454 | * @iter: iterator state | |
1455 | * @tag: tag to set | |
1456 | */ | |
1457 | void radix_tree_iter_tag_set(struct radix_tree_root *root, | |
1458 | const struct radix_tree_iter *iter, unsigned int tag) | |
1459 | { | |
1460 | node_tag_set(root, iter->node, tag, iter_offset(iter)); | |
1461 | } | |
1462 | ||
d604c324 MW |
1463 | static void node_tag_clear(struct radix_tree_root *root, |
1464 | struct radix_tree_node *node, | |
1465 | unsigned int tag, unsigned int offset) | |
1466 | { | |
1467 | while (node) { | |
1468 | if (!tag_get(node, tag, offset)) | |
1469 | return; | |
1470 | tag_clear(node, tag, offset); | |
1471 | if (any_tag_set(node, tag)) | |
1472 | return; | |
1473 | ||
1474 | offset = node->offset; | |
1475 | node = node->parent; | |
1476 | } | |
1477 | ||
1478 | /* clear the root's tag bit */ | |
1479 | if (root_tag_get(root, tag)) | |
1480 | root_tag_clear(root, tag); | |
1481 | } | |
1482 | ||
1da177e4 LT |
1483 | /** |
1484 | * radix_tree_tag_clear - clear a tag on a radix tree node | |
1485 | * @root: radix tree root | |
1486 | * @index: index key | |
2fcd9005 | 1487 | * @tag: tag index |
1da177e4 | 1488 | * |
daff89f3 | 1489 | * Clear the search tag (which must be < RADIX_TREE_MAX_TAGS) |
2fcd9005 MW |
1490 | * corresponding to @index in the radix tree. If this causes |
1491 | * the leaf node to have no tags set then clear the tag in the | |
1da177e4 LT |
1492 | * next-to-leaf node, etc. |
1493 | * | |
1494 | * Returns the address of the tagged item on success, else NULL. ie: | |
1495 | * has the same return value and semantics as radix_tree_lookup(). | |
1496 | */ | |
1497 | void *radix_tree_tag_clear(struct radix_tree_root *root, | |
daff89f3 | 1498 | unsigned long index, unsigned int tag) |
1da177e4 | 1499 | { |
00f47b58 RZ |
1500 | struct radix_tree_node *node, *parent; |
1501 | unsigned long maxindex; | |
e2bdb933 | 1502 | int uninitialized_var(offset); |
1da177e4 | 1503 | |
9e85d811 | 1504 | radix_tree_load_root(root, &node, &maxindex); |
00f47b58 RZ |
1505 | if (index > maxindex) |
1506 | return NULL; | |
1da177e4 | 1507 | |
00f47b58 | 1508 | parent = NULL; |
1da177e4 | 1509 | |
b194d16c | 1510 | while (radix_tree_is_internal_node(node)) { |
4dd6c098 | 1511 | parent = entry_to_node(node); |
9e85d811 | 1512 | offset = radix_tree_descend(parent, &node, index); |
1da177e4 LT |
1513 | } |
1514 | ||
d604c324 MW |
1515 | if (node) |
1516 | node_tag_clear(root, parent, tag, offset); | |
1da177e4 | 1517 | |
00f47b58 | 1518 | return node; |
1da177e4 LT |
1519 | } |
1520 | EXPORT_SYMBOL(radix_tree_tag_clear); | |
1521 | ||
30b888ba MW |
1522 | /** |
1523 | * radix_tree_iter_tag_clear - clear a tag on the current iterator entry | |
1524 | * @root: radix tree root | |
1525 | * @iter: iterator state | |
1526 | * @tag: tag to clear | |
1527 | */ | |
1528 | void radix_tree_iter_tag_clear(struct radix_tree_root *root, | |
1529 | const struct radix_tree_iter *iter, unsigned int tag) | |
1530 | { | |
1531 | node_tag_clear(root, iter->node, tag, iter_offset(iter)); | |
1532 | } | |
1533 | ||
1da177e4 | 1534 | /** |
32605a18 MT |
1535 | * radix_tree_tag_get - get a tag on a radix tree node |
1536 | * @root: radix tree root | |
1537 | * @index: index key | |
2fcd9005 | 1538 | * @tag: tag index (< RADIX_TREE_MAX_TAGS) |
1da177e4 | 1539 | * |
32605a18 | 1540 | * Return values: |
1da177e4 | 1541 | * |
612d6c19 NP |
1542 | * 0: tag not present or not set |
1543 | * 1: tag set | |
ce82653d DH |
1544 | * |
1545 | * Note that the return value of this function may not be relied on, even if | |
1546 | * the RCU lock is held, unless tag modification and node deletion are excluded | |
1547 | * from concurrency. | |
1da177e4 | 1548 | */ |
35534c86 | 1549 | int radix_tree_tag_get(const struct radix_tree_root *root, |
daff89f3 | 1550 | unsigned long index, unsigned int tag) |
1da177e4 | 1551 | { |
4589ba6d RZ |
1552 | struct radix_tree_node *node, *parent; |
1553 | unsigned long maxindex; | |
1da177e4 | 1554 | |
612d6c19 NP |
1555 | if (!root_tag_get(root, tag)) |
1556 | return 0; | |
1557 | ||
9e85d811 | 1558 | radix_tree_load_root(root, &node, &maxindex); |
4589ba6d RZ |
1559 | if (index > maxindex) |
1560 | return 0; | |
7cf9c2c7 | 1561 | |
b194d16c | 1562 | while (radix_tree_is_internal_node(node)) { |
9e85d811 | 1563 | unsigned offset; |
1da177e4 | 1564 | |
4dd6c098 | 1565 | parent = entry_to_node(node); |
9e85d811 | 1566 | offset = radix_tree_descend(parent, &node, index); |
1da177e4 | 1567 | |
4589ba6d | 1568 | if (!tag_get(parent, tag, offset)) |
3fa36acb | 1569 | return 0; |
4589ba6d RZ |
1570 | if (node == RADIX_TREE_RETRY) |
1571 | break; | |
1da177e4 | 1572 | } |
4589ba6d RZ |
1573 | |
1574 | return 1; | |
1da177e4 LT |
1575 | } |
1576 | EXPORT_SYMBOL(radix_tree_tag_get); | |
1da177e4 | 1577 | |
21ef5339 RZ |
1578 | static inline void __set_iter_shift(struct radix_tree_iter *iter, |
1579 | unsigned int shift) | |
1580 | { | |
1581 | #ifdef CONFIG_RADIX_TREE_MULTIORDER | |
1582 | iter->shift = shift; | |
1583 | #endif | |
1584 | } | |
1585 | ||
148deab2 MW |
1586 | /* Construct iter->tags bit-mask from node->tags[tag] array */ |
1587 | static void set_iter_tags(struct radix_tree_iter *iter, | |
1588 | struct radix_tree_node *node, unsigned offset, | |
1589 | unsigned tag) | |
1590 | { | |
1591 | unsigned tag_long = offset / BITS_PER_LONG; | |
1592 | unsigned tag_bit = offset % BITS_PER_LONG; | |
1593 | ||
0a835c4f MW |
1594 | if (!node) { |
1595 | iter->tags = 1; | |
1596 | return; | |
1597 | } | |
1598 | ||
148deab2 MW |
1599 | iter->tags = node->tags[tag][tag_long] >> tag_bit; |
1600 | ||
1601 | /* This never happens if RADIX_TREE_TAG_LONGS == 1 */ | |
1602 | if (tag_long < RADIX_TREE_TAG_LONGS - 1) { | |
1603 | /* Pick tags from next element */ | |
1604 | if (tag_bit) | |
1605 | iter->tags |= node->tags[tag][tag_long + 1] << | |
1606 | (BITS_PER_LONG - tag_bit); | |
1607 | /* Clip chunk size, here only BITS_PER_LONG tags */ | |
1608 | iter->next_index = __radix_tree_iter_add(iter, BITS_PER_LONG); | |
1609 | } | |
1610 | } | |
1611 | ||
1612 | #ifdef CONFIG_RADIX_TREE_MULTIORDER | |
d7b62727 MW |
1613 | static void __rcu **skip_siblings(struct radix_tree_node **nodep, |
1614 | void __rcu **slot, struct radix_tree_iter *iter) | |
148deab2 MW |
1615 | { |
1616 | void *sib = node_to_entry(slot - 1); | |
1617 | ||
1618 | while (iter->index < iter->next_index) { | |
1619 | *nodep = rcu_dereference_raw(*slot); | |
1620 | if (*nodep && *nodep != sib) | |
1621 | return slot; | |
1622 | slot++; | |
1623 | iter->index = __radix_tree_iter_add(iter, 1); | |
1624 | iter->tags >>= 1; | |
1625 | } | |
1626 | ||
1627 | *nodep = NULL; | |
1628 | return NULL; | |
1629 | } | |
1630 | ||
d7b62727 MW |
1631 | void __rcu **__radix_tree_next_slot(void __rcu **slot, |
1632 | struct radix_tree_iter *iter, unsigned flags) | |
148deab2 MW |
1633 | { |
1634 | unsigned tag = flags & RADIX_TREE_ITER_TAG_MASK; | |
1635 | struct radix_tree_node *node = rcu_dereference_raw(*slot); | |
1636 | ||
1637 | slot = skip_siblings(&node, slot, iter); | |
1638 | ||
1639 | while (radix_tree_is_internal_node(node)) { | |
1640 | unsigned offset; | |
1641 | unsigned long next_index; | |
1642 | ||
1643 | if (node == RADIX_TREE_RETRY) | |
1644 | return slot; | |
1645 | node = entry_to_node(node); | |
268f42de | 1646 | iter->node = node; |
148deab2 MW |
1647 | iter->shift = node->shift; |
1648 | ||
1649 | if (flags & RADIX_TREE_ITER_TAGGED) { | |
1650 | offset = radix_tree_find_next_bit(node, tag, 0); | |
1651 | if (offset == RADIX_TREE_MAP_SIZE) | |
1652 | return NULL; | |
1653 | slot = &node->slots[offset]; | |
1654 | iter->index = __radix_tree_iter_add(iter, offset); | |
1655 | set_iter_tags(iter, node, offset, tag); | |
1656 | node = rcu_dereference_raw(*slot); | |
1657 | } else { | |
1658 | offset = 0; | |
1659 | slot = &node->slots[0]; | |
1660 | for (;;) { | |
1661 | node = rcu_dereference_raw(*slot); | |
1662 | if (node) | |
1663 | break; | |
1664 | slot++; | |
1665 | offset++; | |
1666 | if (offset == RADIX_TREE_MAP_SIZE) | |
1667 | return NULL; | |
1668 | } | |
1669 | iter->index = __radix_tree_iter_add(iter, offset); | |
1670 | } | |
1671 | if ((flags & RADIX_TREE_ITER_CONTIG) && (offset > 0)) | |
1672 | goto none; | |
1673 | next_index = (iter->index | shift_maxindex(iter->shift)) + 1; | |
1674 | if (next_index < iter->next_index) | |
1675 | iter->next_index = next_index; | |
1676 | } | |
1677 | ||
1678 | return slot; | |
1679 | none: | |
1680 | iter->next_index = 0; | |
1681 | return NULL; | |
1682 | } | |
1683 | EXPORT_SYMBOL(__radix_tree_next_slot); | |
1684 | #else | |
d7b62727 MW |
1685 | static void __rcu **skip_siblings(struct radix_tree_node **nodep, |
1686 | void __rcu **slot, struct radix_tree_iter *iter) | |
148deab2 MW |
1687 | { |
1688 | return slot; | |
1689 | } | |
1690 | #endif | |
1691 | ||
d7b62727 MW |
1692 | void __rcu **radix_tree_iter_resume(void __rcu **slot, |
1693 | struct radix_tree_iter *iter) | |
148deab2 MW |
1694 | { |
1695 | struct radix_tree_node *node; | |
1696 | ||
1697 | slot++; | |
1698 | iter->index = __radix_tree_iter_add(iter, 1); | |
148deab2 MW |
1699 | skip_siblings(&node, slot, iter); |
1700 | iter->next_index = iter->index; | |
1701 | iter->tags = 0; | |
1702 | return NULL; | |
1703 | } | |
1704 | EXPORT_SYMBOL(radix_tree_iter_resume); | |
1705 | ||
78c1d784 KK |
1706 | /** |
1707 | * radix_tree_next_chunk - find next chunk of slots for iteration | |
1708 | * | |
1709 | * @root: radix tree root | |
1710 | * @iter: iterator state | |
1711 | * @flags: RADIX_TREE_ITER_* flags and tag index | |
1712 | * Returns: pointer to chunk first slot, or NULL if iteration is over | |
1713 | */ | |
d7b62727 | 1714 | void __rcu **radix_tree_next_chunk(const struct radix_tree_root *root, |
78c1d784 KK |
1715 | struct radix_tree_iter *iter, unsigned flags) |
1716 | { | |
9e85d811 | 1717 | unsigned tag = flags & RADIX_TREE_ITER_TAG_MASK; |
8c1244de | 1718 | struct radix_tree_node *node, *child; |
21ef5339 | 1719 | unsigned long index, offset, maxindex; |
78c1d784 KK |
1720 | |
1721 | if ((flags & RADIX_TREE_ITER_TAGGED) && !root_tag_get(root, tag)) | |
1722 | return NULL; | |
1723 | ||
1724 | /* | |
1725 | * Catch next_index overflow after ~0UL. iter->index never overflows | |
1726 | * during iterating; it can be zero only at the beginning. | |
1727 | * And we cannot overflow iter->next_index in a single step, | |
1728 | * because RADIX_TREE_MAP_SHIFT < BITS_PER_LONG. | |
fffaee36 KK |
1729 | * |
1730 | * This condition also used by radix_tree_next_slot() to stop | |
91b9677c | 1731 | * contiguous iterating, and forbid switching to the next chunk. |
78c1d784 KK |
1732 | */ |
1733 | index = iter->next_index; | |
1734 | if (!index && iter->index) | |
1735 | return NULL; | |
1736 | ||
21ef5339 | 1737 | restart: |
9e85d811 | 1738 | radix_tree_load_root(root, &child, &maxindex); |
21ef5339 RZ |
1739 | if (index > maxindex) |
1740 | return NULL; | |
8c1244de MW |
1741 | if (!child) |
1742 | return NULL; | |
21ef5339 | 1743 | |
8c1244de | 1744 | if (!radix_tree_is_internal_node(child)) { |
78c1d784 | 1745 | /* Single-slot tree */ |
21ef5339 RZ |
1746 | iter->index = index; |
1747 | iter->next_index = maxindex + 1; | |
78c1d784 | 1748 | iter->tags = 1; |
268f42de | 1749 | iter->node = NULL; |
8c1244de | 1750 | __set_iter_shift(iter, 0); |
d7b62727 | 1751 | return (void __rcu **)&root->rnode; |
8c1244de | 1752 | } |
21ef5339 | 1753 | |
8c1244de MW |
1754 | do { |
1755 | node = entry_to_node(child); | |
9e85d811 | 1756 | offset = radix_tree_descend(node, &child, index); |
21ef5339 | 1757 | |
78c1d784 | 1758 | if ((flags & RADIX_TREE_ITER_TAGGED) ? |
8c1244de | 1759 | !tag_get(node, tag, offset) : !child) { |
78c1d784 KK |
1760 | /* Hole detected */ |
1761 | if (flags & RADIX_TREE_ITER_CONTIG) | |
1762 | return NULL; | |
1763 | ||
1764 | if (flags & RADIX_TREE_ITER_TAGGED) | |
bc412fca | 1765 | offset = radix_tree_find_next_bit(node, tag, |
78c1d784 KK |
1766 | offset + 1); |
1767 | else | |
1768 | while (++offset < RADIX_TREE_MAP_SIZE) { | |
12320d0f MW |
1769 | void *slot = rcu_dereference_raw( |
1770 | node->slots[offset]); | |
21ef5339 RZ |
1771 | if (is_sibling_entry(node, slot)) |
1772 | continue; | |
1773 | if (slot) | |
78c1d784 KK |
1774 | break; |
1775 | } | |
8c1244de | 1776 | index &= ~node_maxindex(node); |
9e85d811 | 1777 | index += offset << node->shift; |
78c1d784 KK |
1778 | /* Overflow after ~0UL */ |
1779 | if (!index) | |
1780 | return NULL; | |
1781 | if (offset == RADIX_TREE_MAP_SIZE) | |
1782 | goto restart; | |
8c1244de | 1783 | child = rcu_dereference_raw(node->slots[offset]); |
78c1d784 KK |
1784 | } |
1785 | ||
e157b555 | 1786 | if (!child) |
78c1d784 | 1787 | goto restart; |
e157b555 MW |
1788 | if (child == RADIX_TREE_RETRY) |
1789 | break; | |
8c1244de | 1790 | } while (radix_tree_is_internal_node(child)); |
78c1d784 KK |
1791 | |
1792 | /* Update the iterator state */ | |
8c1244de MW |
1793 | iter->index = (index &~ node_maxindex(node)) | (offset << node->shift); |
1794 | iter->next_index = (index | node_maxindex(node)) + 1; | |
268f42de | 1795 | iter->node = node; |
9e85d811 | 1796 | __set_iter_shift(iter, node->shift); |
78c1d784 | 1797 | |
148deab2 MW |
1798 | if (flags & RADIX_TREE_ITER_TAGGED) |
1799 | set_iter_tags(iter, node, offset, tag); | |
78c1d784 KK |
1800 | |
1801 | return node->slots + offset; | |
1802 | } | |
1803 | EXPORT_SYMBOL(radix_tree_next_chunk); | |
1804 | ||
1da177e4 LT |
1805 | /** |
1806 | * radix_tree_gang_lookup - perform multiple lookup on a radix tree | |
1807 | * @root: radix tree root | |
1808 | * @results: where the results of the lookup are placed | |
1809 | * @first_index: start the lookup from this key | |
1810 | * @max_items: place up to this many items at *results | |
1811 | * | |
1812 | * Performs an index-ascending scan of the tree for present items. Places | |
1813 | * them at *@results and returns the number of items which were placed at | |
1814 | * *@results. | |
1815 | * | |
1816 | * The implementation is naive. | |
7cf9c2c7 NP |
1817 | * |
1818 | * Like radix_tree_lookup, radix_tree_gang_lookup may be called under | |
1819 | * rcu_read_lock. In this case, rather than the returned results being | |
2fcd9005 MW |
1820 | * an atomic snapshot of the tree at a single point in time, the |
1821 | * semantics of an RCU protected gang lookup are as though multiple | |
1822 | * radix_tree_lookups have been issued in individual locks, and results | |
1823 | * stored in 'results'. | |
1da177e4 LT |
1824 | */ |
1825 | unsigned int | |
35534c86 | 1826 | radix_tree_gang_lookup(const struct radix_tree_root *root, void **results, |
1da177e4 LT |
1827 | unsigned long first_index, unsigned int max_items) |
1828 | { | |
cebbd29e | 1829 | struct radix_tree_iter iter; |
d7b62727 | 1830 | void __rcu **slot; |
cebbd29e | 1831 | unsigned int ret = 0; |
7cf9c2c7 | 1832 | |
cebbd29e | 1833 | if (unlikely(!max_items)) |
7cf9c2c7 | 1834 | return 0; |
1da177e4 | 1835 | |
cebbd29e | 1836 | radix_tree_for_each_slot(slot, root, &iter, first_index) { |
46437f9a | 1837 | results[ret] = rcu_dereference_raw(*slot); |
cebbd29e KK |
1838 | if (!results[ret]) |
1839 | continue; | |
b194d16c | 1840 | if (radix_tree_is_internal_node(results[ret])) { |
46437f9a MW |
1841 | slot = radix_tree_iter_retry(&iter); |
1842 | continue; | |
1843 | } | |
cebbd29e | 1844 | if (++ret == max_items) |
1da177e4 | 1845 | break; |
1da177e4 | 1846 | } |
7cf9c2c7 | 1847 | |
1da177e4 LT |
1848 | return ret; |
1849 | } | |
1850 | EXPORT_SYMBOL(radix_tree_gang_lookup); | |
1851 | ||
47feff2c NP |
1852 | /** |
1853 | * radix_tree_gang_lookup_slot - perform multiple slot lookup on radix tree | |
1854 | * @root: radix tree root | |
1855 | * @results: where the results of the lookup are placed | |
6328650b | 1856 | * @indices: where their indices should be placed (but usually NULL) |
47feff2c NP |
1857 | * @first_index: start the lookup from this key |
1858 | * @max_items: place up to this many items at *results | |
1859 | * | |
1860 | * Performs an index-ascending scan of the tree for present items. Places | |
1861 | * their slots at *@results and returns the number of items which were | |
1862 | * placed at *@results. | |
1863 | * | |
1864 | * The implementation is naive. | |
1865 | * | |
1866 | * Like radix_tree_gang_lookup as far as RCU and locking goes. Slots must | |
1867 | * be dereferenced with radix_tree_deref_slot, and if using only RCU | |
1868 | * protection, radix_tree_deref_slot may fail requiring a retry. | |
1869 | */ | |
1870 | unsigned int | |
35534c86 | 1871 | radix_tree_gang_lookup_slot(const struct radix_tree_root *root, |
d7b62727 | 1872 | void __rcu ***results, unsigned long *indices, |
47feff2c NP |
1873 | unsigned long first_index, unsigned int max_items) |
1874 | { | |
cebbd29e | 1875 | struct radix_tree_iter iter; |
d7b62727 | 1876 | void __rcu **slot; |
cebbd29e | 1877 | unsigned int ret = 0; |
47feff2c | 1878 | |
cebbd29e | 1879 | if (unlikely(!max_items)) |
47feff2c NP |
1880 | return 0; |
1881 | ||
cebbd29e KK |
1882 | radix_tree_for_each_slot(slot, root, &iter, first_index) { |
1883 | results[ret] = slot; | |
6328650b | 1884 | if (indices) |
cebbd29e KK |
1885 | indices[ret] = iter.index; |
1886 | if (++ret == max_items) | |
47feff2c | 1887 | break; |
47feff2c NP |
1888 | } |
1889 | ||
1890 | return ret; | |
1891 | } | |
1892 | EXPORT_SYMBOL(radix_tree_gang_lookup_slot); | |
1893 | ||
1da177e4 LT |
1894 | /** |
1895 | * radix_tree_gang_lookup_tag - perform multiple lookup on a radix tree | |
1896 | * based on a tag | |
1897 | * @root: radix tree root | |
1898 | * @results: where the results of the lookup are placed | |
1899 | * @first_index: start the lookup from this key | |
1900 | * @max_items: place up to this many items at *results | |
daff89f3 | 1901 | * @tag: the tag index (< RADIX_TREE_MAX_TAGS) |
1da177e4 LT |
1902 | * |
1903 | * Performs an index-ascending scan of the tree for present items which | |
1904 | * have the tag indexed by @tag set. Places the items at *@results and | |
1905 | * returns the number of items which were placed at *@results. | |
1906 | */ | |
1907 | unsigned int | |
35534c86 | 1908 | radix_tree_gang_lookup_tag(const struct radix_tree_root *root, void **results, |
daff89f3 JC |
1909 | unsigned long first_index, unsigned int max_items, |
1910 | unsigned int tag) | |
1da177e4 | 1911 | { |
cebbd29e | 1912 | struct radix_tree_iter iter; |
d7b62727 | 1913 | void __rcu **slot; |
cebbd29e | 1914 | unsigned int ret = 0; |
612d6c19 | 1915 | |
cebbd29e | 1916 | if (unlikely(!max_items)) |
7cf9c2c7 NP |
1917 | return 0; |
1918 | ||
cebbd29e | 1919 | radix_tree_for_each_tagged(slot, root, &iter, first_index, tag) { |
46437f9a | 1920 | results[ret] = rcu_dereference_raw(*slot); |
cebbd29e KK |
1921 | if (!results[ret]) |
1922 | continue; | |
b194d16c | 1923 | if (radix_tree_is_internal_node(results[ret])) { |
46437f9a MW |
1924 | slot = radix_tree_iter_retry(&iter); |
1925 | continue; | |
1926 | } | |
cebbd29e | 1927 | if (++ret == max_items) |
1da177e4 | 1928 | break; |
1da177e4 | 1929 | } |
7cf9c2c7 | 1930 | |
1da177e4 LT |
1931 | return ret; |
1932 | } | |
1933 | EXPORT_SYMBOL(radix_tree_gang_lookup_tag); | |
1934 | ||
47feff2c NP |
1935 | /** |
1936 | * radix_tree_gang_lookup_tag_slot - perform multiple slot lookup on a | |
1937 | * radix tree based on a tag | |
1938 | * @root: radix tree root | |
1939 | * @results: where the results of the lookup are placed | |
1940 | * @first_index: start the lookup from this key | |
1941 | * @max_items: place up to this many items at *results | |
1942 | * @tag: the tag index (< RADIX_TREE_MAX_TAGS) | |
1943 | * | |
1944 | * Performs an index-ascending scan of the tree for present items which | |
1945 | * have the tag indexed by @tag set. Places the slots at *@results and | |
1946 | * returns the number of slots which were placed at *@results. | |
1947 | */ | |
1948 | unsigned int | |
35534c86 | 1949 | radix_tree_gang_lookup_tag_slot(const struct radix_tree_root *root, |
d7b62727 | 1950 | void __rcu ***results, unsigned long first_index, |
35534c86 | 1951 | unsigned int max_items, unsigned int tag) |
47feff2c | 1952 | { |
cebbd29e | 1953 | struct radix_tree_iter iter; |
d7b62727 | 1954 | void __rcu **slot; |
cebbd29e | 1955 | unsigned int ret = 0; |
47feff2c | 1956 | |
cebbd29e | 1957 | if (unlikely(!max_items)) |
47feff2c NP |
1958 | return 0; |
1959 | ||
cebbd29e KK |
1960 | radix_tree_for_each_tagged(slot, root, &iter, first_index, tag) { |
1961 | results[ret] = slot; | |
1962 | if (++ret == max_items) | |
47feff2c | 1963 | break; |
47feff2c NP |
1964 | } |
1965 | ||
1966 | return ret; | |
1967 | } | |
1968 | EXPORT_SYMBOL(radix_tree_gang_lookup_tag_slot); | |
1969 | ||
139e5616 JW |
1970 | /** |
1971 | * __radix_tree_delete_node - try to free node after clearing a slot | |
1972 | * @root: radix tree root | |
139e5616 | 1973 | * @node: node containing @index |
ea07b862 JW |
1974 | * @update_node: callback for changing leaf nodes |
1975 | * @private: private data to pass to @update_node | |
139e5616 JW |
1976 | * |
1977 | * After clearing the slot at @index in @node from radix tree | |
1978 | * rooted at @root, call this function to attempt freeing the | |
1979 | * node and shrinking the tree. | |
139e5616 | 1980 | */ |
14b46879 | 1981 | void __radix_tree_delete_node(struct radix_tree_root *root, |
ea07b862 JW |
1982 | struct radix_tree_node *node, |
1983 | radix_tree_update_node_t update_node, | |
1984 | void *private) | |
139e5616 | 1985 | { |
ea07b862 | 1986 | delete_node(root, node, update_node, private); |
139e5616 JW |
1987 | } |
1988 | ||
0ac398ef | 1989 | static bool __radix_tree_delete(struct radix_tree_root *root, |
d7b62727 | 1990 | struct radix_tree_node *node, void __rcu **slot) |
0ac398ef | 1991 | { |
0a835c4f MW |
1992 | void *old = rcu_dereference_raw(*slot); |
1993 | int exceptional = radix_tree_exceptional_entry(old) ? -1 : 0; | |
0ac398ef MW |
1994 | unsigned offset = get_slot_offset(node, slot); |
1995 | int tag; | |
1996 | ||
0a835c4f MW |
1997 | if (is_idr(root)) |
1998 | node_tag_set(root, node, IDR_FREE, offset); | |
1999 | else | |
2000 | for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) | |
2001 | node_tag_clear(root, node, tag, offset); | |
0ac398ef | 2002 | |
0a835c4f | 2003 | replace_slot(slot, NULL, node, -1, exceptional); |
0ac398ef MW |
2004 | return node && delete_node(root, node, NULL, NULL); |
2005 | } | |
2006 | ||
1da177e4 | 2007 | /** |
0ac398ef MW |
2008 | * radix_tree_iter_delete - delete the entry at this iterator position |
2009 | * @root: radix tree root | |
2010 | * @iter: iterator state | |
2011 | * @slot: pointer to slot | |
1da177e4 | 2012 | * |
0ac398ef MW |
2013 | * Delete the entry at the position currently pointed to by the iterator. |
2014 | * This may result in the current node being freed; if it is, the iterator | |
2015 | * is advanced so that it will not reference the freed memory. This | |
2016 | * function may be called without any locking if there are no other threads | |
2017 | * which can access this tree. | |
2018 | */ | |
2019 | void radix_tree_iter_delete(struct radix_tree_root *root, | |
d7b62727 | 2020 | struct radix_tree_iter *iter, void __rcu **slot) |
0ac398ef MW |
2021 | { |
2022 | if (__radix_tree_delete(root, iter->node, slot)) | |
2023 | iter->index = iter->next_index; | |
2024 | } | |
2025 | ||
2026 | /** | |
2027 | * radix_tree_delete_item - delete an item from a radix tree | |
2028 | * @root: radix tree root | |
2029 | * @index: index key | |
2030 | * @item: expected item | |
1da177e4 | 2031 | * |
0ac398ef | 2032 | * Remove @item at @index from the radix tree rooted at @root. |
1da177e4 | 2033 | * |
0ac398ef MW |
2034 | * Return: the deleted entry, or %NULL if it was not present |
2035 | * or the entry at the given @index was not @item. | |
1da177e4 | 2036 | */ |
53c59f26 JW |
2037 | void *radix_tree_delete_item(struct radix_tree_root *root, |
2038 | unsigned long index, void *item) | |
1da177e4 | 2039 | { |
0a835c4f | 2040 | struct radix_tree_node *node = NULL; |
d7b62727 | 2041 | void __rcu **slot; |
139e5616 | 2042 | void *entry; |
1da177e4 | 2043 | |
139e5616 | 2044 | entry = __radix_tree_lookup(root, index, &node, &slot); |
0a835c4f MW |
2045 | if (!entry && (!is_idr(root) || node_tag_get(root, node, IDR_FREE, |
2046 | get_slot_offset(node, slot)))) | |
139e5616 | 2047 | return NULL; |
1da177e4 | 2048 | |
139e5616 JW |
2049 | if (item && entry != item) |
2050 | return NULL; | |
2051 | ||
0ac398ef | 2052 | __radix_tree_delete(root, node, slot); |
612d6c19 | 2053 | |
139e5616 | 2054 | return entry; |
1da177e4 | 2055 | } |
53c59f26 JW |
2056 | EXPORT_SYMBOL(radix_tree_delete_item); |
2057 | ||
2058 | /** | |
0ac398ef MW |
2059 | * radix_tree_delete - delete an entry from a radix tree |
2060 | * @root: radix tree root | |
2061 | * @index: index key | |
53c59f26 | 2062 | * |
0ac398ef | 2063 | * Remove the entry at @index from the radix tree rooted at @root. |
53c59f26 | 2064 | * |
0ac398ef | 2065 | * Return: The deleted entry, or %NULL if it was not present. |
53c59f26 JW |
2066 | */ |
2067 | void *radix_tree_delete(struct radix_tree_root *root, unsigned long index) | |
2068 | { | |
2069 | return radix_tree_delete_item(root, index, NULL); | |
2070 | } | |
1da177e4 LT |
2071 | EXPORT_SYMBOL(radix_tree_delete); |
2072 | ||
d3798ae8 JW |
2073 | void radix_tree_clear_tags(struct radix_tree_root *root, |
2074 | struct radix_tree_node *node, | |
d7b62727 | 2075 | void __rcu **slot) |
d604c324 | 2076 | { |
d604c324 MW |
2077 | if (node) { |
2078 | unsigned int tag, offset = get_slot_offset(node, slot); | |
2079 | for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) | |
2080 | node_tag_clear(root, node, tag, offset); | |
2081 | } else { | |
0a835c4f | 2082 | root_tag_clear_all(root); |
d604c324 | 2083 | } |
d604c324 MW |
2084 | } |
2085 | ||
1da177e4 LT |
2086 | /** |
2087 | * radix_tree_tagged - test whether any items in the tree are tagged | |
2088 | * @root: radix tree root | |
2089 | * @tag: tag to test | |
2090 | */ | |
35534c86 | 2091 | int radix_tree_tagged(const struct radix_tree_root *root, unsigned int tag) |
1da177e4 | 2092 | { |
612d6c19 | 2093 | return root_tag_get(root, tag); |
1da177e4 LT |
2094 | } |
2095 | EXPORT_SYMBOL(radix_tree_tagged); | |
2096 | ||
0a835c4f MW |
2097 | /** |
2098 | * idr_preload - preload for idr_alloc() | |
2099 | * @gfp_mask: allocation mask to use for preloading | |
2100 | * | |
2101 | * Preallocate memory to use for the next call to idr_alloc(). This function | |
2102 | * returns with preemption disabled. It will be enabled by idr_preload_end(). | |
2103 | */ | |
2104 | void idr_preload(gfp_t gfp_mask) | |
2105 | { | |
2106 | __radix_tree_preload(gfp_mask, IDR_PRELOAD_SIZE); | |
2107 | } | |
2108 | EXPORT_SYMBOL(idr_preload); | |
2109 | ||
7ad3d4d8 MW |
2110 | /** |
2111 | * ida_pre_get - reserve resources for ida allocation | |
2112 | * @ida: ida handle | |
2113 | * @gfp: memory allocation flags | |
2114 | * | |
2115 | * This function should be called before calling ida_get_new_above(). If it | |
2116 | * is unable to allocate memory, it will return %0. On success, it returns %1. | |
2117 | */ | |
2118 | int ida_pre_get(struct ida *ida, gfp_t gfp) | |
2119 | { | |
2120 | __radix_tree_preload(gfp, IDA_PRELOAD_SIZE); | |
2121 | /* | |
2122 | * The IDA API has no preload_end() equivalent. Instead, | |
2123 | * ida_get_new() can return -EAGAIN, prompting the caller | |
2124 | * to return to the ida_pre_get() step. | |
2125 | */ | |
2126 | preempt_enable(); | |
2127 | ||
2128 | if (!this_cpu_read(ida_bitmap)) { | |
2129 | struct ida_bitmap *bitmap = kmalloc(sizeof(*bitmap), gfp); | |
2130 | if (!bitmap) | |
2131 | return 0; | |
4ecd9542 MW |
2132 | if (this_cpu_cmpxchg(ida_bitmap, NULL, bitmap)) |
2133 | kfree(bitmap); | |
7ad3d4d8 MW |
2134 | } |
2135 | ||
2136 | return 1; | |
2137 | } | |
2138 | EXPORT_SYMBOL(ida_pre_get); | |
2139 | ||
d7b62727 | 2140 | void __rcu **idr_get_free(struct radix_tree_root *root, |
0a835c4f MW |
2141 | struct radix_tree_iter *iter, gfp_t gfp, int end) |
2142 | { | |
2143 | struct radix_tree_node *node = NULL, *child; | |
d7b62727 | 2144 | void __rcu **slot = (void __rcu **)&root->rnode; |
0a835c4f MW |
2145 | unsigned long maxindex, start = iter->next_index; |
2146 | unsigned long max = end > 0 ? end - 1 : INT_MAX; | |
2147 | unsigned int shift, offset = 0; | |
2148 | ||
2149 | grow: | |
2150 | shift = radix_tree_load_root(root, &child, &maxindex); | |
2151 | if (!radix_tree_tagged(root, IDR_FREE)) | |
2152 | start = max(start, maxindex + 1); | |
2153 | if (start > max) | |
2154 | return ERR_PTR(-ENOSPC); | |
2155 | ||
2156 | if (start > maxindex) { | |
2157 | int error = radix_tree_extend(root, gfp, start, shift); | |
2158 | if (error < 0) | |
2159 | return ERR_PTR(error); | |
2160 | shift = error; | |
2161 | child = rcu_dereference_raw(root->rnode); | |
2162 | } | |
2163 | ||
2164 | while (shift) { | |
2165 | shift -= RADIX_TREE_MAP_SHIFT; | |
2166 | if (child == NULL) { | |
2167 | /* Have to add a child node. */ | |
d58275bc MW |
2168 | child = radix_tree_node_alloc(gfp, node, root, shift, |
2169 | offset, 0, 0); | |
0a835c4f MW |
2170 | if (!child) |
2171 | return ERR_PTR(-ENOMEM); | |
2172 | all_tag_set(child, IDR_FREE); | |
2173 | rcu_assign_pointer(*slot, node_to_entry(child)); | |
2174 | if (node) | |
2175 | node->count++; | |
2176 | } else if (!radix_tree_is_internal_node(child)) | |
2177 | break; | |
2178 | ||
2179 | node = entry_to_node(child); | |
2180 | offset = radix_tree_descend(node, &child, start); | |
2181 | if (!tag_get(node, IDR_FREE, offset)) { | |
2182 | offset = radix_tree_find_next_bit(node, IDR_FREE, | |
2183 | offset + 1); | |
2184 | start = next_index(start, node, offset); | |
2185 | if (start > max) | |
2186 | return ERR_PTR(-ENOSPC); | |
2187 | while (offset == RADIX_TREE_MAP_SIZE) { | |
2188 | offset = node->offset + 1; | |
2189 | node = node->parent; | |
2190 | if (!node) | |
2191 | goto grow; | |
2192 | shift = node->shift; | |
2193 | } | |
2194 | child = rcu_dereference_raw(node->slots[offset]); | |
2195 | } | |
2196 | slot = &node->slots[offset]; | |
2197 | } | |
2198 | ||
2199 | iter->index = start; | |
2200 | if (node) | |
2201 | iter->next_index = 1 + min(max, (start | node_maxindex(node))); | |
2202 | else | |
2203 | iter->next_index = 1; | |
2204 | iter->node = node; | |
2205 | __set_iter_shift(iter, shift); | |
2206 | set_iter_tags(iter, node, offset, IDR_FREE); | |
2207 | ||
2208 | return slot; | |
2209 | } | |
2210 | ||
2211 | /** | |
2212 | * idr_destroy - release all internal memory from an IDR | |
2213 | * @idr: idr handle | |
2214 | * | |
2215 | * After this function is called, the IDR is empty, and may be reused or | |
2216 | * the data structure containing it may be freed. | |
2217 | * | |
2218 | * A typical clean-up sequence for objects stored in an idr tree will use | |
2219 | * idr_for_each() to free all objects, if necessary, then idr_destroy() to | |
2220 | * free the memory used to keep track of those objects. | |
2221 | */ | |
2222 | void idr_destroy(struct idr *idr) | |
2223 | { | |
2224 | struct radix_tree_node *node = rcu_dereference_raw(idr->idr_rt.rnode); | |
2225 | if (radix_tree_is_internal_node(node)) | |
2226 | radix_tree_free_nodes(node); | |
2227 | idr->idr_rt.rnode = NULL; | |
2228 | root_tag_set(&idr->idr_rt, IDR_FREE); | |
2229 | } | |
2230 | EXPORT_SYMBOL(idr_destroy); | |
2231 | ||
1da177e4 | 2232 | static void |
449dd698 | 2233 | radix_tree_node_ctor(void *arg) |
1da177e4 | 2234 | { |
449dd698 JW |
2235 | struct radix_tree_node *node = arg; |
2236 | ||
2237 | memset(node, 0, sizeof(*node)); | |
2238 | INIT_LIST_HEAD(&node->private_list); | |
1da177e4 LT |
2239 | } |
2240 | ||
c78c66d1 KS |
2241 | static __init unsigned long __maxindex(unsigned int height) |
2242 | { | |
2243 | unsigned int width = height * RADIX_TREE_MAP_SHIFT; | |
2244 | int shift = RADIX_TREE_INDEX_BITS - width; | |
2245 | ||
2246 | if (shift < 0) | |
2247 | return ~0UL; | |
2248 | if (shift >= BITS_PER_LONG) | |
2249 | return 0UL; | |
2250 | return ~0UL >> shift; | |
2251 | } | |
2252 | ||
2253 | static __init void radix_tree_init_maxnodes(void) | |
2254 | { | |
2255 | unsigned long height_to_maxindex[RADIX_TREE_MAX_PATH + 1]; | |
2256 | unsigned int i, j; | |
2257 | ||
2258 | for (i = 0; i < ARRAY_SIZE(height_to_maxindex); i++) | |
2259 | height_to_maxindex[i] = __maxindex(i); | |
2260 | for (i = 0; i < ARRAY_SIZE(height_to_maxnodes); i++) { | |
2261 | for (j = i; j > 0; j--) | |
2262 | height_to_maxnodes[i] += height_to_maxindex[j - 1] + 1; | |
2263 | } | |
2264 | } | |
2265 | ||
d544abd5 | 2266 | static int radix_tree_cpu_dead(unsigned int cpu) |
1da177e4 | 2267 | { |
2fcd9005 MW |
2268 | struct radix_tree_preload *rtp; |
2269 | struct radix_tree_node *node; | |
2270 | ||
2271 | /* Free per-cpu pool of preloaded nodes */ | |
d544abd5 SAS |
2272 | rtp = &per_cpu(radix_tree_preloads, cpu); |
2273 | while (rtp->nr) { | |
2274 | node = rtp->nodes; | |
1293d5c5 | 2275 | rtp->nodes = node->parent; |
d544abd5 SAS |
2276 | kmem_cache_free(radix_tree_node_cachep, node); |
2277 | rtp->nr--; | |
2fcd9005 | 2278 | } |
7ad3d4d8 MW |
2279 | kfree(per_cpu(ida_bitmap, cpu)); |
2280 | per_cpu(ida_bitmap, cpu) = NULL; | |
d544abd5 | 2281 | return 0; |
1da177e4 | 2282 | } |
1da177e4 LT |
2283 | |
2284 | void __init radix_tree_init(void) | |
2285 | { | |
d544abd5 | 2286 | int ret; |
7e784422 MH |
2287 | |
2288 | BUILD_BUG_ON(RADIX_TREE_MAX_TAGS + __GFP_BITS_SHIFT > 32); | |
1da177e4 LT |
2289 | radix_tree_node_cachep = kmem_cache_create("radix_tree_node", |
2290 | sizeof(struct radix_tree_node), 0, | |
488514d1 CL |
2291 | SLAB_PANIC | SLAB_RECLAIM_ACCOUNT, |
2292 | radix_tree_node_ctor); | |
c78c66d1 | 2293 | radix_tree_init_maxnodes(); |
d544abd5 SAS |
2294 | ret = cpuhp_setup_state_nocalls(CPUHP_RADIX_DEAD, "lib/radix:dead", |
2295 | NULL, radix_tree_cpu_dead); | |
2296 | WARN_ON(ret < 0); | |
1da177e4 | 2297 | } |