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de6cc651 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
1da177e4 LT |
2 | /* |
3 | * Copyright (C) 2001 Momchil Velikov | |
4 | * Portions Copyright (C) 2001 Christoph Hellwig | |
cde53535 | 5 | * Copyright (C) 2005 SGI, Christoph Lameter |
7cf9c2c7 | 6 | * Copyright (C) 2006 Nick Piggin |
78c1d784 | 7 | * Copyright (C) 2012 Konstantin Khlebnikov |
6b053b8e MW |
8 | * Copyright (C) 2016 Intel, Matthew Wilcox |
9 | * Copyright (C) 2016 Intel, Ross Zwisler | |
1da177e4 LT |
10 | */ |
11 | ||
0a835c4f MW |
12 | #include <linux/bitmap.h> |
13 | #include <linux/bitops.h> | |
460488c5 | 14 | #include <linux/bug.h> |
e157b555 | 15 | #include <linux/cpu.h> |
1da177e4 | 16 | #include <linux/errno.h> |
0a835c4f MW |
17 | #include <linux/export.h> |
18 | #include <linux/idr.h> | |
1da177e4 LT |
19 | #include <linux/init.h> |
20 | #include <linux/kernel.h> | |
0a835c4f | 21 | #include <linux/kmemleak.h> |
1da177e4 | 22 | #include <linux/percpu.h> |
0a835c4f MW |
23 | #include <linux/preempt.h> /* in_interrupt() */ |
24 | #include <linux/radix-tree.h> | |
25 | #include <linux/rcupdate.h> | |
1da177e4 | 26 | #include <linux/slab.h> |
1da177e4 | 27 | #include <linux/string.h> |
02c02bf1 | 28 | #include <linux/xarray.h> |
1da177e4 | 29 | |
05fdd323 | 30 | |
1da177e4 LT |
31 | /* |
32 | * Radix tree node cache. | |
33 | */ | |
58d6ea30 | 34 | struct kmem_cache *radix_tree_node_cachep; |
1da177e4 | 35 | |
55368052 NP |
36 | /* |
37 | * The radix tree is variable-height, so an insert operation not only has | |
38 | * to build the branch to its corresponding item, it also has to build the | |
39 | * branch to existing items if the size has to be increased (by | |
40 | * radix_tree_extend). | |
41 | * | |
42 | * The worst case is a zero height tree with just a single item at index 0, | |
43 | * and then inserting an item at index ULONG_MAX. This requires 2 new branches | |
44 | * of RADIX_TREE_MAX_PATH size to be created, with only the root node shared. | |
45 | * Hence: | |
46 | */ | |
47 | #define RADIX_TREE_PRELOAD_SIZE (RADIX_TREE_MAX_PATH * 2 - 1) | |
48 | ||
0a835c4f MW |
49 | /* |
50 | * The IDR does not have to be as high as the radix tree since it uses | |
51 | * signed integers, not unsigned longs. | |
52 | */ | |
53 | #define IDR_INDEX_BITS (8 /* CHAR_BIT */ * sizeof(int) - 1) | |
54 | #define IDR_MAX_PATH (DIV_ROUND_UP(IDR_INDEX_BITS, \ | |
55 | RADIX_TREE_MAP_SHIFT)) | |
56 | #define IDR_PRELOAD_SIZE (IDR_MAX_PATH * 2 - 1) | |
57 | ||
1da177e4 LT |
58 | /* |
59 | * Per-cpu pool of preloaded nodes | |
60 | */ | |
05fdd323 SF |
61 | struct radix_tree_preload { |
62 | unsigned nr; | |
63 | /* nodes->parent points to next preallocated node */ | |
64 | struct radix_tree_node *nodes; | |
1da177e4 | 65 | }; |
05fdd323 | 66 | static DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, }; |
1da177e4 | 67 | |
148deab2 MW |
68 | static inline struct radix_tree_node *entry_to_node(void *ptr) |
69 | { | |
70 | return (void *)((unsigned long)ptr & ~RADIX_TREE_INTERNAL_NODE); | |
71 | } | |
72 | ||
a4db4dce | 73 | static inline void *node_to_entry(void *ptr) |
27d20fdd | 74 | { |
30ff46cc | 75 | return (void *)((unsigned long)ptr | RADIX_TREE_INTERNAL_NODE); |
27d20fdd NP |
76 | } |
77 | ||
02c02bf1 | 78 | #define RADIX_TREE_RETRY XA_RETRY_ENTRY |
db050f29 | 79 | |
d7b62727 MW |
80 | static inline unsigned long |
81 | get_slot_offset(const struct radix_tree_node *parent, void __rcu **slot) | |
db050f29 | 82 | { |
76f070b4 | 83 | return parent ? slot - parent->slots : 0; |
db050f29 MW |
84 | } |
85 | ||
35534c86 | 86 | static unsigned int radix_tree_descend(const struct radix_tree_node *parent, |
9e85d811 | 87 | struct radix_tree_node **nodep, unsigned long index) |
db050f29 | 88 | { |
9e85d811 | 89 | unsigned int offset = (index >> parent->shift) & RADIX_TREE_MAP_MASK; |
d7b62727 | 90 | void __rcu **entry = rcu_dereference_raw(parent->slots[offset]); |
db050f29 | 91 | |
db050f29 MW |
92 | *nodep = (void *)entry; |
93 | return offset; | |
94 | } | |
95 | ||
35534c86 | 96 | static inline gfp_t root_gfp_mask(const struct radix_tree_root *root) |
612d6c19 | 97 | { |
f8d5d0cc | 98 | return root->xa_flags & (__GFP_BITS_MASK & ~GFP_ZONEMASK); |
612d6c19 NP |
99 | } |
100 | ||
643b52b9 NP |
101 | static inline void tag_set(struct radix_tree_node *node, unsigned int tag, |
102 | int offset) | |
103 | { | |
104 | __set_bit(offset, node->tags[tag]); | |
105 | } | |
106 | ||
107 | static inline void tag_clear(struct radix_tree_node *node, unsigned int tag, | |
108 | int offset) | |
109 | { | |
110 | __clear_bit(offset, node->tags[tag]); | |
111 | } | |
112 | ||
35534c86 | 113 | static inline int tag_get(const struct radix_tree_node *node, unsigned int tag, |
643b52b9 NP |
114 | int offset) |
115 | { | |
116 | return test_bit(offset, node->tags[tag]); | |
117 | } | |
118 | ||
35534c86 | 119 | static inline void root_tag_set(struct radix_tree_root *root, unsigned tag) |
643b52b9 | 120 | { |
f8d5d0cc | 121 | root->xa_flags |= (__force gfp_t)(1 << (tag + ROOT_TAG_SHIFT)); |
643b52b9 NP |
122 | } |
123 | ||
2fcd9005 | 124 | static inline void root_tag_clear(struct radix_tree_root *root, unsigned tag) |
643b52b9 | 125 | { |
f8d5d0cc | 126 | root->xa_flags &= (__force gfp_t)~(1 << (tag + ROOT_TAG_SHIFT)); |
643b52b9 NP |
127 | } |
128 | ||
129 | static inline void root_tag_clear_all(struct radix_tree_root *root) | |
130 | { | |
f8d5d0cc | 131 | root->xa_flags &= (__force gfp_t)((1 << ROOT_TAG_SHIFT) - 1); |
643b52b9 NP |
132 | } |
133 | ||
35534c86 | 134 | static inline int root_tag_get(const struct radix_tree_root *root, unsigned tag) |
643b52b9 | 135 | { |
f8d5d0cc | 136 | return (__force int)root->xa_flags & (1 << (tag + ROOT_TAG_SHIFT)); |
643b52b9 NP |
137 | } |
138 | ||
35534c86 | 139 | static inline unsigned root_tags_get(const struct radix_tree_root *root) |
643b52b9 | 140 | { |
f8d5d0cc | 141 | return (__force unsigned)root->xa_flags >> ROOT_TAG_SHIFT; |
643b52b9 NP |
142 | } |
143 | ||
0a835c4f | 144 | static inline bool is_idr(const struct radix_tree_root *root) |
7b60e9ad | 145 | { |
f8d5d0cc | 146 | return !!(root->xa_flags & ROOT_IS_IDR); |
7b60e9ad MW |
147 | } |
148 | ||
643b52b9 NP |
149 | /* |
150 | * Returns 1 if any slot in the node has this tag set. | |
151 | * Otherwise returns 0. | |
152 | */ | |
35534c86 MW |
153 | static inline int any_tag_set(const struct radix_tree_node *node, |
154 | unsigned int tag) | |
643b52b9 | 155 | { |
2fcd9005 | 156 | unsigned idx; |
643b52b9 NP |
157 | for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) { |
158 | if (node->tags[tag][idx]) | |
159 | return 1; | |
160 | } | |
161 | return 0; | |
162 | } | |
78c1d784 | 163 | |
0a835c4f MW |
164 | static inline void all_tag_set(struct radix_tree_node *node, unsigned int tag) |
165 | { | |
166 | bitmap_fill(node->tags[tag], RADIX_TREE_MAP_SIZE); | |
167 | } | |
168 | ||
78c1d784 KK |
169 | /** |
170 | * radix_tree_find_next_bit - find the next set bit in a memory region | |
171 | * | |
c95c2d32 RD |
172 | * @node: where to begin the search |
173 | * @tag: the tag index | |
174 | * @offset: the bitnumber to start searching at | |
78c1d784 KK |
175 | * |
176 | * Unrollable variant of find_next_bit() for constant size arrays. | |
177 | * Tail bits starting from size to roundup(size, BITS_PER_LONG) must be zero. | |
178 | * Returns next bit offset, or size if nothing found. | |
179 | */ | |
180 | static __always_inline unsigned long | |
bc412fca MW |
181 | radix_tree_find_next_bit(struct radix_tree_node *node, unsigned int tag, |
182 | unsigned long offset) | |
78c1d784 | 183 | { |
bc412fca | 184 | const unsigned long *addr = node->tags[tag]; |
78c1d784 | 185 | |
bc412fca | 186 | if (offset < RADIX_TREE_MAP_SIZE) { |
78c1d784 KK |
187 | unsigned long tmp; |
188 | ||
189 | addr += offset / BITS_PER_LONG; | |
190 | tmp = *addr >> (offset % BITS_PER_LONG); | |
191 | if (tmp) | |
192 | return __ffs(tmp) + offset; | |
193 | offset = (offset + BITS_PER_LONG) & ~(BITS_PER_LONG - 1); | |
bc412fca | 194 | while (offset < RADIX_TREE_MAP_SIZE) { |
78c1d784 KK |
195 | tmp = *++addr; |
196 | if (tmp) | |
197 | return __ffs(tmp) + offset; | |
198 | offset += BITS_PER_LONG; | |
199 | } | |
200 | } | |
bc412fca | 201 | return RADIX_TREE_MAP_SIZE; |
78c1d784 KK |
202 | } |
203 | ||
268f42de MW |
204 | static unsigned int iter_offset(const struct radix_tree_iter *iter) |
205 | { | |
3a08cd52 | 206 | return iter->index & RADIX_TREE_MAP_MASK; |
268f42de MW |
207 | } |
208 | ||
218ed750 MW |
209 | /* |
210 | * The maximum index which can be stored in a radix tree | |
211 | */ | |
212 | static inline unsigned long shift_maxindex(unsigned int shift) | |
213 | { | |
214 | return (RADIX_TREE_MAP_SIZE << shift) - 1; | |
215 | } | |
216 | ||
35534c86 | 217 | static inline unsigned long node_maxindex(const struct radix_tree_node *node) |
218ed750 MW |
218 | { |
219 | return shift_maxindex(node->shift); | |
220 | } | |
221 | ||
0a835c4f MW |
222 | static unsigned long next_index(unsigned long index, |
223 | const struct radix_tree_node *node, | |
224 | unsigned long offset) | |
225 | { | |
226 | return (index & ~node_maxindex(node)) + (offset << node->shift); | |
227 | } | |
228 | ||
1da177e4 LT |
229 | /* |
230 | * This assumes that the caller has performed appropriate preallocation, and | |
231 | * that the caller has pinned this thread of control to the current CPU. | |
232 | */ | |
233 | static struct radix_tree_node * | |
0a835c4f | 234 | radix_tree_node_alloc(gfp_t gfp_mask, struct radix_tree_node *parent, |
d58275bc | 235 | struct radix_tree_root *root, |
e8de4340 | 236 | unsigned int shift, unsigned int offset, |
01959dfe | 237 | unsigned int count, unsigned int nr_values) |
1da177e4 | 238 | { |
e2848a0e | 239 | struct radix_tree_node *ret = NULL; |
1da177e4 | 240 | |
5e4c0d97 | 241 | /* |
2fcd9005 MW |
242 | * Preload code isn't irq safe and it doesn't make sense to use |
243 | * preloading during an interrupt anyway as all the allocations have | |
244 | * to be atomic. So just do normal allocation when in interrupt. | |
5e4c0d97 | 245 | */ |
d0164adc | 246 | if (!gfpflags_allow_blocking(gfp_mask) && !in_interrupt()) { |
1da177e4 LT |
247 | struct radix_tree_preload *rtp; |
248 | ||
58e698af VD |
249 | /* |
250 | * Even if the caller has preloaded, try to allocate from the | |
05eb6e72 VD |
251 | * cache first for the new node to get accounted to the memory |
252 | * cgroup. | |
58e698af VD |
253 | */ |
254 | ret = kmem_cache_alloc(radix_tree_node_cachep, | |
05eb6e72 | 255 | gfp_mask | __GFP_NOWARN); |
58e698af VD |
256 | if (ret) |
257 | goto out; | |
258 | ||
e2848a0e NP |
259 | /* |
260 | * Provided the caller has preloaded here, we will always | |
261 | * succeed in getting a node here (and never reach | |
262 | * kmem_cache_alloc) | |
263 | */ | |
7c8e0181 | 264 | rtp = this_cpu_ptr(&radix_tree_preloads); |
1da177e4 | 265 | if (rtp->nr) { |
9d2a8da0 | 266 | ret = rtp->nodes; |
1293d5c5 | 267 | rtp->nodes = ret->parent; |
1da177e4 LT |
268 | rtp->nr--; |
269 | } | |
ce80b067 CM |
270 | /* |
271 | * Update the allocation stack trace as this is more useful | |
272 | * for debugging. | |
273 | */ | |
274 | kmemleak_update_trace(ret); | |
58e698af | 275 | goto out; |
1da177e4 | 276 | } |
05eb6e72 | 277 | ret = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask); |
58e698af | 278 | out: |
b194d16c | 279 | BUG_ON(radix_tree_is_internal_node(ret)); |
e8de4340 | 280 | if (ret) { |
e8de4340 MW |
281 | ret->shift = shift; |
282 | ret->offset = offset; | |
283 | ret->count = count; | |
01959dfe | 284 | ret->nr_values = nr_values; |
d58275bc | 285 | ret->parent = parent; |
01959dfe | 286 | ret->array = root; |
e8de4340 | 287 | } |
1da177e4 LT |
288 | return ret; |
289 | } | |
290 | ||
58d6ea30 | 291 | void radix_tree_node_rcu_free(struct rcu_head *head) |
7cf9c2c7 NP |
292 | { |
293 | struct radix_tree_node *node = | |
294 | container_of(head, struct radix_tree_node, rcu_head); | |
643b52b9 NP |
295 | |
296 | /* | |
175542f5 MW |
297 | * Must only free zeroed nodes into the slab. We can be left with |
298 | * non-NULL entries by radix_tree_free_nodes, so clear the entries | |
299 | * and tags here. | |
643b52b9 | 300 | */ |
175542f5 MW |
301 | memset(node->slots, 0, sizeof(node->slots)); |
302 | memset(node->tags, 0, sizeof(node->tags)); | |
91d9c05a | 303 | INIT_LIST_HEAD(&node->private_list); |
643b52b9 | 304 | |
7cf9c2c7 NP |
305 | kmem_cache_free(radix_tree_node_cachep, node); |
306 | } | |
307 | ||
1da177e4 LT |
308 | static inline void |
309 | radix_tree_node_free(struct radix_tree_node *node) | |
310 | { | |
7cf9c2c7 | 311 | call_rcu(&node->rcu_head, radix_tree_node_rcu_free); |
1da177e4 LT |
312 | } |
313 | ||
314 | /* | |
315 | * Load up this CPU's radix_tree_node buffer with sufficient objects to | |
316 | * ensure that the addition of a single element in the tree cannot fail. On | |
317 | * success, return zero, with preemption disabled. On error, return -ENOMEM | |
318 | * with preemption not disabled. | |
b34df792 DH |
319 | * |
320 | * To make use of this facility, the radix tree must be initialised without | |
d0164adc | 321 | * __GFP_DIRECT_RECLAIM being passed to INIT_RADIX_TREE(). |
1da177e4 | 322 | */ |
bc9ae224 | 323 | static __must_check int __radix_tree_preload(gfp_t gfp_mask, unsigned nr) |
1da177e4 LT |
324 | { |
325 | struct radix_tree_preload *rtp; | |
326 | struct radix_tree_node *node; | |
327 | int ret = -ENOMEM; | |
328 | ||
05eb6e72 | 329 | /* |
e0656501 | 330 | * Nodes preloaded by one cgroup can be used by another cgroup, so |
05eb6e72 VD |
331 | * they should never be accounted to any particular memory cgroup. |
332 | */ | |
333 | gfp_mask &= ~__GFP_ACCOUNT; | |
334 | ||
05fdd323 | 335 | preempt_disable(); |
7c8e0181 | 336 | rtp = this_cpu_ptr(&radix_tree_preloads); |
c78c66d1 | 337 | while (rtp->nr < nr) { |
05fdd323 | 338 | preempt_enable(); |
488514d1 | 339 | node = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask); |
1da177e4 LT |
340 | if (node == NULL) |
341 | goto out; | |
05fdd323 | 342 | preempt_disable(); |
7c8e0181 | 343 | rtp = this_cpu_ptr(&radix_tree_preloads); |
c78c66d1 | 344 | if (rtp->nr < nr) { |
1293d5c5 | 345 | node->parent = rtp->nodes; |
9d2a8da0 KS |
346 | rtp->nodes = node; |
347 | rtp->nr++; | |
348 | } else { | |
1da177e4 | 349 | kmem_cache_free(radix_tree_node_cachep, node); |
9d2a8da0 | 350 | } |
1da177e4 LT |
351 | } |
352 | ret = 0; | |
353 | out: | |
354 | return ret; | |
355 | } | |
5e4c0d97 JK |
356 | |
357 | /* | |
358 | * Load up this CPU's radix_tree_node buffer with sufficient objects to | |
359 | * ensure that the addition of a single element in the tree cannot fail. On | |
360 | * success, return zero, with preemption disabled. On error, return -ENOMEM | |
361 | * with preemption not disabled. | |
362 | * | |
363 | * To make use of this facility, the radix tree must be initialised without | |
d0164adc | 364 | * __GFP_DIRECT_RECLAIM being passed to INIT_RADIX_TREE(). |
5e4c0d97 JK |
365 | */ |
366 | int radix_tree_preload(gfp_t gfp_mask) | |
367 | { | |
368 | /* Warn on non-sensical use... */ | |
d0164adc | 369 | WARN_ON_ONCE(!gfpflags_allow_blocking(gfp_mask)); |
c78c66d1 | 370 | return __radix_tree_preload(gfp_mask, RADIX_TREE_PRELOAD_SIZE); |
5e4c0d97 | 371 | } |
d7f0923d | 372 | EXPORT_SYMBOL(radix_tree_preload); |
1da177e4 | 373 | |
5e4c0d97 JK |
374 | /* |
375 | * The same as above function, except we don't guarantee preloading happens. | |
376 | * We do it, if we decide it helps. On success, return zero with preemption | |
377 | * disabled. On error, return -ENOMEM with preemption not disabled. | |
378 | */ | |
379 | int radix_tree_maybe_preload(gfp_t gfp_mask) | |
380 | { | |
d0164adc | 381 | if (gfpflags_allow_blocking(gfp_mask)) |
c78c66d1 | 382 | return __radix_tree_preload(gfp_mask, RADIX_TREE_PRELOAD_SIZE); |
5e4c0d97 | 383 | /* Preloading doesn't help anything with this gfp mask, skip it */ |
05fdd323 | 384 | preempt_disable(); |
5e4c0d97 JK |
385 | return 0; |
386 | } | |
387 | EXPORT_SYMBOL(radix_tree_maybe_preload); | |
388 | ||
35534c86 | 389 | static unsigned radix_tree_load_root(const struct radix_tree_root *root, |
1456a439 MW |
390 | struct radix_tree_node **nodep, unsigned long *maxindex) |
391 | { | |
f8d5d0cc | 392 | struct radix_tree_node *node = rcu_dereference_raw(root->xa_head); |
1456a439 MW |
393 | |
394 | *nodep = node; | |
395 | ||
b194d16c | 396 | if (likely(radix_tree_is_internal_node(node))) { |
4dd6c098 | 397 | node = entry_to_node(node); |
1456a439 | 398 | *maxindex = node_maxindex(node); |
c12e51b0 | 399 | return node->shift + RADIX_TREE_MAP_SHIFT; |
1456a439 MW |
400 | } |
401 | ||
402 | *maxindex = 0; | |
403 | return 0; | |
404 | } | |
405 | ||
1da177e4 LT |
406 | /* |
407 | * Extend a radix tree so it can store key @index. | |
408 | */ | |
0a835c4f | 409 | static int radix_tree_extend(struct radix_tree_root *root, gfp_t gfp, |
d0891265 | 410 | unsigned long index, unsigned int shift) |
1da177e4 | 411 | { |
d7b62727 | 412 | void *entry; |
d0891265 | 413 | unsigned int maxshift; |
1da177e4 LT |
414 | int tag; |
415 | ||
d0891265 MW |
416 | /* Figure out what the shift should be. */ |
417 | maxshift = shift; | |
418 | while (index > shift_maxindex(maxshift)) | |
419 | maxshift += RADIX_TREE_MAP_SHIFT; | |
1da177e4 | 420 | |
f8d5d0cc | 421 | entry = rcu_dereference_raw(root->xa_head); |
d7b62727 | 422 | if (!entry && (!is_idr(root) || root_tag_get(root, IDR_FREE))) |
1da177e4 | 423 | goto out; |
1da177e4 | 424 | |
1da177e4 | 425 | do { |
0a835c4f | 426 | struct radix_tree_node *node = radix_tree_node_alloc(gfp, NULL, |
d58275bc | 427 | root, shift, 0, 1, 0); |
2fcd9005 | 428 | if (!node) |
1da177e4 LT |
429 | return -ENOMEM; |
430 | ||
0a835c4f MW |
431 | if (is_idr(root)) { |
432 | all_tag_set(node, IDR_FREE); | |
433 | if (!root_tag_get(root, IDR_FREE)) { | |
434 | tag_clear(node, IDR_FREE, 0); | |
435 | root_tag_set(root, IDR_FREE); | |
436 | } | |
437 | } else { | |
438 | /* Propagate the aggregated tag info to the new child */ | |
439 | for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { | |
440 | if (root_tag_get(root, tag)) | |
441 | tag_set(node, tag, 0); | |
442 | } | |
1da177e4 LT |
443 | } |
444 | ||
d0891265 | 445 | BUG_ON(shift > BITS_PER_LONG); |
d7b62727 MW |
446 | if (radix_tree_is_internal_node(entry)) { |
447 | entry_to_node(entry)->parent = node; | |
3159f943 | 448 | } else if (xa_is_value(entry)) { |
01959dfe MW |
449 | /* Moving a value entry root->xa_head to a node */ |
450 | node->nr_values = 1; | |
f7942430 | 451 | } |
d7b62727 MW |
452 | /* |
453 | * entry was already in the radix tree, so we do not need | |
454 | * rcu_assign_pointer here | |
455 | */ | |
456 | node->slots[0] = (void __rcu *)entry; | |
457 | entry = node_to_entry(node); | |
f8d5d0cc | 458 | rcu_assign_pointer(root->xa_head, entry); |
d0891265 | 459 | shift += RADIX_TREE_MAP_SHIFT; |
d0891265 | 460 | } while (shift <= maxshift); |
1da177e4 | 461 | out: |
d0891265 | 462 | return maxshift + RADIX_TREE_MAP_SHIFT; |
1da177e4 LT |
463 | } |
464 | ||
f4b109c6 JW |
465 | /** |
466 | * radix_tree_shrink - shrink radix tree to minimum height | |
c95c2d32 | 467 | * @root: radix tree root |
f4b109c6 | 468 | */ |
1cf56f9d | 469 | static inline bool radix_tree_shrink(struct radix_tree_root *root) |
f4b109c6 | 470 | { |
0ac398ef MW |
471 | bool shrunk = false; |
472 | ||
f4b109c6 | 473 | for (;;) { |
f8d5d0cc | 474 | struct radix_tree_node *node = rcu_dereference_raw(root->xa_head); |
f4b109c6 JW |
475 | struct radix_tree_node *child; |
476 | ||
477 | if (!radix_tree_is_internal_node(node)) | |
478 | break; | |
479 | node = entry_to_node(node); | |
480 | ||
481 | /* | |
482 | * The candidate node has more than one child, or its child | |
3a08cd52 | 483 | * is not at the leftmost slot, we cannot shrink. |
f4b109c6 JW |
484 | */ |
485 | if (node->count != 1) | |
486 | break; | |
12320d0f | 487 | child = rcu_dereference_raw(node->slots[0]); |
f4b109c6 JW |
488 | if (!child) |
489 | break; | |
f4b109c6 | 490 | |
66ee620f MW |
491 | /* |
492 | * For an IDR, we must not shrink entry 0 into the root in | |
493 | * case somebody calls idr_replace() with a pointer that | |
494 | * appears to be an internal entry | |
495 | */ | |
496 | if (!node->shift && is_idr(root)) | |
497 | break; | |
498 | ||
f4b109c6 JW |
499 | if (radix_tree_is_internal_node(child)) |
500 | entry_to_node(child)->parent = NULL; | |
501 | ||
502 | /* | |
503 | * We don't need rcu_assign_pointer(), since we are simply | |
504 | * moving the node from one part of the tree to another: if it | |
505 | * was safe to dereference the old pointer to it | |
506 | * (node->slots[0]), it will be safe to dereference the new | |
f8d5d0cc | 507 | * one (root->xa_head) as far as dependent read barriers go. |
f4b109c6 | 508 | */ |
f8d5d0cc | 509 | root->xa_head = (void __rcu *)child; |
0a835c4f MW |
510 | if (is_idr(root) && !tag_get(node, IDR_FREE, 0)) |
511 | root_tag_clear(root, IDR_FREE); | |
f4b109c6 JW |
512 | |
513 | /* | |
514 | * We have a dilemma here. The node's slot[0] must not be | |
515 | * NULLed in case there are concurrent lookups expecting to | |
516 | * find the item. However if this was a bottom-level node, | |
517 | * then it may be subject to the slot pointer being visible | |
518 | * to callers dereferencing it. If item corresponding to | |
519 | * slot[0] is subsequently deleted, these callers would expect | |
520 | * their slot to become empty sooner or later. | |
521 | * | |
522 | * For example, lockless pagecache will look up a slot, deref | |
523 | * the page pointer, and if the page has 0 refcount it means it | |
524 | * was concurrently deleted from pagecache so try the deref | |
525 | * again. Fortunately there is already a requirement for logic | |
526 | * to retry the entire slot lookup -- the indirect pointer | |
527 | * problem (replacing direct root node with an indirect pointer | |
528 | * also results in a stale slot). So tag the slot as indirect | |
529 | * to force callers to retry. | |
530 | */ | |
4d693d08 JW |
531 | node->count = 0; |
532 | if (!radix_tree_is_internal_node(child)) { | |
d7b62727 | 533 | node->slots[0] = (void __rcu *)RADIX_TREE_RETRY; |
4d693d08 | 534 | } |
f4b109c6 | 535 | |
ea07b862 | 536 | WARN_ON_ONCE(!list_empty(&node->private_list)); |
f4b109c6 | 537 | radix_tree_node_free(node); |
0ac398ef | 538 | shrunk = true; |
f4b109c6 | 539 | } |
0ac398ef MW |
540 | |
541 | return shrunk; | |
f4b109c6 JW |
542 | } |
543 | ||
0ac398ef | 544 | static bool delete_node(struct radix_tree_root *root, |
1cf56f9d | 545 | struct radix_tree_node *node) |
f4b109c6 | 546 | { |
0ac398ef MW |
547 | bool deleted = false; |
548 | ||
f4b109c6 JW |
549 | do { |
550 | struct radix_tree_node *parent; | |
551 | ||
552 | if (node->count) { | |
12320d0f | 553 | if (node_to_entry(node) == |
f8d5d0cc | 554 | rcu_dereference_raw(root->xa_head)) |
1cf56f9d | 555 | deleted |= radix_tree_shrink(root); |
0ac398ef | 556 | return deleted; |
f4b109c6 JW |
557 | } |
558 | ||
559 | parent = node->parent; | |
560 | if (parent) { | |
561 | parent->slots[node->offset] = NULL; | |
562 | parent->count--; | |
563 | } else { | |
0a835c4f MW |
564 | /* |
565 | * Shouldn't the tags already have all been cleared | |
566 | * by the caller? | |
567 | */ | |
568 | if (!is_idr(root)) | |
569 | root_tag_clear_all(root); | |
f8d5d0cc | 570 | root->xa_head = NULL; |
f4b109c6 JW |
571 | } |
572 | ||
ea07b862 | 573 | WARN_ON_ONCE(!list_empty(&node->private_list)); |
f4b109c6 | 574 | radix_tree_node_free(node); |
0ac398ef | 575 | deleted = true; |
f4b109c6 JW |
576 | |
577 | node = parent; | |
578 | } while (node); | |
0ac398ef MW |
579 | |
580 | return deleted; | |
f4b109c6 JW |
581 | } |
582 | ||
1da177e4 | 583 | /** |
139e5616 | 584 | * __radix_tree_create - create a slot in a radix tree |
1da177e4 LT |
585 | * @root: radix tree root |
586 | * @index: index key | |
139e5616 JW |
587 | * @nodep: returns node |
588 | * @slotp: returns slot | |
1da177e4 | 589 | * |
139e5616 JW |
590 | * Create, if necessary, and return the node and slot for an item |
591 | * at position @index in the radix tree @root. | |
592 | * | |
593 | * Until there is more than one item in the tree, no nodes are | |
f8d5d0cc | 594 | * allocated and @root->xa_head is used as a direct slot instead of |
139e5616 JW |
595 | * pointing to a node, in which case *@nodep will be NULL. |
596 | * | |
597 | * Returns -ENOMEM, or 0 for success. | |
1da177e4 | 598 | */ |
74d60958 | 599 | static int __radix_tree_create(struct radix_tree_root *root, |
3a08cd52 MW |
600 | unsigned long index, struct radix_tree_node **nodep, |
601 | void __rcu ***slotp) | |
1da177e4 | 602 | { |
89148aa4 | 603 | struct radix_tree_node *node = NULL, *child; |
f8d5d0cc | 604 | void __rcu **slot = (void __rcu **)&root->xa_head; |
49ea6ebc | 605 | unsigned long maxindex; |
89148aa4 | 606 | unsigned int shift, offset = 0; |
3a08cd52 | 607 | unsigned long max = index; |
0a835c4f | 608 | gfp_t gfp = root_gfp_mask(root); |
49ea6ebc | 609 | |
89148aa4 | 610 | shift = radix_tree_load_root(root, &child, &maxindex); |
1da177e4 LT |
611 | |
612 | /* Make sure the tree is high enough. */ | |
49ea6ebc | 613 | if (max > maxindex) { |
0a835c4f | 614 | int error = radix_tree_extend(root, gfp, max, shift); |
49ea6ebc | 615 | if (error < 0) |
1da177e4 | 616 | return error; |
49ea6ebc | 617 | shift = error; |
f8d5d0cc | 618 | child = rcu_dereference_raw(root->xa_head); |
1da177e4 LT |
619 | } |
620 | ||
3a08cd52 | 621 | while (shift > 0) { |
c12e51b0 | 622 | shift -= RADIX_TREE_MAP_SHIFT; |
89148aa4 | 623 | if (child == NULL) { |
1da177e4 | 624 | /* Have to add a child node. */ |
d58275bc | 625 | child = radix_tree_node_alloc(gfp, node, root, shift, |
e8de4340 | 626 | offset, 0, 0); |
89148aa4 | 627 | if (!child) |
1da177e4 | 628 | return -ENOMEM; |
89148aa4 MW |
629 | rcu_assign_pointer(*slot, node_to_entry(child)); |
630 | if (node) | |
1da177e4 | 631 | node->count++; |
89148aa4 | 632 | } else if (!radix_tree_is_internal_node(child)) |
e6145236 | 633 | break; |
1da177e4 LT |
634 | |
635 | /* Go a level down */ | |
89148aa4 | 636 | node = entry_to_node(child); |
9e85d811 | 637 | offset = radix_tree_descend(node, &child, index); |
89148aa4 | 638 | slot = &node->slots[offset]; |
e6145236 MW |
639 | } |
640 | ||
175542f5 MW |
641 | if (nodep) |
642 | *nodep = node; | |
643 | if (slotp) | |
644 | *slotp = slot; | |
645 | return 0; | |
646 | } | |
647 | ||
175542f5 MW |
648 | /* |
649 | * Free any nodes below this node. The tree is presumed to not need | |
650 | * shrinking, and any user data in the tree is presumed to not need a | |
651 | * destructor called on it. If we need to add a destructor, we can | |
652 | * add that functionality later. Note that we may not clear tags or | |
653 | * slots from the tree as an RCU walker may still have a pointer into | |
654 | * this subtree. We could replace the entries with RADIX_TREE_RETRY, | |
655 | * but we'll still have to clear those in rcu_free. | |
656 | */ | |
657 | static void radix_tree_free_nodes(struct radix_tree_node *node) | |
658 | { | |
659 | unsigned offset = 0; | |
660 | struct radix_tree_node *child = entry_to_node(node); | |
661 | ||
662 | for (;;) { | |
12320d0f | 663 | void *entry = rcu_dereference_raw(child->slots[offset]); |
02c02bf1 | 664 | if (xa_is_node(entry) && child->shift) { |
175542f5 MW |
665 | child = entry_to_node(entry); |
666 | offset = 0; | |
667 | continue; | |
668 | } | |
669 | offset++; | |
670 | while (offset == RADIX_TREE_MAP_SIZE) { | |
671 | struct radix_tree_node *old = child; | |
672 | offset = child->offset + 1; | |
673 | child = child->parent; | |
dd040b6f | 674 | WARN_ON_ONCE(!list_empty(&old->private_list)); |
175542f5 MW |
675 | radix_tree_node_free(old); |
676 | if (old == entry_to_node(node)) | |
677 | return; | |
678 | } | |
679 | } | |
680 | } | |
681 | ||
d7b62727 | 682 | static inline int insert_entries(struct radix_tree_node *node, |
3a08cd52 | 683 | void __rcu **slot, void *item, bool replace) |
175542f5 MW |
684 | { |
685 | if (*slot) | |
686 | return -EEXIST; | |
687 | rcu_assign_pointer(*slot, item); | |
688 | if (node) { | |
689 | node->count++; | |
3159f943 | 690 | if (xa_is_value(item)) |
01959dfe | 691 | node->nr_values++; |
175542f5 MW |
692 | } |
693 | return 1; | |
694 | } | |
139e5616 JW |
695 | |
696 | /** | |
c95c2d32 | 697 | * radix_tree_insert - insert into a radix tree |
139e5616 JW |
698 | * @root: radix tree root |
699 | * @index: index key | |
700 | * @item: item to insert | |
701 | * | |
702 | * Insert an item into the radix tree at position @index. | |
703 | */ | |
3a08cd52 MW |
704 | int radix_tree_insert(struct radix_tree_root *root, unsigned long index, |
705 | void *item) | |
139e5616 JW |
706 | { |
707 | struct radix_tree_node *node; | |
d7b62727 | 708 | void __rcu **slot; |
139e5616 JW |
709 | int error; |
710 | ||
b194d16c | 711 | BUG_ON(radix_tree_is_internal_node(item)); |
139e5616 | 712 | |
3a08cd52 | 713 | error = __radix_tree_create(root, index, &node, &slot); |
139e5616 JW |
714 | if (error) |
715 | return error; | |
175542f5 | 716 | |
3a08cd52 | 717 | error = insert_entries(node, slot, item, false); |
175542f5 MW |
718 | if (error < 0) |
719 | return error; | |
201b6264 | 720 | |
612d6c19 | 721 | if (node) { |
7b60e9ad | 722 | unsigned offset = get_slot_offset(node, slot); |
7b60e9ad MW |
723 | BUG_ON(tag_get(node, 0, offset)); |
724 | BUG_ON(tag_get(node, 1, offset)); | |
725 | BUG_ON(tag_get(node, 2, offset)); | |
612d6c19 | 726 | } else { |
7b60e9ad | 727 | BUG_ON(root_tags_get(root)); |
612d6c19 | 728 | } |
1da177e4 | 729 | |
1da177e4 LT |
730 | return 0; |
731 | } | |
3a08cd52 | 732 | EXPORT_SYMBOL(radix_tree_insert); |
1da177e4 | 733 | |
139e5616 JW |
734 | /** |
735 | * __radix_tree_lookup - lookup an item in a radix tree | |
736 | * @root: radix tree root | |
737 | * @index: index key | |
738 | * @nodep: returns node | |
739 | * @slotp: returns slot | |
740 | * | |
741 | * Lookup and return the item at position @index in the radix | |
742 | * tree @root. | |
743 | * | |
744 | * Until there is more than one item in the tree, no nodes are | |
f8d5d0cc | 745 | * allocated and @root->xa_head is used as a direct slot instead of |
139e5616 | 746 | * pointing to a node, in which case *@nodep will be NULL. |
7cf9c2c7 | 747 | */ |
35534c86 MW |
748 | void *__radix_tree_lookup(const struct radix_tree_root *root, |
749 | unsigned long index, struct radix_tree_node **nodep, | |
d7b62727 | 750 | void __rcu ***slotp) |
1da177e4 | 751 | { |
139e5616 | 752 | struct radix_tree_node *node, *parent; |
85829954 | 753 | unsigned long maxindex; |
d7b62727 | 754 | void __rcu **slot; |
612d6c19 | 755 | |
85829954 MW |
756 | restart: |
757 | parent = NULL; | |
f8d5d0cc | 758 | slot = (void __rcu **)&root->xa_head; |
9e85d811 | 759 | radix_tree_load_root(root, &node, &maxindex); |
85829954 | 760 | if (index > maxindex) |
1da177e4 LT |
761 | return NULL; |
762 | ||
b194d16c | 763 | while (radix_tree_is_internal_node(node)) { |
85829954 | 764 | unsigned offset; |
1da177e4 | 765 | |
4dd6c098 | 766 | parent = entry_to_node(node); |
9e85d811 | 767 | offset = radix_tree_descend(parent, &node, index); |
85829954 | 768 | slot = parent->slots + offset; |
eff3860b MW |
769 | if (node == RADIX_TREE_RETRY) |
770 | goto restart; | |
66ee620f MW |
771 | if (parent->shift == 0) |
772 | break; | |
85829954 | 773 | } |
1da177e4 | 774 | |
139e5616 JW |
775 | if (nodep) |
776 | *nodep = parent; | |
777 | if (slotp) | |
778 | *slotp = slot; | |
779 | return node; | |
b72b71c6 HS |
780 | } |
781 | ||
782 | /** | |
783 | * radix_tree_lookup_slot - lookup a slot in a radix tree | |
784 | * @root: radix tree root | |
785 | * @index: index key | |
786 | * | |
787 | * Returns: the slot corresponding to the position @index in the | |
788 | * radix tree @root. This is useful for update-if-exists operations. | |
789 | * | |
790 | * This function can be called under rcu_read_lock iff the slot is not | |
791 | * modified by radix_tree_replace_slot, otherwise it must be called | |
792 | * exclusive from other writers. Any dereference of the slot must be done | |
793 | * using radix_tree_deref_slot. | |
794 | */ | |
d7b62727 | 795 | void __rcu **radix_tree_lookup_slot(const struct radix_tree_root *root, |
35534c86 | 796 | unsigned long index) |
b72b71c6 | 797 | { |
d7b62727 | 798 | void __rcu **slot; |
139e5616 JW |
799 | |
800 | if (!__radix_tree_lookup(root, index, NULL, &slot)) | |
801 | return NULL; | |
802 | return slot; | |
a4331366 | 803 | } |
a4331366 HR |
804 | EXPORT_SYMBOL(radix_tree_lookup_slot); |
805 | ||
806 | /** | |
807 | * radix_tree_lookup - perform lookup operation on a radix tree | |
808 | * @root: radix tree root | |
809 | * @index: index key | |
810 | * | |
811 | * Lookup the item at the position @index in the radix tree @root. | |
7cf9c2c7 NP |
812 | * |
813 | * This function can be called under rcu_read_lock, however the caller | |
814 | * must manage lifetimes of leaf nodes (eg. RCU may also be used to free | |
815 | * them safely). No RCU barriers are required to access or modify the | |
816 | * returned item, however. | |
a4331366 | 817 | */ |
35534c86 | 818 | void *radix_tree_lookup(const struct radix_tree_root *root, unsigned long index) |
a4331366 | 819 | { |
139e5616 | 820 | return __radix_tree_lookup(root, index, NULL, NULL); |
1da177e4 LT |
821 | } |
822 | EXPORT_SYMBOL(radix_tree_lookup); | |
823 | ||
d7b62727 | 824 | static void replace_slot(void __rcu **slot, void *item, |
01959dfe | 825 | struct radix_tree_node *node, int count, int values) |
f7942430 | 826 | { |
01959dfe | 827 | if (node && (count || values)) { |
f4b109c6 | 828 | node->count += count; |
01959dfe | 829 | node->nr_values += values; |
f4b109c6 | 830 | } |
f7942430 JW |
831 | |
832 | rcu_assign_pointer(*slot, item); | |
833 | } | |
834 | ||
0a835c4f MW |
835 | static bool node_tag_get(const struct radix_tree_root *root, |
836 | const struct radix_tree_node *node, | |
837 | unsigned int tag, unsigned int offset) | |
a90eb3a2 | 838 | { |
0a835c4f MW |
839 | if (node) |
840 | return tag_get(node, tag, offset); | |
841 | return root_tag_get(root, tag); | |
842 | } | |
a90eb3a2 | 843 | |
0a835c4f MW |
844 | /* |
845 | * IDR users want to be able to store NULL in the tree, so if the slot isn't | |
846 | * free, don't adjust the count, even if it's transitioning between NULL and | |
847 | * non-NULL. For the IDA, we mark slots as being IDR_FREE while they still | |
848 | * have empty bits, but it only stores NULL in slots when they're being | |
849 | * deleted. | |
850 | */ | |
851 | static int calculate_count(struct radix_tree_root *root, | |
d7b62727 | 852 | struct radix_tree_node *node, void __rcu **slot, |
0a835c4f MW |
853 | void *item, void *old) |
854 | { | |
855 | if (is_idr(root)) { | |
856 | unsigned offset = get_slot_offset(node, slot); | |
857 | bool free = node_tag_get(root, node, IDR_FREE, offset); | |
858 | if (!free) | |
859 | return 0; | |
860 | if (!old) | |
861 | return 1; | |
a90eb3a2 | 862 | } |
0a835c4f | 863 | return !!item - !!old; |
a90eb3a2 MW |
864 | } |
865 | ||
6d75f366 JW |
866 | /** |
867 | * __radix_tree_replace - replace item in a slot | |
4d693d08 JW |
868 | * @root: radix tree root |
869 | * @node: pointer to tree node | |
870 | * @slot: pointer to slot in @node | |
871 | * @item: new item to store in the slot. | |
6d75f366 JW |
872 | * |
873 | * For use with __radix_tree_lookup(). Caller must hold tree write locked | |
874 | * across slot lookup and replacement. | |
875 | */ | |
876 | void __radix_tree_replace(struct radix_tree_root *root, | |
877 | struct radix_tree_node *node, | |
1cf56f9d | 878 | void __rcu **slot, void *item) |
6d75f366 | 879 | { |
0a835c4f | 880 | void *old = rcu_dereference_raw(*slot); |
01959dfe | 881 | int values = !!xa_is_value(item) - !!xa_is_value(old); |
0a835c4f MW |
882 | int count = calculate_count(root, node, slot, item, old); |
883 | ||
6d75f366 | 884 | /* |
01959dfe | 885 | * This function supports replacing value entries and |
f4b109c6 | 886 | * deleting entries, but that needs accounting against the |
f8d5d0cc | 887 | * node unless the slot is root->xa_head. |
6d75f366 | 888 | */ |
f8d5d0cc | 889 | WARN_ON_ONCE(!node && (slot != (void __rcu **)&root->xa_head) && |
01959dfe MW |
890 | (count || values)); |
891 | replace_slot(slot, item, node, count, values); | |
f4b109c6 | 892 | |
4d693d08 JW |
893 | if (!node) |
894 | return; | |
895 | ||
1cf56f9d | 896 | delete_node(root, node); |
6d75f366 JW |
897 | } |
898 | ||
899 | /** | |
900 | * radix_tree_replace_slot - replace item in a slot | |
901 | * @root: radix tree root | |
902 | * @slot: pointer to slot | |
903 | * @item: new item to store in the slot. | |
904 | * | |
7b8d046f | 905 | * For use with radix_tree_lookup_slot() and |
6d75f366 JW |
906 | * radix_tree_gang_lookup_tag_slot(). Caller must hold tree write locked |
907 | * across slot lookup and replacement. | |
908 | * | |
909 | * NOTE: This cannot be used to switch between non-entries (empty slots), | |
01959dfe | 910 | * regular entries, and value entries, as that requires accounting |
f4b109c6 | 911 | * inside the radix tree node. When switching from one type of entry or |
e157b555 MW |
912 | * deleting, use __radix_tree_lookup() and __radix_tree_replace() or |
913 | * radix_tree_iter_replace(). | |
6d75f366 JW |
914 | */ |
915 | void radix_tree_replace_slot(struct radix_tree_root *root, | |
d7b62727 | 916 | void __rcu **slot, void *item) |
6d75f366 | 917 | { |
1cf56f9d | 918 | __radix_tree_replace(root, NULL, slot, item); |
6d75f366 | 919 | } |
10257d71 | 920 | EXPORT_SYMBOL(radix_tree_replace_slot); |
6d75f366 | 921 | |
e157b555 MW |
922 | /** |
923 | * radix_tree_iter_replace - replace item in a slot | |
924 | * @root: radix tree root | |
c95c2d32 | 925 | * @iter: iterator state |
e157b555 MW |
926 | * @slot: pointer to slot |
927 | * @item: new item to store in the slot. | |
928 | * | |
2956c664 MW |
929 | * For use with radix_tree_for_each_slot(). |
930 | * Caller must hold tree write locked. | |
e157b555 MW |
931 | */ |
932 | void radix_tree_iter_replace(struct radix_tree_root *root, | |
d7b62727 MW |
933 | const struct radix_tree_iter *iter, |
934 | void __rcu **slot, void *item) | |
e157b555 | 935 | { |
1cf56f9d | 936 | __radix_tree_replace(root, iter->node, slot, item); |
e157b555 MW |
937 | } |
938 | ||
30b888ba MW |
939 | static void node_tag_set(struct radix_tree_root *root, |
940 | struct radix_tree_node *node, | |
941 | unsigned int tag, unsigned int offset) | |
942 | { | |
943 | while (node) { | |
944 | if (tag_get(node, tag, offset)) | |
945 | return; | |
946 | tag_set(node, tag, offset); | |
947 | offset = node->offset; | |
948 | node = node->parent; | |
949 | } | |
950 | ||
951 | if (!root_tag_get(root, tag)) | |
952 | root_tag_set(root, tag); | |
953 | } | |
954 | ||
1da177e4 LT |
955 | /** |
956 | * radix_tree_tag_set - set a tag on a radix tree node | |
957 | * @root: radix tree root | |
958 | * @index: index key | |
2fcd9005 | 959 | * @tag: tag index |
1da177e4 | 960 | * |
daff89f3 JC |
961 | * Set the search tag (which must be < RADIX_TREE_MAX_TAGS) |
962 | * corresponding to @index in the radix tree. From | |
1da177e4 LT |
963 | * the root all the way down to the leaf node. |
964 | * | |
2fcd9005 | 965 | * Returns the address of the tagged item. Setting a tag on a not-present |
1da177e4 LT |
966 | * item is a bug. |
967 | */ | |
968 | void *radix_tree_tag_set(struct radix_tree_root *root, | |
daff89f3 | 969 | unsigned long index, unsigned int tag) |
1da177e4 | 970 | { |
fb969909 RZ |
971 | struct radix_tree_node *node, *parent; |
972 | unsigned long maxindex; | |
1da177e4 | 973 | |
9e85d811 | 974 | radix_tree_load_root(root, &node, &maxindex); |
fb969909 | 975 | BUG_ON(index > maxindex); |
1da177e4 | 976 | |
b194d16c | 977 | while (radix_tree_is_internal_node(node)) { |
fb969909 | 978 | unsigned offset; |
1da177e4 | 979 | |
4dd6c098 | 980 | parent = entry_to_node(node); |
9e85d811 | 981 | offset = radix_tree_descend(parent, &node, index); |
fb969909 RZ |
982 | BUG_ON(!node); |
983 | ||
984 | if (!tag_get(parent, tag, offset)) | |
985 | tag_set(parent, tag, offset); | |
1da177e4 LT |
986 | } |
987 | ||
612d6c19 | 988 | /* set the root's tag bit */ |
fb969909 | 989 | if (!root_tag_get(root, tag)) |
612d6c19 NP |
990 | root_tag_set(root, tag); |
991 | ||
fb969909 | 992 | return node; |
1da177e4 LT |
993 | } |
994 | EXPORT_SYMBOL(radix_tree_tag_set); | |
995 | ||
d604c324 MW |
996 | static void node_tag_clear(struct radix_tree_root *root, |
997 | struct radix_tree_node *node, | |
998 | unsigned int tag, unsigned int offset) | |
999 | { | |
1000 | while (node) { | |
1001 | if (!tag_get(node, tag, offset)) | |
1002 | return; | |
1003 | tag_clear(node, tag, offset); | |
1004 | if (any_tag_set(node, tag)) | |
1005 | return; | |
1006 | ||
1007 | offset = node->offset; | |
1008 | node = node->parent; | |
1009 | } | |
1010 | ||
1011 | /* clear the root's tag bit */ | |
1012 | if (root_tag_get(root, tag)) | |
1013 | root_tag_clear(root, tag); | |
1014 | } | |
1015 | ||
1da177e4 LT |
1016 | /** |
1017 | * radix_tree_tag_clear - clear a tag on a radix tree node | |
1018 | * @root: radix tree root | |
1019 | * @index: index key | |
2fcd9005 | 1020 | * @tag: tag index |
1da177e4 | 1021 | * |
daff89f3 | 1022 | * Clear the search tag (which must be < RADIX_TREE_MAX_TAGS) |
2fcd9005 MW |
1023 | * corresponding to @index in the radix tree. If this causes |
1024 | * the leaf node to have no tags set then clear the tag in the | |
1da177e4 LT |
1025 | * next-to-leaf node, etc. |
1026 | * | |
1027 | * Returns the address of the tagged item on success, else NULL. ie: | |
1028 | * has the same return value and semantics as radix_tree_lookup(). | |
1029 | */ | |
1030 | void *radix_tree_tag_clear(struct radix_tree_root *root, | |
daff89f3 | 1031 | unsigned long index, unsigned int tag) |
1da177e4 | 1032 | { |
00f47b58 RZ |
1033 | struct radix_tree_node *node, *parent; |
1034 | unsigned long maxindex; | |
3f649ab7 | 1035 | int offset; |
1da177e4 | 1036 | |
9e85d811 | 1037 | radix_tree_load_root(root, &node, &maxindex); |
00f47b58 RZ |
1038 | if (index > maxindex) |
1039 | return NULL; | |
1da177e4 | 1040 | |
00f47b58 | 1041 | parent = NULL; |
1da177e4 | 1042 | |
b194d16c | 1043 | while (radix_tree_is_internal_node(node)) { |
4dd6c098 | 1044 | parent = entry_to_node(node); |
9e85d811 | 1045 | offset = radix_tree_descend(parent, &node, index); |
1da177e4 LT |
1046 | } |
1047 | ||
d604c324 MW |
1048 | if (node) |
1049 | node_tag_clear(root, parent, tag, offset); | |
1da177e4 | 1050 | |
00f47b58 | 1051 | return node; |
1da177e4 LT |
1052 | } |
1053 | EXPORT_SYMBOL(radix_tree_tag_clear); | |
1054 | ||
30b888ba MW |
1055 | /** |
1056 | * radix_tree_iter_tag_clear - clear a tag on the current iterator entry | |
1057 | * @root: radix tree root | |
1058 | * @iter: iterator state | |
1059 | * @tag: tag to clear | |
1060 | */ | |
1061 | void radix_tree_iter_tag_clear(struct radix_tree_root *root, | |
1062 | const struct radix_tree_iter *iter, unsigned int tag) | |
1063 | { | |
1064 | node_tag_clear(root, iter->node, tag, iter_offset(iter)); | |
1065 | } | |
1066 | ||
1da177e4 | 1067 | /** |
32605a18 MT |
1068 | * radix_tree_tag_get - get a tag on a radix tree node |
1069 | * @root: radix tree root | |
1070 | * @index: index key | |
2fcd9005 | 1071 | * @tag: tag index (< RADIX_TREE_MAX_TAGS) |
1da177e4 | 1072 | * |
32605a18 | 1073 | * Return values: |
1da177e4 | 1074 | * |
612d6c19 NP |
1075 | * 0: tag not present or not set |
1076 | * 1: tag set | |
ce82653d DH |
1077 | * |
1078 | * Note that the return value of this function may not be relied on, even if | |
1079 | * the RCU lock is held, unless tag modification and node deletion are excluded | |
1080 | * from concurrency. | |
1da177e4 | 1081 | */ |
35534c86 | 1082 | int radix_tree_tag_get(const struct radix_tree_root *root, |
daff89f3 | 1083 | unsigned long index, unsigned int tag) |
1da177e4 | 1084 | { |
4589ba6d RZ |
1085 | struct radix_tree_node *node, *parent; |
1086 | unsigned long maxindex; | |
1da177e4 | 1087 | |
612d6c19 NP |
1088 | if (!root_tag_get(root, tag)) |
1089 | return 0; | |
1090 | ||
9e85d811 | 1091 | radix_tree_load_root(root, &node, &maxindex); |
4589ba6d RZ |
1092 | if (index > maxindex) |
1093 | return 0; | |
7cf9c2c7 | 1094 | |
b194d16c | 1095 | while (radix_tree_is_internal_node(node)) { |
9e85d811 | 1096 | unsigned offset; |
1da177e4 | 1097 | |
4dd6c098 | 1098 | parent = entry_to_node(node); |
9e85d811 | 1099 | offset = radix_tree_descend(parent, &node, index); |
1da177e4 | 1100 | |
4589ba6d | 1101 | if (!tag_get(parent, tag, offset)) |
3fa36acb | 1102 | return 0; |
4589ba6d RZ |
1103 | if (node == RADIX_TREE_RETRY) |
1104 | break; | |
1da177e4 | 1105 | } |
4589ba6d RZ |
1106 | |
1107 | return 1; | |
1da177e4 LT |
1108 | } |
1109 | EXPORT_SYMBOL(radix_tree_tag_get); | |
1da177e4 | 1110 | |
148deab2 MW |
1111 | /* Construct iter->tags bit-mask from node->tags[tag] array */ |
1112 | static void set_iter_tags(struct radix_tree_iter *iter, | |
1113 | struct radix_tree_node *node, unsigned offset, | |
1114 | unsigned tag) | |
1115 | { | |
1116 | unsigned tag_long = offset / BITS_PER_LONG; | |
1117 | unsigned tag_bit = offset % BITS_PER_LONG; | |
1118 | ||
0a835c4f MW |
1119 | if (!node) { |
1120 | iter->tags = 1; | |
1121 | return; | |
1122 | } | |
1123 | ||
148deab2 MW |
1124 | iter->tags = node->tags[tag][tag_long] >> tag_bit; |
1125 | ||
1126 | /* This never happens if RADIX_TREE_TAG_LONGS == 1 */ | |
1127 | if (tag_long < RADIX_TREE_TAG_LONGS - 1) { | |
1128 | /* Pick tags from next element */ | |
1129 | if (tag_bit) | |
1130 | iter->tags |= node->tags[tag][tag_long + 1] << | |
1131 | (BITS_PER_LONG - tag_bit); | |
1132 | /* Clip chunk size, here only BITS_PER_LONG tags */ | |
1133 | iter->next_index = __radix_tree_iter_add(iter, BITS_PER_LONG); | |
1134 | } | |
1135 | } | |
1136 | ||
d7b62727 MW |
1137 | void __rcu **radix_tree_iter_resume(void __rcu **slot, |
1138 | struct radix_tree_iter *iter) | |
148deab2 | 1139 | { |
148deab2 MW |
1140 | slot++; |
1141 | iter->index = __radix_tree_iter_add(iter, 1); | |
148deab2 MW |
1142 | iter->next_index = iter->index; |
1143 | iter->tags = 0; | |
1144 | return NULL; | |
1145 | } | |
1146 | EXPORT_SYMBOL(radix_tree_iter_resume); | |
1147 | ||
78c1d784 KK |
1148 | /** |
1149 | * radix_tree_next_chunk - find next chunk of slots for iteration | |
1150 | * | |
1151 | * @root: radix tree root | |
1152 | * @iter: iterator state | |
1153 | * @flags: RADIX_TREE_ITER_* flags and tag index | |
1154 | * Returns: pointer to chunk first slot, or NULL if iteration is over | |
1155 | */ | |
d7b62727 | 1156 | void __rcu **radix_tree_next_chunk(const struct radix_tree_root *root, |
78c1d784 KK |
1157 | struct radix_tree_iter *iter, unsigned flags) |
1158 | { | |
9e85d811 | 1159 | unsigned tag = flags & RADIX_TREE_ITER_TAG_MASK; |
8c1244de | 1160 | struct radix_tree_node *node, *child; |
21ef5339 | 1161 | unsigned long index, offset, maxindex; |
78c1d784 KK |
1162 | |
1163 | if ((flags & RADIX_TREE_ITER_TAGGED) && !root_tag_get(root, tag)) | |
1164 | return NULL; | |
1165 | ||
1166 | /* | |
1167 | * Catch next_index overflow after ~0UL. iter->index never overflows | |
1168 | * during iterating; it can be zero only at the beginning. | |
1169 | * And we cannot overflow iter->next_index in a single step, | |
1170 | * because RADIX_TREE_MAP_SHIFT < BITS_PER_LONG. | |
fffaee36 KK |
1171 | * |
1172 | * This condition also used by radix_tree_next_slot() to stop | |
91b9677c | 1173 | * contiguous iterating, and forbid switching to the next chunk. |
78c1d784 KK |
1174 | */ |
1175 | index = iter->next_index; | |
1176 | if (!index && iter->index) | |
1177 | return NULL; | |
1178 | ||
21ef5339 | 1179 | restart: |
9e85d811 | 1180 | radix_tree_load_root(root, &child, &maxindex); |
21ef5339 RZ |
1181 | if (index > maxindex) |
1182 | return NULL; | |
8c1244de MW |
1183 | if (!child) |
1184 | return NULL; | |
21ef5339 | 1185 | |
8c1244de | 1186 | if (!radix_tree_is_internal_node(child)) { |
78c1d784 | 1187 | /* Single-slot tree */ |
21ef5339 RZ |
1188 | iter->index = index; |
1189 | iter->next_index = maxindex + 1; | |
78c1d784 | 1190 | iter->tags = 1; |
268f42de | 1191 | iter->node = NULL; |
f8d5d0cc | 1192 | return (void __rcu **)&root->xa_head; |
8c1244de | 1193 | } |
21ef5339 | 1194 | |
8c1244de MW |
1195 | do { |
1196 | node = entry_to_node(child); | |
9e85d811 | 1197 | offset = radix_tree_descend(node, &child, index); |
21ef5339 | 1198 | |
78c1d784 | 1199 | if ((flags & RADIX_TREE_ITER_TAGGED) ? |
8c1244de | 1200 | !tag_get(node, tag, offset) : !child) { |
78c1d784 KK |
1201 | /* Hole detected */ |
1202 | if (flags & RADIX_TREE_ITER_CONTIG) | |
1203 | return NULL; | |
1204 | ||
1205 | if (flags & RADIX_TREE_ITER_TAGGED) | |
bc412fca | 1206 | offset = radix_tree_find_next_bit(node, tag, |
78c1d784 KK |
1207 | offset + 1); |
1208 | else | |
1209 | while (++offset < RADIX_TREE_MAP_SIZE) { | |
12320d0f MW |
1210 | void *slot = rcu_dereference_raw( |
1211 | node->slots[offset]); | |
21ef5339 | 1212 | if (slot) |
78c1d784 KK |
1213 | break; |
1214 | } | |
8c1244de | 1215 | index &= ~node_maxindex(node); |
9e85d811 | 1216 | index += offset << node->shift; |
78c1d784 KK |
1217 | /* Overflow after ~0UL */ |
1218 | if (!index) | |
1219 | return NULL; | |
1220 | if (offset == RADIX_TREE_MAP_SIZE) | |
1221 | goto restart; | |
8c1244de | 1222 | child = rcu_dereference_raw(node->slots[offset]); |
78c1d784 KK |
1223 | } |
1224 | ||
e157b555 | 1225 | if (!child) |
78c1d784 | 1226 | goto restart; |
e157b555 MW |
1227 | if (child == RADIX_TREE_RETRY) |
1228 | break; | |
66ee620f | 1229 | } while (node->shift && radix_tree_is_internal_node(child)); |
78c1d784 KK |
1230 | |
1231 | /* Update the iterator state */ | |
3a08cd52 | 1232 | iter->index = (index &~ node_maxindex(node)) | offset; |
8c1244de | 1233 | iter->next_index = (index | node_maxindex(node)) + 1; |
268f42de | 1234 | iter->node = node; |
78c1d784 | 1235 | |
148deab2 MW |
1236 | if (flags & RADIX_TREE_ITER_TAGGED) |
1237 | set_iter_tags(iter, node, offset, tag); | |
78c1d784 KK |
1238 | |
1239 | return node->slots + offset; | |
1240 | } | |
1241 | EXPORT_SYMBOL(radix_tree_next_chunk); | |
1242 | ||
1da177e4 LT |
1243 | /** |
1244 | * radix_tree_gang_lookup - perform multiple lookup on a radix tree | |
1245 | * @root: radix tree root | |
1246 | * @results: where the results of the lookup are placed | |
1247 | * @first_index: start the lookup from this key | |
1248 | * @max_items: place up to this many items at *results | |
1249 | * | |
1250 | * Performs an index-ascending scan of the tree for present items. Places | |
1251 | * them at *@results and returns the number of items which were placed at | |
1252 | * *@results. | |
1253 | * | |
1254 | * The implementation is naive. | |
7cf9c2c7 NP |
1255 | * |
1256 | * Like radix_tree_lookup, radix_tree_gang_lookup may be called under | |
1257 | * rcu_read_lock. In this case, rather than the returned results being | |
2fcd9005 MW |
1258 | * an atomic snapshot of the tree at a single point in time, the |
1259 | * semantics of an RCU protected gang lookup are as though multiple | |
1260 | * radix_tree_lookups have been issued in individual locks, and results | |
1261 | * stored in 'results'. | |
1da177e4 LT |
1262 | */ |
1263 | unsigned int | |
35534c86 | 1264 | radix_tree_gang_lookup(const struct radix_tree_root *root, void **results, |
1da177e4 LT |
1265 | unsigned long first_index, unsigned int max_items) |
1266 | { | |
cebbd29e | 1267 | struct radix_tree_iter iter; |
d7b62727 | 1268 | void __rcu **slot; |
cebbd29e | 1269 | unsigned int ret = 0; |
7cf9c2c7 | 1270 | |
cebbd29e | 1271 | if (unlikely(!max_items)) |
7cf9c2c7 | 1272 | return 0; |
1da177e4 | 1273 | |
cebbd29e | 1274 | radix_tree_for_each_slot(slot, root, &iter, first_index) { |
46437f9a | 1275 | results[ret] = rcu_dereference_raw(*slot); |
cebbd29e KK |
1276 | if (!results[ret]) |
1277 | continue; | |
b194d16c | 1278 | if (radix_tree_is_internal_node(results[ret])) { |
46437f9a MW |
1279 | slot = radix_tree_iter_retry(&iter); |
1280 | continue; | |
1281 | } | |
cebbd29e | 1282 | if (++ret == max_items) |
1da177e4 | 1283 | break; |
1da177e4 | 1284 | } |
7cf9c2c7 | 1285 | |
1da177e4 LT |
1286 | return ret; |
1287 | } | |
1288 | EXPORT_SYMBOL(radix_tree_gang_lookup); | |
1289 | ||
1da177e4 LT |
1290 | /** |
1291 | * radix_tree_gang_lookup_tag - perform multiple lookup on a radix tree | |
1292 | * based on a tag | |
1293 | * @root: radix tree root | |
1294 | * @results: where the results of the lookup are placed | |
1295 | * @first_index: start the lookup from this key | |
1296 | * @max_items: place up to this many items at *results | |
daff89f3 | 1297 | * @tag: the tag index (< RADIX_TREE_MAX_TAGS) |
1da177e4 LT |
1298 | * |
1299 | * Performs an index-ascending scan of the tree for present items which | |
1300 | * have the tag indexed by @tag set. Places the items at *@results and | |
1301 | * returns the number of items which were placed at *@results. | |
1302 | */ | |
1303 | unsigned int | |
35534c86 | 1304 | radix_tree_gang_lookup_tag(const struct radix_tree_root *root, void **results, |
daff89f3 JC |
1305 | unsigned long first_index, unsigned int max_items, |
1306 | unsigned int tag) | |
1da177e4 | 1307 | { |
cebbd29e | 1308 | struct radix_tree_iter iter; |
d7b62727 | 1309 | void __rcu **slot; |
cebbd29e | 1310 | unsigned int ret = 0; |
612d6c19 | 1311 | |
cebbd29e | 1312 | if (unlikely(!max_items)) |
7cf9c2c7 NP |
1313 | return 0; |
1314 | ||
cebbd29e | 1315 | radix_tree_for_each_tagged(slot, root, &iter, first_index, tag) { |
46437f9a | 1316 | results[ret] = rcu_dereference_raw(*slot); |
cebbd29e KK |
1317 | if (!results[ret]) |
1318 | continue; | |
b194d16c | 1319 | if (radix_tree_is_internal_node(results[ret])) { |
46437f9a MW |
1320 | slot = radix_tree_iter_retry(&iter); |
1321 | continue; | |
1322 | } | |
cebbd29e | 1323 | if (++ret == max_items) |
1da177e4 | 1324 | break; |
1da177e4 | 1325 | } |
7cf9c2c7 | 1326 | |
1da177e4 LT |
1327 | return ret; |
1328 | } | |
1329 | EXPORT_SYMBOL(radix_tree_gang_lookup_tag); | |
1330 | ||
47feff2c NP |
1331 | /** |
1332 | * radix_tree_gang_lookup_tag_slot - perform multiple slot lookup on a | |
1333 | * radix tree based on a tag | |
1334 | * @root: radix tree root | |
1335 | * @results: where the results of the lookup are placed | |
1336 | * @first_index: start the lookup from this key | |
1337 | * @max_items: place up to this many items at *results | |
1338 | * @tag: the tag index (< RADIX_TREE_MAX_TAGS) | |
1339 | * | |
1340 | * Performs an index-ascending scan of the tree for present items which | |
1341 | * have the tag indexed by @tag set. Places the slots at *@results and | |
1342 | * returns the number of slots which were placed at *@results. | |
1343 | */ | |
1344 | unsigned int | |
35534c86 | 1345 | radix_tree_gang_lookup_tag_slot(const struct radix_tree_root *root, |
d7b62727 | 1346 | void __rcu ***results, unsigned long first_index, |
35534c86 | 1347 | unsigned int max_items, unsigned int tag) |
47feff2c | 1348 | { |
cebbd29e | 1349 | struct radix_tree_iter iter; |
d7b62727 | 1350 | void __rcu **slot; |
cebbd29e | 1351 | unsigned int ret = 0; |
47feff2c | 1352 | |
cebbd29e | 1353 | if (unlikely(!max_items)) |
47feff2c NP |
1354 | return 0; |
1355 | ||
cebbd29e KK |
1356 | radix_tree_for_each_tagged(slot, root, &iter, first_index, tag) { |
1357 | results[ret] = slot; | |
1358 | if (++ret == max_items) | |
47feff2c | 1359 | break; |
47feff2c NP |
1360 | } |
1361 | ||
1362 | return ret; | |
1363 | } | |
1364 | EXPORT_SYMBOL(radix_tree_gang_lookup_tag_slot); | |
1365 | ||
0ac398ef | 1366 | static bool __radix_tree_delete(struct radix_tree_root *root, |
d7b62727 | 1367 | struct radix_tree_node *node, void __rcu **slot) |
0ac398ef | 1368 | { |
0a835c4f | 1369 | void *old = rcu_dereference_raw(*slot); |
01959dfe | 1370 | int values = xa_is_value(old) ? -1 : 0; |
0ac398ef MW |
1371 | unsigned offset = get_slot_offset(node, slot); |
1372 | int tag; | |
1373 | ||
0a835c4f MW |
1374 | if (is_idr(root)) |
1375 | node_tag_set(root, node, IDR_FREE, offset); | |
1376 | else | |
1377 | for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) | |
1378 | node_tag_clear(root, node, tag, offset); | |
0ac398ef | 1379 | |
01959dfe | 1380 | replace_slot(slot, NULL, node, -1, values); |
1cf56f9d | 1381 | return node && delete_node(root, node); |
0ac398ef MW |
1382 | } |
1383 | ||
1da177e4 | 1384 | /** |
0ac398ef MW |
1385 | * radix_tree_iter_delete - delete the entry at this iterator position |
1386 | * @root: radix tree root | |
1387 | * @iter: iterator state | |
1388 | * @slot: pointer to slot | |
1da177e4 | 1389 | * |
0ac398ef MW |
1390 | * Delete the entry at the position currently pointed to by the iterator. |
1391 | * This may result in the current node being freed; if it is, the iterator | |
1392 | * is advanced so that it will not reference the freed memory. This | |
1393 | * function may be called without any locking if there are no other threads | |
1394 | * which can access this tree. | |
1395 | */ | |
1396 | void radix_tree_iter_delete(struct radix_tree_root *root, | |
d7b62727 | 1397 | struct radix_tree_iter *iter, void __rcu **slot) |
0ac398ef MW |
1398 | { |
1399 | if (__radix_tree_delete(root, iter->node, slot)) | |
1400 | iter->index = iter->next_index; | |
1401 | } | |
d1b48c1e | 1402 | EXPORT_SYMBOL(radix_tree_iter_delete); |
0ac398ef MW |
1403 | |
1404 | /** | |
1405 | * radix_tree_delete_item - delete an item from a radix tree | |
1406 | * @root: radix tree root | |
1407 | * @index: index key | |
1408 | * @item: expected item | |
1da177e4 | 1409 | * |
0ac398ef | 1410 | * Remove @item at @index from the radix tree rooted at @root. |
1da177e4 | 1411 | * |
0ac398ef MW |
1412 | * Return: the deleted entry, or %NULL if it was not present |
1413 | * or the entry at the given @index was not @item. | |
1da177e4 | 1414 | */ |
53c59f26 JW |
1415 | void *radix_tree_delete_item(struct radix_tree_root *root, |
1416 | unsigned long index, void *item) | |
1da177e4 | 1417 | { |
0a835c4f | 1418 | struct radix_tree_node *node = NULL; |
7a4deea1 | 1419 | void __rcu **slot = NULL; |
139e5616 | 1420 | void *entry; |
1da177e4 | 1421 | |
139e5616 | 1422 | entry = __radix_tree_lookup(root, index, &node, &slot); |
7a4deea1 MW |
1423 | if (!slot) |
1424 | return NULL; | |
0a835c4f MW |
1425 | if (!entry && (!is_idr(root) || node_tag_get(root, node, IDR_FREE, |
1426 | get_slot_offset(node, slot)))) | |
139e5616 | 1427 | return NULL; |
1da177e4 | 1428 | |
139e5616 JW |
1429 | if (item && entry != item) |
1430 | return NULL; | |
1431 | ||
0ac398ef | 1432 | __radix_tree_delete(root, node, slot); |
612d6c19 | 1433 | |
139e5616 | 1434 | return entry; |
1da177e4 | 1435 | } |
53c59f26 JW |
1436 | EXPORT_SYMBOL(radix_tree_delete_item); |
1437 | ||
1438 | /** | |
0ac398ef MW |
1439 | * radix_tree_delete - delete an entry from a radix tree |
1440 | * @root: radix tree root | |
1441 | * @index: index key | |
53c59f26 | 1442 | * |
0ac398ef | 1443 | * Remove the entry at @index from the radix tree rooted at @root. |
53c59f26 | 1444 | * |
0ac398ef | 1445 | * Return: The deleted entry, or %NULL if it was not present. |
53c59f26 JW |
1446 | */ |
1447 | void *radix_tree_delete(struct radix_tree_root *root, unsigned long index) | |
1448 | { | |
1449 | return radix_tree_delete_item(root, index, NULL); | |
1450 | } | |
1da177e4 LT |
1451 | EXPORT_SYMBOL(radix_tree_delete); |
1452 | ||
1453 | /** | |
1454 | * radix_tree_tagged - test whether any items in the tree are tagged | |
1455 | * @root: radix tree root | |
1456 | * @tag: tag to test | |
1457 | */ | |
35534c86 | 1458 | int radix_tree_tagged(const struct radix_tree_root *root, unsigned int tag) |
1da177e4 | 1459 | { |
612d6c19 | 1460 | return root_tag_get(root, tag); |
1da177e4 LT |
1461 | } |
1462 | EXPORT_SYMBOL(radix_tree_tagged); | |
1463 | ||
0a835c4f MW |
1464 | /** |
1465 | * idr_preload - preload for idr_alloc() | |
1466 | * @gfp_mask: allocation mask to use for preloading | |
1467 | * | |
1468 | * Preallocate memory to use for the next call to idr_alloc(). This function | |
1469 | * returns with preemption disabled. It will be enabled by idr_preload_end(). | |
1470 | */ | |
1471 | void idr_preload(gfp_t gfp_mask) | |
1472 | { | |
bc9ae224 | 1473 | if (__radix_tree_preload(gfp_mask, IDR_PRELOAD_SIZE)) |
05fdd323 | 1474 | preempt_disable(); |
0a835c4f MW |
1475 | } |
1476 | EXPORT_SYMBOL(idr_preload); | |
1477 | ||
460488c5 | 1478 | void __rcu **idr_get_free(struct radix_tree_root *root, |
388f79fd CM |
1479 | struct radix_tree_iter *iter, gfp_t gfp, |
1480 | unsigned long max) | |
0a835c4f MW |
1481 | { |
1482 | struct radix_tree_node *node = NULL, *child; | |
f8d5d0cc | 1483 | void __rcu **slot = (void __rcu **)&root->xa_head; |
0a835c4f | 1484 | unsigned long maxindex, start = iter->next_index; |
0a835c4f MW |
1485 | unsigned int shift, offset = 0; |
1486 | ||
1487 | grow: | |
1488 | shift = radix_tree_load_root(root, &child, &maxindex); | |
1489 | if (!radix_tree_tagged(root, IDR_FREE)) | |
1490 | start = max(start, maxindex + 1); | |
1491 | if (start > max) | |
1492 | return ERR_PTR(-ENOSPC); | |
1493 | ||
1494 | if (start > maxindex) { | |
1495 | int error = radix_tree_extend(root, gfp, start, shift); | |
1496 | if (error < 0) | |
1497 | return ERR_PTR(error); | |
1498 | shift = error; | |
f8d5d0cc | 1499 | child = rcu_dereference_raw(root->xa_head); |
0a835c4f | 1500 | } |
66ee620f MW |
1501 | if (start == 0 && shift == 0) |
1502 | shift = RADIX_TREE_MAP_SHIFT; | |
0a835c4f MW |
1503 | |
1504 | while (shift) { | |
1505 | shift -= RADIX_TREE_MAP_SHIFT; | |
1506 | if (child == NULL) { | |
1507 | /* Have to add a child node. */ | |
d58275bc MW |
1508 | child = radix_tree_node_alloc(gfp, node, root, shift, |
1509 | offset, 0, 0); | |
0a835c4f MW |
1510 | if (!child) |
1511 | return ERR_PTR(-ENOMEM); | |
1512 | all_tag_set(child, IDR_FREE); | |
1513 | rcu_assign_pointer(*slot, node_to_entry(child)); | |
1514 | if (node) | |
1515 | node->count++; | |
1516 | } else if (!radix_tree_is_internal_node(child)) | |
1517 | break; | |
1518 | ||
1519 | node = entry_to_node(child); | |
1520 | offset = radix_tree_descend(node, &child, start); | |
1521 | if (!tag_get(node, IDR_FREE, offset)) { | |
1522 | offset = radix_tree_find_next_bit(node, IDR_FREE, | |
1523 | offset + 1); | |
1524 | start = next_index(start, node, offset); | |
b7e9728f | 1525 | if (start > max || start == 0) |
0a835c4f MW |
1526 | return ERR_PTR(-ENOSPC); |
1527 | while (offset == RADIX_TREE_MAP_SIZE) { | |
1528 | offset = node->offset + 1; | |
1529 | node = node->parent; | |
1530 | if (!node) | |
1531 | goto grow; | |
1532 | shift = node->shift; | |
1533 | } | |
1534 | child = rcu_dereference_raw(node->slots[offset]); | |
1535 | } | |
1536 | slot = &node->slots[offset]; | |
1537 | } | |
1538 | ||
1539 | iter->index = start; | |
1540 | if (node) | |
1541 | iter->next_index = 1 + min(max, (start | node_maxindex(node))); | |
1542 | else | |
1543 | iter->next_index = 1; | |
1544 | iter->node = node; | |
0a835c4f MW |
1545 | set_iter_tags(iter, node, offset, IDR_FREE); |
1546 | ||
1547 | return slot; | |
1548 | } | |
1549 | ||
1550 | /** | |
1551 | * idr_destroy - release all internal memory from an IDR | |
1552 | * @idr: idr handle | |
1553 | * | |
1554 | * After this function is called, the IDR is empty, and may be reused or | |
1555 | * the data structure containing it may be freed. | |
1556 | * | |
1557 | * A typical clean-up sequence for objects stored in an idr tree will use | |
1558 | * idr_for_each() to free all objects, if necessary, then idr_destroy() to | |
1559 | * free the memory used to keep track of those objects. | |
1560 | */ | |
1561 | void idr_destroy(struct idr *idr) | |
1562 | { | |
f8d5d0cc | 1563 | struct radix_tree_node *node = rcu_dereference_raw(idr->idr_rt.xa_head); |
0a835c4f MW |
1564 | if (radix_tree_is_internal_node(node)) |
1565 | radix_tree_free_nodes(node); | |
f8d5d0cc | 1566 | idr->idr_rt.xa_head = NULL; |
0a835c4f MW |
1567 | root_tag_set(&idr->idr_rt, IDR_FREE); |
1568 | } | |
1569 | EXPORT_SYMBOL(idr_destroy); | |
1570 | ||
1da177e4 | 1571 | static void |
449dd698 | 1572 | radix_tree_node_ctor(void *arg) |
1da177e4 | 1573 | { |
449dd698 JW |
1574 | struct radix_tree_node *node = arg; |
1575 | ||
1576 | memset(node, 0, sizeof(*node)); | |
1577 | INIT_LIST_HEAD(&node->private_list); | |
1da177e4 LT |
1578 | } |
1579 | ||
d544abd5 | 1580 | static int radix_tree_cpu_dead(unsigned int cpu) |
1da177e4 | 1581 | { |
2fcd9005 MW |
1582 | struct radix_tree_preload *rtp; |
1583 | struct radix_tree_node *node; | |
1584 | ||
1585 | /* Free per-cpu pool of preloaded nodes */ | |
d544abd5 SAS |
1586 | rtp = &per_cpu(radix_tree_preloads, cpu); |
1587 | while (rtp->nr) { | |
1588 | node = rtp->nodes; | |
1293d5c5 | 1589 | rtp->nodes = node->parent; |
d544abd5 SAS |
1590 | kmem_cache_free(radix_tree_node_cachep, node); |
1591 | rtp->nr--; | |
2fcd9005 | 1592 | } |
d544abd5 | 1593 | return 0; |
1da177e4 | 1594 | } |
1da177e4 LT |
1595 | |
1596 | void __init radix_tree_init(void) | |
1597 | { | |
d544abd5 | 1598 | int ret; |
7e784422 MH |
1599 | |
1600 | BUILD_BUG_ON(RADIX_TREE_MAX_TAGS + __GFP_BITS_SHIFT > 32); | |
fa290cda | 1601 | BUILD_BUG_ON(ROOT_IS_IDR & ~GFP_ZONEMASK); |
02c02bf1 | 1602 | BUILD_BUG_ON(XA_CHUNK_SIZE > 255); |
1da177e4 LT |
1603 | radix_tree_node_cachep = kmem_cache_create("radix_tree_node", |
1604 | sizeof(struct radix_tree_node), 0, | |
488514d1 CL |
1605 | SLAB_PANIC | SLAB_RECLAIM_ACCOUNT, |
1606 | radix_tree_node_ctor); | |
d544abd5 SAS |
1607 | ret = cpuhp_setup_state_nocalls(CPUHP_RADIX_DEAD, "lib/radix:dead", |
1608 | NULL, radix_tree_cpu_dead); | |
1609 | WARN_ON(ret < 0); | |
1da177e4 | 1610 | } |