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1da177e4 LT |
1 | /* |
2 | * Copyright (C) 2001 Momchil Velikov | |
3 | * Portions Copyright (C) 2001 Christoph Hellwig | |
7cf9c2c7 | 4 | * Copyright (C) 2006 Nick Piggin |
78c1d784 | 5 | * Copyright (C) 2012 Konstantin Khlebnikov |
1da177e4 LT |
6 | * |
7 | * This program is free software; you can redistribute it and/or | |
8 | * modify it under the terms of the GNU General Public License as | |
9 | * published by the Free Software Foundation; either version 2, or (at | |
10 | * your option) any later version. | |
11 | * | |
12 | * This program is distributed in the hope that it will be useful, but | |
13 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
15 | * General Public License for more details. | |
16 | * | |
17 | * You should have received a copy of the GNU General Public License | |
18 | * along with this program; if not, write to the Free Software | |
19 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
20 | */ | |
21 | #ifndef _LINUX_RADIX_TREE_H | |
22 | #define _LINUX_RADIX_TREE_H | |
23 | ||
f67c07f0 | 24 | #include <linux/bitops.h> |
187f1882 | 25 | #include <linux/bug.h> |
7cf9c2c7 | 26 | #include <linux/kernel.h> |
15f2e88d MW |
27 | #include <linux/list.h> |
28 | #include <linux/preempt.h> | |
7cf9c2c7 | 29 | #include <linux/rcupdate.h> |
15f2e88d MW |
30 | #include <linux/spinlock.h> |
31 | #include <linux/types.h> | |
7cf9c2c7 NP |
32 | |
33 | /* | |
3bcadd6f MW |
34 | * The bottom two bits of the slot determine how the remaining bits in the |
35 | * slot are interpreted: | |
7cf9c2c7 | 36 | * |
3bcadd6f MW |
37 | * 00 - data pointer |
38 | * 01 - internal entry | |
39 | * 10 - exceptional entry | |
a23216a2 | 40 | * 11 - this bit combination is currently unused/reserved |
3bcadd6f MW |
41 | * |
42 | * The internal entry may be a pointer to the next level in the tree, a | |
43 | * sibling entry, or an indicator that the entry in this slot has been moved | |
44 | * to another location in the tree and the lookup should be restarted. While | |
45 | * NULL fits the 'data pointer' pattern, it means that there is no entry in | |
46 | * the tree for this index (no matter what level of the tree it is found at). | |
47 | * This means that you cannot store NULL in the tree as a value for the index. | |
7cf9c2c7 | 48 | */ |
3bcadd6f MW |
49 | #define RADIX_TREE_ENTRY_MASK 3UL |
50 | #define RADIX_TREE_INTERNAL_NODE 1UL | |
30ff46cc | 51 | |
6328650b | 52 | /* |
3bcadd6f MW |
53 | * Most users of the radix tree store pointers but shmem/tmpfs stores swap |
54 | * entries in the same tree. They are marked as exceptional entries to | |
55 | * distinguish them from pointers to struct page. | |
6328650b HD |
56 | * EXCEPTIONAL_ENTRY tests the bit, EXCEPTIONAL_SHIFT shifts content past it. |
57 | */ | |
58 | #define RADIX_TREE_EXCEPTIONAL_ENTRY 2 | |
59 | #define RADIX_TREE_EXCEPTIONAL_SHIFT 2 | |
7cf9c2c7 | 60 | |
3bcadd6f | 61 | static inline bool radix_tree_is_internal_node(void *ptr) |
7cf9c2c7 | 62 | { |
3bcadd6f MW |
63 | return ((unsigned long)ptr & RADIX_TREE_ENTRY_MASK) == |
64 | RADIX_TREE_INTERNAL_NODE; | |
7cf9c2c7 NP |
65 | } |
66 | ||
67 | /*** radix-tree API starts here ***/ | |
1da177e4 | 68 | |
f446daae | 69 | #define RADIX_TREE_MAX_TAGS 3 |
612d6c19 | 70 | |
97d778b2 | 71 | #ifndef RADIX_TREE_MAP_SHIFT |
139e5616 | 72 | #define RADIX_TREE_MAP_SHIFT (CONFIG_BASE_SMALL ? 4 : 6) |
139e5616 JW |
73 | #endif |
74 | ||
75 | #define RADIX_TREE_MAP_SIZE (1UL << RADIX_TREE_MAP_SHIFT) | |
76 | #define RADIX_TREE_MAP_MASK (RADIX_TREE_MAP_SIZE-1) | |
77 | ||
78 | #define RADIX_TREE_TAG_LONGS \ | |
79 | ((RADIX_TREE_MAP_SIZE + BITS_PER_LONG - 1) / BITS_PER_LONG) | |
80 | ||
449dd698 JW |
81 | #define RADIX_TREE_INDEX_BITS (8 /* CHAR_BIT */ * sizeof(unsigned long)) |
82 | #define RADIX_TREE_MAX_PATH (DIV_ROUND_UP(RADIX_TREE_INDEX_BITS, \ | |
83 | RADIX_TREE_MAP_SHIFT)) | |
84 | ||
e157b555 MW |
85 | /* |
86 | * @count is the count of every non-NULL element in the ->slots array | |
87 | * whether that is an exceptional entry, a retry entry, a user pointer, | |
88 | * a sibling entry or a pointer to the next level of the tree. | |
89 | * @exceptional is the count of every element in ->slots which is | |
90 | * either radix_tree_exceptional_entry() or is a sibling entry for an | |
91 | * exceptional entry. | |
92 | */ | |
139e5616 | 93 | struct radix_tree_node { |
f7942430 JW |
94 | unsigned char shift; /* Bits remaining in each slot */ |
95 | unsigned char offset; /* Slot offset in parent */ | |
14b46879 | 96 | unsigned char count; /* Total entry count */ |
f7942430 | 97 | unsigned char exceptional; /* Exceptional entry count */ |
91d9c05a MW |
98 | struct radix_tree_node *parent; /* Used when ascending tree */ |
99 | void *private_data; /* For tree user */ | |
139e5616 | 100 | union { |
91d9c05a MW |
101 | struct list_head private_list; /* For tree user */ |
102 | struct rcu_head rcu_head; /* Used when freeing node */ | |
139e5616 JW |
103 | }; |
104 | void __rcu *slots[RADIX_TREE_MAP_SIZE]; | |
105 | unsigned long tags[RADIX_TREE_MAX_TAGS][RADIX_TREE_TAG_LONGS]; | |
106 | }; | |
107 | ||
612d6c19 | 108 | /* root tags are stored in gfp_mask, shifted by __GFP_BITS_SHIFT */ |
1da177e4 | 109 | struct radix_tree_root { |
fd4f2df2 | 110 | gfp_t gfp_mask; |
a1115570 | 111 | struct radix_tree_node __rcu *rnode; |
1da177e4 LT |
112 | }; |
113 | ||
114 | #define RADIX_TREE_INIT(mask) { \ | |
1da177e4 LT |
115 | .gfp_mask = (mask), \ |
116 | .rnode = NULL, \ | |
117 | } | |
118 | ||
119 | #define RADIX_TREE(name, mask) \ | |
120 | struct radix_tree_root name = RADIX_TREE_INIT(mask) | |
121 | ||
122 | #define INIT_RADIX_TREE(root, mask) \ | |
123 | do { \ | |
1da177e4 LT |
124 | (root)->gfp_mask = (mask); \ |
125 | (root)->rnode = NULL; \ | |
126 | } while (0) | |
127 | ||
35534c86 | 128 | static inline bool radix_tree_empty(const struct radix_tree_root *root) |
e9256efc MW |
129 | { |
130 | return root->rnode == NULL; | |
131 | } | |
132 | ||
268f42de MW |
133 | /** |
134 | * struct radix_tree_iter - radix tree iterator state | |
135 | * | |
136 | * @index: index of current slot | |
137 | * @next_index: one beyond the last index for this chunk | |
138 | * @tags: bit-mask for tag-iterating | |
139 | * @node: node that contains current slot | |
140 | * @shift: shift for the node that holds our slots | |
141 | * | |
142 | * This radix tree iterator works in terms of "chunks" of slots. A chunk is a | |
143 | * subinterval of slots contained within one radix tree leaf node. It is | |
144 | * described by a pointer to its first slot and a struct radix_tree_iter | |
145 | * which holds the chunk's position in the tree and its size. For tagged | |
146 | * iteration radix_tree_iter also holds the slots' bit-mask for one chosen | |
147 | * radix tree tag. | |
148 | */ | |
149 | struct radix_tree_iter { | |
150 | unsigned long index; | |
151 | unsigned long next_index; | |
152 | unsigned long tags; | |
153 | struct radix_tree_node *node; | |
154 | #ifdef CONFIG_RADIX_TREE_MULTIORDER | |
155 | unsigned int shift; | |
156 | #endif | |
157 | }; | |
158 | ||
159 | static inline unsigned int iter_shift(const struct radix_tree_iter *iter) | |
160 | { | |
161 | #ifdef CONFIG_RADIX_TREE_MULTIORDER | |
162 | return iter->shift; | |
163 | #else | |
164 | return 0; | |
165 | #endif | |
166 | } | |
167 | ||
7cf9c2c7 NP |
168 | /** |
169 | * Radix-tree synchronization | |
170 | * | |
171 | * The radix-tree API requires that users provide all synchronisation (with | |
172 | * specific exceptions, noted below). | |
173 | * | |
174 | * Synchronization of access to the data items being stored in the tree, and | |
175 | * management of their lifetimes must be completely managed by API users. | |
176 | * | |
177 | * For API usage, in general, | |
59c51591 | 178 | * - any function _modifying_ the tree or tags (inserting or deleting |
eb8dc5e7 | 179 | * items, setting or clearing tags) must exclude other modifications, and |
7cf9c2c7 | 180 | * exclude any functions reading the tree. |
59c51591 | 181 | * - any function _reading_ the tree or tags (looking up items or tags, |
7cf9c2c7 NP |
182 | * gang lookups) must exclude modifications to the tree, but may occur |
183 | * concurrently with other readers. | |
184 | * | |
185 | * The notable exceptions to this rule are the following functions: | |
139e5616 | 186 | * __radix_tree_lookup |
7cf9c2c7 | 187 | * radix_tree_lookup |
47feff2c | 188 | * radix_tree_lookup_slot |
7cf9c2c7 NP |
189 | * radix_tree_tag_get |
190 | * radix_tree_gang_lookup | |
47feff2c | 191 | * radix_tree_gang_lookup_slot |
7cf9c2c7 | 192 | * radix_tree_gang_lookup_tag |
47feff2c | 193 | * radix_tree_gang_lookup_tag_slot |
7cf9c2c7 NP |
194 | * radix_tree_tagged |
195 | * | |
243c2137 | 196 | * The first 8 functions are able to be called locklessly, using RCU. The |
7cf9c2c7 NP |
197 | * caller must ensure calls to these functions are made within rcu_read_lock() |
198 | * regions. Other readers (lock-free or otherwise) and modifications may be | |
199 | * running concurrently. | |
200 | * | |
201 | * It is still required that the caller manage the synchronization and lifetimes | |
202 | * of the items. So if RCU lock-free lookups are used, typically this would mean | |
203 | * that the items have their own locks, or are amenable to lock-free access; and | |
204 | * that the items are freed by RCU (or only freed after having been deleted from | |
205 | * the radix tree *and* a synchronize_rcu() grace period). | |
206 | * | |
207 | * (Note, rcu_assign_pointer and rcu_dereference are not needed to control | |
208 | * access to data items when inserting into or looking up from the radix tree) | |
209 | * | |
ce82653d DH |
210 | * Note that the value returned by radix_tree_tag_get() may not be relied upon |
211 | * if only the RCU read lock is held. Functions to set/clear tags and to | |
212 | * delete nodes running concurrently with it may affect its result such that | |
213 | * two consecutive reads in the same locked section may return different | |
214 | * values. If reliability is required, modification functions must also be | |
215 | * excluded from concurrency. | |
216 | * | |
7cf9c2c7 NP |
217 | * radix_tree_tagged is able to be called without locking or RCU. |
218 | */ | |
219 | ||
220 | /** | |
221 | * radix_tree_deref_slot - dereference a slot | |
222 | * @pslot: pointer to slot, returned by radix_tree_lookup_slot | |
223 | * Returns: item that was stored in that slot with any direct pointer flag | |
224 | * removed. | |
225 | * | |
226 | * For use with radix_tree_lookup_slot(). Caller must hold tree at least read | |
27d20fdd NP |
227 | * locked across slot lookup and dereference. Not required if write lock is |
228 | * held (ie. items cannot be concurrently inserted). | |
229 | * | |
230 | * radix_tree_deref_retry must be used to confirm validity of the pointer if | |
231 | * only the read lock is held. | |
7cf9c2c7 NP |
232 | */ |
233 | static inline void *radix_tree_deref_slot(void **pslot) | |
234 | { | |
27d20fdd | 235 | return rcu_dereference(*pslot); |
7cf9c2c7 | 236 | } |
27d20fdd | 237 | |
29c1f677 MG |
238 | /** |
239 | * radix_tree_deref_slot_protected - dereference a slot without RCU lock but with tree lock held | |
240 | * @pslot: pointer to slot, returned by radix_tree_lookup_slot | |
241 | * Returns: item that was stored in that slot with any direct pointer flag | |
242 | * removed. | |
243 | * | |
244 | * Similar to radix_tree_deref_slot but only used during migration when a pages | |
245 | * mapping is being moved. The caller does not hold the RCU read lock but it | |
246 | * must hold the tree lock to prevent parallel updates. | |
247 | */ | |
248 | static inline void *radix_tree_deref_slot_protected(void **pslot, | |
249 | spinlock_t *treelock) | |
250 | { | |
251 | return rcu_dereference_protected(*pslot, lockdep_is_held(treelock)); | |
252 | } | |
253 | ||
27d20fdd NP |
254 | /** |
255 | * radix_tree_deref_retry - check radix_tree_deref_slot | |
256 | * @arg: pointer returned by radix_tree_deref_slot | |
257 | * Returns: 0 if retry is not required, otherwise retry is required | |
258 | * | |
259 | * radix_tree_deref_retry must be used with radix_tree_deref_slot. | |
260 | */ | |
261 | static inline int radix_tree_deref_retry(void *arg) | |
262 | { | |
b194d16c | 263 | return unlikely(radix_tree_is_internal_node(arg)); |
27d20fdd NP |
264 | } |
265 | ||
6328650b HD |
266 | /** |
267 | * radix_tree_exceptional_entry - radix_tree_deref_slot gave exceptional entry? | |
268 | * @arg: value returned by radix_tree_deref_slot | |
269 | * Returns: 0 if well-aligned pointer, non-0 if exceptional entry. | |
270 | */ | |
271 | static inline int radix_tree_exceptional_entry(void *arg) | |
272 | { | |
273 | /* Not unlikely because radix_tree_exception often tested first */ | |
274 | return (unsigned long)arg & RADIX_TREE_EXCEPTIONAL_ENTRY; | |
275 | } | |
276 | ||
277 | /** | |
278 | * radix_tree_exception - radix_tree_deref_slot returned either exception? | |
279 | * @arg: value returned by radix_tree_deref_slot | |
280 | * Returns: 0 if well-aligned pointer, non-0 if either kind of exception. | |
281 | */ | |
282 | static inline int radix_tree_exception(void *arg) | |
283 | { | |
3bcadd6f | 284 | return unlikely((unsigned long)arg & RADIX_TREE_ENTRY_MASK); |
6328650b HD |
285 | } |
286 | ||
139e5616 | 287 | int __radix_tree_create(struct radix_tree_root *root, unsigned long index, |
e6145236 MW |
288 | unsigned order, struct radix_tree_node **nodep, |
289 | void ***slotp); | |
290 | int __radix_tree_insert(struct radix_tree_root *, unsigned long index, | |
291 | unsigned order, void *); | |
292 | static inline int radix_tree_insert(struct radix_tree_root *root, | |
293 | unsigned long index, void *entry) | |
294 | { | |
295 | return __radix_tree_insert(root, index, 0, entry); | |
296 | } | |
35534c86 | 297 | void *__radix_tree_lookup(const struct radix_tree_root *, unsigned long index, |
139e5616 | 298 | struct radix_tree_node **nodep, void ***slotp); |
35534c86 MW |
299 | void *radix_tree_lookup(const struct radix_tree_root *, unsigned long); |
300 | void **radix_tree_lookup_slot(const struct radix_tree_root *, unsigned long); | |
4d693d08 | 301 | typedef void (*radix_tree_update_node_t)(struct radix_tree_node *, void *); |
f7942430 JW |
302 | void __radix_tree_replace(struct radix_tree_root *root, |
303 | struct radix_tree_node *node, | |
4d693d08 JW |
304 | void **slot, void *item, |
305 | radix_tree_update_node_t update_node, void *private); | |
e157b555 MW |
306 | void radix_tree_iter_replace(struct radix_tree_root *, |
307 | const struct radix_tree_iter *, void **slot, void *item); | |
6d75f366 JW |
308 | void radix_tree_replace_slot(struct radix_tree_root *root, |
309 | void **slot, void *item); | |
14b46879 | 310 | void __radix_tree_delete_node(struct radix_tree_root *root, |
ea07b862 JW |
311 | struct radix_tree_node *node, |
312 | radix_tree_update_node_t update_node, | |
313 | void *private); | |
53c59f26 | 314 | void *radix_tree_delete_item(struct radix_tree_root *, unsigned long, void *); |
1da177e4 | 315 | void *radix_tree_delete(struct radix_tree_root *, unsigned long); |
d3798ae8 JW |
316 | void radix_tree_clear_tags(struct radix_tree_root *root, |
317 | struct radix_tree_node *node, | |
318 | void **slot); | |
35534c86 | 319 | unsigned int radix_tree_gang_lookup(const struct radix_tree_root *, |
d604c324 MW |
320 | void **results, unsigned long first_index, |
321 | unsigned int max_items); | |
35534c86 | 322 | unsigned int radix_tree_gang_lookup_slot(const struct radix_tree_root *, |
6328650b | 323 | void ***results, unsigned long *indices, |
47feff2c | 324 | unsigned long first_index, unsigned int max_items); |
dd0fc66f | 325 | int radix_tree_preload(gfp_t gfp_mask); |
5e4c0d97 | 326 | int radix_tree_maybe_preload(gfp_t gfp_mask); |
c78c66d1 | 327 | int radix_tree_maybe_preload_order(gfp_t gfp_mask, int order); |
1da177e4 LT |
328 | void radix_tree_init(void); |
329 | void *radix_tree_tag_set(struct radix_tree_root *root, | |
daff89f3 | 330 | unsigned long index, unsigned int tag); |
1da177e4 | 331 | void *radix_tree_tag_clear(struct radix_tree_root *root, |
daff89f3 | 332 | unsigned long index, unsigned int tag); |
35534c86 | 333 | int radix_tree_tag_get(const struct radix_tree_root *, |
daff89f3 | 334 | unsigned long index, unsigned int tag); |
30b888ba MW |
335 | void radix_tree_iter_tag_set(struct radix_tree_root *, |
336 | const struct radix_tree_iter *iter, unsigned int tag); | |
337 | void radix_tree_iter_tag_clear(struct radix_tree_root *, | |
268f42de | 338 | const struct radix_tree_iter *iter, unsigned int tag); |
1da177e4 | 339 | unsigned int |
35534c86 | 340 | radix_tree_gang_lookup_tag(const struct radix_tree_root *, void **results, |
daff89f3 JC |
341 | unsigned long first_index, unsigned int max_items, |
342 | unsigned int tag); | |
47feff2c | 343 | unsigned int |
35534c86 | 344 | radix_tree_gang_lookup_tag_slot(const struct radix_tree_root *, void ***results, |
47feff2c NP |
345 | unsigned long first_index, unsigned int max_items, |
346 | unsigned int tag); | |
35534c86 | 347 | int radix_tree_tagged(const struct radix_tree_root *root, unsigned int tag); |
1da177e4 LT |
348 | |
349 | static inline void radix_tree_preload_end(void) | |
350 | { | |
351 | preempt_enable(); | |
352 | } | |
353 | ||
2791653a | 354 | int radix_tree_split_preload(unsigned old_order, unsigned new_order, gfp_t); |
e157b555 MW |
355 | int radix_tree_split(struct radix_tree_root *, unsigned long index, |
356 | unsigned new_order); | |
175542f5 MW |
357 | int radix_tree_join(struct radix_tree_root *, unsigned long index, |
358 | unsigned new_order, void *); | |
359 | ||
78c1d784 KK |
360 | #define RADIX_TREE_ITER_TAG_MASK 0x00FF /* tag index in lower byte */ |
361 | #define RADIX_TREE_ITER_TAGGED 0x0100 /* lookup tagged slots */ | |
362 | #define RADIX_TREE_ITER_CONTIG 0x0200 /* stop at first hole */ | |
363 | ||
364 | /** | |
365 | * radix_tree_iter_init - initialize radix tree iterator | |
366 | * | |
367 | * @iter: pointer to iterator state | |
368 | * @start: iteration starting index | |
369 | * Returns: NULL | |
370 | */ | |
371 | static __always_inline void ** | |
372 | radix_tree_iter_init(struct radix_tree_iter *iter, unsigned long start) | |
373 | { | |
374 | /* | |
375 | * Leave iter->tags uninitialized. radix_tree_next_chunk() will fill it | |
376 | * in the case of a successful tagged chunk lookup. If the lookup was | |
377 | * unsuccessful or non-tagged then nobody cares about ->tags. | |
378 | * | |
379 | * Set index to zero to bypass next_index overflow protection. | |
380 | * See the comment in radix_tree_next_chunk() for details. | |
381 | */ | |
382 | iter->index = 0; | |
383 | iter->next_index = start; | |
384 | return NULL; | |
385 | } | |
386 | ||
387 | /** | |
388 | * radix_tree_next_chunk - find next chunk of slots for iteration | |
389 | * | |
390 | * @root: radix tree root | |
391 | * @iter: iterator state | |
392 | * @flags: RADIX_TREE_ITER_* flags and tag index | |
393 | * Returns: pointer to chunk first slot, or NULL if there no more left | |
394 | * | |
395 | * This function looks up the next chunk in the radix tree starting from | |
396 | * @iter->next_index. It returns a pointer to the chunk's first slot. | |
397 | * Also it fills @iter with data about chunk: position in the tree (index), | |
398 | * its end (next_index), and constructs a bit mask for tagged iterating (tags). | |
399 | */ | |
35534c86 | 400 | void **radix_tree_next_chunk(const struct radix_tree_root *, |
78c1d784 KK |
401 | struct radix_tree_iter *iter, unsigned flags); |
402 | ||
46437f9a MW |
403 | /** |
404 | * radix_tree_iter_retry - retry this chunk of the iteration | |
405 | * @iter: iterator state | |
406 | * | |
407 | * If we iterate over a tree protected only by the RCU lock, a race | |
408 | * against deletion or creation may result in seeing a slot for which | |
409 | * radix_tree_deref_retry() returns true. If so, call this function | |
410 | * and continue the iteration. | |
411 | */ | |
412 | static inline __must_check | |
413 | void **radix_tree_iter_retry(struct radix_tree_iter *iter) | |
414 | { | |
415 | iter->next_index = iter->index; | |
3cb9185c | 416 | iter->tags = 0; |
46437f9a MW |
417 | return NULL; |
418 | } | |
419 | ||
21ef5339 RZ |
420 | static inline unsigned long |
421 | __radix_tree_iter_add(struct radix_tree_iter *iter, unsigned long slots) | |
422 | { | |
423 | return iter->index + (slots << iter_shift(iter)); | |
424 | } | |
425 | ||
7165092f | 426 | /** |
148deab2 MW |
427 | * radix_tree_iter_resume - resume iterating when the chunk may be invalid |
428 | * @slot: pointer to current slot | |
429 | * @iter: iterator state | |
430 | * Returns: New slot pointer | |
7165092f MW |
431 | * |
432 | * If the iterator needs to release then reacquire a lock, the chunk may | |
433 | * have been invalidated by an insertion or deletion. Call this function | |
148deab2 | 434 | * before releasing the lock to continue the iteration from the next index. |
7165092f | 435 | */ |
148deab2 MW |
436 | void **__must_check radix_tree_iter_resume(void **slot, |
437 | struct radix_tree_iter *iter); | |
7165092f | 438 | |
78c1d784 KK |
439 | /** |
440 | * radix_tree_chunk_size - get current chunk size | |
441 | * | |
442 | * @iter: pointer to radix tree iterator | |
443 | * Returns: current chunk size | |
444 | */ | |
73204282 | 445 | static __always_inline long |
78c1d784 KK |
446 | radix_tree_chunk_size(struct radix_tree_iter *iter) |
447 | { | |
21ef5339 RZ |
448 | return (iter->next_index - iter->index) >> iter_shift(iter); |
449 | } | |
450 | ||
148deab2 MW |
451 | #ifdef CONFIG_RADIX_TREE_MULTIORDER |
452 | void ** __radix_tree_next_slot(void **slot, struct radix_tree_iter *iter, | |
453 | unsigned flags); | |
454 | #else | |
455 | /* Can't happen without sibling entries, but the compiler can't tell that */ | |
456 | static inline void ** __radix_tree_next_slot(void **slot, | |
457 | struct radix_tree_iter *iter, unsigned flags) | |
21ef5339 | 458 | { |
148deab2 | 459 | return slot; |
78c1d784 | 460 | } |
148deab2 | 461 | #endif |
78c1d784 KK |
462 | |
463 | /** | |
464 | * radix_tree_next_slot - find next slot in chunk | |
465 | * | |
466 | * @slot: pointer to current slot | |
467 | * @iter: pointer to interator state | |
468 | * @flags: RADIX_TREE_ITER_*, should be constant | |
469 | * Returns: pointer to next slot, or NULL if there no more left | |
470 | * | |
471 | * This function updates @iter->index in the case of a successful lookup. | |
472 | * For tagged lookup it also eats @iter->tags. | |
915045fe RZ |
473 | * |
474 | * There are several cases where 'slot' can be passed in as NULL to this | |
148deab2 | 475 | * function. These cases result from the use of radix_tree_iter_resume() or |
915045fe RZ |
476 | * radix_tree_iter_retry(). In these cases we don't end up dereferencing |
477 | * 'slot' because either: | |
478 | * a) we are doing tagged iteration and iter->tags has been set to 0, or | |
479 | * b) we are doing non-tagged iteration, and iter->index and iter->next_index | |
480 | * have been set up so that radix_tree_chunk_size() returns 1 or 0. | |
78c1d784 KK |
481 | */ |
482 | static __always_inline void ** | |
483 | radix_tree_next_slot(void **slot, struct radix_tree_iter *iter, unsigned flags) | |
484 | { | |
485 | if (flags & RADIX_TREE_ITER_TAGGED) { | |
486 | iter->tags >>= 1; | |
21ef5339 RZ |
487 | if (unlikely(!iter->tags)) |
488 | return NULL; | |
78c1d784 | 489 | if (likely(iter->tags & 1ul)) { |
21ef5339 | 490 | iter->index = __radix_tree_iter_add(iter, 1); |
148deab2 MW |
491 | slot++; |
492 | goto found; | |
78c1d784 | 493 | } |
21ef5339 | 494 | if (!(flags & RADIX_TREE_ITER_CONTIG)) { |
78c1d784 KK |
495 | unsigned offset = __ffs(iter->tags); |
496 | ||
148deab2 MW |
497 | iter->tags >>= offset++; |
498 | iter->index = __radix_tree_iter_add(iter, offset); | |
499 | slot += offset; | |
500 | goto found; | |
78c1d784 KK |
501 | } |
502 | } else { | |
21ef5339 | 503 | long count = radix_tree_chunk_size(iter); |
78c1d784 | 504 | |
21ef5339 | 505 | while (--count > 0) { |
78c1d784 | 506 | slot++; |
21ef5339 RZ |
507 | iter->index = __radix_tree_iter_add(iter, 1); |
508 | ||
78c1d784 | 509 | if (likely(*slot)) |
148deab2 | 510 | goto found; |
fffaee36 KK |
511 | if (flags & RADIX_TREE_ITER_CONTIG) { |
512 | /* forbid switching to the next chunk */ | |
513 | iter->next_index = 0; | |
78c1d784 | 514 | break; |
fffaee36 | 515 | } |
78c1d784 KK |
516 | } |
517 | } | |
518 | return NULL; | |
148deab2 MW |
519 | |
520 | found: | |
521 | if (unlikely(radix_tree_is_internal_node(*slot))) | |
522 | return __radix_tree_next_slot(slot, iter, flags); | |
523 | return slot; | |
78c1d784 KK |
524 | } |
525 | ||
78c1d784 KK |
526 | /** |
527 | * radix_tree_for_each_slot - iterate over non-empty slots | |
528 | * | |
529 | * @slot: the void** variable for pointer to slot | |
530 | * @root: the struct radix_tree_root pointer | |
531 | * @iter: the struct radix_tree_iter pointer | |
532 | * @start: iteration starting index | |
533 | * | |
534 | * @slot points to radix tree slot, @iter->index contains its index. | |
535 | */ | |
536 | #define radix_tree_for_each_slot(slot, root, iter, start) \ | |
537 | for (slot = radix_tree_iter_init(iter, start) ; \ | |
538 | slot || (slot = radix_tree_next_chunk(root, iter, 0)) ; \ | |
539 | slot = radix_tree_next_slot(slot, iter, 0)) | |
540 | ||
541 | /** | |
542 | * radix_tree_for_each_contig - iterate over contiguous slots | |
543 | * | |
544 | * @slot: the void** variable for pointer to slot | |
545 | * @root: the struct radix_tree_root pointer | |
546 | * @iter: the struct radix_tree_iter pointer | |
547 | * @start: iteration starting index | |
548 | * | |
549 | * @slot points to radix tree slot, @iter->index contains its index. | |
550 | */ | |
551 | #define radix_tree_for_each_contig(slot, root, iter, start) \ | |
552 | for (slot = radix_tree_iter_init(iter, start) ; \ | |
553 | slot || (slot = radix_tree_next_chunk(root, iter, \ | |
554 | RADIX_TREE_ITER_CONTIG)) ; \ | |
555 | slot = radix_tree_next_slot(slot, iter, \ | |
556 | RADIX_TREE_ITER_CONTIG)) | |
557 | ||
558 | /** | |
559 | * radix_tree_for_each_tagged - iterate over tagged slots | |
560 | * | |
561 | * @slot: the void** variable for pointer to slot | |
562 | * @root: the struct radix_tree_root pointer | |
563 | * @iter: the struct radix_tree_iter pointer | |
564 | * @start: iteration starting index | |
565 | * @tag: tag index | |
566 | * | |
567 | * @slot points to radix tree slot, @iter->index contains its index. | |
568 | */ | |
569 | #define radix_tree_for_each_tagged(slot, root, iter, start, tag) \ | |
570 | for (slot = radix_tree_iter_init(iter, start) ; \ | |
571 | slot || (slot = radix_tree_next_chunk(root, iter, \ | |
572 | RADIX_TREE_ITER_TAGGED | tag)) ; \ | |
573 | slot = radix_tree_next_slot(slot, iter, \ | |
148deab2 | 574 | RADIX_TREE_ITER_TAGGED | tag)) |
78c1d784 | 575 | |
1da177e4 | 576 | #endif /* _LINUX_RADIX_TREE_H */ |