Commit | Line | Data |
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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> |
1da177e4 LT |
25 | #include <linux/preempt.h> |
26 | #include <linux/types.h> | |
187f1882 | 27 | #include <linux/bug.h> |
7cf9c2c7 NP |
28 | #include <linux/kernel.h> |
29 | #include <linux/rcupdate.h> | |
30 | ||
31 | /* | |
3bcadd6f MW |
32 | * The bottom two bits of the slot determine how the remaining bits in the |
33 | * slot are interpreted: | |
7cf9c2c7 | 34 | * |
3bcadd6f MW |
35 | * 00 - data pointer |
36 | * 01 - internal entry | |
37 | * 10 - exceptional entry | |
a23216a2 | 38 | * 11 - this bit combination is currently unused/reserved |
3bcadd6f MW |
39 | * |
40 | * The internal entry may be a pointer to the next level in the tree, a | |
41 | * sibling entry, or an indicator that the entry in this slot has been moved | |
42 | * to another location in the tree and the lookup should be restarted. While | |
43 | * NULL fits the 'data pointer' pattern, it means that there is no entry in | |
44 | * the tree for this index (no matter what level of the tree it is found at). | |
45 | * This means that you cannot store NULL in the tree as a value for the index. | |
7cf9c2c7 | 46 | */ |
3bcadd6f MW |
47 | #define RADIX_TREE_ENTRY_MASK 3UL |
48 | #define RADIX_TREE_INTERNAL_NODE 1UL | |
30ff46cc | 49 | |
6328650b | 50 | /* |
3bcadd6f MW |
51 | * Most users of the radix tree store pointers but shmem/tmpfs stores swap |
52 | * entries in the same tree. They are marked as exceptional entries to | |
53 | * distinguish them from pointers to struct page. | |
6328650b HD |
54 | * EXCEPTIONAL_ENTRY tests the bit, EXCEPTIONAL_SHIFT shifts content past it. |
55 | */ | |
56 | #define RADIX_TREE_EXCEPTIONAL_ENTRY 2 | |
57 | #define RADIX_TREE_EXCEPTIONAL_SHIFT 2 | |
7cf9c2c7 | 58 | |
3bcadd6f | 59 | static inline bool radix_tree_is_internal_node(void *ptr) |
7cf9c2c7 | 60 | { |
3bcadd6f MW |
61 | return ((unsigned long)ptr & RADIX_TREE_ENTRY_MASK) == |
62 | RADIX_TREE_INTERNAL_NODE; | |
7cf9c2c7 NP |
63 | } |
64 | ||
65 | /*** radix-tree API starts here ***/ | |
1da177e4 | 66 | |
f446daae | 67 | #define RADIX_TREE_MAX_TAGS 3 |
612d6c19 | 68 | |
97d778b2 | 69 | #ifndef RADIX_TREE_MAP_SHIFT |
139e5616 | 70 | #define RADIX_TREE_MAP_SHIFT (CONFIG_BASE_SMALL ? 4 : 6) |
139e5616 JW |
71 | #endif |
72 | ||
73 | #define RADIX_TREE_MAP_SIZE (1UL << RADIX_TREE_MAP_SHIFT) | |
74 | #define RADIX_TREE_MAP_MASK (RADIX_TREE_MAP_SIZE-1) | |
75 | ||
76 | #define RADIX_TREE_TAG_LONGS \ | |
77 | ((RADIX_TREE_MAP_SIZE + BITS_PER_LONG - 1) / BITS_PER_LONG) | |
78 | ||
449dd698 JW |
79 | #define RADIX_TREE_INDEX_BITS (8 /* CHAR_BIT */ * sizeof(unsigned long)) |
80 | #define RADIX_TREE_MAX_PATH (DIV_ROUND_UP(RADIX_TREE_INDEX_BITS, \ | |
81 | RADIX_TREE_MAP_SHIFT)) | |
82 | ||
449dd698 JW |
83 | /* Internally used bits of node->count */ |
84 | #define RADIX_TREE_COUNT_SHIFT (RADIX_TREE_MAP_SHIFT + 1) | |
85 | #define RADIX_TREE_COUNT_MASK ((1UL << RADIX_TREE_COUNT_SHIFT) - 1) | |
86 | ||
139e5616 | 87 | struct radix_tree_node { |
f7942430 JW |
88 | unsigned char shift; /* Bits remaining in each slot */ |
89 | unsigned char offset; /* Slot offset in parent */ | |
90 | unsigned int count; /* Total entry count */ | |
91 | unsigned char exceptional; /* Exceptional entry count */ | |
139e5616 | 92 | union { |
449dd698 JW |
93 | struct { |
94 | /* Used when ascending tree */ | |
95 | struct radix_tree_node *parent; | |
96 | /* For tree user */ | |
97 | void *private_data; | |
98 | }; | |
99 | /* Used when freeing node */ | |
100 | struct rcu_head rcu_head; | |
139e5616 | 101 | }; |
449dd698 JW |
102 | /* For tree user */ |
103 | struct list_head private_list; | |
139e5616 JW |
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 | ||
e9256efc MW |
128 | static inline bool radix_tree_empty(struct radix_tree_root *root) |
129 | { | |
130 | return root->rnode == NULL; | |
131 | } | |
132 | ||
7cf9c2c7 NP |
133 | /** |
134 | * Radix-tree synchronization | |
135 | * | |
136 | * The radix-tree API requires that users provide all synchronisation (with | |
137 | * specific exceptions, noted below). | |
138 | * | |
139 | * Synchronization of access to the data items being stored in the tree, and | |
140 | * management of their lifetimes must be completely managed by API users. | |
141 | * | |
142 | * For API usage, in general, | |
59c51591 | 143 | * - any function _modifying_ the tree or tags (inserting or deleting |
eb8dc5e7 | 144 | * items, setting or clearing tags) must exclude other modifications, and |
7cf9c2c7 | 145 | * exclude any functions reading the tree. |
59c51591 | 146 | * - any function _reading_ the tree or tags (looking up items or tags, |
7cf9c2c7 NP |
147 | * gang lookups) must exclude modifications to the tree, but may occur |
148 | * concurrently with other readers. | |
149 | * | |
150 | * The notable exceptions to this rule are the following functions: | |
139e5616 | 151 | * __radix_tree_lookup |
7cf9c2c7 | 152 | * radix_tree_lookup |
47feff2c | 153 | * radix_tree_lookup_slot |
7cf9c2c7 NP |
154 | * radix_tree_tag_get |
155 | * radix_tree_gang_lookup | |
47feff2c | 156 | * radix_tree_gang_lookup_slot |
7cf9c2c7 | 157 | * radix_tree_gang_lookup_tag |
47feff2c | 158 | * radix_tree_gang_lookup_tag_slot |
7cf9c2c7 NP |
159 | * radix_tree_tagged |
160 | * | |
243c2137 | 161 | * The first 8 functions are able to be called locklessly, using RCU. The |
7cf9c2c7 NP |
162 | * caller must ensure calls to these functions are made within rcu_read_lock() |
163 | * regions. Other readers (lock-free or otherwise) and modifications may be | |
164 | * running concurrently. | |
165 | * | |
166 | * It is still required that the caller manage the synchronization and lifetimes | |
167 | * of the items. So if RCU lock-free lookups are used, typically this would mean | |
168 | * that the items have their own locks, or are amenable to lock-free access; and | |
169 | * that the items are freed by RCU (or only freed after having been deleted from | |
170 | * the radix tree *and* a synchronize_rcu() grace period). | |
171 | * | |
172 | * (Note, rcu_assign_pointer and rcu_dereference are not needed to control | |
173 | * access to data items when inserting into or looking up from the radix tree) | |
174 | * | |
ce82653d DH |
175 | * Note that the value returned by radix_tree_tag_get() may not be relied upon |
176 | * if only the RCU read lock is held. Functions to set/clear tags and to | |
177 | * delete nodes running concurrently with it may affect its result such that | |
178 | * two consecutive reads in the same locked section may return different | |
179 | * values. If reliability is required, modification functions must also be | |
180 | * excluded from concurrency. | |
181 | * | |
7cf9c2c7 NP |
182 | * radix_tree_tagged is able to be called without locking or RCU. |
183 | */ | |
184 | ||
185 | /** | |
186 | * radix_tree_deref_slot - dereference a slot | |
187 | * @pslot: pointer to slot, returned by radix_tree_lookup_slot | |
188 | * Returns: item that was stored in that slot with any direct pointer flag | |
189 | * removed. | |
190 | * | |
191 | * For use with radix_tree_lookup_slot(). Caller must hold tree at least read | |
27d20fdd NP |
192 | * locked across slot lookup and dereference. Not required if write lock is |
193 | * held (ie. items cannot be concurrently inserted). | |
194 | * | |
195 | * radix_tree_deref_retry must be used to confirm validity of the pointer if | |
196 | * only the read lock is held. | |
7cf9c2c7 NP |
197 | */ |
198 | static inline void *radix_tree_deref_slot(void **pslot) | |
199 | { | |
27d20fdd | 200 | return rcu_dereference(*pslot); |
7cf9c2c7 | 201 | } |
27d20fdd | 202 | |
29c1f677 MG |
203 | /** |
204 | * radix_tree_deref_slot_protected - dereference a slot without RCU lock but with tree lock held | |
205 | * @pslot: pointer to slot, returned by radix_tree_lookup_slot | |
206 | * Returns: item that was stored in that slot with any direct pointer flag | |
207 | * removed. | |
208 | * | |
209 | * Similar to radix_tree_deref_slot but only used during migration when a pages | |
210 | * mapping is being moved. The caller does not hold the RCU read lock but it | |
211 | * must hold the tree lock to prevent parallel updates. | |
212 | */ | |
213 | static inline void *radix_tree_deref_slot_protected(void **pslot, | |
214 | spinlock_t *treelock) | |
215 | { | |
216 | return rcu_dereference_protected(*pslot, lockdep_is_held(treelock)); | |
217 | } | |
218 | ||
27d20fdd NP |
219 | /** |
220 | * radix_tree_deref_retry - check radix_tree_deref_slot | |
221 | * @arg: pointer returned by radix_tree_deref_slot | |
222 | * Returns: 0 if retry is not required, otherwise retry is required | |
223 | * | |
224 | * radix_tree_deref_retry must be used with radix_tree_deref_slot. | |
225 | */ | |
226 | static inline int radix_tree_deref_retry(void *arg) | |
227 | { | |
b194d16c | 228 | return unlikely(radix_tree_is_internal_node(arg)); |
27d20fdd NP |
229 | } |
230 | ||
6328650b HD |
231 | /** |
232 | * radix_tree_exceptional_entry - radix_tree_deref_slot gave exceptional entry? | |
233 | * @arg: value returned by radix_tree_deref_slot | |
234 | * Returns: 0 if well-aligned pointer, non-0 if exceptional entry. | |
235 | */ | |
236 | static inline int radix_tree_exceptional_entry(void *arg) | |
237 | { | |
238 | /* Not unlikely because radix_tree_exception often tested first */ | |
239 | return (unsigned long)arg & RADIX_TREE_EXCEPTIONAL_ENTRY; | |
240 | } | |
241 | ||
242 | /** | |
243 | * radix_tree_exception - radix_tree_deref_slot returned either exception? | |
244 | * @arg: value returned by radix_tree_deref_slot | |
245 | * Returns: 0 if well-aligned pointer, non-0 if either kind of exception. | |
246 | */ | |
247 | static inline int radix_tree_exception(void *arg) | |
248 | { | |
3bcadd6f | 249 | return unlikely((unsigned long)arg & RADIX_TREE_ENTRY_MASK); |
6328650b HD |
250 | } |
251 | ||
139e5616 | 252 | int __radix_tree_create(struct radix_tree_root *root, unsigned long index, |
e6145236 MW |
253 | unsigned order, struct radix_tree_node **nodep, |
254 | void ***slotp); | |
255 | int __radix_tree_insert(struct radix_tree_root *, unsigned long index, | |
256 | unsigned order, void *); | |
257 | static inline int radix_tree_insert(struct radix_tree_root *root, | |
258 | unsigned long index, void *entry) | |
259 | { | |
260 | return __radix_tree_insert(root, index, 0, entry); | |
261 | } | |
139e5616 JW |
262 | void *__radix_tree_lookup(struct radix_tree_root *root, unsigned long index, |
263 | struct radix_tree_node **nodep, void ***slotp); | |
1da177e4 | 264 | void *radix_tree_lookup(struct radix_tree_root *, unsigned long); |
a4331366 | 265 | void **radix_tree_lookup_slot(struct radix_tree_root *, unsigned long); |
4d693d08 | 266 | typedef void (*radix_tree_update_node_t)(struct radix_tree_node *, void *); |
f7942430 JW |
267 | void __radix_tree_replace(struct radix_tree_root *root, |
268 | struct radix_tree_node *node, | |
4d693d08 JW |
269 | void **slot, void *item, |
270 | radix_tree_update_node_t update_node, void *private); | |
6d75f366 JW |
271 | void radix_tree_replace_slot(struct radix_tree_root *root, |
272 | void **slot, void *item); | |
449dd698 | 273 | bool __radix_tree_delete_node(struct radix_tree_root *root, |
139e5616 | 274 | struct radix_tree_node *node); |
53c59f26 | 275 | void *radix_tree_delete_item(struct radix_tree_root *, unsigned long, void *); |
1da177e4 | 276 | void *radix_tree_delete(struct radix_tree_root *, unsigned long); |
d3798ae8 JW |
277 | void radix_tree_clear_tags(struct radix_tree_root *root, |
278 | struct radix_tree_node *node, | |
279 | void **slot); | |
d604c324 MW |
280 | unsigned int radix_tree_gang_lookup(struct radix_tree_root *root, |
281 | void **results, unsigned long first_index, | |
282 | unsigned int max_items); | |
6328650b HD |
283 | unsigned int radix_tree_gang_lookup_slot(struct radix_tree_root *root, |
284 | void ***results, unsigned long *indices, | |
47feff2c | 285 | unsigned long first_index, unsigned int max_items); |
dd0fc66f | 286 | int radix_tree_preload(gfp_t gfp_mask); |
5e4c0d97 | 287 | int radix_tree_maybe_preload(gfp_t gfp_mask); |
c78c66d1 | 288 | int radix_tree_maybe_preload_order(gfp_t gfp_mask, int order); |
1da177e4 LT |
289 | void radix_tree_init(void); |
290 | void *radix_tree_tag_set(struct radix_tree_root *root, | |
daff89f3 | 291 | unsigned long index, unsigned int tag); |
1da177e4 | 292 | void *radix_tree_tag_clear(struct radix_tree_root *root, |
daff89f3 | 293 | unsigned long index, unsigned int tag); |
1da177e4 | 294 | int radix_tree_tag_get(struct radix_tree_root *root, |
daff89f3 | 295 | unsigned long index, unsigned int tag); |
1da177e4 LT |
296 | unsigned int |
297 | radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results, | |
daff89f3 JC |
298 | unsigned long first_index, unsigned int max_items, |
299 | unsigned int tag); | |
47feff2c NP |
300 | unsigned int |
301 | radix_tree_gang_lookup_tag_slot(struct radix_tree_root *root, void ***results, | |
302 | unsigned long first_index, unsigned int max_items, | |
303 | unsigned int tag); | |
ebf8aa44 JK |
304 | unsigned long radix_tree_range_tag_if_tagged(struct radix_tree_root *root, |
305 | unsigned long *first_indexp, unsigned long last_index, | |
306 | unsigned long nr_to_tag, | |
307 | unsigned int fromtag, unsigned int totag); | |
daff89f3 | 308 | int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag); |
e504f3fd | 309 | unsigned long radix_tree_locate_item(struct radix_tree_root *root, void *item); |
1da177e4 LT |
310 | |
311 | static inline void radix_tree_preload_end(void) | |
312 | { | |
313 | preempt_enable(); | |
314 | } | |
315 | ||
78c1d784 KK |
316 | /** |
317 | * struct radix_tree_iter - radix tree iterator state | |
318 | * | |
319 | * @index: index of current slot | |
21ef5339 | 320 | * @next_index: one beyond the last index for this chunk |
78c1d784 | 321 | * @tags: bit-mask for tag-iterating |
21ef5339 | 322 | * @shift: shift for the node that holds our slots |
78c1d784 KK |
323 | * |
324 | * This radix tree iterator works in terms of "chunks" of slots. A chunk is a | |
325 | * subinterval of slots contained within one radix tree leaf node. It is | |
326 | * described by a pointer to its first slot and a struct radix_tree_iter | |
327 | * which holds the chunk's position in the tree and its size. For tagged | |
328 | * iteration radix_tree_iter also holds the slots' bit-mask for one chosen | |
329 | * radix tree tag. | |
330 | */ | |
331 | struct radix_tree_iter { | |
332 | unsigned long index; | |
333 | unsigned long next_index; | |
334 | unsigned long tags; | |
21ef5339 RZ |
335 | #ifdef CONFIG_RADIX_TREE_MULTIORDER |
336 | unsigned int shift; | |
337 | #endif | |
78c1d784 KK |
338 | }; |
339 | ||
21ef5339 RZ |
340 | static inline unsigned int iter_shift(struct radix_tree_iter *iter) |
341 | { | |
342 | #ifdef CONFIG_RADIX_TREE_MULTIORDER | |
343 | return iter->shift; | |
344 | #else | |
345 | return 0; | |
346 | #endif | |
347 | } | |
348 | ||
78c1d784 KK |
349 | #define RADIX_TREE_ITER_TAG_MASK 0x00FF /* tag index in lower byte */ |
350 | #define RADIX_TREE_ITER_TAGGED 0x0100 /* lookup tagged slots */ | |
351 | #define RADIX_TREE_ITER_CONTIG 0x0200 /* stop at first hole */ | |
352 | ||
353 | /** | |
354 | * radix_tree_iter_init - initialize radix tree iterator | |
355 | * | |
356 | * @iter: pointer to iterator state | |
357 | * @start: iteration starting index | |
358 | * Returns: NULL | |
359 | */ | |
360 | static __always_inline void ** | |
361 | radix_tree_iter_init(struct radix_tree_iter *iter, unsigned long start) | |
362 | { | |
363 | /* | |
364 | * Leave iter->tags uninitialized. radix_tree_next_chunk() will fill it | |
365 | * in the case of a successful tagged chunk lookup. If the lookup was | |
366 | * unsuccessful or non-tagged then nobody cares about ->tags. | |
367 | * | |
368 | * Set index to zero to bypass next_index overflow protection. | |
369 | * See the comment in radix_tree_next_chunk() for details. | |
370 | */ | |
371 | iter->index = 0; | |
372 | iter->next_index = start; | |
373 | return NULL; | |
374 | } | |
375 | ||
376 | /** | |
377 | * radix_tree_next_chunk - find next chunk of slots for iteration | |
378 | * | |
379 | * @root: radix tree root | |
380 | * @iter: iterator state | |
381 | * @flags: RADIX_TREE_ITER_* flags and tag index | |
382 | * Returns: pointer to chunk first slot, or NULL if there no more left | |
383 | * | |
384 | * This function looks up the next chunk in the radix tree starting from | |
385 | * @iter->next_index. It returns a pointer to the chunk's first slot. | |
386 | * Also it fills @iter with data about chunk: position in the tree (index), | |
387 | * its end (next_index), and constructs a bit mask for tagged iterating (tags). | |
388 | */ | |
389 | void **radix_tree_next_chunk(struct radix_tree_root *root, | |
390 | struct radix_tree_iter *iter, unsigned flags); | |
391 | ||
46437f9a MW |
392 | /** |
393 | * radix_tree_iter_retry - retry this chunk of the iteration | |
394 | * @iter: iterator state | |
395 | * | |
396 | * If we iterate over a tree protected only by the RCU lock, a race | |
397 | * against deletion or creation may result in seeing a slot for which | |
398 | * radix_tree_deref_retry() returns true. If so, call this function | |
399 | * and continue the iteration. | |
400 | */ | |
401 | static inline __must_check | |
402 | void **radix_tree_iter_retry(struct radix_tree_iter *iter) | |
403 | { | |
404 | iter->next_index = iter->index; | |
3cb9185c | 405 | iter->tags = 0; |
46437f9a MW |
406 | return NULL; |
407 | } | |
408 | ||
21ef5339 RZ |
409 | static inline unsigned long |
410 | __radix_tree_iter_add(struct radix_tree_iter *iter, unsigned long slots) | |
411 | { | |
412 | return iter->index + (slots << iter_shift(iter)); | |
413 | } | |
414 | ||
7165092f MW |
415 | /** |
416 | * radix_tree_iter_next - resume iterating when the chunk may be invalid | |
417 | * @iter: iterator state | |
418 | * | |
419 | * If the iterator needs to release then reacquire a lock, the chunk may | |
420 | * have been invalidated by an insertion or deletion. Call this function | |
421 | * to continue the iteration from the next index. | |
422 | */ | |
423 | static inline __must_check | |
424 | void **radix_tree_iter_next(struct radix_tree_iter *iter) | |
425 | { | |
21ef5339 | 426 | iter->next_index = __radix_tree_iter_add(iter, 1); |
7165092f MW |
427 | iter->tags = 0; |
428 | return NULL; | |
429 | } | |
430 | ||
78c1d784 KK |
431 | /** |
432 | * radix_tree_chunk_size - get current chunk size | |
433 | * | |
434 | * @iter: pointer to radix tree iterator | |
435 | * Returns: current chunk size | |
436 | */ | |
73204282 | 437 | static __always_inline long |
78c1d784 KK |
438 | radix_tree_chunk_size(struct radix_tree_iter *iter) |
439 | { | |
21ef5339 RZ |
440 | return (iter->next_index - iter->index) >> iter_shift(iter); |
441 | } | |
442 | ||
4dd6c098 | 443 | static inline struct radix_tree_node *entry_to_node(void *ptr) |
21ef5339 | 444 | { |
30ff46cc | 445 | return (void *)((unsigned long)ptr & ~RADIX_TREE_INTERNAL_NODE); |
78c1d784 KK |
446 | } |
447 | ||
448 | /** | |
449 | * radix_tree_next_slot - find next slot in chunk | |
450 | * | |
451 | * @slot: pointer to current slot | |
452 | * @iter: pointer to interator state | |
453 | * @flags: RADIX_TREE_ITER_*, should be constant | |
454 | * Returns: pointer to next slot, or NULL if there no more left | |
455 | * | |
456 | * This function updates @iter->index in the case of a successful lookup. | |
457 | * For tagged lookup it also eats @iter->tags. | |
915045fe RZ |
458 | * |
459 | * There are several cases where 'slot' can be passed in as NULL to this | |
460 | * function. These cases result from the use of radix_tree_iter_next() or | |
461 | * radix_tree_iter_retry(). In these cases we don't end up dereferencing | |
462 | * 'slot' because either: | |
463 | * a) we are doing tagged iteration and iter->tags has been set to 0, or | |
464 | * b) we are doing non-tagged iteration, and iter->index and iter->next_index | |
465 | * have been set up so that radix_tree_chunk_size() returns 1 or 0. | |
78c1d784 KK |
466 | */ |
467 | static __always_inline void ** | |
468 | radix_tree_next_slot(void **slot, struct radix_tree_iter *iter, unsigned flags) | |
469 | { | |
470 | if (flags & RADIX_TREE_ITER_TAGGED) { | |
21ef5339 RZ |
471 | void *canon = slot; |
472 | ||
78c1d784 | 473 | iter->tags >>= 1; |
21ef5339 RZ |
474 | if (unlikely(!iter->tags)) |
475 | return NULL; | |
476 | while (IS_ENABLED(CONFIG_RADIX_TREE_MULTIORDER) && | |
b194d16c | 477 | radix_tree_is_internal_node(slot[1])) { |
4dd6c098 | 478 | if (entry_to_node(slot[1]) == canon) { |
21ef5339 RZ |
479 | iter->tags >>= 1; |
480 | iter->index = __radix_tree_iter_add(iter, 1); | |
481 | slot++; | |
482 | continue; | |
483 | } | |
484 | iter->next_index = __radix_tree_iter_add(iter, 1); | |
485 | return NULL; | |
486 | } | |
78c1d784 | 487 | if (likely(iter->tags & 1ul)) { |
21ef5339 | 488 | iter->index = __radix_tree_iter_add(iter, 1); |
78c1d784 KK |
489 | return slot + 1; |
490 | } | |
21ef5339 | 491 | if (!(flags & RADIX_TREE_ITER_CONTIG)) { |
78c1d784 KK |
492 | unsigned offset = __ffs(iter->tags); |
493 | ||
494 | iter->tags >>= offset; | |
21ef5339 | 495 | iter->index = __radix_tree_iter_add(iter, offset + 1); |
78c1d784 KK |
496 | return slot + offset + 1; |
497 | } | |
498 | } else { | |
21ef5339 RZ |
499 | long count = radix_tree_chunk_size(iter); |
500 | void *canon = slot; | |
78c1d784 | 501 | |
21ef5339 | 502 | while (--count > 0) { |
78c1d784 | 503 | slot++; |
21ef5339 RZ |
504 | iter->index = __radix_tree_iter_add(iter, 1); |
505 | ||
506 | if (IS_ENABLED(CONFIG_RADIX_TREE_MULTIORDER) && | |
b194d16c | 507 | radix_tree_is_internal_node(*slot)) { |
4dd6c098 | 508 | if (entry_to_node(*slot) == canon) |
21ef5339 | 509 | continue; |
4dd6c098 MW |
510 | iter->next_index = iter->index; |
511 | break; | |
21ef5339 RZ |
512 | } |
513 | ||
78c1d784 KK |
514 | if (likely(*slot)) |
515 | return slot; | |
fffaee36 KK |
516 | if (flags & RADIX_TREE_ITER_CONTIG) { |
517 | /* forbid switching to the next chunk */ | |
518 | iter->next_index = 0; | |
78c1d784 | 519 | break; |
fffaee36 | 520 | } |
78c1d784 KK |
521 | } |
522 | } | |
523 | return NULL; | |
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, \ | |
574 | RADIX_TREE_ITER_TAGGED)) | |
575 | ||
1da177e4 | 576 | #endif /* _LINUX_RADIX_TREE_H */ |