Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0-or-later
2 : /*
3 : * Copyright (C) 2001 Momchil Velikov
4 : * Portions Copyright (C) 2001 Christoph Hellwig
5 : * Copyright (C) 2005 SGI, Christoph Lameter
6 : * Copyright (C) 2006 Nick Piggin
7 : * Copyright (C) 2012 Konstantin Khlebnikov
8 : * Copyright (C) 2016 Intel, Matthew Wilcox
9 : * Copyright (C) 2016 Intel, Ross Zwisler
10 : */
11 :
12 : #include <linux/bitmap.h>
13 : #include <linux/bitops.h>
14 : #include <linux/bug.h>
15 : #include <linux/cpu.h>
16 : #include <linux/errno.h>
17 : #include <linux/export.h>
18 : #include <linux/idr.h>
19 : #include <linux/init.h>
20 : #include <linux/kernel.h>
21 : #include <linux/kmemleak.h>
22 : #include <linux/percpu.h>
23 : #include <linux/preempt.h> /* in_interrupt() */
24 : #include <linux/radix-tree.h>
25 : #include <linux/rcupdate.h>
26 : #include <linux/slab.h>
27 : #include <linux/string.h>
28 : #include <linux/xarray.h>
29 :
30 : /*
31 : * Radix tree node cache.
32 : */
33 : struct kmem_cache *radix_tree_node_cachep;
34 :
35 : /*
36 : * The radix tree is variable-height, so an insert operation not only has
37 : * to build the branch to its corresponding item, it also has to build the
38 : * branch to existing items if the size has to be increased (by
39 : * radix_tree_extend).
40 : *
41 : * The worst case is a zero height tree with just a single item at index 0,
42 : * and then inserting an item at index ULONG_MAX. This requires 2 new branches
43 : * of RADIX_TREE_MAX_PATH size to be created, with only the root node shared.
44 : * Hence:
45 : */
46 : #define RADIX_TREE_PRELOAD_SIZE (RADIX_TREE_MAX_PATH * 2 - 1)
47 :
48 : /*
49 : * The IDR does not have to be as high as the radix tree since it uses
50 : * signed integers, not unsigned longs.
51 : */
52 : #define IDR_INDEX_BITS (8 /* CHAR_BIT */ * sizeof(int) - 1)
53 : #define IDR_MAX_PATH (DIV_ROUND_UP(IDR_INDEX_BITS, \
54 : RADIX_TREE_MAP_SHIFT))
55 : #define IDR_PRELOAD_SIZE (IDR_MAX_PATH * 2 - 1)
56 :
57 : /*
58 : * Per-cpu pool of preloaded nodes
59 : */
60 : DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = {
61 : .lock = INIT_LOCAL_LOCK(lock),
62 : };
63 : EXPORT_PER_CPU_SYMBOL_GPL(radix_tree_preloads);
64 :
65 73667 : static inline struct radix_tree_node *entry_to_node(void *ptr)
66 : {
67 73667 : return (void *)((unsigned long)ptr & ~RADIX_TREE_INTERNAL_NODE);
68 : }
69 :
70 18102 : static inline void *node_to_entry(void *ptr)
71 : {
72 18102 : return (void *)((unsigned long)ptr | RADIX_TREE_INTERNAL_NODE);
73 : }
74 :
75 : #define RADIX_TREE_RETRY XA_RETRY_ENTRY
76 :
77 : static inline unsigned long
78 17013 : get_slot_offset(const struct radix_tree_node *parent, void __rcu **slot)
79 : {
80 16983 : return parent ? slot - parent->slots : 0;
81 : }
82 :
83 48307 : static unsigned int radix_tree_descend(const struct radix_tree_node *parent,
84 : struct radix_tree_node **nodep, unsigned long index)
85 : {
86 48307 : unsigned int offset = (index >> parent->shift) & RADIX_TREE_MAP_MASK;
87 48307 : void __rcu **entry = rcu_dereference_raw(parent->slots[offset]);
88 :
89 48307 : *nodep = (void *)entry;
90 48307 : return offset;
91 : }
92 :
93 31 : static inline gfp_t root_gfp_mask(const struct radix_tree_root *root)
94 : {
95 31 : return root->xa_flags & (__GFP_BITS_MASK & ~GFP_ZONEMASK);
96 : }
97 :
98 3411 : static inline void tag_set(struct radix_tree_node *node, unsigned int tag,
99 : int offset)
100 : {
101 3411 : __set_bit(offset, node->tags[tag]);
102 0 : }
103 :
104 11207 : static inline void tag_clear(struct radix_tree_node *node, unsigned int tag,
105 : int offset)
106 : {
107 11207 : __clear_bit(offset, node->tags[tag]);
108 : }
109 :
110 61907 : static inline int tag_get(const struct radix_tree_node *node, unsigned int tag,
111 : int offset)
112 : {
113 0 : return test_bit(offset, node->tags[tag]);
114 : }
115 :
116 7 : static inline void root_tag_set(struct radix_tree_root *root, unsigned tag)
117 : {
118 7 : root->xa_flags |= (__force gfp_t)(1 << (tag + ROOT_TAG_SHIFT));
119 0 : }
120 :
121 0 : static inline void root_tag_clear(struct radix_tree_root *root, unsigned tag)
122 : {
123 0 : root->xa_flags &= (__force gfp_t)~(1 << (tag + ROOT_TAG_SHIFT));
124 0 : }
125 :
126 0 : static inline void root_tag_clear_all(struct radix_tree_root *root)
127 : {
128 0 : root->xa_flags &= (__force gfp_t)((1 << ROOT_TAG_SHIFT) - 1);
129 0 : }
130 :
131 13663 : static inline int root_tag_get(const struct radix_tree_root *root, unsigned tag)
132 : {
133 13663 : return (__force int)root->xa_flags & (1 << (tag + ROOT_TAG_SHIFT));
134 : }
135 :
136 1 : static inline unsigned root_tags_get(const struct radix_tree_root *root)
137 : {
138 1 : return (__force unsigned)root->xa_flags >> ROOT_TAG_SHIFT;
139 : }
140 :
141 17025 : static inline bool is_idr(const struct radix_tree_root *root)
142 : {
143 17025 : return !!(root->xa_flags & ROOT_IS_IDR);
144 : }
145 :
146 : /*
147 : * Returns 1 if any slot in the node has this tag set.
148 : * Otherwise returns 0.
149 : */
150 : static inline int any_tag_set(const struct radix_tree_node *node,
151 : unsigned int tag)
152 : {
153 : unsigned idx;
154 11315 : for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) {
155 11207 : if (node->tags[tag][idx])
156 : return 1;
157 : }
158 : return 0;
159 : }
160 :
161 1124 : static inline void all_tag_set(struct radix_tree_node *node, unsigned int tag)
162 : {
163 1124 : bitmap_fill(node->tags[tag], RADIX_TREE_MAP_SIZE);
164 : }
165 :
166 : /**
167 : * radix_tree_find_next_bit - find the next set bit in a memory region
168 : *
169 : * @addr: The address to base the search on
170 : * @size: The bitmap size in bits
171 : * @offset: The bitnumber to start searching at
172 : *
173 : * Unrollable variant of find_next_bit() for constant size arrays.
174 : * Tail bits starting from size to roundup(size, BITS_PER_LONG) must be zero.
175 : * Returns next bit offset, or size if nothing found.
176 : */
177 : static __always_inline unsigned long
178 8 : radix_tree_find_next_bit(struct radix_tree_node *node, unsigned int tag,
179 : unsigned long offset)
180 : {
181 8 : const unsigned long *addr = node->tags[tag];
182 :
183 8 : if (offset < RADIX_TREE_MAP_SIZE) {
184 8 : unsigned long tmp;
185 :
186 8 : addr += offset / BITS_PER_LONG;
187 8 : tmp = *addr >> (offset % BITS_PER_LONG);
188 8 : if (tmp)
189 8 : return __ffs(tmp) + offset;
190 : offset = (offset + BITS_PER_LONG) & ~(BITS_PER_LONG - 1);
191 : while (offset < RADIX_TREE_MAP_SIZE) {
192 : tmp = *++addr;
193 : if (tmp)
194 : return __ffs(tmp) + offset;
195 : offset += BITS_PER_LONG;
196 : }
197 : }
198 : return RADIX_TREE_MAP_SIZE;
199 : }
200 :
201 11099 : static unsigned int iter_offset(const struct radix_tree_iter *iter)
202 : {
203 11099 : return iter->index & RADIX_TREE_MAP_MASK;
204 : }
205 :
206 : /*
207 : * The maximum index which can be stored in a radix tree
208 : */
209 35104 : static inline unsigned long shift_maxindex(unsigned int shift)
210 : {
211 35104 : return (RADIX_TREE_MAP_SIZE << shift) - 1;
212 : }
213 :
214 35072 : static inline unsigned long node_maxindex(const struct radix_tree_node *node)
215 : {
216 35072 : return shift_maxindex(node->shift);
217 : }
218 :
219 8 : static unsigned long next_index(unsigned long index,
220 : const struct radix_tree_node *node,
221 : unsigned long offset)
222 : {
223 8 : return (index & ~node_maxindex(node)) + (offset << node->shift);
224 : }
225 :
226 : /*
227 : * This assumes that the caller has performed appropriate preallocation, and
228 : * that the caller has pinned this thread of control to the current CPU.
229 : */
230 : static struct radix_tree_node *
231 1126 : radix_tree_node_alloc(gfp_t gfp_mask, struct radix_tree_node *parent,
232 : struct radix_tree_root *root,
233 : unsigned int shift, unsigned int offset,
234 : unsigned int count, unsigned int nr_values)
235 : {
236 1126 : struct radix_tree_node *ret = NULL;
237 :
238 : /*
239 : * Preload code isn't irq safe and it doesn't make sense to use
240 : * preloading during an interrupt anyway as all the allocations have
241 : * to be atomic. So just do normal allocation when in interrupt.
242 : */
243 1126 : if (!gfpflags_allow_blocking(gfp_mask) && !in_interrupt()) {
244 1119 : struct radix_tree_preload *rtp;
245 :
246 : /*
247 : * Even if the caller has preloaded, try to allocate from the
248 : * cache first for the new node to get accounted to the memory
249 : * cgroup.
250 : */
251 1119 : ret = kmem_cache_alloc(radix_tree_node_cachep,
252 : gfp_mask | __GFP_NOWARN);
253 1119 : if (ret)
254 1119 : goto out;
255 :
256 : /*
257 : * Provided the caller has preloaded here, we will always
258 : * succeed in getting a node here (and never reach
259 : * kmem_cache_alloc)
260 : */
261 0 : rtp = this_cpu_ptr(&radix_tree_preloads);
262 0 : if (rtp->nr) {
263 0 : ret = rtp->nodes;
264 0 : rtp->nodes = ret->parent;
265 0 : rtp->nr--;
266 : }
267 : /*
268 : * Update the allocation stack trace as this is more useful
269 : * for debugging.
270 : */
271 0 : kmemleak_update_trace(ret);
272 0 : goto out;
273 : }
274 7 : ret = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask);
275 1126 : out:
276 1126 : BUG_ON(radix_tree_is_internal_node(ret));
277 1126 : if (ret) {
278 1126 : ret->shift = shift;
279 1126 : ret->offset = offset;
280 1126 : ret->count = count;
281 1126 : ret->nr_values = nr_values;
282 1126 : ret->parent = parent;
283 1126 : ret->array = root;
284 : }
285 1126 : return ret;
286 : }
287 :
288 1060 : void radix_tree_node_rcu_free(struct rcu_head *head)
289 : {
290 1060 : struct radix_tree_node *node =
291 1060 : container_of(head, struct radix_tree_node, rcu_head);
292 :
293 : /*
294 : * Must only free zeroed nodes into the slab. We can be left with
295 : * non-NULL entries by radix_tree_free_nodes, so clear the entries
296 : * and tags here.
297 : */
298 1060 : memset(node->slots, 0, sizeof(node->slots));
299 1060 : memset(node->tags, 0, sizeof(node->tags));
300 1060 : INIT_LIST_HEAD(&node->private_list);
301 :
302 1060 : kmem_cache_free(radix_tree_node_cachep, node);
303 1060 : }
304 :
305 : static inline void
306 961 : radix_tree_node_free(struct radix_tree_node *node)
307 : {
308 961 : call_rcu(&node->rcu_head, radix_tree_node_rcu_free);
309 : }
310 :
311 : /*
312 : * Load up this CPU's radix_tree_node buffer with sufficient objects to
313 : * ensure that the addition of a single element in the tree cannot fail. On
314 : * success, return zero, with preemption disabled. On error, return -ENOMEM
315 : * with preemption not disabled.
316 : *
317 : * To make use of this facility, the radix tree must be initialised without
318 : * __GFP_DIRECT_RECLAIM being passed to INIT_RADIX_TREE().
319 : */
320 11073 : static __must_check int __radix_tree_preload(gfp_t gfp_mask, unsigned nr)
321 : {
322 11073 : struct radix_tree_preload *rtp;
323 11073 : struct radix_tree_node *node;
324 11073 : int ret = -ENOMEM;
325 :
326 : /*
327 : * Nodes preloaded by one cgroup can be used by another cgroup, so
328 : * they should never be accounted to any particular memory cgroup.
329 : */
330 11073 : gfp_mask &= ~__GFP_ACCOUNT;
331 :
332 11073 : local_lock(&radix_tree_preloads.lock);
333 11073 : rtp = this_cpu_ptr(&radix_tree_preloads);
334 11117 : while (rtp->nr < nr) {
335 44 : local_unlock(&radix_tree_preloads.lock);
336 44 : node = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask);
337 44 : if (node == NULL)
338 0 : goto out;
339 44 : local_lock(&radix_tree_preloads.lock);
340 44 : rtp = this_cpu_ptr(&radix_tree_preloads);
341 44 : if (rtp->nr < nr) {
342 44 : node->parent = rtp->nodes;
343 44 : rtp->nodes = node;
344 44 : rtp->nr++;
345 : } else {
346 0 : kmem_cache_free(radix_tree_node_cachep, node);
347 : }
348 : }
349 : ret = 0;
350 11073 : out:
351 11073 : return ret;
352 : }
353 :
354 : /*
355 : * Load up this CPU's radix_tree_node buffer with sufficient objects to
356 : * ensure that the addition of a single element in the tree cannot fail. On
357 : * success, return zero, with preemption disabled. On error, return -ENOMEM
358 : * with preemption not disabled.
359 : *
360 : * To make use of this facility, the radix tree must be initialised without
361 : * __GFP_DIRECT_RECLAIM being passed to INIT_RADIX_TREE().
362 : */
363 0 : int radix_tree_preload(gfp_t gfp_mask)
364 : {
365 : /* Warn on non-sensical use... */
366 0 : WARN_ON_ONCE(!gfpflags_allow_blocking(gfp_mask));
367 0 : return __radix_tree_preload(gfp_mask, RADIX_TREE_PRELOAD_SIZE);
368 : }
369 : EXPORT_SYMBOL(radix_tree_preload);
370 :
371 : /*
372 : * The same as above function, except we don't guarantee preloading happens.
373 : * We do it, if we decide it helps. On success, return zero with preemption
374 : * disabled. On error, return -ENOMEM with preemption not disabled.
375 : */
376 0 : int radix_tree_maybe_preload(gfp_t gfp_mask)
377 : {
378 0 : if (gfpflags_allow_blocking(gfp_mask))
379 0 : return __radix_tree_preload(gfp_mask, RADIX_TREE_PRELOAD_SIZE);
380 : /* Preloading doesn't help anything with this gfp mask, skip it */
381 0 : local_lock(&radix_tree_preloads.lock);
382 0 : return 0;
383 : }
384 : EXPORT_SYMBOL(radix_tree_maybe_preload);
385 :
386 24167 : static unsigned radix_tree_load_root(const struct radix_tree_root *root,
387 : struct radix_tree_node **nodep, unsigned long *maxindex)
388 : {
389 24167 : struct radix_tree_node *node = rcu_dereference_raw(root->xa_head);
390 :
391 24167 : *nodep = node;
392 :
393 13037 : if (likely(radix_tree_is_internal_node(node))) {
394 23927 : node = entry_to_node(node);
395 23927 : *maxindex = node_maxindex(node);
396 23927 : return node->shift + RADIX_TREE_MAP_SHIFT;
397 : }
398 :
399 209 : *maxindex = 0;
400 209 : return 0;
401 : }
402 :
403 : /*
404 : * Extend a radix tree so it can store key @index.
405 : */
406 32 : static int radix_tree_extend(struct radix_tree_root *root, gfp_t gfp,
407 : unsigned long index, unsigned int shift)
408 : {
409 32 : void *entry;
410 32 : unsigned int maxshift;
411 32 : int tag;
412 :
413 : /* Figure out what the shift should be. */
414 32 : maxshift = shift;
415 32 : while (index > shift_maxindex(maxshift))
416 0 : maxshift += RADIX_TREE_MAP_SHIFT;
417 :
418 32 : entry = rcu_dereference_raw(root->xa_head);
419 32 : if (!entry && (!is_idr(root) || root_tag_get(root, IDR_FREE)))
420 26 : goto out;
421 :
422 6 : do {
423 6 : struct radix_tree_node *node = radix_tree_node_alloc(gfp, NULL,
424 : root, shift, 0, 1, 0);
425 6 : if (!node)
426 : return -ENOMEM;
427 :
428 6 : if (is_idr(root)) {
429 5 : all_tag_set(node, IDR_FREE);
430 5 : if (!root_tag_get(root, IDR_FREE)) {
431 0 : tag_clear(node, IDR_FREE, 0);
432 0 : root_tag_set(root, IDR_FREE);
433 : }
434 : } else {
435 : /* Propagate the aggregated tag info to the new child */
436 4 : for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) {
437 3 : if (root_tag_get(root, tag))
438 3 : tag_set(node, tag, 0);
439 : }
440 : }
441 :
442 6 : BUG_ON(shift > BITS_PER_LONG);
443 6 : if (radix_tree_is_internal_node(entry)) {
444 5 : entry_to_node(entry)->parent = node;
445 1 : } else if (xa_is_value(entry)) {
446 : /* Moving a value entry root->xa_head to a node */
447 0 : node->nr_values = 1;
448 : }
449 : /*
450 : * entry was already in the radix tree, so we do not need
451 : * rcu_assign_pointer here
452 : */
453 6 : node->slots[0] = (void __rcu *)entry;
454 6 : entry = node_to_entry(node);
455 6 : rcu_assign_pointer(root->xa_head, entry);
456 6 : shift += RADIX_TREE_MAP_SHIFT;
457 6 : } while (shift <= maxshift);
458 6 : out:
459 32 : return maxshift + RADIX_TREE_MAP_SHIFT;
460 : }
461 :
462 : /**
463 : * radix_tree_shrink - shrink radix tree to minimum height
464 : * @root radix tree root
465 : */
466 1428 : static inline bool radix_tree_shrink(struct radix_tree_root *root)
467 : {
468 1428 : bool shrunk = false;
469 :
470 0 : for (;;) {
471 1428 : struct radix_tree_node *node = rcu_dereference_raw(root->xa_head);
472 1428 : struct radix_tree_node *child;
473 :
474 1428 : if (!radix_tree_is_internal_node(node))
475 : break;
476 1428 : node = entry_to_node(node);
477 :
478 : /*
479 : * The candidate node has more than one child, or its child
480 : * is not at the leftmost slot, we cannot shrink.
481 : */
482 1428 : if (node->count != 1)
483 : break;
484 31 : child = rcu_dereference_raw(node->slots[0]);
485 31 : if (!child)
486 : break;
487 :
488 : /*
489 : * For an IDR, we must not shrink entry 0 into the root in
490 : * case somebody calls idr_replace() with a pointer that
491 : * appears to be an internal entry
492 : */
493 3 : if (!node->shift && is_idr(root))
494 : break;
495 :
496 0 : if (radix_tree_is_internal_node(child))
497 0 : entry_to_node(child)->parent = NULL;
498 :
499 : /*
500 : * We don't need rcu_assign_pointer(), since we are simply
501 : * moving the node from one part of the tree to another: if it
502 : * was safe to dereference the old pointer to it
503 : * (node->slots[0]), it will be safe to dereference the new
504 : * one (root->xa_head) as far as dependent read barriers go.
505 : */
506 0 : root->xa_head = (void __rcu *)child;
507 0 : if (is_idr(root) && !tag_get(node, IDR_FREE, 0))
508 0 : root_tag_clear(root, IDR_FREE);
509 :
510 : /*
511 : * We have a dilemma here. The node's slot[0] must not be
512 : * NULLed in case there are concurrent lookups expecting to
513 : * find the item. However if this was a bottom-level node,
514 : * then it may be subject to the slot pointer being visible
515 : * to callers dereferencing it. If item corresponding to
516 : * slot[0] is subsequently deleted, these callers would expect
517 : * their slot to become empty sooner or later.
518 : *
519 : * For example, lockless pagecache will look up a slot, deref
520 : * the page pointer, and if the page has 0 refcount it means it
521 : * was concurrently deleted from pagecache so try the deref
522 : * again. Fortunately there is already a requirement for logic
523 : * to retry the entire slot lookup -- the indirect pointer
524 : * problem (replacing direct root node with an indirect pointer
525 : * also results in a stale slot). So tag the slot as indirect
526 : * to force callers to retry.
527 : */
528 0 : node->count = 0;
529 0 : if (!radix_tree_is_internal_node(child)) {
530 0 : node->slots[0] = (void __rcu *)RADIX_TREE_RETRY;
531 : }
532 :
533 0 : WARN_ON_ONCE(!list_empty(&node->private_list));
534 0 : radix_tree_node_free(node);
535 0 : shrunk = true;
536 : }
537 :
538 1428 : return shrunk;
539 : }
540 :
541 16983 : static bool delete_node(struct radix_tree_root *root,
542 : struct radix_tree_node *node)
543 : {
544 16983 : bool deleted = false;
545 :
546 17937 : do {
547 17937 : struct radix_tree_node *parent;
548 :
549 17937 : if (node->count) {
550 16976 : if (node_to_entry(node) ==
551 16976 : rcu_dereference_raw(root->xa_head))
552 1428 : deleted |= radix_tree_shrink(root);
553 16976 : return deleted;
554 : }
555 :
556 961 : parent = node->parent;
557 961 : if (parent) {
558 954 : parent->slots[node->offset] = NULL;
559 954 : parent->count--;
560 : } else {
561 : /*
562 : * Shouldn't the tags already have all been cleared
563 : * by the caller?
564 : */
565 7 : if (!is_idr(root))
566 0 : root_tag_clear_all(root);
567 7 : root->xa_head = NULL;
568 : }
569 :
570 961 : WARN_ON_ONCE(!list_empty(&node->private_list));
571 961 : radix_tree_node_free(node);
572 961 : deleted = true;
573 :
574 961 : node = parent;
575 961 : } while (node);
576 :
577 : return deleted;
578 : }
579 :
580 : /**
581 : * __radix_tree_create - create a slot in a radix tree
582 : * @root: radix tree root
583 : * @index: index key
584 : * @nodep: returns node
585 : * @slotp: returns slot
586 : *
587 : * Create, if necessary, and return the node and slot for an item
588 : * at position @index in the radix tree @root.
589 : *
590 : * Until there is more than one item in the tree, no nodes are
591 : * allocated and @root->xa_head is used as a direct slot instead of
592 : * pointing to a node, in which case *@nodep will be NULL.
593 : *
594 : * Returns -ENOMEM, or 0 for success.
595 : */
596 31 : static int __radix_tree_create(struct radix_tree_root *root,
597 : unsigned long index, struct radix_tree_node **nodep,
598 : void __rcu ***slotp)
599 : {
600 31 : struct radix_tree_node *node = NULL, *child;
601 31 : void __rcu **slot = (void __rcu **)&root->xa_head;
602 31 : unsigned long maxindex;
603 31 : unsigned int shift, offset = 0;
604 31 : unsigned long max = index;
605 31 : gfp_t gfp = root_gfp_mask(root);
606 :
607 31 : shift = radix_tree_load_root(root, &child, &maxindex);
608 :
609 : /* Make sure the tree is high enough. */
610 31 : if (max > maxindex) {
611 2 : int error = radix_tree_extend(root, gfp, max, shift);
612 2 : if (error < 0)
613 : return error;
614 2 : shift = error;
615 2 : child = rcu_dereference_raw(root->xa_head);
616 : }
617 :
618 61 : while (shift > 0) {
619 30 : shift -= RADIX_TREE_MAP_SHIFT;
620 30 : if (child == NULL) {
621 : /* Have to add a child node. */
622 1 : child = radix_tree_node_alloc(gfp, node, root, shift,
623 : offset, 0, 0);
624 1 : if (!child)
625 : return -ENOMEM;
626 1 : rcu_assign_pointer(*slot, node_to_entry(child));
627 1 : if (node)
628 0 : node->count++;
629 29 : } else if (!radix_tree_is_internal_node(child))
630 : break;
631 :
632 : /* Go a level down */
633 30 : node = entry_to_node(child);
634 30 : offset = radix_tree_descend(node, &child, index);
635 30 : slot = &node->slots[offset];
636 : }
637 :
638 31 : if (nodep)
639 31 : *nodep = node;
640 31 : if (slotp)
641 31 : *slotp = slot;
642 : return 0;
643 : }
644 :
645 : /*
646 : * Free any nodes below this node. The tree is presumed to not need
647 : * shrinking, and any user data in the tree is presumed to not need a
648 : * destructor called on it. If we need to add a destructor, we can
649 : * add that functionality later. Note that we may not clear tags or
650 : * slots from the tree as an RCU walker may still have a pointer into
651 : * this subtree. We could replace the entries with RADIX_TREE_RETRY,
652 : * but we'll still have to clear those in rcu_free.
653 : */
654 0 : static void radix_tree_free_nodes(struct radix_tree_node *node)
655 : {
656 0 : unsigned offset = 0;
657 0 : struct radix_tree_node *child = entry_to_node(node);
658 :
659 0 : for (;;) {
660 0 : void *entry = rcu_dereference_raw(child->slots[offset]);
661 0 : if (xa_is_node(entry) && child->shift) {
662 0 : child = entry_to_node(entry);
663 0 : offset = 0;
664 0 : continue;
665 : }
666 0 : offset++;
667 0 : while (offset == RADIX_TREE_MAP_SIZE) {
668 0 : struct radix_tree_node *old = child;
669 0 : offset = child->offset + 1;
670 0 : child = child->parent;
671 0 : WARN_ON_ONCE(!list_empty(&old->private_list));
672 0 : radix_tree_node_free(old);
673 0 : if (old == entry_to_node(node))
674 0 : return;
675 : }
676 : }
677 : }
678 :
679 31 : static inline int insert_entries(struct radix_tree_node *node,
680 : void __rcu **slot, void *item, bool replace)
681 : {
682 31 : if (*slot)
683 : return -EEXIST;
684 31 : rcu_assign_pointer(*slot, item);
685 31 : if (node) {
686 30 : node->count++;
687 30 : if (xa_is_value(item))
688 0 : node->nr_values++;
689 : }
690 : return 1;
691 : }
692 :
693 : /**
694 : * __radix_tree_insert - insert into a radix tree
695 : * @root: radix tree root
696 : * @index: index key
697 : * @item: item to insert
698 : *
699 : * Insert an item into the radix tree at position @index.
700 : */
701 31 : int radix_tree_insert(struct radix_tree_root *root, unsigned long index,
702 : void *item)
703 : {
704 31 : struct radix_tree_node *node;
705 31 : void __rcu **slot;
706 31 : int error;
707 :
708 31 : BUG_ON(radix_tree_is_internal_node(item));
709 :
710 31 : error = __radix_tree_create(root, index, &node, &slot);
711 31 : if (error)
712 : return error;
713 :
714 31 : error = insert_entries(node, slot, item, false);
715 0 : if (error < 0)
716 : return error;
717 :
718 31 : if (node) {
719 30 : unsigned offset = get_slot_offset(node, slot);
720 30 : BUG_ON(tag_get(node, 0, offset));
721 30 : BUG_ON(tag_get(node, 1, offset));
722 30 : BUG_ON(tag_get(node, 2, offset));
723 : } else {
724 1 : BUG_ON(root_tags_get(root));
725 : }
726 :
727 : return 0;
728 : }
729 : EXPORT_SYMBOL(radix_tree_insert);
730 :
731 : /**
732 : * __radix_tree_lookup - lookup an item in a radix tree
733 : * @root: radix tree root
734 : * @index: index key
735 : * @nodep: returns node
736 : * @slotp: returns slot
737 : *
738 : * Lookup and return the item at position @index in the radix
739 : * tree @root.
740 : *
741 : * Until there is more than one item in the tree, no nodes are
742 : * allocated and @root->xa_head is used as a direct slot instead of
743 : * pointing to a node, in which case *@nodep will be NULL.
744 : */
745 10310 : void *__radix_tree_lookup(const struct radix_tree_root *root,
746 : unsigned long index, struct radix_tree_node **nodep,
747 : void __rcu ***slotp)
748 : {
749 10310 : struct radix_tree_node *node, *parent;
750 10310 : unsigned long maxindex;
751 10310 : void __rcu **slot;
752 :
753 10310 : restart:
754 10310 : parent = NULL;
755 10310 : slot = (void __rcu **)&root->xa_head;
756 10310 : radix_tree_load_root(root, &node, &maxindex);
757 10314 : if (index > maxindex)
758 : return NULL;
759 :
760 17971 : while (radix_tree_is_internal_node(node)) {
761 17970 : unsigned offset;
762 :
763 17970 : parent = entry_to_node(node);
764 17970 : offset = radix_tree_descend(parent, &node, index);
765 17970 : slot = parent->slots + offset;
766 17970 : if (node == RADIX_TREE_RETRY)
767 0 : goto restart;
768 17970 : if (parent->shift == 0)
769 : break;
770 : }
771 :
772 10296 : if (nodep)
773 5884 : *nodep = parent;
774 10296 : if (slotp)
775 5882 : *slotp = slot;
776 10296 : return node;
777 : }
778 :
779 : /**
780 : * radix_tree_lookup_slot - lookup a slot in a radix tree
781 : * @root: radix tree root
782 : * @index: index key
783 : *
784 : * Returns: the slot corresponding to the position @index in the
785 : * radix tree @root. This is useful for update-if-exists operations.
786 : *
787 : * This function can be called under rcu_read_lock iff the slot is not
788 : * modified by radix_tree_replace_slot, otherwise it must be called
789 : * exclusive from other writers. Any dereference of the slot must be done
790 : * using radix_tree_deref_slot.
791 : */
792 0 : void __rcu **radix_tree_lookup_slot(const struct radix_tree_root *root,
793 : unsigned long index)
794 : {
795 0 : void __rcu **slot;
796 :
797 0 : if (!__radix_tree_lookup(root, index, NULL, &slot))
798 : return NULL;
799 0 : return slot;
800 : }
801 : EXPORT_SYMBOL(radix_tree_lookup_slot);
802 :
803 : /**
804 : * radix_tree_lookup - perform lookup operation on a radix tree
805 : * @root: radix tree root
806 : * @index: index key
807 : *
808 : * Lookup the item at the position @index in the radix tree @root.
809 : *
810 : * This function can be called under rcu_read_lock, however the caller
811 : * must manage lifetimes of leaf nodes (eg. RCU may also be used to free
812 : * them safely). No RCU barriers are required to access or modify the
813 : * returned item, however.
814 : */
815 4426 : void *radix_tree_lookup(const struct radix_tree_root *root, unsigned long index)
816 : {
817 4426 : return __radix_tree_lookup(root, index, NULL, NULL);
818 : }
819 : EXPORT_SYMBOL(radix_tree_lookup);
820 :
821 16983 : static void replace_slot(void __rcu **slot, void *item,
822 : struct radix_tree_node *node, int count, int values)
823 : {
824 13574 : if (node && (count || values)) {
825 14508 : node->count += count;
826 14508 : node->nr_values += values;
827 : }
828 :
829 16983 : rcu_assign_pointer(*slot, item);
830 : }
831 :
832 13574 : static bool node_tag_get(const struct radix_tree_root *root,
833 : const struct radix_tree_node *node,
834 : unsigned int tag, unsigned int offset)
835 : {
836 13574 : if (node)
837 13574 : return tag_get(node, tag, offset);
838 0 : return root_tag_get(root, tag);
839 : }
840 :
841 : /*
842 : * IDR users want to be able to store NULL in the tree, so if the slot isn't
843 : * free, don't adjust the count, even if it's transitioning between NULL and
844 : * non-NULL. For the IDA, we mark slots as being IDR_FREE while they still
845 : * have empty bits, but it only stores NULL in slots when they're being
846 : * deleted.
847 : */
848 13574 : static int calculate_count(struct radix_tree_root *root,
849 : struct radix_tree_node *node, void __rcu **slot,
850 : void *item, void *old)
851 : {
852 13574 : if (is_idr(root)) {
853 13574 : unsigned offset = get_slot_offset(node, slot);
854 13574 : bool free = node_tag_get(root, node, IDR_FREE, offset);
855 13574 : if (!free)
856 : return 0;
857 11099 : if (!old)
858 : return 1;
859 : }
860 0 : return !!item - !!old;
861 : }
862 :
863 : /**
864 : * __radix_tree_replace - replace item in a slot
865 : * @root: radix tree root
866 : * @node: pointer to tree node
867 : * @slot: pointer to slot in @node
868 : * @item: new item to store in the slot.
869 : *
870 : * For use with __radix_tree_lookup(). Caller must hold tree write locked
871 : * across slot lookup and replacement.
872 : */
873 13574 : void __radix_tree_replace(struct radix_tree_root *root,
874 : struct radix_tree_node *node,
875 : void __rcu **slot, void *item)
876 : {
877 13574 : void *old = rcu_dereference_raw(*slot);
878 13574 : int values = !!xa_is_value(item) - !!xa_is_value(old);
879 13574 : int count = calculate_count(root, node, slot, item, old);
880 :
881 : /*
882 : * This function supports replacing value entries and
883 : * deleting entries, but that needs accounting against the
884 : * node unless the slot is root->xa_head.
885 : */
886 27148 : WARN_ON_ONCE(!node && (slot != (void __rcu **)&root->xa_head) &&
887 : (count || values));
888 13574 : replace_slot(slot, item, node, count, values);
889 :
890 13574 : if (!node)
891 : return;
892 :
893 13574 : delete_node(root, node);
894 : }
895 :
896 : /**
897 : * radix_tree_replace_slot - replace item in a slot
898 : * @root: radix tree root
899 : * @slot: pointer to slot
900 : * @item: new item to store in the slot.
901 : *
902 : * For use with radix_tree_lookup_slot() and
903 : * radix_tree_gang_lookup_tag_slot(). Caller must hold tree write locked
904 : * across slot lookup and replacement.
905 : *
906 : * NOTE: This cannot be used to switch between non-entries (empty slots),
907 : * regular entries, and value entries, as that requires accounting
908 : * inside the radix tree node. When switching from one type of entry or
909 : * deleting, use __radix_tree_lookup() and __radix_tree_replace() or
910 : * radix_tree_iter_replace().
911 : */
912 0 : void radix_tree_replace_slot(struct radix_tree_root *root,
913 : void __rcu **slot, void *item)
914 : {
915 0 : __radix_tree_replace(root, NULL, slot, item);
916 0 : }
917 : EXPORT_SYMBOL(radix_tree_replace_slot);
918 :
919 : /**
920 : * radix_tree_iter_replace - replace item in a slot
921 : * @root: radix tree root
922 : * @slot: pointer to slot
923 : * @item: new item to store in the slot.
924 : *
925 : * For use with radix_tree_for_each_slot().
926 : * Caller must hold tree write locked.
927 : */
928 11099 : void radix_tree_iter_replace(struct radix_tree_root *root,
929 : const struct radix_tree_iter *iter,
930 : void __rcu **slot, void *item)
931 : {
932 11099 : __radix_tree_replace(root, iter->node, slot, item);
933 11099 : }
934 :
935 3409 : static void node_tag_set(struct radix_tree_root *root,
936 : struct radix_tree_node *node,
937 : unsigned int tag, unsigned int offset)
938 : {
939 6820 : while (node) {
940 6764 : if (tag_get(node, tag, offset))
941 : return;
942 3411 : tag_set(node, tag, offset);
943 3411 : offset = node->offset;
944 3411 : node = node->parent;
945 : }
946 :
947 56 : if (!root_tag_get(root, tag))
948 0 : root_tag_set(root, tag);
949 : }
950 :
951 : /**
952 : * radix_tree_tag_set - set a tag on a radix tree node
953 : * @root: radix tree root
954 : * @index: index key
955 : * @tag: tag index
956 : *
957 : * Set the search tag (which must be < RADIX_TREE_MAX_TAGS)
958 : * corresponding to @index in the radix tree. From
959 : * the root all the way down to the leaf node.
960 : *
961 : * Returns the address of the tagged item. Setting a tag on a not-present
962 : * item is a bug.
963 : */
964 0 : void *radix_tree_tag_set(struct radix_tree_root *root,
965 : unsigned long index, unsigned int tag)
966 : {
967 0 : struct radix_tree_node *node, *parent;
968 0 : unsigned long maxindex;
969 :
970 0 : radix_tree_load_root(root, &node, &maxindex);
971 0 : BUG_ON(index > maxindex);
972 :
973 0 : while (radix_tree_is_internal_node(node)) {
974 0 : unsigned offset;
975 :
976 0 : parent = entry_to_node(node);
977 0 : offset = radix_tree_descend(parent, &node, index);
978 0 : BUG_ON(!node);
979 :
980 0 : if (!tag_get(parent, tag, offset))
981 0 : tag_set(parent, tag, offset);
982 : }
983 :
984 : /* set the root's tag bit */
985 0 : if (!root_tag_get(root, tag))
986 0 : root_tag_set(root, tag);
987 :
988 0 : return node;
989 : }
990 : EXPORT_SYMBOL(radix_tree_tag_set);
991 :
992 11099 : static void node_tag_clear(struct radix_tree_root *root,
993 : struct radix_tree_node *node,
994 : unsigned int tag, unsigned int offset)
995 : {
996 11207 : while (node) {
997 11207 : if (!tag_get(node, tag, offset))
998 : return;
999 11207 : tag_clear(node, tag, offset);
1000 11207 : if (any_tag_set(node, tag))
1001 : return;
1002 :
1003 108 : offset = node->offset;
1004 108 : node = node->parent;
1005 : }
1006 :
1007 : /* clear the root's tag bit */
1008 0 : if (root_tag_get(root, tag))
1009 0 : root_tag_clear(root, tag);
1010 : }
1011 :
1012 : /**
1013 : * radix_tree_tag_clear - clear a tag on a radix tree node
1014 : * @root: radix tree root
1015 : * @index: index key
1016 : * @tag: tag index
1017 : *
1018 : * Clear the search tag (which must be < RADIX_TREE_MAX_TAGS)
1019 : * corresponding to @index in the radix tree. If this causes
1020 : * the leaf node to have no tags set then clear the tag in the
1021 : * next-to-leaf node, etc.
1022 : *
1023 : * Returns the address of the tagged item on success, else NULL. ie:
1024 : * has the same return value and semantics as radix_tree_lookup().
1025 : */
1026 0 : void *radix_tree_tag_clear(struct radix_tree_root *root,
1027 : unsigned long index, unsigned int tag)
1028 : {
1029 0 : struct radix_tree_node *node, *parent;
1030 0 : unsigned long maxindex;
1031 0 : int offset;
1032 :
1033 0 : radix_tree_load_root(root, &node, &maxindex);
1034 0 : if (index > maxindex)
1035 : return NULL;
1036 :
1037 : parent = NULL;
1038 :
1039 0 : while (radix_tree_is_internal_node(node)) {
1040 0 : parent = entry_to_node(node);
1041 0 : offset = radix_tree_descend(parent, &node, index);
1042 : }
1043 :
1044 0 : if (node)
1045 0 : node_tag_clear(root, parent, tag, offset);
1046 :
1047 0 : return node;
1048 : }
1049 : EXPORT_SYMBOL(radix_tree_tag_clear);
1050 :
1051 : /**
1052 : * radix_tree_iter_tag_clear - clear a tag on the current iterator entry
1053 : * @root: radix tree root
1054 : * @iter: iterator state
1055 : * @tag: tag to clear
1056 : */
1057 11099 : void radix_tree_iter_tag_clear(struct radix_tree_root *root,
1058 : const struct radix_tree_iter *iter, unsigned int tag)
1059 : {
1060 11099 : node_tag_clear(root, iter->node, tag, iter_offset(iter));
1061 11099 : }
1062 :
1063 : /**
1064 : * radix_tree_tag_get - get a tag on a radix tree node
1065 : * @root: radix tree root
1066 : * @index: index key
1067 : * @tag: tag index (< RADIX_TREE_MAX_TAGS)
1068 : *
1069 : * Return values:
1070 : *
1071 : * 0: tag not present or not set
1072 : * 1: tag set
1073 : *
1074 : * Note that the return value of this function may not be relied on, even if
1075 : * the RCU lock is held, unless tag modification and node deletion are excluded
1076 : * from concurrency.
1077 : */
1078 2475 : int radix_tree_tag_get(const struct radix_tree_root *root,
1079 : unsigned long index, unsigned int tag)
1080 : {
1081 2475 : struct radix_tree_node *node, *parent;
1082 2475 : unsigned long maxindex;
1083 :
1084 2475 : if (!root_tag_get(root, tag))
1085 : return 0;
1086 :
1087 2475 : radix_tree_load_root(root, &node, &maxindex);
1088 2475 : if (index > maxindex)
1089 : return 0;
1090 :
1091 4887 : while (radix_tree_is_internal_node(node)) {
1092 4887 : unsigned offset;
1093 :
1094 4887 : parent = entry_to_node(node);
1095 4887 : offset = radix_tree_descend(parent, &node, index);
1096 :
1097 4887 : if (!tag_get(parent, tag, offset))
1098 : return 0;
1099 2412 : if (node == RADIX_TREE_RETRY)
1100 : break;
1101 : }
1102 :
1103 : return 1;
1104 : }
1105 : EXPORT_SYMBOL(radix_tree_tag_get);
1106 :
1107 : /* Construct iter->tags bit-mask from node->tags[tag] array */
1108 11099 : static void set_iter_tags(struct radix_tree_iter *iter,
1109 : struct radix_tree_node *node, unsigned offset,
1110 : unsigned tag)
1111 : {
1112 11099 : unsigned tag_long = offset / BITS_PER_LONG;
1113 11099 : unsigned tag_bit = offset % BITS_PER_LONG;
1114 :
1115 11099 : if (!node) {
1116 0 : iter->tags = 1;
1117 0 : return;
1118 : }
1119 :
1120 11099 : iter->tags = node->tags[tag][tag_long] >> tag_bit;
1121 :
1122 : /* This never happens if RADIX_TREE_TAG_LONGS == 1 */
1123 11099 : if (tag_long < RADIX_TREE_TAG_LONGS - 1) {
1124 : /* Pick tags from next element */
1125 : if (tag_bit)
1126 : iter->tags |= node->tags[tag][tag_long + 1] <<
1127 : (BITS_PER_LONG - tag_bit);
1128 : /* Clip chunk size, here only BITS_PER_LONG tags */
1129 : iter->next_index = __radix_tree_iter_add(iter, BITS_PER_LONG);
1130 : }
1131 : }
1132 :
1133 0 : void __rcu **radix_tree_iter_resume(void __rcu **slot,
1134 : struct radix_tree_iter *iter)
1135 : {
1136 0 : slot++;
1137 0 : iter->index = __radix_tree_iter_add(iter, 1);
1138 0 : iter->next_index = iter->index;
1139 0 : iter->tags = 0;
1140 0 : return NULL;
1141 : }
1142 : EXPORT_SYMBOL(radix_tree_iter_resume);
1143 :
1144 : /**
1145 : * radix_tree_next_chunk - find next chunk of slots for iteration
1146 : *
1147 : * @root: radix tree root
1148 : * @iter: iterator state
1149 : * @flags: RADIX_TREE_ITER_* flags and tag index
1150 : * Returns: pointer to chunk first slot, or NULL if iteration is over
1151 : */
1152 244 : void __rcu **radix_tree_next_chunk(const struct radix_tree_root *root,
1153 : struct radix_tree_iter *iter, unsigned flags)
1154 : {
1155 244 : unsigned tag = flags & RADIX_TREE_ITER_TAG_MASK;
1156 244 : struct radix_tree_node *node, *child;
1157 244 : unsigned long index, offset, maxindex;
1158 :
1159 244 : if ((flags & RADIX_TREE_ITER_TAGGED) && !root_tag_get(root, tag))
1160 : return NULL;
1161 :
1162 : /*
1163 : * Catch next_index overflow after ~0UL. iter->index never overflows
1164 : * during iterating; it can be zero only at the beginning.
1165 : * And we cannot overflow iter->next_index in a single step,
1166 : * because RADIX_TREE_MAP_SHIFT < BITS_PER_LONG.
1167 : *
1168 : * This condition also used by radix_tree_next_slot() to stop
1169 : * contiguous iterating, and forbid switching to the next chunk.
1170 : */
1171 244 : index = iter->next_index;
1172 244 : if (!index && iter->index)
1173 : return NULL;
1174 :
1175 244 : restart:
1176 249 : radix_tree_load_root(root, &child, &maxindex);
1177 249 : if (index > maxindex)
1178 : return NULL;
1179 244 : if (!child)
1180 : return NULL;
1181 :
1182 35 : if (!radix_tree_is_internal_node(child)) {
1183 : /* Single-slot tree */
1184 0 : iter->index = index;
1185 0 : iter->next_index = maxindex + 1;
1186 0 : iter->tags = 1;
1187 0 : iter->node = NULL;
1188 0 : return (void __rcu **)&root->xa_head;
1189 : }
1190 :
1191 35 : do {
1192 35 : node = entry_to_node(child);
1193 35 : offset = radix_tree_descend(node, &child, index);
1194 :
1195 35 : if ((flags & RADIX_TREE_ITER_TAGGED) ?
1196 0 : !tag_get(node, tag, offset) : !child) {
1197 : /* Hole detected */
1198 8 : if (flags & RADIX_TREE_ITER_CONTIG)
1199 : return NULL;
1200 :
1201 8 : if (flags & RADIX_TREE_ITER_TAGGED)
1202 0 : offset = radix_tree_find_next_bit(node, tag,
1203 : offset + 1);
1204 : else
1205 290 : while (++offset < RADIX_TREE_MAP_SIZE) {
1206 285 : void *slot = rcu_dereference_raw(
1207 : node->slots[offset]);
1208 285 : if (slot)
1209 : break;
1210 : }
1211 8 : index &= ~node_maxindex(node);
1212 8 : index += offset << node->shift;
1213 : /* Overflow after ~0UL */
1214 8 : if (!index)
1215 : return NULL;
1216 8 : if (offset == RADIX_TREE_MAP_SIZE)
1217 5 : goto restart;
1218 3 : child = rcu_dereference_raw(node->slots[offset]);
1219 : }
1220 :
1221 30 : if (!child)
1222 0 : goto restart;
1223 30 : if (child == RADIX_TREE_RETRY)
1224 : break;
1225 30 : } while (node->shift && radix_tree_is_internal_node(child));
1226 :
1227 : /* Update the iterator state */
1228 30 : iter->index = (index &~ node_maxindex(node)) | offset;
1229 30 : iter->next_index = (index | node_maxindex(node)) + 1;
1230 30 : iter->node = node;
1231 :
1232 30 : if (flags & RADIX_TREE_ITER_TAGGED)
1233 0 : set_iter_tags(iter, node, offset, tag);
1234 :
1235 30 : return node->slots + offset;
1236 : }
1237 : EXPORT_SYMBOL(radix_tree_next_chunk);
1238 :
1239 : /**
1240 : * radix_tree_gang_lookup - perform multiple lookup on a radix tree
1241 : * @root: radix tree root
1242 : * @results: where the results of the lookup are placed
1243 : * @first_index: start the lookup from this key
1244 : * @max_items: place up to this many items at *results
1245 : *
1246 : * Performs an index-ascending scan of the tree for present items. Places
1247 : * them at *@results and returns the number of items which were placed at
1248 : * *@results.
1249 : *
1250 : * The implementation is naive.
1251 : *
1252 : * Like radix_tree_lookup, radix_tree_gang_lookup may be called under
1253 : * rcu_read_lock. In this case, rather than the returned results being
1254 : * an atomic snapshot of the tree at a single point in time, the
1255 : * semantics of an RCU protected gang lookup are as though multiple
1256 : * radix_tree_lookups have been issued in individual locks, and results
1257 : * stored in 'results'.
1258 : */
1259 : unsigned int
1260 0 : radix_tree_gang_lookup(const struct radix_tree_root *root, void **results,
1261 : unsigned long first_index, unsigned int max_items)
1262 : {
1263 0 : struct radix_tree_iter iter;
1264 0 : void __rcu **slot;
1265 0 : unsigned int ret = 0;
1266 :
1267 0 : if (unlikely(!max_items))
1268 : return 0;
1269 :
1270 0 : radix_tree_for_each_slot(slot, root, &iter, first_index) {
1271 0 : results[ret] = rcu_dereference_raw(*slot);
1272 0 : if (!results[ret])
1273 0 : continue;
1274 0 : if (radix_tree_is_internal_node(results[ret])) {
1275 0 : slot = radix_tree_iter_retry(&iter);
1276 0 : continue;
1277 : }
1278 0 : if (++ret == max_items)
1279 : break;
1280 : }
1281 :
1282 : return ret;
1283 : }
1284 : EXPORT_SYMBOL(radix_tree_gang_lookup);
1285 :
1286 : /**
1287 : * radix_tree_gang_lookup_tag - perform multiple lookup on a radix tree
1288 : * based on a tag
1289 : * @root: radix tree root
1290 : * @results: where the results of the lookup are placed
1291 : * @first_index: start the lookup from this key
1292 : * @max_items: place up to this many items at *results
1293 : * @tag: the tag index (< RADIX_TREE_MAX_TAGS)
1294 : *
1295 : * Performs an index-ascending scan of the tree for present items which
1296 : * have the tag indexed by @tag set. Places the items at *@results and
1297 : * returns the number of items which were placed at *@results.
1298 : */
1299 : unsigned int
1300 0 : radix_tree_gang_lookup_tag(const struct radix_tree_root *root, void **results,
1301 : unsigned long first_index, unsigned int max_items,
1302 : unsigned int tag)
1303 : {
1304 0 : struct radix_tree_iter iter;
1305 0 : void __rcu **slot;
1306 0 : unsigned int ret = 0;
1307 :
1308 0 : if (unlikely(!max_items))
1309 : return 0;
1310 :
1311 0 : radix_tree_for_each_tagged(slot, root, &iter, first_index, tag) {
1312 0 : results[ret] = rcu_dereference_raw(*slot);
1313 0 : if (!results[ret])
1314 0 : continue;
1315 0 : if (radix_tree_is_internal_node(results[ret])) {
1316 0 : slot = radix_tree_iter_retry(&iter);
1317 0 : continue;
1318 : }
1319 0 : if (++ret == max_items)
1320 : break;
1321 : }
1322 :
1323 : return ret;
1324 : }
1325 : EXPORT_SYMBOL(radix_tree_gang_lookup_tag);
1326 :
1327 : /**
1328 : * radix_tree_gang_lookup_tag_slot - perform multiple slot lookup on a
1329 : * radix tree based on a tag
1330 : * @root: radix tree root
1331 : * @results: where the results of the lookup are placed
1332 : * @first_index: start the lookup from this key
1333 : * @max_items: place up to this many items at *results
1334 : * @tag: the tag index (< RADIX_TREE_MAX_TAGS)
1335 : *
1336 : * Performs an index-ascending scan of the tree for present items which
1337 : * have the tag indexed by @tag set. Places the slots at *@results and
1338 : * returns the number of slots which were placed at *@results.
1339 : */
1340 : unsigned int
1341 0 : radix_tree_gang_lookup_tag_slot(const struct radix_tree_root *root,
1342 : void __rcu ***results, unsigned long first_index,
1343 : unsigned int max_items, unsigned int tag)
1344 : {
1345 0 : struct radix_tree_iter iter;
1346 0 : void __rcu **slot;
1347 0 : unsigned int ret = 0;
1348 :
1349 0 : if (unlikely(!max_items))
1350 : return 0;
1351 :
1352 0 : radix_tree_for_each_tagged(slot, root, &iter, first_index, tag) {
1353 0 : results[ret] = slot;
1354 0 : if (++ret == max_items)
1355 : break;
1356 : }
1357 :
1358 : return ret;
1359 : }
1360 : EXPORT_SYMBOL(radix_tree_gang_lookup_tag_slot);
1361 :
1362 3409 : static bool __radix_tree_delete(struct radix_tree_root *root,
1363 : struct radix_tree_node *node, void __rcu **slot)
1364 : {
1365 3409 : void *old = rcu_dereference_raw(*slot);
1366 3409 : int values = xa_is_value(old) ? -1 : 0;
1367 3409 : unsigned offset = get_slot_offset(node, slot);
1368 3409 : int tag;
1369 :
1370 3409 : if (is_idr(root))
1371 3409 : node_tag_set(root, node, IDR_FREE, offset);
1372 : else
1373 0 : for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
1374 0 : node_tag_clear(root, node, tag, offset);
1375 :
1376 3409 : replace_slot(slot, NULL, node, -1, values);
1377 3409 : return node && delete_node(root, node);
1378 : }
1379 :
1380 : /**
1381 : * radix_tree_iter_delete - delete the entry at this iterator position
1382 : * @root: radix tree root
1383 : * @iter: iterator state
1384 : * @slot: pointer to slot
1385 : *
1386 : * Delete the entry at the position currently pointed to by the iterator.
1387 : * This may result in the current node being freed; if it is, the iterator
1388 : * is advanced so that it will not reference the freed memory. This
1389 : * function may be called without any locking if there are no other threads
1390 : * which can access this tree.
1391 : */
1392 0 : void radix_tree_iter_delete(struct radix_tree_root *root,
1393 : struct radix_tree_iter *iter, void __rcu **slot)
1394 : {
1395 0 : if (__radix_tree_delete(root, iter->node, slot))
1396 0 : iter->index = iter->next_index;
1397 0 : }
1398 : EXPORT_SYMBOL(radix_tree_iter_delete);
1399 :
1400 : /**
1401 : * radix_tree_delete_item - delete an item from a radix tree
1402 : * @root: radix tree root
1403 : * @index: index key
1404 : * @item: expected item
1405 : *
1406 : * Remove @item at @index from the radix tree rooted at @root.
1407 : *
1408 : * Return: the deleted entry, or %NULL if it was not present
1409 : * or the entry at the given @index was not @item.
1410 : */
1411 3409 : void *radix_tree_delete_item(struct radix_tree_root *root,
1412 : unsigned long index, void *item)
1413 : {
1414 3409 : struct radix_tree_node *node = NULL;
1415 3409 : void __rcu **slot = NULL;
1416 3409 : void *entry;
1417 :
1418 3409 : entry = __radix_tree_lookup(root, index, &node, &slot);
1419 3409 : if (!slot)
1420 : return NULL;
1421 3409 : if (!entry && (!is_idr(root) || node_tag_get(root, node, IDR_FREE,
1422 0 : get_slot_offset(node, slot))))
1423 0 : return NULL;
1424 :
1425 3409 : if (item && entry != item)
1426 : return NULL;
1427 :
1428 3409 : __radix_tree_delete(root, node, slot);
1429 :
1430 3409 : return entry;
1431 : }
1432 : EXPORT_SYMBOL(radix_tree_delete_item);
1433 :
1434 : /**
1435 : * radix_tree_delete - delete an entry from a radix tree
1436 : * @root: radix tree root
1437 : * @index: index key
1438 : *
1439 : * Remove the entry at @index from the radix tree rooted at @root.
1440 : *
1441 : * Return: The deleted entry, or %NULL if it was not present.
1442 : */
1443 0 : void *radix_tree_delete(struct radix_tree_root *root, unsigned long index)
1444 : {
1445 0 : return radix_tree_delete_item(root, index, NULL);
1446 : }
1447 : EXPORT_SYMBOL(radix_tree_delete);
1448 :
1449 : /**
1450 : * radix_tree_tagged - test whether any items in the tree are tagged
1451 : * @root: radix tree root
1452 : * @tag: tag to test
1453 : */
1454 11099 : int radix_tree_tagged(const struct radix_tree_root *root, unsigned int tag)
1455 : {
1456 11099 : return root_tag_get(root, tag);
1457 : }
1458 : EXPORT_SYMBOL(radix_tree_tagged);
1459 :
1460 : /**
1461 : * idr_preload - preload for idr_alloc()
1462 : * @gfp_mask: allocation mask to use for preloading
1463 : *
1464 : * Preallocate memory to use for the next call to idr_alloc(). This function
1465 : * returns with preemption disabled. It will be enabled by idr_preload_end().
1466 : */
1467 11073 : void idr_preload(gfp_t gfp_mask)
1468 : {
1469 11073 : if (__radix_tree_preload(gfp_mask, IDR_PRELOAD_SIZE))
1470 0 : local_lock(&radix_tree_preloads.lock);
1471 11073 : }
1472 : EXPORT_SYMBOL(idr_preload);
1473 :
1474 11099 : void __rcu **idr_get_free(struct radix_tree_root *root,
1475 : struct radix_tree_iter *iter, gfp_t gfp,
1476 : unsigned long max)
1477 : {
1478 11099 : struct radix_tree_node *node = NULL, *child;
1479 11099 : void __rcu **slot = (void __rcu **)&root->xa_head;
1480 11099 : unsigned long maxindex, start = iter->next_index;
1481 11099 : unsigned int shift, offset = 0;
1482 :
1483 11099 : grow:
1484 11099 : shift = radix_tree_load_root(root, &child, &maxindex);
1485 11099 : if (!radix_tree_tagged(root, IDR_FREE))
1486 0 : start = max(start, maxindex + 1);
1487 11099 : if (start > max)
1488 11099 : return ERR_PTR(-ENOSPC);
1489 :
1490 11099 : if (start > maxindex) {
1491 30 : int error = radix_tree_extend(root, gfp, start, shift);
1492 30 : if (error < 0)
1493 0 : return ERR_PTR(error);
1494 30 : shift = error;
1495 30 : child = rcu_dereference_raw(root->xa_head);
1496 : }
1497 11099 : if (start == 0 && shift == 0)
1498 3 : shift = RADIX_TREE_MAP_SHIFT;
1499 :
1500 36484 : while (shift) {
1501 25385 : shift -= RADIX_TREE_MAP_SHIFT;
1502 25385 : if (child == NULL) {
1503 : /* Have to add a child node. */
1504 1119 : child = radix_tree_node_alloc(gfp, node, root, shift,
1505 : offset, 0, 0);
1506 1119 : if (!child)
1507 11099 : return ERR_PTR(-ENOMEM);
1508 1119 : all_tag_set(child, IDR_FREE);
1509 1119 : rcu_assign_pointer(*slot, node_to_entry(child));
1510 1119 : if (node)
1511 1091 : node->count++;
1512 24266 : } else if (!radix_tree_is_internal_node(child))
1513 : break;
1514 :
1515 25385 : node = entry_to_node(child);
1516 25385 : offset = radix_tree_descend(node, &child, start);
1517 25385 : if (!tag_get(node, IDR_FREE, offset)) {
1518 16 : offset = radix_tree_find_next_bit(node, IDR_FREE,
1519 8 : offset + 1);
1520 8 : start = next_index(start, node, offset);
1521 8 : if (start > max || start == 0)
1522 11099 : return ERR_PTR(-ENOSPC);
1523 8 : while (offset == RADIX_TREE_MAP_SIZE) {
1524 0 : offset = node->offset + 1;
1525 0 : node = node->parent;
1526 0 : if (!node)
1527 0 : goto grow;
1528 0 : shift = node->shift;
1529 : }
1530 8 : child = rcu_dereference_raw(node->slots[offset]);
1531 : }
1532 25385 : slot = &node->slots[offset];
1533 : }
1534 :
1535 11099 : iter->index = start;
1536 11099 : if (node)
1537 11099 : iter->next_index = 1 + min(max, (start | node_maxindex(node)));
1538 : else
1539 0 : iter->next_index = 1;
1540 11099 : iter->node = node;
1541 11099 : set_iter_tags(iter, node, offset, IDR_FREE);
1542 :
1543 : return slot;
1544 : }
1545 :
1546 : /**
1547 : * idr_destroy - release all internal memory from an IDR
1548 : * @idr: idr handle
1549 : *
1550 : * After this function is called, the IDR is empty, and may be reused or
1551 : * the data structure containing it may be freed.
1552 : *
1553 : * A typical clean-up sequence for objects stored in an idr tree will use
1554 : * idr_for_each() to free all objects, if necessary, then idr_destroy() to
1555 : * free the memory used to keep track of those objects.
1556 : */
1557 7 : void idr_destroy(struct idr *idr)
1558 : {
1559 7 : struct radix_tree_node *node = rcu_dereference_raw(idr->idr_rt.xa_head);
1560 7 : if (radix_tree_is_internal_node(node))
1561 0 : radix_tree_free_nodes(node);
1562 7 : idr->idr_rt.xa_head = NULL;
1563 7 : root_tag_set(&idr->idr_rt, IDR_FREE);
1564 7 : }
1565 : EXPORT_SYMBOL(idr_destroy);
1566 :
1567 : static void
1568 1426 : radix_tree_node_ctor(void *arg)
1569 : {
1570 1426 : struct radix_tree_node *node = arg;
1571 :
1572 1426 : memset(node, 0, sizeof(*node));
1573 1426 : INIT_LIST_HEAD(&node->private_list);
1574 1426 : }
1575 :
1576 0 : static int radix_tree_cpu_dead(unsigned int cpu)
1577 : {
1578 0 : struct radix_tree_preload *rtp;
1579 0 : struct radix_tree_node *node;
1580 :
1581 : /* Free per-cpu pool of preloaded nodes */
1582 0 : rtp = &per_cpu(radix_tree_preloads, cpu);
1583 0 : while (rtp->nr) {
1584 0 : node = rtp->nodes;
1585 0 : rtp->nodes = node->parent;
1586 0 : kmem_cache_free(radix_tree_node_cachep, node);
1587 0 : rtp->nr--;
1588 : }
1589 0 : return 0;
1590 : }
1591 :
1592 1 : void __init radix_tree_init(void)
1593 : {
1594 1 : int ret;
1595 :
1596 1 : BUILD_BUG_ON(RADIX_TREE_MAX_TAGS + __GFP_BITS_SHIFT > 32);
1597 1 : BUILD_BUG_ON(ROOT_IS_IDR & ~GFP_ZONEMASK);
1598 1 : BUILD_BUG_ON(XA_CHUNK_SIZE > 255);
1599 1 : radix_tree_node_cachep = kmem_cache_create("radix_tree_node",
1600 : sizeof(struct radix_tree_node), 0,
1601 : SLAB_PANIC | SLAB_RECLAIM_ACCOUNT,
1602 : radix_tree_node_ctor);
1603 1 : ret = cpuhp_setup_state_nocalls(CPUHP_RADIX_DEAD, "lib/radix:dead",
1604 : NULL, radix_tree_cpu_dead);
1605 1 : WARN_ON(ret < 0);
1606 1 : }
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