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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>
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
32
33struct kmem_cache *radix_tree_node_cachep;
34
35
36
37
38
39
40
41
42
43
44
45
46#define RADIX_TREE_PRELOAD_SIZE (RADIX_TREE_MAX_PATH * 2 - 1)
47
48
49
50
51
52#define IDR_INDEX_BITS (8 * 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
59
60DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = {
61 .lock = INIT_LOCAL_LOCK(lock),
62};
63EXPORT_PER_CPU_SYMBOL_GPL(radix_tree_preloads);
64
65static inline struct radix_tree_node *entry_to_node(void *ptr)
66{
67 return (void *)((unsigned long)ptr & ~RADIX_TREE_INTERNAL_NODE);
68}
69
70static inline void *node_to_entry(void *ptr)
71{
72 return (void *)((unsigned long)ptr | RADIX_TREE_INTERNAL_NODE);
73}
74
75#define RADIX_TREE_RETRY XA_RETRY_ENTRY
76
77static inline unsigned long
78get_slot_offset(const struct radix_tree_node *parent, void __rcu **slot)
79{
80 return parent ? slot - parent->slots : 0;
81}
82
83static unsigned int radix_tree_descend(const struct radix_tree_node *parent,
84 struct radix_tree_node **nodep, unsigned long index)
85{
86 unsigned int offset = (index >> parent->shift) & RADIX_TREE_MAP_MASK;
87 void __rcu **entry = rcu_dereference_raw(parent->slots[offset]);
88
89 *nodep = (void *)entry;
90 return offset;
91}
92
93static inline gfp_t root_gfp_mask(const struct radix_tree_root *root)
94{
95 return root->xa_flags & (__GFP_BITS_MASK & ~GFP_ZONEMASK);
96}
97
98static inline void tag_set(struct radix_tree_node *node, unsigned int tag,
99 int offset)
100{
101 __set_bit(offset, node->tags[tag]);
102}
103
104static inline void tag_clear(struct radix_tree_node *node, unsigned int tag,
105 int offset)
106{
107 __clear_bit(offset, node->tags[tag]);
108}
109
110static inline int tag_get(const struct radix_tree_node *node, unsigned int tag,
111 int offset)
112{
113 return test_bit(offset, node->tags[tag]);
114}
115
116static inline void root_tag_set(struct radix_tree_root *root, unsigned tag)
117{
118 root->xa_flags |= (__force gfp_t)(1 << (tag + ROOT_TAG_SHIFT));
119}
120
121static inline void root_tag_clear(struct radix_tree_root *root, unsigned tag)
122{
123 root->xa_flags &= (__force gfp_t)~(1 << (tag + ROOT_TAG_SHIFT));
124}
125
126static inline void root_tag_clear_all(struct radix_tree_root *root)
127{
128 root->xa_flags &= (__force gfp_t)((1 << ROOT_TAG_SHIFT) - 1);
129}
130
131static inline int root_tag_get(const struct radix_tree_root *root, unsigned tag)
132{
133 return (__force int)root->xa_flags & (1 << (tag + ROOT_TAG_SHIFT));
134}
135
136static inline unsigned root_tags_get(const struct radix_tree_root *root)
137{
138 return (__force unsigned)root->xa_flags >> ROOT_TAG_SHIFT;
139}
140
141static inline bool is_idr(const struct radix_tree_root *root)
142{
143 return !!(root->xa_flags & ROOT_IS_IDR);
144}
145
146
147
148
149
150static inline int any_tag_set(const struct radix_tree_node *node,
151 unsigned int tag)
152{
153 unsigned idx;
154 for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) {
155 if (node->tags[tag][idx])
156 return 1;
157 }
158 return 0;
159}
160
161static inline void all_tag_set(struct radix_tree_node *node, unsigned int tag)
162{
163 bitmap_fill(node->tags[tag], RADIX_TREE_MAP_SIZE);
164}
165
166
167
168
169
170
171
172
173
174
175
176
177static __always_inline unsigned long
178radix_tree_find_next_bit(struct radix_tree_node *node, unsigned int tag,
179 unsigned long offset)
180{
181 const unsigned long *addr = node->tags[tag];
182
183 if (offset < RADIX_TREE_MAP_SIZE) {
184 unsigned long tmp;
185
186 addr += offset / BITS_PER_LONG;
187 tmp = *addr >> (offset % BITS_PER_LONG);
188 if (tmp)
189 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
201static unsigned int iter_offset(const struct radix_tree_iter *iter)
202{
203 return iter->index & RADIX_TREE_MAP_MASK;
204}
205
206
207
208
209static inline unsigned long shift_maxindex(unsigned int shift)
210{
211 return (RADIX_TREE_MAP_SIZE << shift) - 1;
212}
213
214static inline unsigned long node_maxindex(const struct radix_tree_node *node)
215{
216 return shift_maxindex(node->shift);
217}
218
219static unsigned long next_index(unsigned long index,
220 const struct radix_tree_node *node,
221 unsigned long offset)
222{
223 return (index & ~node_maxindex(node)) + (offset << node->shift);
224}
225
226
227
228
229
230static struct radix_tree_node *
231radix_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 struct radix_tree_node *ret = NULL;
237
238
239
240
241
242
243 if (!gfpflags_allow_blocking(gfp_mask) && !in_interrupt()) {
244 struct radix_tree_preload *rtp;
245
246
247
248
249
250
251 ret = kmem_cache_alloc(radix_tree_node_cachep,
252 gfp_mask | __GFP_NOWARN);
253 if (ret)
254 goto out;
255
256
257
258
259
260
261 rtp = this_cpu_ptr(&radix_tree_preloads);
262 if (rtp->nr) {
263 ret = rtp->nodes;
264 rtp->nodes = ret->parent;
265 rtp->nr--;
266 }
267
268
269
270
271 kmemleak_update_trace(ret);
272 goto out;
273 }
274 ret = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask);
275out:
276 BUG_ON(radix_tree_is_internal_node(ret));
277 if (ret) {
278 ret->shift = shift;
279 ret->offset = offset;
280 ret->count = count;
281 ret->nr_values = nr_values;
282 ret->parent = parent;
283 ret->array = root;
284 }
285 return ret;
286}
287
288void radix_tree_node_rcu_free(struct rcu_head *head)
289{
290 struct radix_tree_node *node =
291 container_of(head, struct radix_tree_node, rcu_head);
292
293
294
295
296
297
298 memset(node->slots, 0, sizeof(node->slots));
299 memset(node->tags, 0, sizeof(node->tags));
300 INIT_LIST_HEAD(&node->private_list);
301
302 kmem_cache_free(radix_tree_node_cachep, node);
303}
304
305static inline void
306radix_tree_node_free(struct radix_tree_node *node)
307{
308 call_rcu(&node->rcu_head, radix_tree_node_rcu_free);
309}
310
311
312
313
314
315
316
317
318
319
320static __must_check int __radix_tree_preload(gfp_t gfp_mask, unsigned nr)
321{
322 struct radix_tree_preload *rtp;
323 struct radix_tree_node *node;
324 int ret = -ENOMEM;
325
326
327
328
329
330 gfp_mask &= ~__GFP_ACCOUNT;
331
332 local_lock(&radix_tree_preloads.lock);
333 rtp = this_cpu_ptr(&radix_tree_preloads);
334 while (rtp->nr < nr) {
335 local_unlock(&radix_tree_preloads.lock);
336 node = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask);
337 if (node == NULL)
338 goto out;
339 local_lock(&radix_tree_preloads.lock);
340 rtp = this_cpu_ptr(&radix_tree_preloads);
341 if (rtp->nr < nr) {
342 node->parent = rtp->nodes;
343 rtp->nodes = node;
344 rtp->nr++;
345 } else {
346 kmem_cache_free(radix_tree_node_cachep, node);
347 }
348 }
349 ret = 0;
350out:
351 return ret;
352}
353
354
355
356
357
358
359
360
361
362
363int radix_tree_preload(gfp_t gfp_mask)
364{
365
366 WARN_ON_ONCE(!gfpflags_allow_blocking(gfp_mask));
367 return __radix_tree_preload(gfp_mask, RADIX_TREE_PRELOAD_SIZE);
368}
369EXPORT_SYMBOL(radix_tree_preload);
370
371
372
373
374
375
376int radix_tree_maybe_preload(gfp_t gfp_mask)
377{
378 if (gfpflags_allow_blocking(gfp_mask))
379 return __radix_tree_preload(gfp_mask, RADIX_TREE_PRELOAD_SIZE);
380
381 local_lock(&radix_tree_preloads.lock);
382 return 0;
383}
384EXPORT_SYMBOL(radix_tree_maybe_preload);
385
386static unsigned radix_tree_load_root(const struct radix_tree_root *root,
387 struct radix_tree_node **nodep, unsigned long *maxindex)
388{
389 struct radix_tree_node *node = rcu_dereference_raw(root->xa_head);
390
391 *nodep = node;
392
393 if (likely(radix_tree_is_internal_node(node))) {
394 node = entry_to_node(node);
395 *maxindex = node_maxindex(node);
396 return node->shift + RADIX_TREE_MAP_SHIFT;
397 }
398
399 *maxindex = 0;
400 return 0;
401}
402
403
404
405
406static int radix_tree_extend(struct radix_tree_root *root, gfp_t gfp,
407 unsigned long index, unsigned int shift)
408{
409 void *entry;
410 unsigned int maxshift;
411 int tag;
412
413
414 maxshift = shift;
415 while (index > shift_maxindex(maxshift))
416 maxshift += RADIX_TREE_MAP_SHIFT;
417
418 entry = rcu_dereference_raw(root->xa_head);
419 if (!entry && (!is_idr(root) || root_tag_get(root, IDR_FREE)))
420 goto out;
421
422 do {
423 struct radix_tree_node *node = radix_tree_node_alloc(gfp, NULL,
424 root, shift, 0, 1, 0);
425 if (!node)
426 return -ENOMEM;
427
428 if (is_idr(root)) {
429 all_tag_set(node, IDR_FREE);
430 if (!root_tag_get(root, IDR_FREE)) {
431 tag_clear(node, IDR_FREE, 0);
432 root_tag_set(root, IDR_FREE);
433 }
434 } else {
435
436 for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) {
437 if (root_tag_get(root, tag))
438 tag_set(node, tag, 0);
439 }
440 }
441
442 BUG_ON(shift > BITS_PER_LONG);
443 if (radix_tree_is_internal_node(entry)) {
444 entry_to_node(entry)->parent = node;
445 } else if (xa_is_value(entry)) {
446
447 node->nr_values = 1;
448 }
449
450
451
452
453 node->slots[0] = (void __rcu *)entry;
454 entry = node_to_entry(node);
455 rcu_assign_pointer(root->xa_head, entry);
456 shift += RADIX_TREE_MAP_SHIFT;
457 } while (shift <= maxshift);
458out:
459 return maxshift + RADIX_TREE_MAP_SHIFT;
460}
461
462
463
464
465
466static inline bool radix_tree_shrink(struct radix_tree_root *root)
467{
468 bool shrunk = false;
469
470 for (;;) {
471 struct radix_tree_node *node = rcu_dereference_raw(root->xa_head);
472 struct radix_tree_node *child;
473
474 if (!radix_tree_is_internal_node(node))
475 break;
476 node = entry_to_node(node);
477
478
479
480
481
482 if (node->count != 1)
483 break;
484 child = rcu_dereference_raw(node->slots[0]);
485 if (!child)
486 break;
487
488
489
490
491
492
493 if (!node->shift && is_idr(root))
494 break;
495
496 if (radix_tree_is_internal_node(child))
497 entry_to_node(child)->parent = NULL;
498
499
500
501
502
503
504
505
506 root->xa_head = (void __rcu *)child;
507 if (is_idr(root) && !tag_get(node, IDR_FREE, 0))
508 root_tag_clear(root, IDR_FREE);
509
510
511
512
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515
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520
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523
524
525
526
527
528 node->count = 0;
529 if (!radix_tree_is_internal_node(child)) {
530 node->slots[0] = (void __rcu *)RADIX_TREE_RETRY;
531 }
532
533 WARN_ON_ONCE(!list_empty(&node->private_list));
534 radix_tree_node_free(node);
535 shrunk = true;
536 }
537
538 return shrunk;
539}
540
541static bool delete_node(struct radix_tree_root *root,
542 struct radix_tree_node *node)
543{
544 bool deleted = false;
545
546 do {
547 struct radix_tree_node *parent;
548
549 if (node->count) {
550 if (node_to_entry(node) ==
551 rcu_dereference_raw(root->xa_head))
552 deleted |= radix_tree_shrink(root);
553 return deleted;
554 }
555
556 parent = node->parent;
557 if (parent) {
558 parent->slots[node->offset] = NULL;
559 parent->count--;
560 } else {
561
562
563
564
565 if (!is_idr(root))
566 root_tag_clear_all(root);
567 root->xa_head = NULL;
568 }
569
570 WARN_ON_ONCE(!list_empty(&node->private_list));
571 radix_tree_node_free(node);
572 deleted = true;
573
574 node = parent;
575 } while (node);
576
577 return deleted;
578}
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596static int __radix_tree_create(struct radix_tree_root *root,
597 unsigned long index, struct radix_tree_node **nodep,
598 void __rcu ***slotp)
599{
600 struct radix_tree_node *node = NULL, *child;
601 void __rcu **slot = (void __rcu **)&root->xa_head;
602 unsigned long maxindex;
603 unsigned int shift, offset = 0;
604 unsigned long max = index;
605 gfp_t gfp = root_gfp_mask(root);
606
607 shift = radix_tree_load_root(root, &child, &maxindex);
608
609
610 if (max > maxindex) {
611 int error = radix_tree_extend(root, gfp, max, shift);
612 if (error < 0)
613 return error;
614 shift = error;
615 child = rcu_dereference_raw(root->xa_head);
616 }
617
618 while (shift > 0) {
619 shift -= RADIX_TREE_MAP_SHIFT;
620 if (child == NULL) {
621
622 child = radix_tree_node_alloc(gfp, node, root, shift,
623 offset, 0, 0);
624 if (!child)
625 return -ENOMEM;
626 rcu_assign_pointer(*slot, node_to_entry(child));
627 if (node)
628 node->count++;
629 } else if (!radix_tree_is_internal_node(child))
630 break;
631
632
633 node = entry_to_node(child);
634 offset = radix_tree_descend(node, &child, index);
635 slot = &node->slots[offset];
636 }
637
638 if (nodep)
639 *nodep = node;
640 if (slotp)
641 *slotp = slot;
642 return 0;
643}
644
645
646
647
648
649
650
651
652
653
654static void radix_tree_free_nodes(struct radix_tree_node *node)
655{
656 unsigned offset = 0;
657 struct radix_tree_node *child = entry_to_node(node);
658
659 for (;;) {
660 void *entry = rcu_dereference_raw(child->slots[offset]);
661 if (xa_is_node(entry) && child->shift) {
662 child = entry_to_node(entry);
663 offset = 0;
664 continue;
665 }
666 offset++;
667 while (offset == RADIX_TREE_MAP_SIZE) {
668 struct radix_tree_node *old = child;
669 offset = child->offset + 1;
670 child = child->parent;
671 WARN_ON_ONCE(!list_empty(&old->private_list));
672 radix_tree_node_free(old);
673 if (old == entry_to_node(node))
674 return;
675 }
676 }
677}
678
679static inline int insert_entries(struct radix_tree_node *node,
680 void __rcu **slot, void *item, bool replace)
681{
682 if (*slot)
683 return -EEXIST;
684 rcu_assign_pointer(*slot, item);
685 if (node) {
686 node->count++;
687 if (xa_is_value(item))
688 node->nr_values++;
689 }
690 return 1;
691}
692
693
694
695
696
697
698
699
700
701int radix_tree_insert(struct radix_tree_root *root, unsigned long index,
702 void *item)
703{
704 struct radix_tree_node *node;
705 void __rcu **slot;
706 int error;
707
708 BUG_ON(radix_tree_is_internal_node(item));
709
710 error = __radix_tree_create(root, index, &node, &slot);
711 if (error)
712 return error;
713
714 error = insert_entries(node, slot, item, false);
715 if (error < 0)
716 return error;
717
718 if (node) {
719 unsigned offset = get_slot_offset(node, slot);
720 BUG_ON(tag_get(node, 0, offset));
721 BUG_ON(tag_get(node, 1, offset));
722 BUG_ON(tag_get(node, 2, offset));
723 } else {
724 BUG_ON(root_tags_get(root));
725 }
726
727 return 0;
728}
729EXPORT_SYMBOL(radix_tree_insert);
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745void *__radix_tree_lookup(const struct radix_tree_root *root,
746 unsigned long index, struct radix_tree_node **nodep,
747 void __rcu ***slotp)
748{
749 struct radix_tree_node *node, *parent;
750 unsigned long maxindex;
751 void __rcu **slot;
752
753 restart:
754 parent = NULL;
755 slot = (void __rcu **)&root->xa_head;
756 radix_tree_load_root(root, &node, &maxindex);
757 if (index > maxindex)
758 return NULL;
759
760 while (radix_tree_is_internal_node(node)) {
761 unsigned offset;
762
763 parent = entry_to_node(node);
764 offset = radix_tree_descend(parent, &node, index);
765 slot = parent->slots + offset;
766 if (node == RADIX_TREE_RETRY)
767 goto restart;
768 if (parent->shift == 0)
769 break;
770 }
771
772 if (nodep)
773 *nodep = parent;
774 if (slotp)
775 *slotp = slot;
776 return node;
777}
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792void __rcu **radix_tree_lookup_slot(const struct radix_tree_root *root,
793 unsigned long index)
794{
795 void __rcu **slot;
796
797 if (!__radix_tree_lookup(root, index, NULL, &slot))
798 return NULL;
799 return slot;
800}
801EXPORT_SYMBOL(radix_tree_lookup_slot);
802
803
804
805
806
807
808
809
810
811
812
813
814
815void *radix_tree_lookup(const struct radix_tree_root *root, unsigned long index)
816{
817 return __radix_tree_lookup(root, index, NULL, NULL);
818}
819EXPORT_SYMBOL(radix_tree_lookup);
820
821static void replace_slot(void __rcu **slot, void *item,
822 struct radix_tree_node *node, int count, int values)
823{
824 if (node && (count || values)) {
825 node->count += count;
826 node->nr_values += values;
827 }
828
829 rcu_assign_pointer(*slot, item);
830}
831
832static 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 if (node)
837 return tag_get(node, tag, offset);
838 return root_tag_get(root, tag);
839}
840
841
842
843
844
845
846
847
848static int calculate_count(struct radix_tree_root *root,
849 struct radix_tree_node *node, void __rcu **slot,
850 void *item, void *old)
851{
852 if (is_idr(root)) {
853 unsigned offset = get_slot_offset(node, slot);
854 bool free = node_tag_get(root, node, IDR_FREE, offset);
855 if (!free)
856 return 0;
857 if (!old)
858 return 1;
859 }
860 return !!item - !!old;
861}
862
863
864
865
866
867
868
869
870
871
872
873void __radix_tree_replace(struct radix_tree_root *root,
874 struct radix_tree_node *node,
875 void __rcu **slot, void *item)
876{
877 void *old = rcu_dereference_raw(*slot);
878 int values = !!xa_is_value(item) - !!xa_is_value(old);
879 int count = calculate_count(root, node, slot, item, old);
880
881
882
883
884
885
886 WARN_ON_ONCE(!node && (slot != (void __rcu **)&root->xa_head) &&
887 (count || values));
888 replace_slot(slot, item, node, count, values);
889
890 if (!node)
891 return;
892
893 delete_node(root, node);
894}
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912void radix_tree_replace_slot(struct radix_tree_root *root,
913 void __rcu **slot, void *item)
914{
915 __radix_tree_replace(root, NULL, slot, item);
916}
917EXPORT_SYMBOL(radix_tree_replace_slot);
918
919
920
921
922
923
924
925
926
927
928
929void radix_tree_iter_replace(struct radix_tree_root *root,
930 const struct radix_tree_iter *iter,
931 void __rcu **slot, void *item)
932{
933 __radix_tree_replace(root, iter->node, slot, item);
934}
935
936static void node_tag_set(struct radix_tree_root *root,
937 struct radix_tree_node *node,
938 unsigned int tag, unsigned int offset)
939{
940 while (node) {
941 if (tag_get(node, tag, offset))
942 return;
943 tag_set(node, tag, offset);
944 offset = node->offset;
945 node = node->parent;
946 }
947
948 if (!root_tag_get(root, tag))
949 root_tag_set(root, tag);
950}
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965void *radix_tree_tag_set(struct radix_tree_root *root,
966 unsigned long index, unsigned int tag)
967{
968 struct radix_tree_node *node, *parent;
969 unsigned long maxindex;
970
971 radix_tree_load_root(root, &node, &maxindex);
972 BUG_ON(index > maxindex);
973
974 while (radix_tree_is_internal_node(node)) {
975 unsigned offset;
976
977 parent = entry_to_node(node);
978 offset = radix_tree_descend(parent, &node, index);
979 BUG_ON(!node);
980
981 if (!tag_get(parent, tag, offset))
982 tag_set(parent, tag, offset);
983 }
984
985
986 if (!root_tag_get(root, tag))
987 root_tag_set(root, tag);
988
989 return node;
990}
991EXPORT_SYMBOL(radix_tree_tag_set);
992
993static void node_tag_clear(struct radix_tree_root *root,
994 struct radix_tree_node *node,
995 unsigned int tag, unsigned int offset)
996{
997 while (node) {
998 if (!tag_get(node, tag, offset))
999 return;
1000 tag_clear(node, tag, offset);
1001 if (any_tag_set(node, tag))
1002 return;
1003
1004 offset = node->offset;
1005 node = node->parent;
1006 }
1007
1008
1009 if (root_tag_get(root, tag))
1010 root_tag_clear(root, tag);
1011}
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027void *radix_tree_tag_clear(struct radix_tree_root *root,
1028 unsigned long index, unsigned int tag)
1029{
1030 struct radix_tree_node *node, *parent;
1031 unsigned long maxindex;
1032 int offset;
1033
1034 radix_tree_load_root(root, &node, &maxindex);
1035 if (index > maxindex)
1036 return NULL;
1037
1038 parent = NULL;
1039
1040 while (radix_tree_is_internal_node(node)) {
1041 parent = entry_to_node(node);
1042 offset = radix_tree_descend(parent, &node, index);
1043 }
1044
1045 if (node)
1046 node_tag_clear(root, parent, tag, offset);
1047
1048 return node;
1049}
1050EXPORT_SYMBOL(radix_tree_tag_clear);
1051
1052
1053
1054
1055
1056
1057
1058void radix_tree_iter_tag_clear(struct radix_tree_root *root,
1059 const struct radix_tree_iter *iter, unsigned int tag)
1060{
1061 node_tag_clear(root, iter->node, tag, iter_offset(iter));
1062}
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079int radix_tree_tag_get(const struct radix_tree_root *root,
1080 unsigned long index, unsigned int tag)
1081{
1082 struct radix_tree_node *node, *parent;
1083 unsigned long maxindex;
1084
1085 if (!root_tag_get(root, tag))
1086 return 0;
1087
1088 radix_tree_load_root(root, &node, &maxindex);
1089 if (index > maxindex)
1090 return 0;
1091
1092 while (radix_tree_is_internal_node(node)) {
1093 unsigned offset;
1094
1095 parent = entry_to_node(node);
1096 offset = radix_tree_descend(parent, &node, index);
1097
1098 if (!tag_get(parent, tag, offset))
1099 return 0;
1100 if (node == RADIX_TREE_RETRY)
1101 break;
1102 }
1103
1104 return 1;
1105}
1106EXPORT_SYMBOL(radix_tree_tag_get);
1107
1108
1109static void set_iter_tags(struct radix_tree_iter *iter,
1110 struct radix_tree_node *node, unsigned offset,
1111 unsigned tag)
1112{
1113 unsigned tag_long = offset / BITS_PER_LONG;
1114 unsigned tag_bit = offset % BITS_PER_LONG;
1115
1116 if (!node) {
1117 iter->tags = 1;
1118 return;
1119 }
1120
1121 iter->tags = node->tags[tag][tag_long] >> tag_bit;
1122
1123
1124 if (tag_long < RADIX_TREE_TAG_LONGS - 1) {
1125
1126 if (tag_bit)
1127 iter->tags |= node->tags[tag][tag_long + 1] <<
1128 (BITS_PER_LONG - tag_bit);
1129
1130 iter->next_index = __radix_tree_iter_add(iter, BITS_PER_LONG);
1131 }
1132}
1133
1134void __rcu **radix_tree_iter_resume(void __rcu **slot,
1135 struct radix_tree_iter *iter)
1136{
1137 slot++;
1138 iter->index = __radix_tree_iter_add(iter, 1);
1139 iter->next_index = iter->index;
1140 iter->tags = 0;
1141 return NULL;
1142}
1143EXPORT_SYMBOL(radix_tree_iter_resume);
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153void __rcu **radix_tree_next_chunk(const struct radix_tree_root *root,
1154 struct radix_tree_iter *iter, unsigned flags)
1155{
1156 unsigned tag = flags & RADIX_TREE_ITER_TAG_MASK;
1157 struct radix_tree_node *node, *child;
1158 unsigned long index, offset, maxindex;
1159
1160 if ((flags & RADIX_TREE_ITER_TAGGED) && !root_tag_get(root, tag))
1161 return NULL;
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172 index = iter->next_index;
1173 if (!index && iter->index)
1174 return NULL;
1175
1176 restart:
1177 radix_tree_load_root(root, &child, &maxindex);
1178 if (index > maxindex)
1179 return NULL;
1180 if (!child)
1181 return NULL;
1182
1183 if (!radix_tree_is_internal_node(child)) {
1184
1185 iter->index = index;
1186 iter->next_index = maxindex + 1;
1187 iter->tags = 1;
1188 iter->node = NULL;
1189 return (void __rcu **)&root->xa_head;
1190 }
1191
1192 do {
1193 node = entry_to_node(child);
1194 offset = radix_tree_descend(node, &child, index);
1195
1196 if ((flags & RADIX_TREE_ITER_TAGGED) ?
1197 !tag_get(node, tag, offset) : !child) {
1198
1199 if (flags & RADIX_TREE_ITER_CONTIG)
1200 return NULL;
1201
1202 if (flags & RADIX_TREE_ITER_TAGGED)
1203 offset = radix_tree_find_next_bit(node, tag,
1204 offset + 1);
1205 else
1206 while (++offset < RADIX_TREE_MAP_SIZE) {
1207 void *slot = rcu_dereference_raw(
1208 node->slots[offset]);
1209 if (slot)
1210 break;
1211 }
1212 index &= ~node_maxindex(node);
1213 index += offset << node->shift;
1214
1215 if (!index)
1216 return NULL;
1217 if (offset == RADIX_TREE_MAP_SIZE)
1218 goto restart;
1219 child = rcu_dereference_raw(node->slots[offset]);
1220 }
1221
1222 if (!child)
1223 goto restart;
1224 if (child == RADIX_TREE_RETRY)
1225 break;
1226 } while (node->shift && radix_tree_is_internal_node(child));
1227
1228
1229 iter->index = (index &~ node_maxindex(node)) | offset;
1230 iter->next_index = (index | node_maxindex(node)) + 1;
1231 iter->node = node;
1232
1233 if (flags & RADIX_TREE_ITER_TAGGED)
1234 set_iter_tags(iter, node, offset, tag);
1235
1236 return node->slots + offset;
1237}
1238EXPORT_SYMBOL(radix_tree_next_chunk);
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260unsigned int
1261radix_tree_gang_lookup(const struct radix_tree_root *root, void **results,
1262 unsigned long first_index, unsigned int max_items)
1263{
1264 struct radix_tree_iter iter;
1265 void __rcu **slot;
1266 unsigned int ret = 0;
1267
1268 if (unlikely(!max_items))
1269 return 0;
1270
1271 radix_tree_for_each_slot(slot, root, &iter, first_index) {
1272 results[ret] = rcu_dereference_raw(*slot);
1273 if (!results[ret])
1274 continue;
1275 if (radix_tree_is_internal_node(results[ret])) {
1276 slot = radix_tree_iter_retry(&iter);
1277 continue;
1278 }
1279 if (++ret == max_items)
1280 break;
1281 }
1282
1283 return ret;
1284}
1285EXPORT_SYMBOL(radix_tree_gang_lookup);
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300unsigned int
1301radix_tree_gang_lookup_tag(const struct radix_tree_root *root, void **results,
1302 unsigned long first_index, unsigned int max_items,
1303 unsigned int tag)
1304{
1305 struct radix_tree_iter iter;
1306 void __rcu **slot;
1307 unsigned int ret = 0;
1308
1309 if (unlikely(!max_items))
1310 return 0;
1311
1312 radix_tree_for_each_tagged(slot, root, &iter, first_index, tag) {
1313 results[ret] = rcu_dereference_raw(*slot);
1314 if (!results[ret])
1315 continue;
1316 if (radix_tree_is_internal_node(results[ret])) {
1317 slot = radix_tree_iter_retry(&iter);
1318 continue;
1319 }
1320 if (++ret == max_items)
1321 break;
1322 }
1323
1324 return ret;
1325}
1326EXPORT_SYMBOL(radix_tree_gang_lookup_tag);
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341unsigned int
1342radix_tree_gang_lookup_tag_slot(const struct radix_tree_root *root,
1343 void __rcu ***results, unsigned long first_index,
1344 unsigned int max_items, unsigned int tag)
1345{
1346 struct radix_tree_iter iter;
1347 void __rcu **slot;
1348 unsigned int ret = 0;
1349
1350 if (unlikely(!max_items))
1351 return 0;
1352
1353 radix_tree_for_each_tagged(slot, root, &iter, first_index, tag) {
1354 results[ret] = slot;
1355 if (++ret == max_items)
1356 break;
1357 }
1358
1359 return ret;
1360}
1361EXPORT_SYMBOL(radix_tree_gang_lookup_tag_slot);
1362
1363static bool __radix_tree_delete(struct radix_tree_root *root,
1364 struct radix_tree_node *node, void __rcu **slot)
1365{
1366 void *old = rcu_dereference_raw(*slot);
1367 int values = xa_is_value(old) ? -1 : 0;
1368 unsigned offset = get_slot_offset(node, slot);
1369 int tag;
1370
1371 if (is_idr(root))
1372 node_tag_set(root, node, IDR_FREE, offset);
1373 else
1374 for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
1375 node_tag_clear(root, node, tag, offset);
1376
1377 replace_slot(slot, NULL, node, -1, values);
1378 return node && delete_node(root, node);
1379}
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393void radix_tree_iter_delete(struct radix_tree_root *root,
1394 struct radix_tree_iter *iter, void __rcu **slot)
1395{
1396 if (__radix_tree_delete(root, iter->node, slot))
1397 iter->index = iter->next_index;
1398}
1399EXPORT_SYMBOL(radix_tree_iter_delete);
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412void *radix_tree_delete_item(struct radix_tree_root *root,
1413 unsigned long index, void *item)
1414{
1415 struct radix_tree_node *node = NULL;
1416 void __rcu **slot = NULL;
1417 void *entry;
1418
1419 entry = __radix_tree_lookup(root, index, &node, &slot);
1420 if (!slot)
1421 return NULL;
1422 if (!entry && (!is_idr(root) || node_tag_get(root, node, IDR_FREE,
1423 get_slot_offset(node, slot))))
1424 return NULL;
1425
1426 if (item && entry != item)
1427 return NULL;
1428
1429 __radix_tree_delete(root, node, slot);
1430
1431 return entry;
1432}
1433EXPORT_SYMBOL(radix_tree_delete_item);
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444void *radix_tree_delete(struct radix_tree_root *root, unsigned long index)
1445{
1446 return radix_tree_delete_item(root, index, NULL);
1447}
1448EXPORT_SYMBOL(radix_tree_delete);
1449
1450
1451
1452
1453
1454
1455int radix_tree_tagged(const struct radix_tree_root *root, unsigned int tag)
1456{
1457 return root_tag_get(root, tag);
1458}
1459EXPORT_SYMBOL(radix_tree_tagged);
1460
1461
1462
1463
1464
1465
1466
1467
1468void idr_preload(gfp_t gfp_mask)
1469{
1470 if (__radix_tree_preload(gfp_mask, IDR_PRELOAD_SIZE))
1471 local_lock(&radix_tree_preloads.lock);
1472}
1473EXPORT_SYMBOL(idr_preload);
1474
1475void __rcu **idr_get_free(struct radix_tree_root *root,
1476 struct radix_tree_iter *iter, gfp_t gfp,
1477 unsigned long max)
1478{
1479 struct radix_tree_node *node = NULL, *child;
1480 void __rcu **slot = (void __rcu **)&root->xa_head;
1481 unsigned long maxindex, start = iter->next_index;
1482 unsigned int shift, offset = 0;
1483
1484 grow:
1485 shift = radix_tree_load_root(root, &child, &maxindex);
1486 if (!radix_tree_tagged(root, IDR_FREE))
1487 start = max(start, maxindex + 1);
1488 if (start > max)
1489 return ERR_PTR(-ENOSPC);
1490
1491 if (start > maxindex) {
1492 int error = radix_tree_extend(root, gfp, start, shift);
1493 if (error < 0)
1494 return ERR_PTR(error);
1495 shift = error;
1496 child = rcu_dereference_raw(root->xa_head);
1497 }
1498 if (start == 0 && shift == 0)
1499 shift = RADIX_TREE_MAP_SHIFT;
1500
1501 while (shift) {
1502 shift -= RADIX_TREE_MAP_SHIFT;
1503 if (child == NULL) {
1504
1505 child = radix_tree_node_alloc(gfp, node, root, shift,
1506 offset, 0, 0);
1507 if (!child)
1508 return ERR_PTR(-ENOMEM);
1509 all_tag_set(child, IDR_FREE);
1510 rcu_assign_pointer(*slot, node_to_entry(child));
1511 if (node)
1512 node->count++;
1513 } else if (!radix_tree_is_internal_node(child))
1514 break;
1515
1516 node = entry_to_node(child);
1517 offset = radix_tree_descend(node, &child, start);
1518 if (!tag_get(node, IDR_FREE, offset)) {
1519 offset = radix_tree_find_next_bit(node, IDR_FREE,
1520 offset + 1);
1521 start = next_index(start, node, offset);
1522 if (start > max || start == 0)
1523 return ERR_PTR(-ENOSPC);
1524 while (offset == RADIX_TREE_MAP_SIZE) {
1525 offset = node->offset + 1;
1526 node = node->parent;
1527 if (!node)
1528 goto grow;
1529 shift = node->shift;
1530 }
1531 child = rcu_dereference_raw(node->slots[offset]);
1532 }
1533 slot = &node->slots[offset];
1534 }
1535
1536 iter->index = start;
1537 if (node)
1538 iter->next_index = 1 + min(max, (start | node_maxindex(node)));
1539 else
1540 iter->next_index = 1;
1541 iter->node = node;
1542 set_iter_tags(iter, node, offset, IDR_FREE);
1543
1544 return slot;
1545}
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558void idr_destroy(struct idr *idr)
1559{
1560 struct radix_tree_node *node = rcu_dereference_raw(idr->idr_rt.xa_head);
1561 if (radix_tree_is_internal_node(node))
1562 radix_tree_free_nodes(node);
1563 idr->idr_rt.xa_head = NULL;
1564 root_tag_set(&idr->idr_rt, IDR_FREE);
1565}
1566EXPORT_SYMBOL(idr_destroy);
1567
1568static void
1569radix_tree_node_ctor(void *arg)
1570{
1571 struct radix_tree_node *node = arg;
1572
1573 memset(node, 0, sizeof(*node));
1574 INIT_LIST_HEAD(&node->private_list);
1575}
1576
1577static int radix_tree_cpu_dead(unsigned int cpu)
1578{
1579 struct radix_tree_preload *rtp;
1580 struct radix_tree_node *node;
1581
1582
1583 rtp = &per_cpu(radix_tree_preloads, cpu);
1584 while (rtp->nr) {
1585 node = rtp->nodes;
1586 rtp->nodes = node->parent;
1587 kmem_cache_free(radix_tree_node_cachep, node);
1588 rtp->nr--;
1589 }
1590 return 0;
1591}
1592
1593void __init radix_tree_init(void)
1594{
1595 int ret;
1596
1597 BUILD_BUG_ON(RADIX_TREE_MAX_TAGS + __GFP_BITS_SHIFT > 32);
1598 BUILD_BUG_ON(ROOT_IS_IDR & ~GFP_ZONEMASK);
1599 BUILD_BUG_ON(XA_CHUNK_SIZE > 255);
1600 radix_tree_node_cachep = kmem_cache_create("radix_tree_node",
1601 sizeof(struct radix_tree_node), 0,
1602 SLAB_PANIC | SLAB_RECLAIM_ACCOUNT,
1603 radix_tree_node_ctor);
1604 ret = cpuhp_setup_state_nocalls(CPUHP_RADIX_DEAD, "lib/radix:dead",
1605 NULL, radix_tree_cpu_dead);
1606 WARN_ON(ret < 0);
1607}
1608