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22#include <linux/errno.h>
23#include <linux/init.h>
24#include <linux/kernel.h>
25#include <linux/module.h>
26#include <linux/radix-tree.h>
27#include <linux/percpu.h>
28#include <linux/slab.h>
29#include <linux/notifier.h>
30#include <linux/cpu.h>
31#include <linux/gfp.h>
32#include <linux/string.h>
33#include <linux/bitops.h>
34#include <linux/rcupdate.h>
35
36
37#ifdef __KERNEL__
38#define RADIX_TREE_MAP_SHIFT (CONFIG_BASE_SMALL ? 4 : 6)
39#else
40#define RADIX_TREE_MAP_SHIFT 3
41#endif
42
43#define RADIX_TREE_MAP_SIZE (1UL << RADIX_TREE_MAP_SHIFT)
44#define RADIX_TREE_MAP_MASK (RADIX_TREE_MAP_SIZE-1)
45
46#define RADIX_TREE_TAG_LONGS \
47 ((RADIX_TREE_MAP_SIZE + BITS_PER_LONG - 1) / BITS_PER_LONG)
48
49struct radix_tree_node {
50 unsigned int height;
51 unsigned int count;
52 struct rcu_head rcu_head;
53 void *slots[RADIX_TREE_MAP_SIZE];
54 unsigned long tags[RADIX_TREE_MAX_TAGS][RADIX_TREE_TAG_LONGS];
55};
56
57struct radix_tree_path {
58 struct radix_tree_node *node;
59 int offset;
60};
61
62#define RADIX_TREE_INDEX_BITS (8 * sizeof(unsigned long))
63#define RADIX_TREE_MAX_PATH (DIV_ROUND_UP(RADIX_TREE_INDEX_BITS, \
64 RADIX_TREE_MAP_SHIFT))
65
66
67
68
69
70static unsigned long height_to_maxindex[RADIX_TREE_MAX_PATH + 1] __read_mostly;
71
72
73
74
75static struct kmem_cache *radix_tree_node_cachep;
76
77
78
79
80struct radix_tree_preload {
81 int nr;
82 struct radix_tree_node *nodes[RADIX_TREE_MAX_PATH];
83};
84static DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, };
85
86static inline gfp_t root_gfp_mask(struct radix_tree_root *root)
87{
88 return root->gfp_mask & __GFP_BITS_MASK;
89}
90
91static inline void tag_set(struct radix_tree_node *node, unsigned int tag,
92 int offset)
93{
94 __set_bit(offset, node->tags[tag]);
95}
96
97static inline void tag_clear(struct radix_tree_node *node, unsigned int tag,
98 int offset)
99{
100 __clear_bit(offset, node->tags[tag]);
101}
102
103static inline int tag_get(struct radix_tree_node *node, unsigned int tag,
104 int offset)
105{
106 return test_bit(offset, node->tags[tag]);
107}
108
109static inline void root_tag_set(struct radix_tree_root *root, unsigned int tag)
110{
111 root->gfp_mask |= (__force gfp_t)(1 << (tag + __GFP_BITS_SHIFT));
112}
113
114static inline void root_tag_clear(struct radix_tree_root *root, unsigned int tag)
115{
116 root->gfp_mask &= (__force gfp_t)~(1 << (tag + __GFP_BITS_SHIFT));
117}
118
119static inline void root_tag_clear_all(struct radix_tree_root *root)
120{
121 root->gfp_mask &= __GFP_BITS_MASK;
122}
123
124static inline int root_tag_get(struct radix_tree_root *root, unsigned int tag)
125{
126 return (__force unsigned)root->gfp_mask & (1 << (tag + __GFP_BITS_SHIFT));
127}
128
129
130
131
132
133static inline int any_tag_set(struct radix_tree_node *node, unsigned int tag)
134{
135 int idx;
136 for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) {
137 if (node->tags[tag][idx])
138 return 1;
139 }
140 return 0;
141}
142
143
144
145
146static struct radix_tree_node *
147radix_tree_node_alloc(struct radix_tree_root *root)
148{
149 struct radix_tree_node *ret = NULL;
150 gfp_t gfp_mask = root_gfp_mask(root);
151
152 if (!(gfp_mask & __GFP_WAIT)) {
153 struct radix_tree_preload *rtp;
154
155
156
157
158
159
160 rtp = &__get_cpu_var(radix_tree_preloads);
161 if (rtp->nr) {
162 ret = rtp->nodes[rtp->nr - 1];
163 rtp->nodes[rtp->nr - 1] = NULL;
164 rtp->nr--;
165 }
166 }
167 if (ret == NULL)
168 ret = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask);
169
170 BUG_ON(radix_tree_is_indirect_ptr(ret));
171 return ret;
172}
173
174static void radix_tree_node_rcu_free(struct rcu_head *head)
175{
176 struct radix_tree_node *node =
177 container_of(head, struct radix_tree_node, rcu_head);
178
179
180
181
182
183
184 tag_clear(node, 0, 0);
185 tag_clear(node, 1, 0);
186 node->slots[0] = NULL;
187 node->count = 0;
188
189 kmem_cache_free(radix_tree_node_cachep, node);
190}
191
192static inline void
193radix_tree_node_free(struct radix_tree_node *node)
194{
195 call_rcu(&node->rcu_head, radix_tree_node_rcu_free);
196}
197
198
199
200
201
202
203
204
205
206
207int radix_tree_preload(gfp_t gfp_mask)
208{
209 struct radix_tree_preload *rtp;
210 struct radix_tree_node *node;
211 int ret = -ENOMEM;
212
213 preempt_disable();
214 rtp = &__get_cpu_var(radix_tree_preloads);
215 while (rtp->nr < ARRAY_SIZE(rtp->nodes)) {
216 preempt_enable();
217 node = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask);
218 if (node == NULL)
219 goto out;
220 preempt_disable();
221 rtp = &__get_cpu_var(radix_tree_preloads);
222 if (rtp->nr < ARRAY_SIZE(rtp->nodes))
223 rtp->nodes[rtp->nr++] = node;
224 else
225 kmem_cache_free(radix_tree_node_cachep, node);
226 }
227 ret = 0;
228out:
229 return ret;
230}
231EXPORT_SYMBOL(radix_tree_preload);
232
233
234
235
236
237static inline unsigned long radix_tree_maxindex(unsigned int height)
238{
239 return height_to_maxindex[height];
240}
241
242
243
244
245static int radix_tree_extend(struct radix_tree_root *root, unsigned long index)
246{
247 struct radix_tree_node *node;
248 unsigned int height;
249 int tag;
250
251
252 height = root->height + 1;
253 while (index > radix_tree_maxindex(height))
254 height++;
255
256 if (root->rnode == NULL) {
257 root->height = height;
258 goto out;
259 }
260
261 do {
262 unsigned int newheight;
263 if (!(node = radix_tree_node_alloc(root)))
264 return -ENOMEM;
265
266
267 node->slots[0] = radix_tree_indirect_to_ptr(root->rnode);
268
269
270 for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) {
271 if (root_tag_get(root, tag))
272 tag_set(node, tag, 0);
273 }
274
275 newheight = root->height+1;
276 node->height = newheight;
277 node->count = 1;
278 node = radix_tree_ptr_to_indirect(node);
279 rcu_assign_pointer(root->rnode, node);
280 root->height = newheight;
281 } while (height > root->height);
282out:
283 return 0;
284}
285
286
287
288
289
290
291
292
293
294int radix_tree_insert(struct radix_tree_root *root,
295 unsigned long index, void *item)
296{
297 struct radix_tree_node *node = NULL, *slot;
298 unsigned int height, shift;
299 int offset;
300 int error;
301
302 BUG_ON(radix_tree_is_indirect_ptr(item));
303
304
305 if (index > radix_tree_maxindex(root->height)) {
306 error = radix_tree_extend(root, index);
307 if (error)
308 return error;
309 }
310
311 slot = radix_tree_indirect_to_ptr(root->rnode);
312
313 height = root->height;
314 shift = (height-1) * RADIX_TREE_MAP_SHIFT;
315
316 offset = 0;
317 while (height > 0) {
318 if (slot == NULL) {
319
320 if (!(slot = radix_tree_node_alloc(root)))
321 return -ENOMEM;
322 slot->height = height;
323 if (node) {
324 rcu_assign_pointer(node->slots[offset], slot);
325 node->count++;
326 } else
327 rcu_assign_pointer(root->rnode,
328 radix_tree_ptr_to_indirect(slot));
329 }
330
331
332 offset = (index >> shift) & RADIX_TREE_MAP_MASK;
333 node = slot;
334 slot = node->slots[offset];
335 shift -= RADIX_TREE_MAP_SHIFT;
336 height--;
337 }
338
339 if (slot != NULL)
340 return -EEXIST;
341
342 if (node) {
343 node->count++;
344 rcu_assign_pointer(node->slots[offset], item);
345 BUG_ON(tag_get(node, 0, offset));
346 BUG_ON(tag_get(node, 1, offset));
347 } else {
348 rcu_assign_pointer(root->rnode, item);
349 BUG_ON(root_tag_get(root, 0));
350 BUG_ON(root_tag_get(root, 1));
351 }
352
353 return 0;
354}
355EXPORT_SYMBOL(radix_tree_insert);
356
357
358
359
360
361static void *radix_tree_lookup_element(struct radix_tree_root *root,
362 unsigned long index, int is_slot)
363{
364 unsigned int height, shift;
365 struct radix_tree_node *node, **slot;
366
367 node = rcu_dereference(root->rnode);
368 if (node == NULL)
369 return NULL;
370
371 if (!radix_tree_is_indirect_ptr(node)) {
372 if (index > 0)
373 return NULL;
374 return is_slot ? (void *)&root->rnode : node;
375 }
376 node = radix_tree_indirect_to_ptr(node);
377
378 height = node->height;
379 if (index > radix_tree_maxindex(height))
380 return NULL;
381
382 shift = (height-1) * RADIX_TREE_MAP_SHIFT;
383
384 do {
385 slot = (struct radix_tree_node **)
386 (node->slots + ((index>>shift) & RADIX_TREE_MAP_MASK));
387 node = rcu_dereference(*slot);
388 if (node == NULL)
389 return NULL;
390
391 shift -= RADIX_TREE_MAP_SHIFT;
392 height--;
393 } while (height > 0);
394
395 return is_slot ? (void *)slot:node;
396}
397
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409
410
411void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index)
412{
413 return (void **)radix_tree_lookup_element(root, index, 1);
414}
415EXPORT_SYMBOL(radix_tree_lookup_slot);
416
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428
429void *radix_tree_lookup(struct radix_tree_root *root, unsigned long index)
430{
431 return radix_tree_lookup_element(root, index, 0);
432}
433EXPORT_SYMBOL(radix_tree_lookup);
434
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446
447
448void *radix_tree_tag_set(struct radix_tree_root *root,
449 unsigned long index, unsigned int tag)
450{
451 unsigned int height, shift;
452 struct radix_tree_node *slot;
453
454 height = root->height;
455 BUG_ON(index > radix_tree_maxindex(height));
456
457 slot = radix_tree_indirect_to_ptr(root->rnode);
458 shift = (height - 1) * RADIX_TREE_MAP_SHIFT;
459
460 while (height > 0) {
461 int offset;
462
463 offset = (index >> shift) & RADIX_TREE_MAP_MASK;
464 if (!tag_get(slot, tag, offset))
465 tag_set(slot, tag, offset);
466 slot = slot->slots[offset];
467 BUG_ON(slot == NULL);
468 shift -= RADIX_TREE_MAP_SHIFT;
469 height--;
470 }
471
472
473 if (slot && !root_tag_get(root, tag))
474 root_tag_set(root, tag);
475
476 return slot;
477}
478EXPORT_SYMBOL(radix_tree_tag_set);
479
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492
493
494void *radix_tree_tag_clear(struct radix_tree_root *root,
495 unsigned long index, unsigned int tag)
496{
497
498
499
500
501 struct radix_tree_path path[RADIX_TREE_MAX_PATH + 1], *pathp = path;
502 struct radix_tree_node *slot = NULL;
503 unsigned int height, shift;
504
505 height = root->height;
506 if (index > radix_tree_maxindex(height))
507 goto out;
508
509 shift = (height - 1) * RADIX_TREE_MAP_SHIFT;
510 pathp->node = NULL;
511 slot = radix_tree_indirect_to_ptr(root->rnode);
512
513 while (height > 0) {
514 int offset;
515
516 if (slot == NULL)
517 goto out;
518
519 offset = (index >> shift) & RADIX_TREE_MAP_MASK;
520 pathp[1].offset = offset;
521 pathp[1].node = slot;
522 slot = slot->slots[offset];
523 pathp++;
524 shift -= RADIX_TREE_MAP_SHIFT;
525 height--;
526 }
527
528 if (slot == NULL)
529 goto out;
530
531 while (pathp->node) {
532 if (!tag_get(pathp->node, tag, pathp->offset))
533 goto out;
534 tag_clear(pathp->node, tag, pathp->offset);
535 if (any_tag_set(pathp->node, tag))
536 goto out;
537 pathp--;
538 }
539
540
541 if (root_tag_get(root, tag))
542 root_tag_clear(root, tag);
543
544out:
545 return slot;
546}
547EXPORT_SYMBOL(radix_tree_tag_clear);
548
549
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555
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557
558
559
560int radix_tree_tag_get(struct radix_tree_root *root,
561 unsigned long index, unsigned int tag)
562{
563 unsigned int height, shift;
564 struct radix_tree_node *node;
565 int saw_unset_tag = 0;
566
567
568 if (!root_tag_get(root, tag))
569 return 0;
570
571 node = rcu_dereference(root->rnode);
572 if (node == NULL)
573 return 0;
574
575 if (!radix_tree_is_indirect_ptr(node))
576 return (index == 0);
577 node = radix_tree_indirect_to_ptr(node);
578
579 height = node->height;
580 if (index > radix_tree_maxindex(height))
581 return 0;
582
583 shift = (height - 1) * RADIX_TREE_MAP_SHIFT;
584
585 for ( ; ; ) {
586 int offset;
587
588 if (node == NULL)
589 return 0;
590
591 offset = (index >> shift) & RADIX_TREE_MAP_MASK;
592
593
594
595
596
597 if (!tag_get(node, tag, offset))
598 saw_unset_tag = 1;
599 if (height == 1) {
600 int ret = tag_get(node, tag, offset);
601
602 BUG_ON(ret && saw_unset_tag);
603 return !!ret;
604 }
605 node = rcu_dereference(node->slots[offset]);
606 shift -= RADIX_TREE_MAP_SHIFT;
607 height--;
608 }
609}
610EXPORT_SYMBOL(radix_tree_tag_get);
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619
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631
632unsigned long radix_tree_next_hole(struct radix_tree_root *root,
633 unsigned long index, unsigned long max_scan)
634{
635 unsigned long i;
636
637 for (i = 0; i < max_scan; i++) {
638 if (!radix_tree_lookup(root, index))
639 break;
640 index++;
641 if (index == 0)
642 break;
643 }
644
645 return index;
646}
647EXPORT_SYMBOL(radix_tree_next_hole);
648
649
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652
653
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655
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657
658
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660
661
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664
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666
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668
669unsigned long radix_tree_prev_hole(struct radix_tree_root *root,
670 unsigned long index, unsigned long max_scan)
671{
672 unsigned long i;
673
674 for (i = 0; i < max_scan; i++) {
675 if (!radix_tree_lookup(root, index))
676 break;
677 index--;
678 if (index == LONG_MAX)
679 break;
680 }
681
682 return index;
683}
684EXPORT_SYMBOL(radix_tree_prev_hole);
685
686static unsigned int
687__lookup(struct radix_tree_node *slot, void ***results, unsigned long index,
688 unsigned int max_items, unsigned long *next_index)
689{
690 unsigned int nr_found = 0;
691 unsigned int shift, height;
692 unsigned long i;
693
694 height = slot->height;
695 if (height == 0)
696 goto out;
697 shift = (height-1) * RADIX_TREE_MAP_SHIFT;
698
699 for ( ; height > 1; height--) {
700 i = (index >> shift) & RADIX_TREE_MAP_MASK;
701 for (;;) {
702 if (slot->slots[i] != NULL)
703 break;
704 index &= ~((1UL << shift) - 1);
705 index += 1UL << shift;
706 if (index == 0)
707 goto out;
708 i++;
709 if (i == RADIX_TREE_MAP_SIZE)
710 goto out;
711 }
712
713 shift -= RADIX_TREE_MAP_SHIFT;
714 slot = rcu_dereference(slot->slots[i]);
715 if (slot == NULL)
716 goto out;
717 }
718
719
720 for (i = index & RADIX_TREE_MAP_MASK; i < RADIX_TREE_MAP_SIZE; i++) {
721 index++;
722 if (slot->slots[i]) {
723 results[nr_found++] = &(slot->slots[i]);
724 if (nr_found == max_items)
725 goto out;
726 }
727 }
728out:
729 *next_index = index;
730 return nr_found;
731}
732
733
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750
751
752unsigned int
753radix_tree_gang_lookup(struct radix_tree_root *root, void **results,
754 unsigned long first_index, unsigned int max_items)
755{
756 unsigned long max_index;
757 struct radix_tree_node *node;
758 unsigned long cur_index = first_index;
759 unsigned int ret;
760
761 node = rcu_dereference(root->rnode);
762 if (!node)
763 return 0;
764
765 if (!radix_tree_is_indirect_ptr(node)) {
766 if (first_index > 0)
767 return 0;
768 results[0] = node;
769 return 1;
770 }
771 node = radix_tree_indirect_to_ptr(node);
772
773 max_index = radix_tree_maxindex(node->height);
774
775 ret = 0;
776 while (ret < max_items) {
777 unsigned int nr_found, slots_found, i;
778 unsigned long next_index;
779
780 if (cur_index > max_index)
781 break;
782 slots_found = __lookup(node, (void ***)results + ret, cur_index,
783 max_items - ret, &next_index);
784 nr_found = 0;
785 for (i = 0; i < slots_found; i++) {
786 struct radix_tree_node *slot;
787 slot = *(((void ***)results)[ret + i]);
788 if (!slot)
789 continue;
790 results[ret + nr_found] = rcu_dereference(slot);
791 nr_found++;
792 }
793 ret += nr_found;
794 if (next_index == 0)
795 break;
796 cur_index = next_index;
797 }
798
799 return ret;
800}
801EXPORT_SYMBOL(radix_tree_gang_lookup);
802
803
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819
820unsigned int
821radix_tree_gang_lookup_slot(struct radix_tree_root *root, void ***results,
822 unsigned long first_index, unsigned int max_items)
823{
824 unsigned long max_index;
825 struct radix_tree_node *node;
826 unsigned long cur_index = first_index;
827 unsigned int ret;
828
829 node = rcu_dereference(root->rnode);
830 if (!node)
831 return 0;
832
833 if (!radix_tree_is_indirect_ptr(node)) {
834 if (first_index > 0)
835 return 0;
836 results[0] = (void **)&root->rnode;
837 return 1;
838 }
839 node = radix_tree_indirect_to_ptr(node);
840
841 max_index = radix_tree_maxindex(node->height);
842
843 ret = 0;
844 while (ret < max_items) {
845 unsigned int slots_found;
846 unsigned long next_index;
847
848 if (cur_index > max_index)
849 break;
850 slots_found = __lookup(node, results + ret, cur_index,
851 max_items - ret, &next_index);
852 ret += slots_found;
853 if (next_index == 0)
854 break;
855 cur_index = next_index;
856 }
857
858 return ret;
859}
860EXPORT_SYMBOL(radix_tree_gang_lookup_slot);
861
862
863
864
865
866static unsigned int
867__lookup_tag(struct radix_tree_node *slot, void ***results, unsigned long index,
868 unsigned int max_items, unsigned long *next_index, unsigned int tag)
869{
870 unsigned int nr_found = 0;
871 unsigned int shift, height;
872
873 height = slot->height;
874 if (height == 0)
875 goto out;
876 shift = (height-1) * RADIX_TREE_MAP_SHIFT;
877
878 while (height > 0) {
879 unsigned long i = (index >> shift) & RADIX_TREE_MAP_MASK ;
880
881 for (;;) {
882 if (tag_get(slot, tag, i))
883 break;
884 index &= ~((1UL << shift) - 1);
885 index += 1UL << shift;
886 if (index == 0)
887 goto out;
888 i++;
889 if (i == RADIX_TREE_MAP_SIZE)
890 goto out;
891 }
892 height--;
893 if (height == 0) {
894 unsigned long j = index & RADIX_TREE_MAP_MASK;
895
896 for ( ; j < RADIX_TREE_MAP_SIZE; j++) {
897 index++;
898 if (!tag_get(slot, tag, j))
899 continue;
900
901
902
903
904
905
906
907
908
909
910 if (slot->slots[j]) {
911 results[nr_found++] = &(slot->slots[j]);
912 if (nr_found == max_items)
913 goto out;
914 }
915 }
916 }
917 shift -= RADIX_TREE_MAP_SHIFT;
918 slot = rcu_dereference(slot->slots[i]);
919 if (slot == NULL)
920 break;
921 }
922out:
923 *next_index = index;
924 return nr_found;
925}
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940unsigned int
941radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results,
942 unsigned long first_index, unsigned int max_items,
943 unsigned int tag)
944{
945 struct radix_tree_node *node;
946 unsigned long max_index;
947 unsigned long cur_index = first_index;
948 unsigned int ret;
949
950
951 if (!root_tag_get(root, tag))
952 return 0;
953
954 node = rcu_dereference(root->rnode);
955 if (!node)
956 return 0;
957
958 if (!radix_tree_is_indirect_ptr(node)) {
959 if (first_index > 0)
960 return 0;
961 results[0] = node;
962 return 1;
963 }
964 node = radix_tree_indirect_to_ptr(node);
965
966 max_index = radix_tree_maxindex(node->height);
967
968 ret = 0;
969 while (ret < max_items) {
970 unsigned int nr_found, slots_found, i;
971 unsigned long next_index;
972
973 if (cur_index > max_index)
974 break;
975 slots_found = __lookup_tag(node, (void ***)results + ret,
976 cur_index, max_items - ret, &next_index, tag);
977 nr_found = 0;
978 for (i = 0; i < slots_found; i++) {
979 struct radix_tree_node *slot;
980 slot = *(((void ***)results)[ret + i]);
981 if (!slot)
982 continue;
983 results[ret + nr_found] = rcu_dereference(slot);
984 nr_found++;
985 }
986 ret += nr_found;
987 if (next_index == 0)
988 break;
989 cur_index = next_index;
990 }
991
992 return ret;
993}
994EXPORT_SYMBOL(radix_tree_gang_lookup_tag);
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009unsigned int
1010radix_tree_gang_lookup_tag_slot(struct radix_tree_root *root, void ***results,
1011 unsigned long first_index, unsigned int max_items,
1012 unsigned int tag)
1013{
1014 struct radix_tree_node *node;
1015 unsigned long max_index;
1016 unsigned long cur_index = first_index;
1017 unsigned int ret;
1018
1019
1020 if (!root_tag_get(root, tag))
1021 return 0;
1022
1023 node = rcu_dereference(root->rnode);
1024 if (!node)
1025 return 0;
1026
1027 if (!radix_tree_is_indirect_ptr(node)) {
1028 if (first_index > 0)
1029 return 0;
1030 results[0] = (void **)&root->rnode;
1031 return 1;
1032 }
1033 node = radix_tree_indirect_to_ptr(node);
1034
1035 max_index = radix_tree_maxindex(node->height);
1036
1037 ret = 0;
1038 while (ret < max_items) {
1039 unsigned int slots_found;
1040 unsigned long next_index;
1041
1042 if (cur_index > max_index)
1043 break;
1044 slots_found = __lookup_tag(node, results + ret,
1045 cur_index, max_items - ret, &next_index, tag);
1046 ret += slots_found;
1047 if (next_index == 0)
1048 break;
1049 cur_index = next_index;
1050 }
1051
1052 return ret;
1053}
1054EXPORT_SYMBOL(radix_tree_gang_lookup_tag_slot);
1055
1056
1057
1058
1059
1060
1061static inline void radix_tree_shrink(struct radix_tree_root *root)
1062{
1063
1064 while (root->height > 0) {
1065 struct radix_tree_node *to_free = root->rnode;
1066 void *newptr;
1067
1068 BUG_ON(!radix_tree_is_indirect_ptr(to_free));
1069 to_free = radix_tree_indirect_to_ptr(to_free);
1070
1071
1072
1073
1074
1075 if (to_free->count != 1)
1076 break;
1077 if (!to_free->slots[0])
1078 break;
1079
1080
1081
1082
1083
1084
1085
1086
1087 newptr = to_free->slots[0];
1088 if (root->height > 1)
1089 newptr = radix_tree_ptr_to_indirect(newptr);
1090 root->rnode = newptr;
1091 root->height--;
1092 radix_tree_node_free(to_free);
1093 }
1094}
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105void *radix_tree_delete(struct radix_tree_root *root, unsigned long index)
1106{
1107
1108
1109
1110
1111 struct radix_tree_path path[RADIX_TREE_MAX_PATH + 1], *pathp = path;
1112 struct radix_tree_node *slot = NULL;
1113 struct radix_tree_node *to_free;
1114 unsigned int height, shift;
1115 int tag;
1116 int offset;
1117
1118 height = root->height;
1119 if (index > radix_tree_maxindex(height))
1120 goto out;
1121
1122 slot = root->rnode;
1123 if (height == 0) {
1124 root_tag_clear_all(root);
1125 root->rnode = NULL;
1126 goto out;
1127 }
1128 slot = radix_tree_indirect_to_ptr(slot);
1129
1130 shift = (height - 1) * RADIX_TREE_MAP_SHIFT;
1131 pathp->node = NULL;
1132
1133 do {
1134 if (slot == NULL)
1135 goto out;
1136
1137 pathp++;
1138 offset = (index >> shift) & RADIX_TREE_MAP_MASK;
1139 pathp->offset = offset;
1140 pathp->node = slot;
1141 slot = slot->slots[offset];
1142 shift -= RADIX_TREE_MAP_SHIFT;
1143 height--;
1144 } while (height > 0);
1145
1146 if (slot == NULL)
1147 goto out;
1148
1149
1150
1151
1152 for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) {
1153 if (tag_get(pathp->node, tag, pathp->offset))
1154 radix_tree_tag_clear(root, index, tag);
1155 }
1156
1157 to_free = NULL;
1158
1159 while (pathp->node) {
1160 pathp->node->slots[pathp->offset] = NULL;
1161 pathp->node->count--;
1162
1163
1164
1165
1166 if (to_free)
1167 radix_tree_node_free(to_free);
1168
1169 if (pathp->node->count) {
1170 if (pathp->node ==
1171 radix_tree_indirect_to_ptr(root->rnode))
1172 radix_tree_shrink(root);
1173 goto out;
1174 }
1175
1176
1177 to_free = pathp->node;
1178 pathp--;
1179
1180 }
1181 root_tag_clear_all(root);
1182 root->height = 0;
1183 root->rnode = NULL;
1184 if (to_free)
1185 radix_tree_node_free(to_free);
1186
1187out:
1188 return slot;
1189}
1190EXPORT_SYMBOL(radix_tree_delete);
1191
1192
1193
1194
1195
1196
1197int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag)
1198{
1199 return root_tag_get(root, tag);
1200}
1201EXPORT_SYMBOL(radix_tree_tagged);
1202
1203static void
1204radix_tree_node_ctor(void *node)
1205{
1206 memset(node, 0, sizeof(struct radix_tree_node));
1207}
1208
1209static __init unsigned long __maxindex(unsigned int height)
1210{
1211 unsigned int width = height * RADIX_TREE_MAP_SHIFT;
1212 int shift = RADIX_TREE_INDEX_BITS - width;
1213
1214 if (shift < 0)
1215 return ~0UL;
1216 if (shift >= BITS_PER_LONG)
1217 return 0UL;
1218 return ~0UL >> shift;
1219}
1220
1221static __init void radix_tree_init_maxindex(void)
1222{
1223 unsigned int i;
1224
1225 for (i = 0; i < ARRAY_SIZE(height_to_maxindex); i++)
1226 height_to_maxindex[i] = __maxindex(i);
1227}
1228
1229static int radix_tree_callback(struct notifier_block *nfb,
1230 unsigned long action,
1231 void *hcpu)
1232{
1233 int cpu = (long)hcpu;
1234 struct radix_tree_preload *rtp;
1235
1236
1237 if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {
1238 rtp = &per_cpu(radix_tree_preloads, cpu);
1239 while (rtp->nr) {
1240 kmem_cache_free(radix_tree_node_cachep,
1241 rtp->nodes[rtp->nr-1]);
1242 rtp->nodes[rtp->nr-1] = NULL;
1243 rtp->nr--;
1244 }
1245 }
1246 return NOTIFY_OK;
1247}
1248
1249void __init radix_tree_init(void)
1250{
1251 radix_tree_node_cachep = kmem_cache_create("radix_tree_node",
1252 sizeof(struct radix_tree_node), 0,
1253 SLAB_PANIC | SLAB_RECLAIM_ACCOUNT,
1254 radix_tree_node_ctor);
1255 radix_tree_init_maxindex();
1256 hotcpu_notifier(radix_tree_callback, 0);
1257}
1258