2 * Copyright (C) 2001 Momchil Velikov
3 * Portions Copyright (C) 2001 Christoph Hellwig
4 * Copyright (C) 2005 SGI, Christoph Lameter
5 * Copyright (C) 2006 Nick Piggin
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License as
9 * published by the Free Software Foundation; either version 2, or (at
10 * your option) any later version.
12 * This program is distributed in the hope that it will be useful, but
13 * WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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>
38 #define RADIX_TREE_MAP_SHIFT (CONFIG_BASE_SMALL ? 4 : 6)
40 #define RADIX_TREE_MAP_SHIFT 3 /* For more stressful testing */
43 #define RADIX_TREE_MAP_SIZE (1UL << RADIX_TREE_MAP_SHIFT)
44 #define RADIX_TREE_MAP_MASK (RADIX_TREE_MAP_SIZE-1)
46 #define RADIX_TREE_TAG_LONGS \
47 ((RADIX_TREE_MAP_SIZE + BITS_PER_LONG - 1) / BITS_PER_LONG)
49 struct radix_tree_node {
50 unsigned int height; /* Height from the bottom */
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];
57 struct radix_tree_path {
58 struct radix_tree_node *node;
62 #define RADIX_TREE_INDEX_BITS (8 /* CHAR_BIT */ * sizeof(unsigned long))
63 #define RADIX_TREE_MAX_PATH (DIV_ROUND_UP(RADIX_TREE_INDEX_BITS, \
64 RADIX_TREE_MAP_SHIFT))
67 * The height_to_maxindex array needs to be one deeper than the maximum
68 * path as height 0 holds only 1 entry.
70 static unsigned long height_to_maxindex[RADIX_TREE_MAX_PATH + 1] __read_mostly;
73 * Radix tree node cache.
75 static struct kmem_cache *radix_tree_node_cachep;
78 * Per-cpu pool of preloaded nodes
80 struct radix_tree_preload {
82 struct radix_tree_node *nodes[RADIX_TREE_MAX_PATH];
84 DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, };
86 static inline gfp_t root_gfp_mask(struct radix_tree_root *root)
88 return root->gfp_mask & __GFP_BITS_MASK;
91 static inline void tag_set(struct radix_tree_node *node, unsigned int tag,
94 __set_bit(offset, node->tags[tag]);
97 static inline void tag_clear(struct radix_tree_node *node, unsigned int tag,
100 __clear_bit(offset, node->tags[tag]);
103 static inline int tag_get(struct radix_tree_node *node, unsigned int tag,
106 return test_bit(offset, node->tags[tag]);
109 static inline void root_tag_set(struct radix_tree_root *root, unsigned int tag)
111 root->gfp_mask |= (__force gfp_t)(1 << (tag + __GFP_BITS_SHIFT));
114 static inline void root_tag_clear(struct radix_tree_root *root, unsigned int tag)
116 root->gfp_mask &= (__force gfp_t)~(1 << (tag + __GFP_BITS_SHIFT));
119 static inline void root_tag_clear_all(struct radix_tree_root *root)
121 root->gfp_mask &= __GFP_BITS_MASK;
124 static inline int root_tag_get(struct radix_tree_root *root, unsigned int tag)
126 return (__force unsigned)root->gfp_mask & (1 << (tag + __GFP_BITS_SHIFT));
130 * Returns 1 if any slot in the node has this tag set.
131 * Otherwise returns 0.
133 static inline int any_tag_set(struct radix_tree_node *node, unsigned int tag)
136 for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) {
137 if (node->tags[tag][idx])
143 * This assumes that the caller has performed appropriate preallocation, and
144 * that the caller has pinned this thread of control to the current CPU.
146 static struct radix_tree_node *
147 radix_tree_node_alloc(struct radix_tree_root *root)
149 struct radix_tree_node *ret = NULL;
150 gfp_t gfp_mask = root_gfp_mask(root);
152 if (!(gfp_mask & __GFP_WAIT)) {
153 struct radix_tree_preload *rtp;
156 * Provided the caller has preloaded here, we will always
157 * succeed in getting a node here (and never reach
160 rtp = &__get_cpu_var(radix_tree_preloads);
162 ret = rtp->nodes[rtp->nr - 1];
163 rtp->nodes[rtp->nr - 1] = NULL;
168 ret = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask);
170 BUG_ON(radix_tree_is_indirect_ptr(ret));
174 static void radix_tree_node_rcu_free(struct rcu_head *head)
176 struct radix_tree_node *node =
177 container_of(head, struct radix_tree_node, rcu_head);
180 * must only free zeroed nodes into the slab. radix_tree_shrink
181 * can leave us with a non-NULL entry in the first slot, so clear
182 * that here to make sure.
184 tag_clear(node, 0, 0);
185 tag_clear(node, 1, 0);
186 node->slots[0] = NULL;
189 kmem_cache_free(radix_tree_node_cachep, node);
193 radix_tree_node_free(struct radix_tree_node *node)
195 call_rcu(&node->rcu_head, radix_tree_node_rcu_free);
199 * Load up this CPU's radix_tree_node buffer with sufficient objects to
200 * ensure that the addition of a single element in the tree cannot fail. On
201 * success, return zero, with preemption disabled. On error, return -ENOMEM
202 * with preemption not disabled.
204 int radix_tree_preload(gfp_t gfp_mask)
206 struct radix_tree_preload *rtp;
207 struct radix_tree_node *node;
211 rtp = &__get_cpu_var(radix_tree_preloads);
212 while (rtp->nr < ARRAY_SIZE(rtp->nodes)) {
214 node = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask);
218 rtp = &__get_cpu_var(radix_tree_preloads);
219 if (rtp->nr < ARRAY_SIZE(rtp->nodes))
220 rtp->nodes[rtp->nr++] = node;
222 kmem_cache_free(radix_tree_node_cachep, node);
228 EXPORT_SYMBOL(radix_tree_preload);
231 * Return the maximum key which can be store into a
232 * radix tree with height HEIGHT.
234 static inline unsigned long radix_tree_maxindex(unsigned int height)
236 return height_to_maxindex[height];
240 * Extend a radix tree so it can store key @index.
242 static int radix_tree_extend(struct radix_tree_root *root, unsigned long index)
244 struct radix_tree_node *node;
248 /* Figure out what the height should be. */
249 height = root->height + 1;
250 while (index > radix_tree_maxindex(height))
253 if (root->rnode == NULL) {
254 root->height = height;
259 unsigned int newheight;
260 if (!(node = radix_tree_node_alloc(root)))
263 /* Increase the height. */
264 node->slots[0] = radix_tree_indirect_to_ptr(root->rnode);
266 /* Propagate the aggregated tag info into the new root */
267 for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) {
268 if (root_tag_get(root, tag))
269 tag_set(node, tag, 0);
272 newheight = root->height+1;
273 node->height = newheight;
275 node = radix_tree_ptr_to_indirect(node);
276 rcu_assign_pointer(root->rnode, node);
277 root->height = newheight;
278 } while (height > root->height);
284 * radix_tree_insert - insert into a radix tree
285 * @root: radix tree root
287 * @item: item to insert
289 * Insert an item into the radix tree at position @index.
291 int radix_tree_insert(struct radix_tree_root *root,
292 unsigned long index, void *item)
294 struct radix_tree_node *node = NULL, *slot;
295 unsigned int height, shift;
299 BUG_ON(radix_tree_is_indirect_ptr(item));
301 /* Make sure the tree is high enough. */
302 if (index > radix_tree_maxindex(root->height)) {
303 error = radix_tree_extend(root, index);
308 slot = radix_tree_indirect_to_ptr(root->rnode);
310 height = root->height;
311 shift = (height-1) * RADIX_TREE_MAP_SHIFT;
313 offset = 0; /* uninitialised var warning */
316 /* Have to add a child node. */
317 if (!(slot = radix_tree_node_alloc(root)))
319 slot->height = height;
321 rcu_assign_pointer(node->slots[offset], slot);
324 rcu_assign_pointer(root->rnode,
325 radix_tree_ptr_to_indirect(slot));
328 /* Go a level down */
329 offset = (index >> shift) & RADIX_TREE_MAP_MASK;
331 slot = node->slots[offset];
332 shift -= RADIX_TREE_MAP_SHIFT;
341 rcu_assign_pointer(node->slots[offset], item);
342 BUG_ON(tag_get(node, 0, offset));
343 BUG_ON(tag_get(node, 1, offset));
345 rcu_assign_pointer(root->rnode, item);
346 BUG_ON(root_tag_get(root, 0));
347 BUG_ON(root_tag_get(root, 1));
352 EXPORT_SYMBOL(radix_tree_insert);
355 * radix_tree_lookup_slot - lookup a slot in a radix tree
356 * @root: radix tree root
359 * Returns: the slot corresponding to the position @index in the
360 * radix tree @root. This is useful for update-if-exists operations.
362 * This function cannot be called under rcu_read_lock, it must be
363 * excluded from writers, as must the returned slot for subsequent
364 * use by radix_tree_deref_slot() and radix_tree_replace slot.
365 * Caller must hold tree write locked across slot lookup and
368 void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index)
370 unsigned int height, shift;
371 struct radix_tree_node *node, **slot;
377 if (!radix_tree_is_indirect_ptr(node)) {
380 return (void **)&root->rnode;
382 node = radix_tree_indirect_to_ptr(node);
384 height = node->height;
385 if (index > radix_tree_maxindex(height))
388 shift = (height-1) * RADIX_TREE_MAP_SHIFT;
391 slot = (struct radix_tree_node **)
392 (node->slots + ((index>>shift) & RADIX_TREE_MAP_MASK));
397 shift -= RADIX_TREE_MAP_SHIFT;
399 } while (height > 0);
401 return (void **)slot;
403 EXPORT_SYMBOL(radix_tree_lookup_slot);
406 * radix_tree_lookup - perform lookup operation on a radix tree
407 * @root: radix tree root
410 * Lookup the item at the position @index in the radix tree @root.
412 * This function can be called under rcu_read_lock, however the caller
413 * must manage lifetimes of leaf nodes (eg. RCU may also be used to free
414 * them safely). No RCU barriers are required to access or modify the
415 * returned item, however.
417 void *radix_tree_lookup(struct radix_tree_root *root, unsigned long index)
419 unsigned int height, shift;
420 struct radix_tree_node *node, **slot;
422 node = rcu_dereference(root->rnode);
426 if (!radix_tree_is_indirect_ptr(node)) {
431 node = radix_tree_indirect_to_ptr(node);
433 height = node->height;
434 if (index > radix_tree_maxindex(height))
437 shift = (height-1) * RADIX_TREE_MAP_SHIFT;
440 slot = (struct radix_tree_node **)
441 (node->slots + ((index>>shift) & RADIX_TREE_MAP_MASK));
442 node = rcu_dereference(*slot);
446 shift -= RADIX_TREE_MAP_SHIFT;
448 } while (height > 0);
452 EXPORT_SYMBOL(radix_tree_lookup);
455 * radix_tree_tag_set - set a tag on a radix tree node
456 * @root: radix tree root
460 * Set the search tag (which must be < RADIX_TREE_MAX_TAGS)
461 * corresponding to @index in the radix tree. From
462 * the root all the way down to the leaf node.
464 * Returns the address of the tagged item. Setting a tag on a not-present
467 void *radix_tree_tag_set(struct radix_tree_root *root,
468 unsigned long index, unsigned int tag)
470 unsigned int height, shift;
471 struct radix_tree_node *slot;
473 height = root->height;
474 BUG_ON(index > radix_tree_maxindex(height));
476 slot = radix_tree_indirect_to_ptr(root->rnode);
477 shift = (height - 1) * RADIX_TREE_MAP_SHIFT;
482 offset = (index >> shift) & RADIX_TREE_MAP_MASK;
483 if (!tag_get(slot, tag, offset))
484 tag_set(slot, tag, offset);
485 slot = slot->slots[offset];
486 BUG_ON(slot == NULL);
487 shift -= RADIX_TREE_MAP_SHIFT;
491 /* set the root's tag bit */
492 if (slot && !root_tag_get(root, tag))
493 root_tag_set(root, tag);
497 EXPORT_SYMBOL(radix_tree_tag_set);
500 * radix_tree_tag_clear - clear a tag on a radix tree node
501 * @root: radix tree root
505 * Clear the search tag (which must be < RADIX_TREE_MAX_TAGS)
506 * corresponding to @index in the radix tree. If
507 * this causes the leaf node to have no tags set then clear the tag in the
508 * next-to-leaf node, etc.
510 * Returns the address of the tagged item on success, else NULL. ie:
511 * has the same return value and semantics as radix_tree_lookup().
513 void *radix_tree_tag_clear(struct radix_tree_root *root,
514 unsigned long index, unsigned int tag)
517 * The radix tree path needs to be one longer than the maximum path
518 * since the "list" is null terminated.
520 struct radix_tree_path path[RADIX_TREE_MAX_PATH + 1], *pathp = path;
521 struct radix_tree_node *slot = NULL;
522 unsigned int height, shift;
524 height = root->height;
525 if (index > radix_tree_maxindex(height))
528 shift = (height - 1) * RADIX_TREE_MAP_SHIFT;
530 slot = radix_tree_indirect_to_ptr(root->rnode);
538 offset = (index >> shift) & RADIX_TREE_MAP_MASK;
539 pathp[1].offset = offset;
540 pathp[1].node = slot;
541 slot = slot->slots[offset];
543 shift -= RADIX_TREE_MAP_SHIFT;
550 while (pathp->node) {
551 if (!tag_get(pathp->node, tag, pathp->offset))
553 tag_clear(pathp->node, tag, pathp->offset);
554 if (any_tag_set(pathp->node, tag))
559 /* clear the root's tag bit */
560 if (root_tag_get(root, tag))
561 root_tag_clear(root, tag);
566 EXPORT_SYMBOL(radix_tree_tag_clear);
568 #ifndef __KERNEL__ /* Only the test harness uses this at present */
570 * radix_tree_tag_get - get a tag on a radix tree node
571 * @root: radix tree root
573 * @tag: tag index (< RADIX_TREE_MAX_TAGS)
577 * 0: tag not present or not set
580 int radix_tree_tag_get(struct radix_tree_root *root,
581 unsigned long index, unsigned int tag)
583 unsigned int height, shift;
584 struct radix_tree_node *node;
585 int saw_unset_tag = 0;
587 /* check the root's tag bit */
588 if (!root_tag_get(root, tag))
591 node = rcu_dereference(root->rnode);
595 if (!radix_tree_is_indirect_ptr(node))
597 node = radix_tree_indirect_to_ptr(node);
599 height = node->height;
600 if (index > radix_tree_maxindex(height))
603 shift = (height - 1) * RADIX_TREE_MAP_SHIFT;
611 offset = (index >> shift) & RADIX_TREE_MAP_MASK;
614 * This is just a debug check. Later, we can bale as soon as
615 * we see an unset tag.
617 if (!tag_get(node, tag, offset))
620 int ret = tag_get(node, tag, offset);
622 BUG_ON(ret && saw_unset_tag);
625 node = rcu_dereference(node->slots[offset]);
626 shift -= RADIX_TREE_MAP_SHIFT;
630 EXPORT_SYMBOL(radix_tree_tag_get);
634 * radix_tree_next_hole - find the next hole (not-present entry)
637 * @max_scan: maximum range to search
639 * Search the set [index, min(index+max_scan-1, MAX_INDEX)] for the lowest
642 * Returns: the index of the hole if found, otherwise returns an index
643 * outside of the set specified (in which case 'return - index >= max_scan'
646 * radix_tree_next_hole may be called under rcu_read_lock. However, like
647 * radix_tree_gang_lookup, this will not atomically search a snapshot of the
648 * tree at a single point in time. For example, if a hole is created at index
649 * 5, then subsequently a hole is created at index 10, radix_tree_next_hole
650 * covering both indexes may return 10 if called under rcu_read_lock.
652 unsigned long radix_tree_next_hole(struct radix_tree_root *root,
653 unsigned long index, unsigned long max_scan)
657 for (i = 0; i < max_scan; i++) {
658 if (!radix_tree_lookup(root, index))
667 EXPORT_SYMBOL(radix_tree_next_hole);
670 __lookup(struct radix_tree_node *slot, void **results, unsigned long index,
671 unsigned int max_items, unsigned long *next_index)
673 unsigned int nr_found = 0;
674 unsigned int shift, height;
677 height = slot->height;
680 shift = (height-1) * RADIX_TREE_MAP_SHIFT;
682 for ( ; height > 1; height--) {
683 i = (index >> shift) & RADIX_TREE_MAP_MASK;
685 if (slot->slots[i] != NULL)
687 index &= ~((1UL << shift) - 1);
688 index += 1UL << shift;
690 goto out; /* 32-bit wraparound */
692 if (i == RADIX_TREE_MAP_SIZE)
696 shift -= RADIX_TREE_MAP_SHIFT;
697 slot = rcu_dereference(slot->slots[i]);
702 /* Bottom level: grab some items */
703 for (i = index & RADIX_TREE_MAP_MASK; i < RADIX_TREE_MAP_SIZE; i++) {
704 struct radix_tree_node *node;
706 node = slot->slots[i];
708 results[nr_found++] = rcu_dereference(node);
709 if (nr_found == max_items)
719 * radix_tree_gang_lookup - perform multiple lookup on a radix tree
720 * @root: radix tree root
721 * @results: where the results of the lookup are placed
722 * @first_index: start the lookup from this key
723 * @max_items: place up to this many items at *results
725 * Performs an index-ascending scan of the tree for present items. Places
726 * them at *@results and returns the number of items which were placed at
729 * The implementation is naive.
731 * Like radix_tree_lookup, radix_tree_gang_lookup may be called under
732 * rcu_read_lock. In this case, rather than the returned results being
733 * an atomic snapshot of the tree at a single point in time, the semantics
734 * of an RCU protected gang lookup are as though multiple radix_tree_lookups
735 * have been issued in individual locks, and results stored in 'results'.
738 radix_tree_gang_lookup(struct radix_tree_root *root, void **results,
739 unsigned long first_index, unsigned int max_items)
741 unsigned long max_index;
742 struct radix_tree_node *node;
743 unsigned long cur_index = first_index;
746 node = rcu_dereference(root->rnode);
750 if (!radix_tree_is_indirect_ptr(node)) {
756 node = radix_tree_indirect_to_ptr(node);
758 max_index = radix_tree_maxindex(node->height);
761 while (ret < max_items) {
762 unsigned int nr_found;
763 unsigned long next_index; /* Index of next search */
765 if (cur_index > max_index)
767 nr_found = __lookup(node, results + ret, cur_index,
768 max_items - ret, &next_index);
772 cur_index = next_index;
777 EXPORT_SYMBOL(radix_tree_gang_lookup);
780 * FIXME: the two tag_get()s here should use find_next_bit() instead of
781 * open-coding the search.
784 __lookup_tag(struct radix_tree_node *slot, void **results, unsigned long index,
785 unsigned int max_items, unsigned long *next_index, unsigned int tag)
787 unsigned int nr_found = 0;
788 unsigned int shift, height;
790 height = slot->height;
793 shift = (height-1) * RADIX_TREE_MAP_SHIFT;
796 unsigned long i = (index >> shift) & RADIX_TREE_MAP_MASK ;
799 if (tag_get(slot, tag, i))
801 index &= ~((1UL << shift) - 1);
802 index += 1UL << shift;
804 goto out; /* 32-bit wraparound */
806 if (i == RADIX_TREE_MAP_SIZE)
810 if (height == 0) { /* Bottom level: grab some items */
811 unsigned long j = index & RADIX_TREE_MAP_MASK;
813 for ( ; j < RADIX_TREE_MAP_SIZE; j++) {
814 struct radix_tree_node *node;
816 if (!tag_get(slot, tag, j))
818 node = slot->slots[j];
820 * Even though the tag was found set, we need to
821 * recheck that we have a non-NULL node, because
822 * if this lookup is lockless, it may have been
823 * subsequently deleted.
825 * Similar care must be taken in any place that
826 * lookup ->slots[x] without a lock (ie. can't
827 * rely on its value remaining the same).
830 node = rcu_dereference(node);
831 results[nr_found++] = node;
832 if (nr_found == max_items)
837 shift -= RADIX_TREE_MAP_SHIFT;
838 slot = rcu_dereference(slot->slots[i]);
848 * radix_tree_gang_lookup_tag - perform multiple lookup on a radix tree
850 * @root: radix tree root
851 * @results: where the results of the lookup are placed
852 * @first_index: start the lookup from this key
853 * @max_items: place up to this many items at *results
854 * @tag: the tag index (< RADIX_TREE_MAX_TAGS)
856 * Performs an index-ascending scan of the tree for present items which
857 * have the tag indexed by @tag set. Places the items at *@results and
858 * returns the number of items which were placed at *@results.
861 radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results,
862 unsigned long first_index, unsigned int max_items,
865 struct radix_tree_node *node;
866 unsigned long max_index;
867 unsigned long cur_index = first_index;
870 /* check the root's tag bit */
871 if (!root_tag_get(root, tag))
874 node = rcu_dereference(root->rnode);
878 if (!radix_tree_is_indirect_ptr(node)) {
884 node = radix_tree_indirect_to_ptr(node);
886 max_index = radix_tree_maxindex(node->height);
889 while (ret < max_items) {
890 unsigned int nr_found;
891 unsigned long next_index; /* Index of next search */
893 if (cur_index > max_index)
895 nr_found = __lookup_tag(node, results + ret, cur_index,
896 max_items - ret, &next_index, tag);
900 cur_index = next_index;
905 EXPORT_SYMBOL(radix_tree_gang_lookup_tag);
908 * radix_tree_shrink - shrink height of a radix tree to minimal
909 * @root radix tree root
911 static inline void radix_tree_shrink(struct radix_tree_root *root)
913 /* try to shrink tree height */
914 while (root->height > 0) {
915 struct radix_tree_node *to_free = root->rnode;
918 BUG_ON(!radix_tree_is_indirect_ptr(to_free));
919 to_free = radix_tree_indirect_to_ptr(to_free);
922 * The candidate node has more than one child, or its child
923 * is not at the leftmost slot, we cannot shrink.
925 if (to_free->count != 1)
927 if (!to_free->slots[0])
931 * We don't need rcu_assign_pointer(), since we are simply
932 * moving the node from one part of the tree to another. If
933 * it was safe to dereference the old pointer to it
934 * (to_free->slots[0]), it will be safe to dereference the new
937 newptr = to_free->slots[0];
938 if (root->height > 1)
939 newptr = radix_tree_ptr_to_indirect(newptr);
940 root->rnode = newptr;
942 radix_tree_node_free(to_free);
947 * radix_tree_delete - delete an item from a radix tree
948 * @root: radix tree root
951 * Remove the item at @index from the radix tree rooted at @root.
953 * Returns the address of the deleted item, or NULL if it was not present.
955 void *radix_tree_delete(struct radix_tree_root *root, unsigned long index)
958 * The radix tree path needs to be one longer than the maximum path
959 * since the "list" is null terminated.
961 struct radix_tree_path path[RADIX_TREE_MAX_PATH + 1], *pathp = path;
962 struct radix_tree_node *slot = NULL;
963 struct radix_tree_node *to_free;
964 unsigned int height, shift;
968 height = root->height;
969 if (index > radix_tree_maxindex(height))
974 root_tag_clear_all(root);
978 slot = radix_tree_indirect_to_ptr(slot);
980 shift = (height - 1) * RADIX_TREE_MAP_SHIFT;
988 offset = (index >> shift) & RADIX_TREE_MAP_MASK;
989 pathp->offset = offset;
991 slot = slot->slots[offset];
992 shift -= RADIX_TREE_MAP_SHIFT;
994 } while (height > 0);
1000 * Clear all tags associated with the just-deleted item
1002 for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) {
1003 if (tag_get(pathp->node, tag, pathp->offset))
1004 radix_tree_tag_clear(root, index, tag);
1008 /* Now free the nodes we do not need anymore */
1009 while (pathp->node) {
1010 pathp->node->slots[pathp->offset] = NULL;
1011 pathp->node->count--;
1013 * Queue the node for deferred freeing after the
1014 * last reference to it disappears (set NULL, above).
1017 radix_tree_node_free(to_free);
1019 if (pathp->node->count) {
1021 radix_tree_indirect_to_ptr(root->rnode))
1022 radix_tree_shrink(root);
1026 /* Node with zero slots in use so free it */
1027 to_free = pathp->node;
1031 root_tag_clear_all(root);
1035 radix_tree_node_free(to_free);
1040 EXPORT_SYMBOL(radix_tree_delete);
1043 * radix_tree_tagged - test whether any items in the tree are tagged
1044 * @root: radix tree root
1047 int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag)
1049 return root_tag_get(root, tag);
1051 EXPORT_SYMBOL(radix_tree_tagged);
1054 radix_tree_node_ctor(struct kmem_cache *cachep, void *node)
1056 memset(node, 0, sizeof(struct radix_tree_node));
1059 static __init unsigned long __maxindex(unsigned int height)
1061 unsigned int width = height * RADIX_TREE_MAP_SHIFT;
1062 int shift = RADIX_TREE_INDEX_BITS - width;
1066 if (shift >= BITS_PER_LONG)
1068 return ~0UL >> shift;
1071 static __init void radix_tree_init_maxindex(void)
1075 for (i = 0; i < ARRAY_SIZE(height_to_maxindex); i++)
1076 height_to_maxindex[i] = __maxindex(i);
1079 static int radix_tree_callback(struct notifier_block *nfb,
1080 unsigned long action,
1083 int cpu = (long)hcpu;
1084 struct radix_tree_preload *rtp;
1086 /* Free per-cpu pool of perloaded nodes */
1087 if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {
1088 rtp = &per_cpu(radix_tree_preloads, cpu);
1090 kmem_cache_free(radix_tree_node_cachep,
1091 rtp->nodes[rtp->nr-1]);
1092 rtp->nodes[rtp->nr-1] = NULL;
1099 void __init radix_tree_init(void)
1101 radix_tree_node_cachep = kmem_cache_create("radix_tree_node",
1102 sizeof(struct radix_tree_node), 0,
1103 SLAB_PANIC | SLAB_RECLAIM_ACCOUNT,
1104 radix_tree_node_ctor);
1105 radix_tree_init_maxindex();
1106 hotcpu_notifier(radix_tree_callback, 0);