blob: 9927cca14cb70fd0d65a9ca63c297258dfebdc87 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Copyright (C) 2001 Momchil Velikov
3 * Portions Copyright (C) 2001 Christoph Hellwig
Christoph Lameter201b6262005-09-06 15:16:46 -07004 * Copyright (C) 2005 SGI, Christoph Lameter <clameter@sgi.com>
Nick Piggin7cf9c2c2006-12-06 20:33:44 -08005 * Copyright (C) 2006 Nick Piggin
Linus Torvalds1da177e2005-04-16 15:20:36 -07006 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License as
9 * published by the Free Software Foundation; either version 2, or (at
10 * your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful, but
13 * WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 */
21
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>
Nick Piggin7cf9c2c2006-12-06 20:33:44 -080034#include <linux/rcupdate.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070035
36
37#ifdef __KERNEL__
Nick Piggincfd9b7d2006-06-23 02:03:22 -070038#define RADIX_TREE_MAP_SHIFT (CONFIG_BASE_SMALL ? 4 : 6)
Linus Torvalds1da177e2005-04-16 15:20:36 -070039#else
40#define RADIX_TREE_MAP_SHIFT 3 /* For more stressful testing */
41#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -070042
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 {
Nick Piggin7cf9c2c2006-12-06 20:33:44 -080050 unsigned int height; /* Height from the bottom */
Linus Torvalds1da177e2005-04-16 15:20:36 -070051 unsigned int count;
Nick Piggin7cf9c2c2006-12-06 20:33:44 -080052 struct rcu_head rcu_head;
Linus Torvalds1da177e2005-04-16 15:20:36 -070053 void *slots[RADIX_TREE_MAP_SIZE];
Jonathan Corbetdaff89f2006-03-25 03:08:05 -080054 unsigned long tags[RADIX_TREE_MAX_TAGS][RADIX_TREE_TAG_LONGS];
Linus Torvalds1da177e2005-04-16 15:20:36 -070055};
56
57struct radix_tree_path {
Christoph Lameter201b6262005-09-06 15:16:46 -070058 struct radix_tree_node *node;
Linus Torvalds1da177e2005-04-16 15:20:36 -070059 int offset;
60};
61
62#define RADIX_TREE_INDEX_BITS (8 /* CHAR_BIT */ * sizeof(unsigned long))
63#define RADIX_TREE_MAX_PATH (RADIX_TREE_INDEX_BITS/RADIX_TREE_MAP_SHIFT + 2)
64
Christoph Lameter6c036522005-07-07 17:56:59 -070065static unsigned long height_to_maxindex[RADIX_TREE_MAX_PATH] __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -070066
67/*
68 * Radix tree node cache.
69 */
Christoph Lametere18b8902006-12-06 20:33:20 -080070static struct kmem_cache *radix_tree_node_cachep;
Linus Torvalds1da177e2005-04-16 15:20:36 -070071
72/*
73 * Per-cpu pool of preloaded nodes
74 */
75struct radix_tree_preload {
76 int nr;
77 struct radix_tree_node *nodes[RADIX_TREE_MAX_PATH];
78};
79DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, };
80
Nick Piggin612d6c12006-06-23 02:03:22 -070081static inline gfp_t root_gfp_mask(struct radix_tree_root *root)
82{
83 return root->gfp_mask & __GFP_BITS_MASK;
84}
85
Linus Torvalds1da177e2005-04-16 15:20:36 -070086/*
87 * This assumes that the caller has performed appropriate preallocation, and
88 * that the caller has pinned this thread of control to the current CPU.
89 */
90static struct radix_tree_node *
91radix_tree_node_alloc(struct radix_tree_root *root)
92{
93 struct radix_tree_node *ret;
Nick Piggin612d6c12006-06-23 02:03:22 -070094 gfp_t gfp_mask = root_gfp_mask(root);
Linus Torvalds1da177e2005-04-16 15:20:36 -070095
Nick Piggin612d6c12006-06-23 02:03:22 -070096 ret = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask);
97 if (ret == NULL && !(gfp_mask & __GFP_WAIT)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070098 struct radix_tree_preload *rtp;
99
100 rtp = &__get_cpu_var(radix_tree_preloads);
101 if (rtp->nr) {
102 ret = rtp->nodes[rtp->nr - 1];
103 rtp->nodes[rtp->nr - 1] = NULL;
104 rtp->nr--;
105 }
106 }
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800107 BUG_ON(radix_tree_is_direct_ptr(ret));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108 return ret;
109}
110
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800111static void radix_tree_node_rcu_free(struct rcu_head *head)
112{
113 struct radix_tree_node *node =
114 container_of(head, struct radix_tree_node, rcu_head);
115 kmem_cache_free(radix_tree_node_cachep, node);
116}
117
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118static inline void
119radix_tree_node_free(struct radix_tree_node *node)
120{
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800121 call_rcu(&node->rcu_head, radix_tree_node_rcu_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122}
123
124/*
125 * Load up this CPU's radix_tree_node buffer with sufficient objects to
126 * ensure that the addition of a single element in the tree cannot fail. On
127 * success, return zero, with preemption disabled. On error, return -ENOMEM
128 * with preemption not disabled.
129 */
Al Virodd0fc662005-10-07 07:46:04 +0100130int radix_tree_preload(gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131{
132 struct radix_tree_preload *rtp;
133 struct radix_tree_node *node;
134 int ret = -ENOMEM;
135
136 preempt_disable();
137 rtp = &__get_cpu_var(radix_tree_preloads);
138 while (rtp->nr < ARRAY_SIZE(rtp->nodes)) {
139 preempt_enable();
140 node = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask);
141 if (node == NULL)
142 goto out;
143 preempt_disable();
144 rtp = &__get_cpu_var(radix_tree_preloads);
145 if (rtp->nr < ARRAY_SIZE(rtp->nodes))
146 rtp->nodes[rtp->nr++] = node;
147 else
148 kmem_cache_free(radix_tree_node_cachep, node);
149 }
150 ret = 0;
151out:
152 return ret;
153}
David Chinnerd7f09232007-07-14 16:05:04 +1000154EXPORT_SYMBOL(radix_tree_preload);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155
Jonathan Corbetdaff89f2006-03-25 03:08:05 -0800156static inline void tag_set(struct radix_tree_node *node, unsigned int tag,
157 int offset)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158{
Nick Piggind5274262006-01-08 01:01:41 -0800159 __set_bit(offset, node->tags[tag]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160}
161
Jonathan Corbetdaff89f2006-03-25 03:08:05 -0800162static inline void tag_clear(struct radix_tree_node *node, unsigned int tag,
163 int offset)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164{
Nick Piggind5274262006-01-08 01:01:41 -0800165 __clear_bit(offset, node->tags[tag]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166}
167
Jonathan Corbetdaff89f2006-03-25 03:08:05 -0800168static inline int tag_get(struct radix_tree_node *node, unsigned int tag,
169 int offset)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170{
Nick Piggind5274262006-01-08 01:01:41 -0800171 return test_bit(offset, node->tags[tag]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172}
173
Nick Piggin612d6c12006-06-23 02:03:22 -0700174static inline void root_tag_set(struct radix_tree_root *root, unsigned int tag)
175{
Al Viro20241ad2006-10-10 22:47:57 +0100176 root->gfp_mask |= (__force gfp_t)(1 << (tag + __GFP_BITS_SHIFT));
Nick Piggin612d6c12006-06-23 02:03:22 -0700177}
178
179
180static inline void root_tag_clear(struct radix_tree_root *root, unsigned int tag)
181{
Al Viro20241ad2006-10-10 22:47:57 +0100182 root->gfp_mask &= (__force gfp_t)~(1 << (tag + __GFP_BITS_SHIFT));
Nick Piggin612d6c12006-06-23 02:03:22 -0700183}
184
185static inline void root_tag_clear_all(struct radix_tree_root *root)
186{
187 root->gfp_mask &= __GFP_BITS_MASK;
188}
189
190static inline int root_tag_get(struct radix_tree_root *root, unsigned int tag)
191{
Al Viro20241ad2006-10-10 22:47:57 +0100192 return (__force unsigned)root->gfp_mask & (1 << (tag + __GFP_BITS_SHIFT));
Nick Piggin612d6c12006-06-23 02:03:22 -0700193}
194
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195/*
Nick Piggin6e954b92006-01-08 01:01:40 -0800196 * Returns 1 if any slot in the node has this tag set.
197 * Otherwise returns 0.
198 */
Jonathan Corbetdaff89f2006-03-25 03:08:05 -0800199static inline int any_tag_set(struct radix_tree_node *node, unsigned int tag)
Nick Piggin6e954b92006-01-08 01:01:40 -0800200{
201 int idx;
202 for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) {
203 if (node->tags[tag][idx])
204 return 1;
205 }
206 return 0;
207}
208
209/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210 * Return the maximum key which can be store into a
211 * radix tree with height HEIGHT.
212 */
213static inline unsigned long radix_tree_maxindex(unsigned int height)
214{
215 return height_to_maxindex[height];
216}
217
218/*
219 * Extend a radix tree so it can store key @index.
220 */
221static int radix_tree_extend(struct radix_tree_root *root, unsigned long index)
222{
223 struct radix_tree_node *node;
224 unsigned int height;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225 int tag;
226
227 /* Figure out what the height should be. */
228 height = root->height + 1;
229 while (index > radix_tree_maxindex(height))
230 height++;
231
232 if (root->rnode == NULL) {
233 root->height = height;
234 goto out;
235 }
236
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237 do {
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800238 unsigned int newheight;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239 if (!(node = radix_tree_node_alloc(root)))
240 return -ENOMEM;
241
242 /* Increase the height. */
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800243 node->slots[0] = radix_tree_direct_to_ptr(root->rnode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244
245 /* Propagate the aggregated tag info into the new root */
Jonathan Corbetdaff89f2006-03-25 03:08:05 -0800246 for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) {
Nick Piggin612d6c12006-06-23 02:03:22 -0700247 if (root_tag_get(root, tag))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248 tag_set(node, tag, 0);
249 }
250
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800251 newheight = root->height+1;
252 node->height = newheight;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253 node->count = 1;
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800254 rcu_assign_pointer(root->rnode, node);
255 root->height = newheight;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256 } while (height > root->height);
257out:
258 return 0;
259}
260
261/**
262 * radix_tree_insert - insert into a radix tree
263 * @root: radix tree root
264 * @index: index key
265 * @item: item to insert
266 *
267 * Insert an item into the radix tree at position @index.
268 */
269int radix_tree_insert(struct radix_tree_root *root,
270 unsigned long index, void *item)
271{
Christoph Lameter201b6262005-09-06 15:16:46 -0700272 struct radix_tree_node *node = NULL, *slot;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700273 unsigned int height, shift;
274 int offset;
275 int error;
276
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800277 BUG_ON(radix_tree_is_direct_ptr(item));
278
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279 /* Make sure the tree is high enough. */
Nick Piggin612d6c12006-06-23 02:03:22 -0700280 if (index > radix_tree_maxindex(root->height)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281 error = radix_tree_extend(root, index);
282 if (error)
283 return error;
284 }
285
Christoph Lameter201b6262005-09-06 15:16:46 -0700286 slot = root->rnode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287 height = root->height;
288 shift = (height-1) * RADIX_TREE_MAP_SHIFT;
289
290 offset = 0; /* uninitialised var warning */
Nick Piggin612d6c12006-06-23 02:03:22 -0700291 while (height > 0) {
Christoph Lameter201b6262005-09-06 15:16:46 -0700292 if (slot == NULL) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293 /* Have to add a child node. */
Christoph Lameter201b6262005-09-06 15:16:46 -0700294 if (!(slot = radix_tree_node_alloc(root)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295 return -ENOMEM;
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800296 slot->height = height;
Christoph Lameter201b6262005-09-06 15:16:46 -0700297 if (node) {
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800298 rcu_assign_pointer(node->slots[offset], slot);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299 node->count++;
Christoph Lameter201b6262005-09-06 15:16:46 -0700300 } else
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800301 rcu_assign_pointer(root->rnode, slot);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302 }
303
304 /* Go a level down */
305 offset = (index >> shift) & RADIX_TREE_MAP_MASK;
Christoph Lameter201b6262005-09-06 15:16:46 -0700306 node = slot;
307 slot = node->slots[offset];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308 shift -= RADIX_TREE_MAP_SHIFT;
309 height--;
Nick Piggin612d6c12006-06-23 02:03:22 -0700310 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311
Christoph Lameter201b6262005-09-06 15:16:46 -0700312 if (slot != NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313 return -EEXIST;
Christoph Lameter201b6262005-09-06 15:16:46 -0700314
Nick Piggin612d6c12006-06-23 02:03:22 -0700315 if (node) {
316 node->count++;
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800317 rcu_assign_pointer(node->slots[offset], item);
Nick Piggin612d6c12006-06-23 02:03:22 -0700318 BUG_ON(tag_get(node, 0, offset));
319 BUG_ON(tag_get(node, 1, offset));
320 } else {
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800321 rcu_assign_pointer(root->rnode, radix_tree_ptr_to_direct(item));
Nick Piggin612d6c12006-06-23 02:03:22 -0700322 BUG_ON(root_tag_get(root, 0));
323 BUG_ON(root_tag_get(root, 1));
324 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326 return 0;
327}
328EXPORT_SYMBOL(radix_tree_insert);
329
Hans Reisera4331362005-11-07 00:59:29 -0800330/**
331 * radix_tree_lookup_slot - lookup a slot in a radix tree
332 * @root: radix tree root
333 * @index: index key
334 *
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800335 * Returns: the slot corresponding to the position @index in the
336 * radix tree @root. This is useful for update-if-exists operations.
337 *
338 * This function cannot be called under rcu_read_lock, it must be
339 * excluded from writers, as must the returned slot for subsequent
340 * use by radix_tree_deref_slot() and radix_tree_replace slot.
341 * Caller must hold tree write locked across slot lookup and
342 * replace.
Hans Reisera4331362005-11-07 00:59:29 -0800343 */
344void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index)
345{
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800346 unsigned int height, shift;
347 struct radix_tree_node *node, **slot;
348
349 node = root->rnode;
350 if (node == NULL)
351 return NULL;
352
353 if (radix_tree_is_direct_ptr(node)) {
354 if (index > 0)
355 return NULL;
356 return (void **)&root->rnode;
357 }
358
359 height = node->height;
360 if (index > radix_tree_maxindex(height))
361 return NULL;
362
363 shift = (height-1) * RADIX_TREE_MAP_SHIFT;
364
365 do {
366 slot = (struct radix_tree_node **)
367 (node->slots + ((index>>shift) & RADIX_TREE_MAP_MASK));
368 node = *slot;
369 if (node == NULL)
370 return NULL;
371
372 shift -= RADIX_TREE_MAP_SHIFT;
373 height--;
374 } while (height > 0);
375
376 return (void **)slot;
Hans Reisera4331362005-11-07 00:59:29 -0800377}
378EXPORT_SYMBOL(radix_tree_lookup_slot);
379
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380/**
381 * radix_tree_lookup - perform lookup operation on a radix tree
382 * @root: radix tree root
383 * @index: index key
384 *
385 * Lookup the item at the position @index in the radix tree @root.
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800386 *
387 * This function can be called under rcu_read_lock, however the caller
388 * must manage lifetimes of leaf nodes (eg. RCU may also be used to free
389 * them safely). No RCU barriers are required to access or modify the
390 * returned item, however.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700391 */
392void *radix_tree_lookup(struct radix_tree_root *root, unsigned long index)
393{
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800394 unsigned int height, shift;
395 struct radix_tree_node *node, **slot;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700396
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800397 node = rcu_dereference(root->rnode);
398 if (node == NULL)
399 return NULL;
400
401 if (radix_tree_is_direct_ptr(node)) {
402 if (index > 0)
403 return NULL;
404 return radix_tree_direct_to_ptr(node);
405 }
406
407 height = node->height;
408 if (index > radix_tree_maxindex(height))
409 return NULL;
410
411 shift = (height-1) * RADIX_TREE_MAP_SHIFT;
412
413 do {
414 slot = (struct radix_tree_node **)
415 (node->slots + ((index>>shift) & RADIX_TREE_MAP_MASK));
416 node = rcu_dereference(*slot);
417 if (node == NULL)
418 return NULL;
419
420 shift -= RADIX_TREE_MAP_SHIFT;
421 height--;
422 } while (height > 0);
423
424 return node;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425}
426EXPORT_SYMBOL(radix_tree_lookup);
427
428/**
429 * radix_tree_tag_set - set a tag on a radix tree node
430 * @root: radix tree root
431 * @index: index key
432 * @tag: tag index
433 *
Jonathan Corbetdaff89f2006-03-25 03:08:05 -0800434 * Set the search tag (which must be < RADIX_TREE_MAX_TAGS)
435 * corresponding to @index in the radix tree. From
Linus Torvalds1da177e2005-04-16 15:20:36 -0700436 * the root all the way down to the leaf node.
437 *
438 * Returns the address of the tagged item. Setting a tag on a not-present
439 * item is a bug.
440 */
441void *radix_tree_tag_set(struct radix_tree_root *root,
Jonathan Corbetdaff89f2006-03-25 03:08:05 -0800442 unsigned long index, unsigned int tag)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700443{
444 unsigned int height, shift;
Christoph Lameter201b6262005-09-06 15:16:46 -0700445 struct radix_tree_node *slot;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700446
447 height = root->height;
Peter Zijlstra4c91c362006-06-23 02:03:25 -0700448 BUG_ON(index > radix_tree_maxindex(height));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700449
Christoph Lameter201b6262005-09-06 15:16:46 -0700450 slot = root->rnode;
Nick Piggin612d6c12006-06-23 02:03:22 -0700451 shift = (height - 1) * RADIX_TREE_MAP_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700452
453 while (height > 0) {
454 int offset;
455
456 offset = (index >> shift) & RADIX_TREE_MAP_MASK;
Nick Piggind5274262006-01-08 01:01:41 -0800457 if (!tag_get(slot, tag, offset))
458 tag_set(slot, tag, offset);
Christoph Lameter201b6262005-09-06 15:16:46 -0700459 slot = slot->slots[offset];
460 BUG_ON(slot == NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461 shift -= RADIX_TREE_MAP_SHIFT;
462 height--;
463 }
464
Nick Piggin612d6c12006-06-23 02:03:22 -0700465 /* set the root's tag bit */
466 if (slot && !root_tag_get(root, tag))
467 root_tag_set(root, tag);
468
Christoph Lameter201b6262005-09-06 15:16:46 -0700469 return slot;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700470}
471EXPORT_SYMBOL(radix_tree_tag_set);
472
473/**
474 * radix_tree_tag_clear - clear a tag on a radix tree node
475 * @root: radix tree root
476 * @index: index key
477 * @tag: tag index
478 *
Jonathan Corbetdaff89f2006-03-25 03:08:05 -0800479 * Clear the search tag (which must be < RADIX_TREE_MAX_TAGS)
480 * corresponding to @index in the radix tree. If
Linus Torvalds1da177e2005-04-16 15:20:36 -0700481 * this causes the leaf node to have no tags set then clear the tag in the
482 * next-to-leaf node, etc.
483 *
484 * Returns the address of the tagged item on success, else NULL. ie:
485 * has the same return value and semantics as radix_tree_lookup().
486 */
487void *radix_tree_tag_clear(struct radix_tree_root *root,
Jonathan Corbetdaff89f2006-03-25 03:08:05 -0800488 unsigned long index, unsigned int tag)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489{
490 struct radix_tree_path path[RADIX_TREE_MAX_PATH], *pathp = path;
Nick Piggin612d6c12006-06-23 02:03:22 -0700491 struct radix_tree_node *slot = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700492 unsigned int height, shift;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700493
494 height = root->height;
495 if (index > radix_tree_maxindex(height))
496 goto out;
497
498 shift = (height - 1) * RADIX_TREE_MAP_SHIFT;
499 pathp->node = NULL;
Christoph Lameter201b6262005-09-06 15:16:46 -0700500 slot = root->rnode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700501
502 while (height > 0) {
503 int offset;
504
Christoph Lameter201b6262005-09-06 15:16:46 -0700505 if (slot == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700506 goto out;
507
508 offset = (index >> shift) & RADIX_TREE_MAP_MASK;
509 pathp[1].offset = offset;
Christoph Lameter201b6262005-09-06 15:16:46 -0700510 pathp[1].node = slot;
511 slot = slot->slots[offset];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700512 pathp++;
513 shift -= RADIX_TREE_MAP_SHIFT;
514 height--;
515 }
516
Nick Piggin612d6c12006-06-23 02:03:22 -0700517 if (slot == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700518 goto out;
519
Nick Piggin612d6c12006-06-23 02:03:22 -0700520 while (pathp->node) {
Nick Piggind5274262006-01-08 01:01:41 -0800521 if (!tag_get(pathp->node, tag, pathp->offset))
522 goto out;
Christoph Lameter201b6262005-09-06 15:16:46 -0700523 tag_clear(pathp->node, tag, pathp->offset);
Nick Piggin6e954b92006-01-08 01:01:40 -0800524 if (any_tag_set(pathp->node, tag))
525 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526 pathp--;
Nick Piggin612d6c12006-06-23 02:03:22 -0700527 }
528
529 /* clear the root's tag bit */
530 if (root_tag_get(root, tag))
531 root_tag_clear(root, tag);
532
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533out:
Nick Piggin612d6c12006-06-23 02:03:22 -0700534 return slot;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535}
536EXPORT_SYMBOL(radix_tree_tag_clear);
537
538#ifndef __KERNEL__ /* Only the test harness uses this at present */
539/**
Marcelo Tosatti32605a12005-09-06 15:16:48 -0700540 * radix_tree_tag_get - get a tag on a radix tree node
541 * @root: radix tree root
542 * @index: index key
Jonathan Corbetdaff89f2006-03-25 03:08:05 -0800543 * @tag: tag index (< RADIX_TREE_MAX_TAGS)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700544 *
Marcelo Tosatti32605a12005-09-06 15:16:48 -0700545 * Return values:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700546 *
Nick Piggin612d6c12006-06-23 02:03:22 -0700547 * 0: tag not present or not set
548 * 1: tag set
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549 */
550int radix_tree_tag_get(struct radix_tree_root *root,
Jonathan Corbetdaff89f2006-03-25 03:08:05 -0800551 unsigned long index, unsigned int tag)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700552{
553 unsigned int height, shift;
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800554 struct radix_tree_node *node;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700555 int saw_unset_tag = 0;
556
Nick Piggin612d6c12006-06-23 02:03:22 -0700557 /* check the root's tag bit */
558 if (!root_tag_get(root, tag))
559 return 0;
560
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800561 node = rcu_dereference(root->rnode);
562 if (node == NULL)
563 return 0;
564
565 if (radix_tree_is_direct_ptr(node))
566 return (index == 0);
567
568 height = node->height;
569 if (index > radix_tree_maxindex(height))
570 return 0;
Nick Piggin612d6c12006-06-23 02:03:22 -0700571
Linus Torvalds1da177e2005-04-16 15:20:36 -0700572 shift = (height - 1) * RADIX_TREE_MAP_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700573
574 for ( ; ; ) {
575 int offset;
576
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800577 if (node == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700578 return 0;
579
580 offset = (index >> shift) & RADIX_TREE_MAP_MASK;
581
582 /*
583 * This is just a debug check. Later, we can bale as soon as
584 * we see an unset tag.
585 */
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800586 if (!tag_get(node, tag, offset))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700587 saw_unset_tag = 1;
588 if (height == 1) {
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800589 int ret = tag_get(node, tag, offset);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590
591 BUG_ON(ret && saw_unset_tag);
Wu Fengguange5dcd902006-06-25 05:48:14 -0700592 return !!ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593 }
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800594 node = rcu_dereference(node->slots[offset]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700595 shift -= RADIX_TREE_MAP_SHIFT;
596 height--;
597 }
598}
599EXPORT_SYMBOL(radix_tree_tag_get);
600#endif
601
602static unsigned int
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800603__lookup(struct radix_tree_node *slot, void **results, unsigned long index,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700604 unsigned int max_items, unsigned long *next_index)
605{
606 unsigned int nr_found = 0;
Christoph Lameter201b6262005-09-06 15:16:46 -0700607 unsigned int shift, height;
Christoph Lameter201b6262005-09-06 15:16:46 -0700608 unsigned long i;
609
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800610 height = slot->height;
611 if (height == 0)
Christoph Lameter201b6262005-09-06 15:16:46 -0700612 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700613 shift = (height-1) * RADIX_TREE_MAP_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614
Christoph Lameter201b6262005-09-06 15:16:46 -0700615 for ( ; height > 1; height--) {
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800616 i = (index >> shift) & RADIX_TREE_MAP_MASK;
617 for (;;) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700618 if (slot->slots[i] != NULL)
619 break;
620 index &= ~((1UL << shift) - 1);
621 index += 1UL << shift;
622 if (index == 0)
623 goto out; /* 32-bit wraparound */
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800624 i++;
625 if (i == RADIX_TREE_MAP_SIZE)
626 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700627 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700628
Linus Torvalds1da177e2005-04-16 15:20:36 -0700629 shift -= RADIX_TREE_MAP_SHIFT;
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800630 slot = rcu_dereference(slot->slots[i]);
631 if (slot == NULL)
632 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633 }
Christoph Lameter201b6262005-09-06 15:16:46 -0700634
635 /* Bottom level: grab some items */
636 for (i = index & RADIX_TREE_MAP_MASK; i < RADIX_TREE_MAP_SIZE; i++) {
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800637 struct radix_tree_node *node;
Christoph Lameter201b6262005-09-06 15:16:46 -0700638 index++;
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800639 node = slot->slots[i];
640 if (node) {
641 results[nr_found++] = rcu_dereference(node);
Christoph Lameter201b6262005-09-06 15:16:46 -0700642 if (nr_found == max_items)
643 goto out;
644 }
645 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700646out:
647 *next_index = index;
648 return nr_found;
649}
650
651/**
652 * radix_tree_gang_lookup - perform multiple lookup on a radix tree
653 * @root: radix tree root
654 * @results: where the results of the lookup are placed
655 * @first_index: start the lookup from this key
656 * @max_items: place up to this many items at *results
657 *
658 * Performs an index-ascending scan of the tree for present items. Places
659 * them at *@results and returns the number of items which were placed at
660 * *@results.
661 *
662 * The implementation is naive.
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800663 *
664 * Like radix_tree_lookup, radix_tree_gang_lookup may be called under
665 * rcu_read_lock. In this case, rather than the returned results being
666 * an atomic snapshot of the tree at a single point in time, the semantics
667 * of an RCU protected gang lookup are as though multiple radix_tree_lookups
668 * have been issued in individual locks, and results stored in 'results'.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700669 */
670unsigned int
671radix_tree_gang_lookup(struct radix_tree_root *root, void **results,
672 unsigned long first_index, unsigned int max_items)
673{
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800674 unsigned long max_index;
675 struct radix_tree_node *node;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700676 unsigned long cur_index = first_index;
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800677 unsigned int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700678
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800679 node = rcu_dereference(root->rnode);
680 if (!node)
681 return 0;
682
683 if (radix_tree_is_direct_ptr(node)) {
684 if (first_index > 0)
685 return 0;
686 node = radix_tree_direct_to_ptr(node);
687 results[0] = rcu_dereference(node);
688 return 1;
689 }
690
691 max_index = radix_tree_maxindex(node->height);
692
693 ret = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700694 while (ret < max_items) {
695 unsigned int nr_found;
696 unsigned long next_index; /* Index of next search */
697
698 if (cur_index > max_index)
699 break;
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800700 nr_found = __lookup(node, results + ret, cur_index,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700701 max_items - ret, &next_index);
702 ret += nr_found;
703 if (next_index == 0)
704 break;
705 cur_index = next_index;
706 }
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800707
Linus Torvalds1da177e2005-04-16 15:20:36 -0700708 return ret;
709}
710EXPORT_SYMBOL(radix_tree_gang_lookup);
711
712/*
713 * FIXME: the two tag_get()s here should use find_next_bit() instead of
714 * open-coding the search.
715 */
716static unsigned int
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800717__lookup_tag(struct radix_tree_node *slot, void **results, unsigned long index,
Jonathan Corbetdaff89f2006-03-25 03:08:05 -0800718 unsigned int max_items, unsigned long *next_index, unsigned int tag)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700719{
720 unsigned int nr_found = 0;
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800721 unsigned int shift, height;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700722
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800723 height = slot->height;
724 if (height == 0)
Nick Piggin612d6c12006-06-23 02:03:22 -0700725 goto out;
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800726 shift = (height-1) * RADIX_TREE_MAP_SHIFT;
Nick Piggin612d6c12006-06-23 02:03:22 -0700727
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800728 while (height > 0) {
729 unsigned long i = (index >> shift) & RADIX_TREE_MAP_MASK ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800731 for (;;) {
732 if (tag_get(slot, tag, i))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700733 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700734 index &= ~((1UL << shift) - 1);
735 index += 1UL << shift;
736 if (index == 0)
737 goto out; /* 32-bit wraparound */
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800738 i++;
739 if (i == RADIX_TREE_MAP_SIZE)
740 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700741 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700742 height--;
743 if (height == 0) { /* Bottom level: grab some items */
744 unsigned long j = index & RADIX_TREE_MAP_MASK;
745
746 for ( ; j < RADIX_TREE_MAP_SIZE; j++) {
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800747 struct radix_tree_node *node;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700748 index++;
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800749 if (!tag_get(slot, tag, j))
750 continue;
751 node = slot->slots[j];
752 /*
753 * Even though the tag was found set, we need to
754 * recheck that we have a non-NULL node, because
755 * if this lookup is lockless, it may have been
756 * subsequently deleted.
757 *
758 * Similar care must be taken in any place that
759 * lookup ->slots[x] without a lock (ie. can't
760 * rely on its value remaining the same).
761 */
762 if (node) {
763 node = rcu_dereference(node);
764 results[nr_found++] = node;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700765 if (nr_found == max_items)
766 goto out;
767 }
768 }
769 }
770 shift -= RADIX_TREE_MAP_SHIFT;
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800771 slot = rcu_dereference(slot->slots[i]);
772 if (slot == NULL)
773 break;
774 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700775out:
776 *next_index = index;
777 return nr_found;
778}
779
780/**
781 * radix_tree_gang_lookup_tag - perform multiple lookup on a radix tree
782 * based on a tag
783 * @root: radix tree root
784 * @results: where the results of the lookup are placed
785 * @first_index: start the lookup from this key
786 * @max_items: place up to this many items at *results
Jonathan Corbetdaff89f2006-03-25 03:08:05 -0800787 * @tag: the tag index (< RADIX_TREE_MAX_TAGS)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700788 *
789 * Performs an index-ascending scan of the tree for present items which
790 * have the tag indexed by @tag set. Places the items at *@results and
791 * returns the number of items which were placed at *@results.
792 */
793unsigned int
794radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results,
Jonathan Corbetdaff89f2006-03-25 03:08:05 -0800795 unsigned long first_index, unsigned int max_items,
796 unsigned int tag)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700797{
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800798 struct radix_tree_node *node;
799 unsigned long max_index;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700800 unsigned long cur_index = first_index;
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800801 unsigned int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700802
Nick Piggin612d6c12006-06-23 02:03:22 -0700803 /* check the root's tag bit */
804 if (!root_tag_get(root, tag))
805 return 0;
806
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800807 node = rcu_dereference(root->rnode);
808 if (!node)
809 return 0;
810
811 if (radix_tree_is_direct_ptr(node)) {
812 if (first_index > 0)
813 return 0;
814 node = radix_tree_direct_to_ptr(node);
815 results[0] = rcu_dereference(node);
816 return 1;
817 }
818
819 max_index = radix_tree_maxindex(node->height);
820
821 ret = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700822 while (ret < max_items) {
823 unsigned int nr_found;
824 unsigned long next_index; /* Index of next search */
825
826 if (cur_index > max_index)
827 break;
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800828 nr_found = __lookup_tag(node, results + ret, cur_index,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700829 max_items - ret, &next_index, tag);
830 ret += nr_found;
831 if (next_index == 0)
832 break;
833 cur_index = next_index;
834 }
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800835
Linus Torvalds1da177e2005-04-16 15:20:36 -0700836 return ret;
837}
838EXPORT_SYMBOL(radix_tree_gang_lookup_tag);
839
840/**
Nick Piggina5f51c92006-01-08 01:01:41 -0800841 * radix_tree_shrink - shrink height of a radix tree to minimal
842 * @root radix tree root
843 */
844static inline void radix_tree_shrink(struct radix_tree_root *root)
845{
846 /* try to shrink tree height */
Nick Piggin612d6c12006-06-23 02:03:22 -0700847 while (root->height > 0 &&
Nick Piggina5f51c92006-01-08 01:01:41 -0800848 root->rnode->count == 1 &&
849 root->rnode->slots[0]) {
850 struct radix_tree_node *to_free = root->rnode;
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800851 void *newptr;
Nick Piggina5f51c92006-01-08 01:01:41 -0800852
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800853 /*
854 * We don't need rcu_assign_pointer(), since we are simply
855 * moving the node from one part of the tree to another. If
856 * it was safe to dereference the old pointer to it
857 * (to_free->slots[0]), it will be safe to dereference the new
858 * one (root->rnode).
859 */
860 newptr = to_free->slots[0];
861 if (root->height == 1)
862 newptr = radix_tree_ptr_to_direct(newptr);
863 root->rnode = newptr;
Nick Piggina5f51c92006-01-08 01:01:41 -0800864 root->height--;
865 /* must only free zeroed nodes into the slab */
866 tag_clear(to_free, 0, 0);
867 tag_clear(to_free, 1, 0);
868 to_free->slots[0] = NULL;
869 to_free->count = 0;
870 radix_tree_node_free(to_free);
871 }
872}
873
874/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700875 * radix_tree_delete - delete an item from a radix tree
876 * @root: radix tree root
877 * @index: index key
878 *
879 * Remove the item at @index from the radix tree rooted at @root.
880 *
881 * Returns the address of the deleted item, or NULL if it was not present.
882 */
883void *radix_tree_delete(struct radix_tree_root *root, unsigned long index)
884{
885 struct radix_tree_path path[RADIX_TREE_MAX_PATH], *pathp = path;
Nick Piggin612d6c12006-06-23 02:03:22 -0700886 struct radix_tree_node *slot = NULL;
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800887 struct radix_tree_node *to_free;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700888 unsigned int height, shift;
Nick Piggind5274262006-01-08 01:01:41 -0800889 int tag;
890 int offset;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700891
892 height = root->height;
893 if (index > radix_tree_maxindex(height))
894 goto out;
895
Nick Piggin612d6c12006-06-23 02:03:22 -0700896 slot = root->rnode;
897 if (height == 0 && root->rnode) {
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800898 slot = radix_tree_direct_to_ptr(slot);
Nick Piggin612d6c12006-06-23 02:03:22 -0700899 root_tag_clear_all(root);
900 root->rnode = NULL;
901 goto out;
902 }
903
Linus Torvalds1da177e2005-04-16 15:20:36 -0700904 shift = (height - 1) * RADIX_TREE_MAP_SHIFT;
905 pathp->node = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700906
Nick Piggin612d6c12006-06-23 02:03:22 -0700907 do {
Christoph Lameter201b6262005-09-06 15:16:46 -0700908 if (slot == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700909 goto out;
910
Linus Torvalds1da177e2005-04-16 15:20:36 -0700911 pathp++;
Nick Piggind5274262006-01-08 01:01:41 -0800912 offset = (index >> shift) & RADIX_TREE_MAP_MASK;
913 pathp->offset = offset;
914 pathp->node = slot;
915 slot = slot->slots[offset];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700916 shift -= RADIX_TREE_MAP_SHIFT;
Nick Piggin612d6c12006-06-23 02:03:22 -0700917 height--;
918 } while (height > 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700919
Nick Piggin612d6c12006-06-23 02:03:22 -0700920 if (slot == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700921 goto out;
922
Linus Torvalds1da177e2005-04-16 15:20:36 -0700923 /*
924 * Clear all tags associated with the just-deleted item
925 */
Jonathan Corbetdaff89f2006-03-25 03:08:05 -0800926 for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) {
Nick Piggin612d6c12006-06-23 02:03:22 -0700927 if (tag_get(pathp->node, tag, pathp->offset))
928 radix_tree_tag_clear(root, index, tag);
Nick Piggind5274262006-01-08 01:01:41 -0800929 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700930
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800931 to_free = NULL;
Christoph Lameter201b6262005-09-06 15:16:46 -0700932 /* Now free the nodes we do not need anymore */
Nick Piggin612d6c12006-06-23 02:03:22 -0700933 while (pathp->node) {
Christoph Lameter201b6262005-09-06 15:16:46 -0700934 pathp->node->slots[pathp->offset] = NULL;
Nick Piggina5f51c92006-01-08 01:01:41 -0800935 pathp->node->count--;
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800936 /*
937 * Queue the node for deferred freeing after the
938 * last reference to it disappears (set NULL, above).
939 */
940 if (to_free)
941 radix_tree_node_free(to_free);
Nick Piggina5f51c92006-01-08 01:01:41 -0800942
943 if (pathp->node->count) {
944 if (pathp->node == root->rnode)
945 radix_tree_shrink(root);
Christoph Lameter201b6262005-09-06 15:16:46 -0700946 goto out;
Nick Piggina5f51c92006-01-08 01:01:41 -0800947 }
Christoph Lameter201b6262005-09-06 15:16:46 -0700948
949 /* Node with zero slots in use so free it */
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800950 to_free = pathp->node;
Nick Piggin612d6c12006-06-23 02:03:22 -0700951 pathp--;
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800952
Linus Torvalds1da177e2005-04-16 15:20:36 -0700953 }
Nick Piggin612d6c12006-06-23 02:03:22 -0700954 root_tag_clear_all(root);
Christoph Lameter201b6262005-09-06 15:16:46 -0700955 root->height = 0;
Nick Piggin612d6c12006-06-23 02:03:22 -0700956 root->rnode = NULL;
Nick Piggin7cf9c2c2006-12-06 20:33:44 -0800957 if (to_free)
958 radix_tree_node_free(to_free);
Nick Piggin612d6c12006-06-23 02:03:22 -0700959
Linus Torvalds1da177e2005-04-16 15:20:36 -0700960out:
Nick Piggin612d6c12006-06-23 02:03:22 -0700961 return slot;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700962}
963EXPORT_SYMBOL(radix_tree_delete);
964
965/**
966 * radix_tree_tagged - test whether any items in the tree are tagged
967 * @root: radix tree root
968 * @tag: tag to test
969 */
Jonathan Corbetdaff89f2006-03-25 03:08:05 -0800970int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700971{
Nick Piggin612d6c12006-06-23 02:03:22 -0700972 return root_tag_get(root, tag);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700973}
974EXPORT_SYMBOL(radix_tree_tagged);
975
976static void
Christoph Lametere18b8902006-12-06 20:33:20 -0800977radix_tree_node_ctor(void *node, struct kmem_cache *cachep, unsigned long flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700978{
979 memset(node, 0, sizeof(struct radix_tree_node));
980}
981
982static __init unsigned long __maxindex(unsigned int height)
983{
984 unsigned int tmp = height * RADIX_TREE_MAP_SHIFT;
985 unsigned long index = (~0UL >> (RADIX_TREE_INDEX_BITS - tmp - 1)) >> 1;
986
987 if (tmp >= RADIX_TREE_INDEX_BITS)
988 index = ~0UL;
989 return index;
990}
991
992static __init void radix_tree_init_maxindex(void)
993{
994 unsigned int i;
995
996 for (i = 0; i < ARRAY_SIZE(height_to_maxindex); i++)
997 height_to_maxindex[i] = __maxindex(i);
998}
999
Linus Torvalds1da177e2005-04-16 15:20:36 -07001000static int radix_tree_callback(struct notifier_block *nfb,
1001 unsigned long action,
1002 void *hcpu)
1003{
1004 int cpu = (long)hcpu;
1005 struct radix_tree_preload *rtp;
1006
1007 /* Free per-cpu pool of perloaded nodes */
Rafael J. Wysocki8bb78442007-05-09 02:35:10 -07001008 if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001009 rtp = &per_cpu(radix_tree_preloads, cpu);
1010 while (rtp->nr) {
1011 kmem_cache_free(radix_tree_node_cachep,
1012 rtp->nodes[rtp->nr-1]);
1013 rtp->nodes[rtp->nr-1] = NULL;
1014 rtp->nr--;
1015 }
1016 }
1017 return NOTIFY_OK;
1018}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001019
1020void __init radix_tree_init(void)
1021{
1022 radix_tree_node_cachep = kmem_cache_create("radix_tree_node",
1023 sizeof(struct radix_tree_node), 0,
1024 SLAB_PANIC, radix_tree_node_ctor, NULL);
1025 radix_tree_init_maxindex();
1026 hotcpu_notifier(radix_tree_callback, 0);
1027}