Branch data Line data Source code
1 : : /*
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
6 : : * Copyright (C) 2012 Konstantin Khlebnikov
7 : : *
8 : : * This program is free software; you can redistribute it and/or
9 : : * modify it under the terms of the GNU General Public License as
10 : : * published by the Free Software Foundation; either version 2, or (at
11 : : * your option) any later version.
12 : : *
13 : : * This program is distributed in the hope that it will be useful, but
14 : : * WITHOUT ANY WARRANTY; without even the implied warranty of
15 : : * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 : : * General Public License for more details.
17 : : *
18 : : * You should have received a copy of the GNU General Public License
19 : : * along with this program; if not, write to the Free Software
20 : : * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21 : : */
22 : :
23 : : #include <linux/errno.h>
24 : : #include <linux/init.h>
25 : : #include <linux/kernel.h>
26 : : #include <linux/export.h>
27 : : #include <linux/radix-tree.h>
28 : : #include <linux/percpu.h>
29 : : #include <linux/slab.h>
30 : : #include <linux/notifier.h>
31 : : #include <linux/cpu.h>
32 : : #include <linux/string.h>
33 : : #include <linux/bitops.h>
34 : : #include <linux/rcupdate.h>
35 : : #include <linux/hardirq.h> /* in_interrupt() */
36 : :
37 : :
38 : : #ifdef __KERNEL__
39 : : #define RADIX_TREE_MAP_SHIFT (CONFIG_BASE_SMALL ? 4 : 6)
40 : : #else
41 : : #define RADIX_TREE_MAP_SHIFT 3 /* For more stressful testing */
42 : : #endif
43 : :
44 : : #define RADIX_TREE_MAP_SIZE (1UL << RADIX_TREE_MAP_SHIFT)
45 : : #define RADIX_TREE_MAP_MASK (RADIX_TREE_MAP_SIZE-1)
46 : :
47 : : #define RADIX_TREE_TAG_LONGS \
48 : : ((RADIX_TREE_MAP_SIZE + BITS_PER_LONG - 1) / BITS_PER_LONG)
49 : :
50 : : struct radix_tree_node {
51 : : unsigned int height; /* Height from the bottom */
52 : : unsigned int count;
53 : : union {
54 : : struct radix_tree_node *parent; /* Used when ascending tree */
55 : : struct rcu_head rcu_head; /* Used when freeing node */
56 : : };
57 : : void __rcu *slots[RADIX_TREE_MAP_SIZE];
58 : : unsigned long tags[RADIX_TREE_MAX_TAGS][RADIX_TREE_TAG_LONGS];
59 : : };
60 : :
61 : : #define RADIX_TREE_INDEX_BITS (8 /* CHAR_BIT */ * sizeof(unsigned long))
62 : : #define RADIX_TREE_MAX_PATH (DIV_ROUND_UP(RADIX_TREE_INDEX_BITS, \
63 : : RADIX_TREE_MAP_SHIFT))
64 : :
65 : : /*
66 : : * The height_to_maxindex array needs to be one deeper than the maximum
67 : : * path as height 0 holds only 1 entry.
68 : : */
69 : : static unsigned long height_to_maxindex[RADIX_TREE_MAX_PATH + 1] __read_mostly;
70 : :
71 : : /*
72 : : * Radix tree node cache.
73 : : */
74 : : static struct kmem_cache *radix_tree_node_cachep;
75 : :
76 : : /*
77 : : * The radix tree is variable-height, so an insert operation not only has
78 : : * to build the branch to its corresponding item, it also has to build the
79 : : * branch to existing items if the size has to be increased (by
80 : : * radix_tree_extend).
81 : : *
82 : : * The worst case is a zero height tree with just a single item at index 0,
83 : : * and then inserting an item at index ULONG_MAX. This requires 2 new branches
84 : : * of RADIX_TREE_MAX_PATH size to be created, with only the root node shared.
85 : : * Hence:
86 : : */
87 : : #define RADIX_TREE_PRELOAD_SIZE (RADIX_TREE_MAX_PATH * 2 - 1)
88 : :
89 : : /*
90 : : * Per-cpu pool of preloaded nodes
91 : : */
92 : : struct radix_tree_preload {
93 : : int nr;
94 : : struct radix_tree_node *nodes[RADIX_TREE_PRELOAD_SIZE];
95 : : };
96 : : static DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, };
97 : :
98 : : static inline void *ptr_to_indirect(void *ptr)
99 : : {
100 : 5120 : return (void *)((unsigned long)ptr | RADIX_TREE_INDIRECT_PTR);
101 : : }
102 : :
103 : : static inline void *indirect_to_ptr(void *ptr)
104 : : {
105 : 17244465 : return (void *)((unsigned long)ptr & ~RADIX_TREE_INDIRECT_PTR);
106 : : }
107 : :
108 : : static inline gfp_t root_gfp_mask(struct radix_tree_root *root)
109 : : {
110 : 104821 : return root->gfp_mask & __GFP_BITS_MASK;
111 : : }
112 : :
113 : : static inline void tag_set(struct radix_tree_node *node, unsigned int tag,
114 : : int offset)
115 : : {
116 : 572815 : __set_bit(offset, node->tags[tag]);
117 : : }
118 : :
119 : : static inline void tag_clear(struct radix_tree_node *node, unsigned int tag,
120 : : int offset)
121 : : {
122 : : __clear_bit(offset, node->tags[tag]);
123 : : }
124 : :
125 : : static inline int tag_get(struct radix_tree_node *node, unsigned int tag,
126 : : int offset)
127 : : {
128 : 23817475 : return test_bit(offset, node->tags[tag]);
129 : : }
130 : :
131 : : static inline void root_tag_set(struct radix_tree_root *root, unsigned int tag)
132 : : {
133 : 213799 : root->gfp_mask |= (__force gfp_t)(1 << (tag + __GFP_BITS_SHIFT));
134 : : }
135 : :
136 : : static inline void root_tag_clear(struct radix_tree_root *root, unsigned int tag)
137 : : {
138 : 201095 : root->gfp_mask &= (__force gfp_t)~(1 << (tag + __GFP_BITS_SHIFT));
139 : : }
140 : :
141 : : static inline void root_tag_clear_all(struct radix_tree_root *root)
142 : : {
143 : 87825 : root->gfp_mask &= __GFP_BITS_MASK;
144 : : }
145 : :
146 : : static inline int root_tag_get(struct radix_tree_root *root, unsigned int tag)
147 : : {
148 : 6654531 : return (__force unsigned)root->gfp_mask & (1 << (tag + __GFP_BITS_SHIFT));
149 : : }
150 : :
151 : : /*
152 : : * Returns 1 if any slot in the node has this tag set.
153 : : * Otherwise returns 0.
154 : : */
155 : : static inline int any_tag_set(struct radix_tree_node *node, unsigned int tag)
156 : : {
157 : : int idx;
158 [ + + ]: 6080364 : for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) {
159 [ + + ]: 5628379 : if (node->tags[tag][idx])
160 : : return 1;
161 : : }
162 : : return 0;
163 : : }
164 : :
165 : : /**
166 : : * radix_tree_find_next_bit - find the next set bit in a memory region
167 : : *
168 : : * @addr: The address to base the search on
169 : : * @size: The bitmap size in bits
170 : : * @offset: The bitnumber to start searching at
171 : : *
172 : : * Unrollable variant of find_next_bit() for constant size arrays.
173 : : * Tail bits starting from size to roundup(size, BITS_PER_LONG) must be zero.
174 : : * Returns next bit offset, or size if nothing found.
175 : : */
176 : : static __always_inline unsigned long
177 : : radix_tree_find_next_bit(const unsigned long *addr,
178 : : unsigned long size, unsigned long offset)
179 : : {
180 : : if (!__builtin_constant_p(size))
181 : : return find_next_bit(addr, size, offset);
182 : :
183 [ + + ]: 5831099 : if (offset < size) {
184 : : unsigned long tmp;
185 : :
186 : 650652 : addr += offset / BITS_PER_LONG;
187 : 650652 : tmp = *addr >> (offset % BITS_PER_LONG);
188 [ + + ]: 650652 : if (tmp)
189 : 358094 : return __ffs(tmp) + offset;
190 : 292558 : offset = (offset + BITS_PER_LONG) & ~(BITS_PER_LONG - 1);
191 [ + + ]: 854957 : while (offset < size) {
192 : 201608 : tmp = *++addr;
193 [ + + ]: 201608 : if (tmp)
194 : 72582 : return __ffs(tmp) + offset;
195 : 129026 : offset += BITS_PER_LONG;
196 : : }
197 : : }
198 : : return size;
199 : : }
200 : :
201 : : /*
202 : : * This assumes that the caller has performed appropriate preallocation, and
203 : : * that the caller has pinned this thread of control to the current CPU.
204 : : */
205 : : static struct radix_tree_node *
206 : 0 : radix_tree_node_alloc(struct radix_tree_root *root)
207 : : {
208 : : struct radix_tree_node *ret = NULL;
209 : : gfp_t gfp_mask = root_gfp_mask(root);
210 : :
211 : : /*
212 : : * Preload code isn't irq safe and it doesn't make sence to use
213 : : * preloading in the interrupt anyway as all the allocations have to
214 : : * be atomic. So just do normal allocation when in interrupt.
215 : : */
216 [ + + ][ + ]: 104821 : if (!(gfp_mask & __GFP_WAIT) && !in_interrupt()) {
217 : : struct radix_tree_preload *rtp;
218 : :
219 : : /*
220 : : * Provided the caller has preloaded here, we will always
221 : : * succeed in getting a node here (and never reach
222 : : * kmem_cache_alloc)
223 : : */
224 : 209642 : rtp = &__get_cpu_var(radix_tree_preloads);
225 [ + + ]: 104821 : if (rtp->nr) {
226 : 104820 : ret = rtp->nodes[rtp->nr - 1];
227 : 104820 : rtp->nodes[rtp->nr - 1] = NULL;
228 : 104820 : rtp->nr--;
229 : : }
230 : : }
231 [ # # ]: 104821 : if (ret == NULL)
232 : 0 : ret = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask);
233 : :
234 [ - + ]: 104819 : BUG_ON(radix_tree_is_indirect_ptr(ret));
235 : 104819 : return ret;
236 : : }
237 : :
238 : 0 : static void radix_tree_node_rcu_free(struct rcu_head *head)
239 : : {
240 : 104025 : struct radix_tree_node *node =
241 : : container_of(head, struct radix_tree_node, rcu_head);
242 : : int i;
243 : :
244 : : /*
245 : : * must only free zeroed nodes into the slab. radix_tree_shrink
246 : : * can leave us with a non-NULL entry in the first slot, so clear
247 : : * that here to make sure.
248 : : */
249 [ + + ]: 416138 : for (i = 0; i < RADIX_TREE_MAX_TAGS; i++)
250 : 312113 : tag_clear(node, i, 0);
251 : :
252 : 104025 : node->slots[0] = NULL;
253 : 104025 : node->count = 0;
254 : :
255 : 104025 : kmem_cache_free(radix_tree_node_cachep, node);
256 : 104062 : }
257 : :
258 : : static inline void
259 : : radix_tree_node_free(struct radix_tree_node *node)
260 : : {
261 : 104065 : call_rcu(&node->rcu_head, radix_tree_node_rcu_free);
262 : : }
263 : :
264 : : /*
265 : : * Load up this CPU's radix_tree_node buffer with sufficient objects to
266 : : * ensure that the addition of a single element in the tree cannot fail. On
267 : : * success, return zero, with preemption disabled. On error, return -ENOMEM
268 : : * with preemption not disabled.
269 : : *
270 : : * To make use of this facility, the radix tree must be initialised without
271 : : * __GFP_WAIT being passed to INIT_RADIX_TREE().
272 : : */
273 : 0 : static int __radix_tree_preload(gfp_t gfp_mask)
274 : : {
275 : : struct radix_tree_preload *rtp;
276 : : struct radix_tree_node *node;
277 : : int ret = -ENOMEM;
278 : :
279 : 2196872 : preempt_disable();
280 : 4393496 : rtp = &__get_cpu_var(radix_tree_preloads);
281 [ + + ]: 2301570 : while (rtp->nr < ARRAY_SIZE(rtp->nodes)) {
282 : 104822 : preempt_enable();
283 : 104821 : node = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask);
284 [ + - ]: 104822 : if (node == NULL)
285 : : goto out;
286 : 104822 : preempt_disable();
287 : 209644 : rtp = &__get_cpu_var(radix_tree_preloads);
288 [ + - ]: 104822 : if (rtp->nr < ARRAY_SIZE(rtp->nodes))
289 : 104822 : rtp->nodes[rtp->nr++] = node;
290 : : else
291 : 104822 : kmem_cache_free(radix_tree_node_cachep, node);
292 : : }
293 : : ret = 0;
294 : : out:
295 : 2196748 : return ret;
296 : : }
297 : :
298 : : /*
299 : : * Load up this CPU's radix_tree_node buffer with sufficient objects to
300 : : * ensure that the addition of a single element in the tree cannot fail. On
301 : : * success, return zero, with preemption disabled. On error, return -ENOMEM
302 : : * with preemption not disabled.
303 : : *
304 : : * To make use of this facility, the radix tree must be initialised without
305 : : * __GFP_WAIT being passed to INIT_RADIX_TREE().
306 : : */
307 : 0 : int radix_tree_preload(gfp_t gfp_mask)
308 : : {
309 : : /* Warn on non-sensical use... */
310 [ # # ][ # # ]: 0 : WARN_ON_ONCE(!(gfp_mask & __GFP_WAIT));
[ # # ]
311 : 0 : return __radix_tree_preload(gfp_mask);
312 : : }
313 : : EXPORT_SYMBOL(radix_tree_preload);
314 : :
315 : : /*
316 : : * The same as above function, except we don't guarantee preloading happens.
317 : : * We do it, if we decide it helps. On success, return zero with preemption
318 : : * disabled. On error, return -ENOMEM with preemption not disabled.
319 : : */
320 : 0 : int radix_tree_maybe_preload(gfp_t gfp_mask)
321 : : {
322 [ + - ]: 2196898 : if (gfp_mask & __GFP_WAIT)
323 : 2196898 : return __radix_tree_preload(gfp_mask);
324 : : /* Preloading doesn't help anything with this gfp mask, skip it */
325 : 0 : preempt_disable();
326 : 0 : return 0;
327 : : }
328 : : EXPORT_SYMBOL(radix_tree_maybe_preload);
329 : :
330 : : /*
331 : : * Return the maximum key which can be store into a
332 : : * radix tree with height HEIGHT.
333 : : */
334 : : static inline unsigned long radix_tree_maxindex(unsigned int height)
335 : : {
336 : 94227340 : return height_to_maxindex[height];
337 : : }
338 : :
339 : : /*
340 : : * Extend a radix tree so it can store key @index.
341 : : */
342 : 0 : static int radix_tree_extend(struct radix_tree_root *root, unsigned long index)
343 : : {
344 : : struct radix_tree_node *node;
345 : : struct radix_tree_node *slot;
346 : : unsigned int height;
347 : : int tag;
348 : :
349 : : /* Figure out what the height should be. */
350 : 54438 : height = root->height + 1;
351 [ + + ]: 70178 : while (index > radix_tree_maxindex(height))
352 : 15740 : height++;
353 : :
354 [ + + ]: 54438 : if (root->rnode == NULL) {
355 : 20248 : root->height = height;
356 : 54438 : goto out;
357 : : }
358 : :
359 : : do {
360 : : unsigned int newheight;
361 [ + - ]: 34213 : if (!(node = radix_tree_node_alloc(root)))
362 : : return -ENOMEM;
363 : :
364 : : /* Propagate the aggregated tag info into the new root */
365 [ + + ]: 136852 : for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) {
366 [ + + ]: 102639 : if (root_tag_get(root, tag))
367 : : tag_set(node, tag, 0);
368 : : }
369 : :
370 : : /* Increase the height. */
371 : 34213 : newheight = root->height+1;
372 : 34213 : node->height = newheight;
373 : 34213 : node->count = 1;
374 : 34213 : node->parent = NULL;
375 : 34213 : slot = root->rnode;
376 [ + + ]: 34213 : if (newheight > 1) {
377 : : slot = indirect_to_ptr(slot);
378 : 5638 : slot->parent = node;
379 : : }
380 : 34213 : node->slots[0] = slot;
381 : : node = ptr_to_indirect(node);
382 : 34213 : rcu_assign_pointer(root->rnode, node);
383 : 34213 : root->height = newheight;
384 [ + + ]: 34213 : } while (height > root->height);
385 : : out:
386 : : return 0;
387 : : }
388 : :
389 : : /**
390 : : * radix_tree_insert - insert into a radix tree
391 : : * @root: radix tree root
392 : : * @index: index key
393 : : * @item: item to insert
394 : : *
395 : : * Insert an item into the radix tree at position @index.
396 : : */
397 : 0 : int radix_tree_insert(struct radix_tree_root *root,
398 : : unsigned long index, void *item)
399 : : {
400 : : struct radix_tree_node *node = NULL, *slot;
401 : : unsigned int height, shift;
402 : : int offset;
403 : : int error;
404 : :
405 [ - + ]: 2196936 : BUG_ON(radix_tree_is_indirect_ptr(item));
406 : :
407 : : /* Make sure the tree is high enough. */
408 [ + + ]: 2196936 : if (index > radix_tree_maxindex(root->height)) {
409 : 54439 : error = radix_tree_extend(root, index);
410 [ + ]: 54439 : if (error)
411 : : return error;
412 : : }
413 : :
414 : 2197072 : slot = indirect_to_ptr(root->rnode);
415 : :
416 : 2197072 : height = root->height;
417 : 2197072 : shift = (height-1) * RADIX_TREE_MAP_SHIFT;
418 : :
419 : : offset = 0; /* uninitialised var warning */
420 [ + + ]: 6781146 : while (height > 0) {
421 [ + + ]: 4584298 : if (slot == NULL) {
422 : : /* Have to add a child node. */
423 [ + ]: 70831 : if (!(slot = radix_tree_node_alloc(root)))
424 : : return -ENOMEM;
425 : 70608 : slot->height = height;
426 : 70608 : slot->parent = node;
427 [ + + ]: 70608 : if (node) {
428 : 50360 : rcu_assign_pointer(node->slots[offset], slot);
429 : 50360 : node->count++;
430 : : } else
431 : 20248 : rcu_assign_pointer(root->rnode, ptr_to_indirect(slot));
432 : : }
433 : :
434 : : /* Go a level down */
435 : 4584074 : offset = (index >> shift) & RADIX_TREE_MAP_MASK;
436 : : node = slot;
437 : 4584074 : slot = node->slots[offset];
438 : 4584074 : shift -= RADIX_TREE_MAP_SHIFT;
439 : 4584074 : height--;
440 : : }
441 : :
442 [ + ]: 2196848 : if (slot != NULL)
443 : : return -EEXIST;
444 : :
445 [ + + ]: 2196883 : if (node) {
446 : 2132377 : node->count++;
447 : 2132377 : rcu_assign_pointer(node->slots[offset], item);
448 [ - + ]: 2132341 : BUG_ON(tag_get(node, 0, offset));
449 [ - + ]: 2132341 : BUG_ON(tag_get(node, 1, offset));
450 : : } else {
451 : 64506 : rcu_assign_pointer(root->rnode, item);
452 [ - + ]: 64506 : BUG_ON(root_tag_get(root, 0));
453 [ - + ]: 64506 : BUG_ON(root_tag_get(root, 1));
454 : : }
455 : :
456 : : return 0;
457 : : }
458 : : EXPORT_SYMBOL(radix_tree_insert);
459 : :
460 : : /*
461 : : * is_slot == 1 : search for the slot.
462 : : * is_slot == 0 : search for the node.
463 : : */
464 : 0 : static void *radix_tree_lookup_element(struct radix_tree_root *root,
465 : : unsigned long index, int is_slot)
466 : : {
467 : : unsigned int height, shift;
468 : : struct radix_tree_node *node, **slot;
469 : :
470 : 83841294 : node = rcu_dereference_raw(root->rnode);
471 [ + + ]: 83841294 : if (node == NULL)
472 : : return NULL;
473 : :
474 [ + + ]: 83697284 : if (!radix_tree_is_indirect_ptr(node)) {
475 [ + + ]: 1244751 : if (index > 0)
476 : : return NULL;
477 [ + - ]: 1217623 : return is_slot ? (void *)&root->rnode : node;
478 : : }
479 : : node = indirect_to_ptr(node);
480 : :
481 : 82452533 : height = node->height;
482 [ + + ]: 82452533 : if (index > radix_tree_maxindex(height))
483 : : return NULL;
484 : :
485 : 80594383 : shift = (height-1) * RADIX_TREE_MAP_SHIFT;
486 : :
487 : : do {
488 : 143915090 : slot = (struct radix_tree_node **)
489 : 143915090 : (node->slots + ((index>>shift) & RADIX_TREE_MAP_MASK));
490 : 143915090 : node = rcu_dereference_raw(*slot);
491 [ + ]: 143915090 : if (node == NULL)
492 : : return NULL;
493 : :
494 : 140722789 : shift -= RADIX_TREE_MAP_SHIFT;
495 : 140722789 : height--;
496 [ + + ]: 224564083 : } while (height > 0);
497 : :
498 [ + + ]: 88635370 : return is_slot ? (void *)slot : indirect_to_ptr(node);
499 : : }
500 : :
501 : : /**
502 : : * radix_tree_lookup_slot - lookup a slot in a radix tree
503 : : * @root: radix tree root
504 : : * @index: index key
505 : : *
506 : : * Returns: the slot corresponding to the position @index in the
507 : : * radix tree @root. This is useful for update-if-exists operations.
508 : : *
509 : : * This function can be called under rcu_read_lock iff the slot is not
510 : : * modified by radix_tree_replace_slot, otherwise it must be called
511 : : * exclusive from other writers. Any dereference of the slot must be done
512 : : * using radix_tree_deref_slot.
513 : : */
514 : 0 : void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index)
515 : : {
516 : 72067940 : return (void **)radix_tree_lookup_element(root, index, 1);
517 : : }
518 : : EXPORT_SYMBOL(radix_tree_lookup_slot);
519 : :
520 : : /**
521 : : * radix_tree_lookup - perform lookup operation on a radix tree
522 : : * @root: radix tree root
523 : : * @index: index key
524 : : *
525 : : * Lookup the item at the position @index in the radix tree @root.
526 : : *
527 : : * This function can be called under rcu_read_lock, however the caller
528 : : * must manage lifetimes of leaf nodes (eg. RCU may also be used to free
529 : : * them safely). No RCU barriers are required to access or modify the
530 : : * returned item, however.
531 : : */
532 : 0 : void *radix_tree_lookup(struct radix_tree_root *root, unsigned long index)
533 : : {
534 : 11771472 : return radix_tree_lookup_element(root, index, 0);
535 : : }
536 : : EXPORT_SYMBOL(radix_tree_lookup);
537 : :
538 : : /**
539 : : * radix_tree_tag_set - set a tag on a radix tree node
540 : : * @root: radix tree root
541 : : * @index: index key
542 : : * @tag: tag index
543 : : *
544 : : * Set the search tag (which must be < RADIX_TREE_MAX_TAGS)
545 : : * corresponding to @index in the radix tree. From
546 : : * the root all the way down to the leaf node.
547 : : *
548 : : * Returns the address of the tagged item. Setting a tag on a not-present
549 : : * item is a bug.
550 : : */
551 : 0 : void *radix_tree_tag_set(struct radix_tree_root *root,
552 : : unsigned long index, unsigned int tag)
553 : : {
554 : : unsigned int height, shift;
555 : : struct radix_tree_node *slot;
556 : :
557 : 3171114 : height = root->height;
558 [ - + ]: 3171114 : BUG_ON(index > radix_tree_maxindex(height));
559 : :
560 : 3171114 : slot = indirect_to_ptr(root->rnode);
561 : 3171114 : shift = (height - 1) * RADIX_TREE_MAP_SHIFT;
562 : :
563 [ + + ]: 9881516 : while (height > 0) {
564 : : int offset;
565 : :
566 : 6710296 : offset = (index >> shift) & RADIX_TREE_MAP_MASK;
567 [ + + ]: 6710296 : if (!tag_get(slot, tag, offset))
568 : : tag_set(slot, tag, offset);
569 : 6710296 : slot = slot->slots[offset];
570 [ + ]: 6710296 : BUG_ON(slot == NULL);
571 : 6710402 : shift -= RADIX_TREE_MAP_SHIFT;
572 : 6710402 : height--;
573 : : }
574 : :
575 : : /* set the root's tag bit */
576 [ + ][ + + ]: 3171220 : if (slot && !root_tag_get(root, tag))
577 : : root_tag_set(root, tag);
578 : :
579 : 3171220 : return slot;
580 : : }
581 : : EXPORT_SYMBOL(radix_tree_tag_set);
582 : :
583 : : /**
584 : : * radix_tree_tag_clear - clear a tag on a radix tree node
585 : : * @root: radix tree root
586 : : * @index: index key
587 : : * @tag: tag index
588 : : *
589 : : * Clear the search tag (which must be < RADIX_TREE_MAX_TAGS)
590 : : * corresponding to @index in the radix tree. If
591 : : * this causes the leaf node to have no tags set then clear the tag in the
592 : : * next-to-leaf node, etc.
593 : : *
594 : : * Returns the address of the tagged item on success, else NULL. ie:
595 : : * has the same return value and semantics as radix_tree_lookup().
596 : : */
597 : 0 : void *radix_tree_tag_clear(struct radix_tree_root *root,
598 : : unsigned long index, unsigned int tag)
599 : : {
600 : : struct radix_tree_node *node = NULL;
601 : : struct radix_tree_node *slot = NULL;
602 : : unsigned int height, shift;
603 : : int uninitialized_var(offset);
604 : :
605 : 4103573 : height = root->height;
606 [ + ]: 4103573 : if (index > radix_tree_maxindex(height))
607 : : goto out;
608 : :
609 : 4104136 : shift = height * RADIX_TREE_MAP_SHIFT;
610 : 4104136 : slot = indirect_to_ptr(root->rnode);
611 : :
612 [ + + ]: 13279572 : while (shift) {
613 [ + + ]: 9175943 : if (slot == NULL)
614 : : goto out;
615 : :
616 : 9175436 : shift -= RADIX_TREE_MAP_SHIFT;
617 : 9175436 : offset = (index >> shift) & RADIX_TREE_MAP_MASK;
618 : : node = slot;
619 : 9175436 : slot = slot->slots[offset];
620 : : }
621 : :
622 [ + ]: 4103629 : if (slot == NULL)
623 : : goto out;
624 : :
625 [ + + ]: 4555552 : while (node) {
626 [ + + ]: 4339643 : if (!tag_get(node, tag, offset))
627 : : goto out;
628 : : tag_clear(node, tag, offset);
629 [ + + ]: 3915709 : if (any_tag_set(node, tag))
630 : : goto out;
631 : :
632 : 451954 : index >>= RADIX_TREE_MAP_SHIFT;
633 : 451954 : offset = index & RADIX_TREE_MAP_MASK;
634 : 451954 : node = node->parent;
635 : : }
636 : :
637 : : /* clear the root's tag bit */
638 [ + + ]: 215909 : if (root_tag_get(root, tag))
639 : : root_tag_clear(root, tag);
640 : :
641 : : out:
642 : 0 : return slot;
643 : : }
644 : : EXPORT_SYMBOL(radix_tree_tag_clear);
645 : :
646 : : /**
647 : : * radix_tree_tag_get - get a tag on a radix tree node
648 : : * @root: radix tree root
649 : : * @index: index key
650 : : * @tag: tag index (< RADIX_TREE_MAX_TAGS)
651 : : *
652 : : * Return values:
653 : : *
654 : : * 0: tag not present or not set
655 : : * 1: tag set
656 : : *
657 : : * Note that the return value of this function may not be relied on, even if
658 : : * the RCU lock is held, unless tag modification and node deletion are excluded
659 : : * from concurrency.
660 : : */
661 : 0 : int radix_tree_tag_get(struct radix_tree_root *root,
662 : : unsigned long index, unsigned int tag)
663 : : {
664 : : unsigned int height, shift;
665 : : struct radix_tree_node *node;
666 : :
667 : : /* check the root's tag bit */
668 [ # # ]: 0 : if (!root_tag_get(root, tag))
669 : : return 0;
670 : :
671 : 0 : node = rcu_dereference_raw(root->rnode);
672 [ # # ]: 0 : if (node == NULL)
673 : : return 0;
674 : :
675 [ # # ]: 0 : if (!radix_tree_is_indirect_ptr(node))
676 : 0 : return (index == 0);
677 : : node = indirect_to_ptr(node);
678 : :
679 : 0 : height = node->height;
680 [ # # ]: 0 : if (index > radix_tree_maxindex(height))
681 : : return 0;
682 : :
683 : 0 : shift = (height - 1) * RADIX_TREE_MAP_SHIFT;
684 : :
685 : : for ( ; ; ) {
686 : : int offset;
687 : :
688 [ # # ]: 0 : if (node == NULL)
689 : : return 0;
690 : :
691 : 0 : offset = (index >> shift) & RADIX_TREE_MAP_MASK;
692 [ # # ]: 0 : if (!tag_get(node, tag, offset))
693 : : return 0;
694 [ # # ]: 0 : if (height == 1)
695 : : return 1;
696 : 0 : node = rcu_dereference_raw(node->slots[offset]);
697 : 0 : shift -= RADIX_TREE_MAP_SHIFT;
698 : 0 : height--;
699 : 0 : }
700 : : }
701 : : EXPORT_SYMBOL(radix_tree_tag_get);
702 : :
703 : : /**
704 : : * radix_tree_next_chunk - find next chunk of slots for iteration
705 : : *
706 : : * @root: radix tree root
707 : : * @iter: iterator state
708 : : * @flags: RADIX_TREE_ITER_* flags and tag index
709 : : * Returns: pointer to chunk first slot, or NULL if iteration is over
710 : : */
711 : 0 : void **radix_tree_next_chunk(struct radix_tree_root *root,
712 : : struct radix_tree_iter *iter, unsigned flags)
713 : : {
714 : 5177750 : unsigned shift, tag = flags & RADIX_TREE_ITER_TAG_MASK;
715 : : struct radix_tree_node *rnode, *node;
716 : : unsigned long index, offset;
717 : :
718 [ + + ][ + + ]: 5177750 : if ((flags & RADIX_TREE_ITER_TAGGED) && !root_tag_get(root, tag))
719 : : return NULL;
720 : :
721 : : /*
722 : : * Catch next_index overflow after ~0UL. iter->index never overflows
723 : : * during iterating; it can be zero only at the beginning.
724 : : * And we cannot overflow iter->next_index in a single step,
725 : : * because RADIX_TREE_MAP_SHIFT < BITS_PER_LONG.
726 : : *
727 : : * This condition also used by radix_tree_next_slot() to stop
728 : : * contiguous iterating, and forbid swithing to the next chunk.
729 : : */
730 : 3199719 : index = iter->next_index;
731 [ + + ][ + + ]: 3199719 : if (!index && iter->index)
732 : : return NULL;
733 : :
734 : 3199716 : rnode = rcu_dereference_raw(root->rnode);
735 [ + + ]: 3199716 : if (radix_tree_is_indirect_ptr(rnode)) {
736 : : rnode = indirect_to_ptr(rnode);
737 [ + + ]: 2011851 : } else if (rnode && !index) {
738 : : /* Single-slot tree */
739 : 71048 : iter->index = 0;
740 : 71048 : iter->next_index = 1;
741 : 71048 : iter->tags = 1;
742 : 462314 : return (void **)&root->rnode;
743 : : } else
744 : : return NULL;
745 : :
746 : : restart:
747 : 1579131 : shift = (rnode->height - 1) * RADIX_TREE_MAP_SHIFT;
748 : 1579131 : offset = index >> shift;
749 : :
750 : : /* Index outside of the tree */
751 [ + + ]: 1579131 : if (offset >= RADIX_TREE_MAP_SIZE)
752 : : return NULL;
753 : :
754 : : node = rnode;
755 : : while (1) {
756 [ + + ][ + + ]: 2586187 : if ((flags & RADIX_TREE_ITER_TAGGED) ?
757 : 1437379 : !test_bit(offset, node->tags[tag]) :
758 : 1148808 : !node->slots[offset]) {
759 : : /* Hole detected */
760 [ + ]: 893211 : if (flags & RADIX_TREE_ITER_CONTIG)
761 : : return NULL;
762 : :
763 [ + + ]: 6071012 : if (flags & RADIX_TREE_ITER_TAGGED)
764 : 5831099 : offset = radix_tree_find_next_bit(
765 : 5831099 : node->tags[tag],
766 : : RADIX_TREE_MAP_SIZE,
767 : : offset + 1);
768 : : else
769 [ + + ]: 9029369 : while (++offset < RADIX_TREE_MAP_SIZE) {
770 [ + + ]: 9099582 : if (node->slots[offset])
771 : : break;
772 : : }
773 : 893262 : index &= ~((RADIX_TREE_MAP_SIZE << shift) - 1);
774 : 893262 : index += offset << shift;
775 : : /* Overflow after ~0UL */
776 [ + + ]: 893262 : if (!index)
777 : : return NULL;
778 [ + + ]: 893202 : if (offset == RADIX_TREE_MAP_SIZE)
779 : : goto restart;
780 : : }
781 : :
782 : : /* This is leaf-node */
783 [ + + ]: 2194935 : if (!shift)
784 : : break;
785 : :
786 : 1285923 : node = rcu_dereference_raw(node->slots[offset]);
787 [ + + ]: 1285923 : if (node == NULL)
788 : : goto restart;
789 : 1285900 : shift -= RADIX_TREE_MAP_SHIFT;
790 : 1285900 : offset = (index >> shift) & RADIX_TREE_MAP_MASK;
791 : 1285900 : }
792 : :
793 : : /* Update the iterator state */
794 : 909012 : iter->index = index;
795 : 909012 : iter->next_index = (index | RADIX_TREE_MAP_MASK) + 1;
796 : :
797 : : /* Construct iter->tags bit-mask from node->tags[tag] array */
798 [ + + ]: 909012 : if (flags & RADIX_TREE_ITER_TAGGED) {
799 : : unsigned tag_long, tag_bit;
800 : :
801 : 487226 : tag_long = offset / BITS_PER_LONG;
802 : 487226 : tag_bit = offset % BITS_PER_LONG;
803 : 487226 : iter->tags = node->tags[tag][tag_long] >> tag_bit;
804 : : /* This never happens if RADIX_TREE_TAG_LONGS == 1 */
805 [ + + ]: 487226 : if (tag_long < RADIX_TREE_TAG_LONGS - 1) {
806 : : /* Pick tags from next element */
807 [ + + ]: 252923 : if (tag_bit)
808 : 204100 : iter->tags |= node->tags[tag][tag_long + 1] <<
809 : 204100 : (BITS_PER_LONG - tag_bit);
810 : : /* Clip chunk size, here only BITS_PER_LONG tags */
811 : 252923 : iter->next_index = index + BITS_PER_LONG;
812 : : }
813 : : }
814 : :
815 : 909012 : return node->slots + offset;
816 : : }
817 : : EXPORT_SYMBOL(radix_tree_next_chunk);
818 : :
819 : : /**
820 : : * radix_tree_range_tag_if_tagged - for each item in given range set given
821 : : * tag if item has another tag set
822 : : * @root: radix tree root
823 : : * @first_indexp: pointer to a starting index of a range to scan
824 : : * @last_index: last index of a range to scan
825 : : * @nr_to_tag: maximum number items to tag
826 : : * @iftag: tag index to test
827 : : * @settag: tag index to set if tested tag is set
828 : : *
829 : : * This function scans range of radix tree from first_index to last_index
830 : : * (inclusive). For each item in the range if iftag is set, the function sets
831 : : * also settag. The function stops either after tagging nr_to_tag items or
832 : : * after reaching last_index.
833 : : *
834 : : * The tags must be set from the leaf level only and propagated back up the
835 : : * path to the root. We must do this so that we resolve the full path before
836 : : * setting any tags on intermediate nodes. If we set tags as we descend, then
837 : : * we can get to the leaf node and find that the index that has the iftag
838 : : * set is outside the range we are scanning. This reults in dangling tags and
839 : : * can lead to problems with later tag operations (e.g. livelocks on lookups).
840 : : *
841 : : * The function returns number of leaves where the tag was set and sets
842 : : * *first_indexp to the first unscanned index.
843 : : * WARNING! *first_indexp can wrap if last_index is ULONG_MAX. Caller must
844 : : * be prepared to handle that.
845 : : */
846 : 0 : unsigned long radix_tree_range_tag_if_tagged(struct radix_tree_root *root,
847 : : unsigned long *first_indexp, unsigned long last_index,
848 : : unsigned long nr_to_tag,
849 : : unsigned int iftag, unsigned int settag)
850 : : {
851 : 39127 : unsigned int height = root->height;
852 : : struct radix_tree_node *node = NULL;
853 : : struct radix_tree_node *slot;
854 : : unsigned int shift;
855 : : unsigned long tagged = 0;
856 : 39127 : unsigned long index = *first_indexp;
857 : :
858 : 39127 : last_index = min(last_index, radix_tree_maxindex(height));
859 [ + + ]: 39127 : if (index > last_index)
860 : : return 0;
861 [ + ]: 39125 : if (!nr_to_tag)
862 : : return 0;
863 [ + + ]: 78257 : if (!root_tag_get(root, iftag)) {
864 : 1900 : *first_indexp = last_index + 1;
865 : 1900 : return 0;
866 : : }
867 [ + + ]: 76357 : if (height == 0) {
868 : 2918 : *first_indexp = last_index + 1;
869 : : root_tag_set(root, settag);
870 : 2918 : return 1;
871 : : }
872 : :
873 : 34312 : shift = (height - 1) * RADIX_TREE_MAP_SHIFT;
874 : 34312 : slot = indirect_to_ptr(root->rnode);
875 : :
876 : : for (;;) {
877 : : unsigned long upindex;
878 : : int offset;
879 : :
880 : 4784185 : offset = (index >> shift) & RADIX_TREE_MAP_MASK;
881 [ + + ]: 4784185 : if (!slot->slots[offset])
882 : : goto next;
883 [ + + ]: 1974740 : if (!tag_get(slot, iftag, offset))
884 : : goto next;
885 [ + + ]: 641624 : if (shift) {
886 : : /* Go down one level */
887 : 68809 : shift -= RADIX_TREE_MAP_SHIFT;
888 : : node = slot;
889 : : slot = slot->slots[offset];
890 : 68809 : continue;
891 : : }
892 : :
893 : : /* tag the leaf */
894 : 572815 : tagged++;
895 : : tag_set(slot, settag, offset);
896 : :
897 : : /* walk back up the path tagging interior nodes */
898 : : upindex = index;
899 [ + + ]: 631707 : while (node) {
900 : 68416 : upindex >>= RADIX_TREE_MAP_SHIFT;
901 : 68416 : offset = upindex & RADIX_TREE_MAP_MASK;
902 : :
903 : : /* stop if we find a node with the tag already set */
904 [ + + ]: 68416 : if (tag_get(node, settag, offset))
905 : : break;
906 : : tag_set(node, settag, offset);
907 : 58892 : node = node->parent;
908 : : }
909 : :
910 : : /*
911 : : * Small optimization: now clear that node pointer.
912 : : * Since all of this slot's ancestors now have the tag set
913 : : * from setting it above, we have no further need to walk
914 : : * back up the tree setting tags, until we update slot to
915 : : * point to another radix_tree_node.
916 : : */
917 : : node = NULL;
918 : :
919 : : next:
920 : : /* Go to next item at level determined by 'shift' */
921 : 4715376 : index = ((index >> shift) + 1) << shift;
922 : : /* Overflow can happen when last_index is ~0UL... */
923 [ + + ]: 4715376 : if (index > last_index || !index)
924 : : break;
925 [ + + ]: 4681613 : if (tagged >= nr_to_tag)
926 : : break;
927 [ + + ]: 4736687 : while (((index >> shift) & RADIX_TREE_MAP_MASK) == 0) {
928 : : /*
929 : : * We've fully scanned this node. Go up. Because
930 : : * last_index is guaranteed to be in the tree, what
931 : : * we do below cannot wander astray.
932 : : */
933 : 55623 : slot = slot->parent;
934 : 55623 : shift += RADIX_TREE_MAP_SHIFT;
935 : : }
936 : : }
937 : : /*
938 : : * We need not to tag the root tag if there is no tag which is set with
939 : : * settag within the range from *first_indexp to last_index.
940 : : */
941 [ + + ]: 34312 : if (tagged > 0)
942 : : root_tag_set(root, settag);
943 : 34312 : *first_indexp = index;
944 : :
945 : 34312 : return tagged;
946 : : }
947 : : EXPORT_SYMBOL(radix_tree_range_tag_if_tagged);
948 : :
949 : :
950 : : /**
951 : : * radix_tree_next_hole - find the next hole (not-present entry)
952 : : * @root: tree root
953 : : * @index: index key
954 : : * @max_scan: maximum range to search
955 : : *
956 : : * Search the set [index, min(index+max_scan-1, MAX_INDEX)] for the lowest
957 : : * indexed hole.
958 : : *
959 : : * Returns: the index of the hole if found, otherwise returns an index
960 : : * outside of the set specified (in which case 'return - index >= max_scan'
961 : : * will be true). In rare cases of index wrap-around, 0 will be returned.
962 : : *
963 : : * radix_tree_next_hole may be called under rcu_read_lock. However, like
964 : : * radix_tree_gang_lookup, this will not atomically search a snapshot of
965 : : * the tree at a single point in time. For example, if a hole is created
966 : : * at index 5, then subsequently a hole is created at index 10,
967 : : * radix_tree_next_hole covering both indexes may return 10 if called
968 : : * under rcu_read_lock.
969 : : */
970 : 0 : unsigned long radix_tree_next_hole(struct radix_tree_root *root,
971 : : unsigned long index, unsigned long max_scan)
972 : : {
973 : : unsigned long i;
974 : :
975 [ + + ]: 38142 : for (i = 0; i < max_scan; i++) {
976 [ + + ]: 37673 : if (!radix_tree_lookup(root, index))
977 : : break;
978 : 35857 : index++;
979 [ + - ]: 35857 : if (index == 0)
980 : : break;
981 : : }
982 : :
983 : 0 : return index;
984 : : }
985 : : EXPORT_SYMBOL(radix_tree_next_hole);
986 : :
987 : : /**
988 : : * radix_tree_prev_hole - find the prev hole (not-present entry)
989 : : * @root: tree root
990 : : * @index: index key
991 : : * @max_scan: maximum range to search
992 : : *
993 : : * Search backwards in the range [max(index-max_scan+1, 0), index]
994 : : * for the first hole.
995 : : *
996 : : * Returns: the index of the hole if found, otherwise returns an index
997 : : * outside of the set specified (in which case 'index - return >= max_scan'
998 : : * will be true). In rare cases of wrap-around, ULONG_MAX will be returned.
999 : : *
1000 : : * radix_tree_next_hole may be called under rcu_read_lock. However, like
1001 : : * radix_tree_gang_lookup, this will not atomically search a snapshot of
1002 : : * the tree at a single point in time. For example, if a hole is created
1003 : : * at index 10, then subsequently a hole is created at index 5,
1004 : : * radix_tree_prev_hole covering both indexes may return 5 if called under
1005 : : * rcu_read_lock.
1006 : : */
1007 : 0 : unsigned long radix_tree_prev_hole(struct radix_tree_root *root,
1008 : : unsigned long index, unsigned long max_scan)
1009 : : {
1010 : : unsigned long i;
1011 : :
1012 [ + + ]: 301752 : for (i = 0; i < max_scan; i++) {
1013 [ + + ]: 296556 : if (!radix_tree_lookup(root, index))
1014 : : break;
1015 : 199682 : index--;
1016 [ + + ]: 199682 : if (index == ULONG_MAX)
1017 : : break;
1018 : : }
1019 : :
1020 : 208 : return index;
1021 : : }
1022 : : EXPORT_SYMBOL(radix_tree_prev_hole);
1023 : :
1024 : : /**
1025 : : * radix_tree_gang_lookup - perform multiple lookup on a radix tree
1026 : : * @root: radix tree root
1027 : : * @results: where the results of the lookup are placed
1028 : : * @first_index: start the lookup from this key
1029 : : * @max_items: place up to this many items at *results
1030 : : *
1031 : : * Performs an index-ascending scan of the tree for present items. Places
1032 : : * them at *@results and returns the number of items which were placed at
1033 : : * *@results.
1034 : : *
1035 : : * The implementation is naive.
1036 : : *
1037 : : * Like radix_tree_lookup, radix_tree_gang_lookup may be called under
1038 : : * rcu_read_lock. In this case, rather than the returned results being
1039 : : * an atomic snapshot of the tree at a single point in time, the semantics
1040 : : * of an RCU protected gang lookup are as though multiple radix_tree_lookups
1041 : : * have been issued in individual locks, and results stored in 'results'.
1042 : : */
1043 : : unsigned int
1044 : 0 : radix_tree_gang_lookup(struct radix_tree_root *root, void **results,
1045 : : unsigned long first_index, unsigned int max_items)
1046 : : {
1047 : : struct radix_tree_iter iter;
1048 : : void **slot;
1049 : : unsigned int ret = 0;
1050 : :
1051 [ # # ]: 0 : if (unlikely(!max_items))
1052 : : return 0;
1053 : :
1054 [ # # ][ # # ]: 0 : radix_tree_for_each_slot(slot, root, &iter, first_index) {
1055 : 0 : results[ret] = indirect_to_ptr(rcu_dereference_raw(*slot));
1056 [ # # ]: 0 : if (!results[ret])
1057 : 0 : continue;
1058 [ # # ]: 0 : if (++ret == max_items)
1059 : : break;
1060 : : }
1061 : :
1062 : 0 : return ret;
1063 : : }
1064 : : EXPORT_SYMBOL(radix_tree_gang_lookup);
1065 : :
1066 : : /**
1067 : : * radix_tree_gang_lookup_slot - perform multiple slot lookup on radix tree
1068 : : * @root: radix tree root
1069 : : * @results: where the results of the lookup are placed
1070 : : * @indices: where their indices should be placed (but usually NULL)
1071 : : * @first_index: start the lookup from this key
1072 : : * @max_items: place up to this many items at *results
1073 : : *
1074 : : * Performs an index-ascending scan of the tree for present items. Places
1075 : : * their slots at *@results and returns the number of items which were
1076 : : * placed at *@results.
1077 : : *
1078 : : * The implementation is naive.
1079 : : *
1080 : : * Like radix_tree_gang_lookup as far as RCU and locking goes. Slots must
1081 : : * be dereferenced with radix_tree_deref_slot, and if using only RCU
1082 : : * protection, radix_tree_deref_slot may fail requiring a retry.
1083 : : */
1084 : : unsigned int
1085 : 0 : radix_tree_gang_lookup_slot(struct radix_tree_root *root,
1086 : : void ***results, unsigned long *indices,
1087 : : unsigned long first_index, unsigned int max_items)
1088 : : {
1089 : : struct radix_tree_iter iter;
1090 : : void **slot;
1091 : : unsigned int ret = 0;
1092 : :
1093 [ # # ]: 0 : if (unlikely(!max_items))
1094 : : return 0;
1095 : :
1096 [ # # ][ # # ]: 0 : radix_tree_for_each_slot(slot, root, &iter, first_index) {
1097 : 0 : results[ret] = slot;
1098 [ # # ]: 0 : if (indices)
1099 : 0 : indices[ret] = iter.index;
1100 [ # # ]: 0 : if (++ret == max_items)
1101 : : break;
1102 : : }
1103 : :
1104 : 0 : return ret;
1105 : : }
1106 : : EXPORT_SYMBOL(radix_tree_gang_lookup_slot);
1107 : :
1108 : : /**
1109 : : * radix_tree_gang_lookup_tag - perform multiple lookup on a radix tree
1110 : : * based on a tag
1111 : : * @root: radix tree root
1112 : : * @results: where the results of the lookup are placed
1113 : : * @first_index: start the lookup from this key
1114 : : * @max_items: place up to this many items at *results
1115 : : * @tag: the tag index (< RADIX_TREE_MAX_TAGS)
1116 : : *
1117 : : * Performs an index-ascending scan of the tree for present items which
1118 : : * have the tag indexed by @tag set. Places the items at *@results and
1119 : : * returns the number of items which were placed at *@results.
1120 : : */
1121 : : unsigned int
1122 : 0 : radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results,
1123 : : unsigned long first_index, unsigned int max_items,
1124 : : unsigned int tag)
1125 : : {
1126 : : struct radix_tree_iter iter;
1127 : : void **slot;
1128 : : unsigned int ret = 0;
1129 : :
1130 [ # # ]: 0 : if (unlikely(!max_items))
1131 : : return 0;
1132 : :
1133 [ # # ][ # # ]: 0 : radix_tree_for_each_tagged(slot, root, &iter, first_index, tag) {
1134 : 0 : results[ret] = indirect_to_ptr(rcu_dereference_raw(*slot));
1135 [ # # ]: 0 : if (!results[ret])
1136 : 0 : continue;
1137 [ # # ]: 0 : if (++ret == max_items)
1138 : : break;
1139 : : }
1140 : :
1141 : 0 : return ret;
1142 : : }
1143 : : EXPORT_SYMBOL(radix_tree_gang_lookup_tag);
1144 : :
1145 : : /**
1146 : : * radix_tree_gang_lookup_tag_slot - perform multiple slot lookup on a
1147 : : * radix tree based on a tag
1148 : : * @root: radix tree root
1149 : : * @results: where the results of the lookup are placed
1150 : : * @first_index: start the lookup from this key
1151 : : * @max_items: place up to this many items at *results
1152 : : * @tag: the tag index (< RADIX_TREE_MAX_TAGS)
1153 : : *
1154 : : * Performs an index-ascending scan of the tree for present items which
1155 : : * have the tag indexed by @tag set. Places the slots at *@results and
1156 : : * returns the number of slots which were placed at *@results.
1157 : : */
1158 : : unsigned int
1159 : 0 : radix_tree_gang_lookup_tag_slot(struct radix_tree_root *root, void ***results,
1160 : : unsigned long first_index, unsigned int max_items,
1161 : : unsigned int tag)
1162 : : {
1163 : : struct radix_tree_iter iter;
1164 : : void **slot;
1165 : : unsigned int ret = 0;
1166 : :
1167 [ # # ]: 0 : if (unlikely(!max_items))
1168 : : return 0;
1169 : :
1170 [ # # ][ # # ]: 0 : radix_tree_for_each_tagged(slot, root, &iter, first_index, tag) {
1171 : 0 : results[ret] = slot;
1172 [ # # ]: 0 : if (++ret == max_items)
1173 : : break;
1174 : : }
1175 : :
1176 : 0 : return ret;
1177 : : }
1178 : : EXPORT_SYMBOL(radix_tree_gang_lookup_tag_slot);
1179 : :
1180 : : #if defined(CONFIG_SHMEM) && defined(CONFIG_SWAP)
1181 : : #include <linux/sched.h> /* for cond_resched() */
1182 : :
1183 : : /*
1184 : : * This linear search is at present only useful to shmem_unuse_inode().
1185 : : */
1186 : 0 : static unsigned long __locate(struct radix_tree_node *slot, void *item,
1187 : : unsigned long index, unsigned long *found_index)
1188 : : {
1189 : : unsigned int shift, height;
1190 : : unsigned long i;
1191 : :
1192 : 0 : height = slot->height;
1193 : 0 : shift = (height-1) * RADIX_TREE_MAP_SHIFT;
1194 : :
1195 [ # # ]: 0 : for ( ; height > 1; height--) {
1196 : 0 : i = (index >> shift) & RADIX_TREE_MAP_MASK;
1197 : : for (;;) {
1198 [ # # ]: 0 : if (slot->slots[i] != NULL)
1199 : : break;
1200 : 0 : index &= ~((1UL << shift) - 1);
1201 : 0 : index += 1UL << shift;
1202 [ # # ]: 0 : if (index == 0)
1203 : : goto out; /* 32-bit wraparound */
1204 : 0 : i++;
1205 [ # # ]: 0 : if (i == RADIX_TREE_MAP_SIZE)
1206 : : goto out;
1207 : : }
1208 : :
1209 : 0 : shift -= RADIX_TREE_MAP_SHIFT;
1210 : 0 : slot = rcu_dereference_raw(slot->slots[i]);
1211 [ # # ]: 0 : if (slot == NULL)
1212 : : goto out;
1213 : : }
1214 : :
1215 : : /* Bottom level: check items */
1216 [ # # ]: 0 : for (i = 0; i < RADIX_TREE_MAP_SIZE; i++) {
1217 [ # # ]: 0 : if (slot->slots[i] == item) {
1218 : 0 : *found_index = index + i;
1219 : : index = 0;
1220 : 0 : goto out;
1221 : : }
1222 : : }
1223 : 0 : index += RADIX_TREE_MAP_SIZE;
1224 : : out:
1225 : 0 : return index;
1226 : : }
1227 : :
1228 : : /**
1229 : : * radix_tree_locate_item - search through radix tree for item
1230 : : * @root: radix tree root
1231 : : * @item: item to be found
1232 : : *
1233 : : * Returns index where item was found, or -1 if not found.
1234 : : * Caller must hold no lock (since this time-consuming function needs
1235 : : * to be preemptible), and must check afterwards if item is still there.
1236 : : */
1237 : 0 : unsigned long radix_tree_locate_item(struct radix_tree_root *root, void *item)
1238 : : {
1239 : : struct radix_tree_node *node;
1240 : : unsigned long max_index;
1241 : : unsigned long cur_index = 0;
1242 : 0 : unsigned long found_index = -1;
1243 : :
1244 : : do {
1245 : : rcu_read_lock();
1246 : 0 : node = rcu_dereference_raw(root->rnode);
1247 [ # # ]: 0 : if (!radix_tree_is_indirect_ptr(node)) {
1248 : : rcu_read_unlock();
1249 [ # # ]: 0 : if (node == item)
1250 : 0 : found_index = 0;
1251 : : break;
1252 : : }
1253 : :
1254 : : node = indirect_to_ptr(node);
1255 : 0 : max_index = radix_tree_maxindex(node->height);
1256 [ # # ]: 0 : if (cur_index > max_index)
1257 : : break;
1258 : :
1259 : 0 : cur_index = __locate(node, item, cur_index, &found_index);
1260 : : rcu_read_unlock();
1261 : 0 : cond_resched();
1262 [ # # ]: 0 : } while (cur_index != 0 && cur_index <= max_index);
1263 : :
1264 : 0 : return found_index;
1265 : : }
1266 : : #else
1267 : : unsigned long radix_tree_locate_item(struct radix_tree_root *root, void *item)
1268 : : {
1269 : : return -1;
1270 : : }
1271 : : #endif /* CONFIG_SHMEM && CONFIG_SWAP */
1272 : :
1273 : : /**
1274 : : * radix_tree_shrink - shrink height of a radix tree to minimal
1275 : : * @root radix tree root
1276 : : */
1277 : : static inline void radix_tree_shrink(struct radix_tree_root *root)
1278 : : {
1279 : : /* try to shrink tree height */
1280 [ + + ]: 356646 : while (root->height > 0) {
1281 : 355790 : struct radix_tree_node *to_free = root->rnode;
1282 : : struct radix_tree_node *slot;
1283 : :
1284 [ + + ]: 355790 : BUG_ON(!radix_tree_is_indirect_ptr(to_free));
1285 : : to_free = indirect_to_ptr(to_free);
1286 : :
1287 : : /*
1288 : : * The candidate node has more than one child, or its child
1289 : : * is not at the leftmost slot, we cannot shrink.
1290 : : */
1291 [ + + ]: 355784 : if (to_free->count != 1)
1292 : : break;
1293 [ + + ]: 35879 : if (!to_free->slots[0])
1294 : : break;
1295 : :
1296 : : /*
1297 : : * We don't need rcu_assign_pointer(), since we are simply
1298 : : * moving the node from one part of the tree to another: if it
1299 : : * was safe to dereference the old pointer to it
1300 : : * (to_free->slots[0]), it will be safe to dereference the new
1301 : : * one (root->rnode) as far as dependent read barriers go.
1302 : : */
1303 : : slot = to_free->slots[0];
1304 [ + + ]: 5976 : if (root->height > 1) {
1305 : 5120 : slot->parent = NULL;
1306 : : slot = ptr_to_indirect(slot);
1307 : : }
1308 : 5976 : root->rnode = slot;
1309 : 5976 : root->height--;
1310 : :
1311 : : /*
1312 : : * We have a dilemma here. The node's slot[0] must not be
1313 : : * NULLed in case there are concurrent lookups expecting to
1314 : : * find the item. However if this was a bottom-level node,
1315 : : * then it may be subject to the slot pointer being visible
1316 : : * to callers dereferencing it. If item corresponding to
1317 : : * slot[0] is subsequently deleted, these callers would expect
1318 : : * their slot to become empty sooner or later.
1319 : : *
1320 : : * For example, lockless pagecache will look up a slot, deref
1321 : : * the page pointer, and if the page is 0 refcount it means it
1322 : : * was concurrently deleted from pagecache so try the deref
1323 : : * again. Fortunately there is already a requirement for logic
1324 : : * to retry the entire slot lookup -- the indirect pointer
1325 : : * problem (replacing direct root node with an indirect pointer
1326 : : * also results in a stale slot). So tag the slot as indirect
1327 : : * to force callers to retry.
1328 : : */
1329 [ + + ]: 5976 : if (root->height == 0)
1330 : 856 : *((unsigned long *)&to_free->slots[0]) |=
1331 : : RADIX_TREE_INDIRECT_PTR;
1332 : :
1333 : : radix_tree_node_free(to_free);
1334 : : }
1335 : : }
1336 : :
1337 : : /**
1338 : : * radix_tree_delete - delete an item from a radix tree
1339 : : * @root: radix tree root
1340 : : * @index: index key
1341 : : *
1342 : : * Remove the item at @index from the radix tree rooted at @root.
1343 : : *
1344 : : * Returns the address of the deleted item, or NULL if it was not present.
1345 : : */
1346 : 0 : void *radix_tree_delete(struct radix_tree_root *root, unsigned long index)
1347 : : {
1348 : : struct radix_tree_node *node = NULL;
1349 : : struct radix_tree_node *slot = NULL;
1350 : : struct radix_tree_node *to_free;
1351 : : unsigned int height, shift;
1352 : : int tag;
1353 : : int uninitialized_var(offset);
1354 : :
1355 : 2193879 : height = root->height;
1356 [ + + ]: 2193879 : if (index > radix_tree_maxindex(height))
1357 : : goto out;
1358 : :
1359 : 2193844 : slot = root->rnode;
1360 [ + + ]: 2193844 : if (height == 0) {
1361 : : root_tag_clear_all(root);
1362 : 40589 : root->rnode = NULL;
1363 : 40589 : goto out;
1364 : : }
1365 : : slot = indirect_to_ptr(slot);
1366 : 2153255 : shift = height * RADIX_TREE_MAP_SHIFT;
1367 : :
1368 : : do {
1369 [ + ]: 4949487 : if (slot == NULL)
1370 : : goto out;
1371 : :
1372 : 4949497 : shift -= RADIX_TREE_MAP_SHIFT;
1373 : 4949497 : offset = (index >> shift) & RADIX_TREE_MAP_MASK;
1374 : : node = slot;
1375 : 4949497 : slot = slot->slots[offset];
1376 [ + + ]: 4949497 : } while (shift);
1377 : :
1378 [ + ]: 2153265 : if (slot == NULL)
1379 : : goto out;
1380 : :
1381 : : /*
1382 : : * Clear all tags associated with the item to be deleted.
1383 : : * This way of doing it would be inefficient, but seldom is any set.
1384 : : */
1385 [ + + ]: 8612984 : for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) {
1386 [ + + ]: 6459698 : if (tag_get(node, tag, offset))
1387 : 1180081 : radix_tree_tag_clear(root, index, tag);
1388 : : }
1389 : :
1390 : : to_free = NULL;
1391 : : /* Now free the nodes we do not need anymore */
1392 [ + + ]: 2251376 : while (node) {
1393 : 2204140 : node->slots[offset] = NULL;
1394 : 2204140 : node->count--;
1395 : : /*
1396 : : * Queue the node for deferred freeing after the
1397 : : * last reference to it disappears (set NULL, above).
1398 : : */
1399 [ + + ]: 2204140 : if (to_free)
1400 : : radix_tree_node_free(to_free);
1401 : :
1402 [ + + ]: 2204139 : if (node->count) {
1403 [ + + ]: 2106049 : if (node == indirect_to_ptr(root->rnode))
1404 : : radix_tree_shrink(root);
1405 : : goto out;
1406 : : }
1407 : :
1408 : : /* Node with zero slots in use so free it */
1409 : : to_free = node;
1410 : :
1411 : 98090 : index >>= RADIX_TREE_MAP_SHIFT;
1412 : 98090 : offset = index & RADIX_TREE_MAP_MASK;
1413 : 98090 : node = node->parent;
1414 : : }
1415 : :
1416 : : root_tag_clear_all(root);
1417 : 47236 : root->height = 0;
1418 : 47236 : root->rnode = NULL;
1419 [ + - ]: 47236 : if (to_free)
1420 : : radix_tree_node_free(to_free);
1421 : :
1422 : : out:
1423 : 0 : return slot;
1424 : : }
1425 : : EXPORT_SYMBOL(radix_tree_delete);
1426 : :
1427 : : /**
1428 : : * radix_tree_tagged - test whether any items in the tree are tagged
1429 : : * @root: radix tree root
1430 : : * @tag: tag to test
1431 : : */
1432 : 0 : int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag)
1433 : : {
1434 : 342390 : return root_tag_get(root, tag);
1435 : : }
1436 : : EXPORT_SYMBOL(radix_tree_tagged);
1437 : :
1438 : : static void
1439 : 0 : radix_tree_node_ctor(void *node)
1440 : : {
1441 : 14924 : memset(node, 0, sizeof(struct radix_tree_node));
1442 : 14924 : }
1443 : :
1444 : 0 : static __init unsigned long __maxindex(unsigned int height)
1445 : : {
1446 : 0 : unsigned int width = height * RADIX_TREE_MAP_SHIFT;
1447 : 0 : int shift = RADIX_TREE_INDEX_BITS - width;
1448 : :
1449 [ # # ]: 0 : if (shift < 0)
1450 : : return ~0UL;
1451 [ # # ]: 0 : if (shift >= BITS_PER_LONG)
1452 : : return 0UL;
1453 : 0 : return ~0UL >> shift;
1454 : : }
1455 : :
1456 : 0 : static __init void radix_tree_init_maxindex(void)
1457 : : {
1458 : : unsigned int i;
1459 : :
1460 [ # # ]: 0 : for (i = 0; i < ARRAY_SIZE(height_to_maxindex); i++)
1461 : 0 : height_to_maxindex[i] = __maxindex(i);
1462 : 0 : }
1463 : :
1464 : 0 : static int radix_tree_callback(struct notifier_block *nfb,
1465 : : unsigned long action,
1466 : : void *hcpu)
1467 : : {
1468 : 0 : int cpu = (long)hcpu;
1469 : : struct radix_tree_preload *rtp;
1470 : :
1471 : : /* Free per-cpu pool of perloaded nodes */
1472 [ # # ]: 0 : if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {
1473 : 0 : rtp = &per_cpu(radix_tree_preloads, cpu);
1474 [ # # ]: 0 : while (rtp->nr) {
1475 : 0 : kmem_cache_free(radix_tree_node_cachep,
1476 : 0 : rtp->nodes[rtp->nr-1]);
1477 : 0 : rtp->nodes[rtp->nr-1] = NULL;
1478 : 0 : rtp->nr--;
1479 : : }
1480 : : }
1481 : 0 : return NOTIFY_OK;
1482 : : }
1483 : :
1484 : 0 : void __init radix_tree_init(void)
1485 : : {
1486 : 0 : radix_tree_node_cachep = kmem_cache_create("radix_tree_node",
1487 : : sizeof(struct radix_tree_node), 0,
1488 : : SLAB_PANIC | SLAB_RECLAIM_ACCOUNT,
1489 : : radix_tree_node_ctor);
1490 : 0 : radix_tree_init_maxindex();
1491 : 0 : hotcpu_notifier(radix_tree_callback, 0);
1492 : 0 : }
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