aboutsummaryrefslogtreecommitdiffstats
path: root/lib/idr.c
diff options
context:
space:
mode:
Diffstat (limited to 'lib/idr.c')
-rw-r--r--lib/idr.c1242
1 files changed, 284 insertions, 958 deletions
diff --git a/lib/idr.c b/lib/idr.c
index 52d2979a05e8..b13682bb0a1c 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -1,1068 +1,409 @@
1/* 1#include <linux/bitmap.h>
2 * 2002-10-18 written by Jim Houston jim.houston@ccur.com
3 * Copyright (C) 2002 by Concurrent Computer Corporation
4 * Distributed under the GNU GPL license version 2.
5 *
6 * Modified by George Anzinger to reuse immediately and to use
7 * find bit instructions. Also removed _irq on spinlocks.
8 *
9 * Modified by Nadia Derbey to make it RCU safe.
10 *
11 * Small id to pointer translation service.
12 *
13 * It uses a radix tree like structure as a sparse array indexed
14 * by the id to obtain the pointer. The bitmap makes allocating
15 * a new id quick.
16 *
17 * You call it to allocate an id (an int) an associate with that id a
18 * pointer or what ever, we treat it as a (void *). You can pass this
19 * id to a user for him to pass back at a later time. You then pass
20 * that id to this code and it returns your pointer.
21 */
22
23#ifndef TEST // to test in user space...
24#include <linux/slab.h>
25#include <linux/init.h>
26#include <linux/export.h> 2#include <linux/export.h>
27#endif
28#include <linux/err.h>
29#include <linux/string.h>
30#include <linux/idr.h> 3#include <linux/idr.h>
4#include <linux/slab.h>
31#include <linux/spinlock.h> 5#include <linux/spinlock.h>
32#include <linux/percpu.h>
33
34#define MAX_IDR_SHIFT (sizeof(int) * 8 - 1)
35#define MAX_IDR_BIT (1U << MAX_IDR_SHIFT)
36
37/* Leave the possibility of an incomplete final layer */
38#define MAX_IDR_LEVEL ((MAX_IDR_SHIFT + IDR_BITS - 1) / IDR_BITS)
39 6
40/* Number of id_layer structs to leave in free list */ 7DEFINE_PER_CPU(struct ida_bitmap *, ida_bitmap);
41#define MAX_IDR_FREE (MAX_IDR_LEVEL * 2)
42
43static struct kmem_cache *idr_layer_cache;
44static DEFINE_PER_CPU(struct idr_layer *, idr_preload_head);
45static DEFINE_PER_CPU(int, idr_preload_cnt);
46static DEFINE_SPINLOCK(simple_ida_lock); 8static DEFINE_SPINLOCK(simple_ida_lock);
47 9
48/* the maximum ID which can be allocated given idr->layers */
49static int idr_max(int layers)
50{
51 int bits = min_t(int, layers * IDR_BITS, MAX_IDR_SHIFT);
52
53 return (1 << bits) - 1;
54}
55
56/*
57 * Prefix mask for an idr_layer at @layer. For layer 0, the prefix mask is
58 * all bits except for the lower IDR_BITS. For layer 1, 2 * IDR_BITS, and
59 * so on.
60 */
61static int idr_layer_prefix_mask(int layer)
62{
63 return ~idr_max(layer + 1);
64}
65
66static struct idr_layer *get_from_free_list(struct idr *idp)
67{
68 struct idr_layer *p;
69 unsigned long flags;
70
71 spin_lock_irqsave(&idp->lock, flags);
72 if ((p = idp->id_free)) {
73 idp->id_free = p->ary[0];
74 idp->id_free_cnt--;
75 p->ary[0] = NULL;
76 }
77 spin_unlock_irqrestore(&idp->lock, flags);
78 return(p);
79}
80
81/** 10/**
82 * idr_layer_alloc - allocate a new idr_layer 11 * idr_alloc - allocate an id
83 * @gfp_mask: allocation mask 12 * @idr: idr handle
84 * @layer_idr: optional idr to allocate from
85 *
86 * If @layer_idr is %NULL, directly allocate one using @gfp_mask or fetch
87 * one from the per-cpu preload buffer. If @layer_idr is not %NULL, fetch
88 * an idr_layer from @idr->id_free.
89 *
90 * @layer_idr is to maintain backward compatibility with the old alloc
91 * interface - idr_pre_get() and idr_get_new*() - and will be removed
92 * together with per-pool preload buffer.
93 */
94static struct idr_layer *idr_layer_alloc(gfp_t gfp_mask, struct idr *layer_idr)
95{
96 struct idr_layer *new;
97
98 /* this is the old path, bypass to get_from_free_list() */
99 if (layer_idr)
100 return get_from_free_list(layer_idr);
101
102 /*
103 * Try to allocate directly from kmem_cache. We want to try this
104 * before preload buffer; otherwise, non-preloading idr_alloc()
105 * users will end up taking advantage of preloading ones. As the
106 * following is allowed to fail for preloaded cases, suppress
107 * warning this time.
108 */
109 new = kmem_cache_zalloc(idr_layer_cache, gfp_mask | __GFP_NOWARN);
110 if (new)
111 return new;
112
113 /*
114 * Try to fetch one from the per-cpu preload buffer if in process
115 * context. See idr_preload() for details.
116 */
117 if (!in_interrupt()) {
118 preempt_disable();
119 new = __this_cpu_read(idr_preload_head);
120 if (new) {
121 __this_cpu_write(idr_preload_head, new->ary[0]);
122 __this_cpu_dec(idr_preload_cnt);
123 new->ary[0] = NULL;
124 }
125 preempt_enable();
126 if (new)
127 return new;
128 }
129
130 /*
131 * Both failed. Try kmem_cache again w/o adding __GFP_NOWARN so
132 * that memory allocation failure warning is printed as intended.
133 */
134 return kmem_cache_zalloc(idr_layer_cache, gfp_mask);
135}
136
137static void idr_layer_rcu_free(struct rcu_head *head)
138{
139 struct idr_layer *layer;
140
141 layer = container_of(head, struct idr_layer, rcu_head);
142 kmem_cache_free(idr_layer_cache, layer);
143}
144
145static inline void free_layer(struct idr *idr, struct idr_layer *p)
146{
147 if (idr->hint == p)
148 RCU_INIT_POINTER(idr->hint, NULL);
149 call_rcu(&p->rcu_head, idr_layer_rcu_free);
150}
151
152/* only called when idp->lock is held */
153static void __move_to_free_list(struct idr *idp, struct idr_layer *p)
154{
155 p->ary[0] = idp->id_free;
156 idp->id_free = p;
157 idp->id_free_cnt++;
158}
159
160static void move_to_free_list(struct idr *idp, struct idr_layer *p)
161{
162 unsigned long flags;
163
164 /*
165 * Depends on the return element being zeroed.
166 */
167 spin_lock_irqsave(&idp->lock, flags);
168 __move_to_free_list(idp, p);
169 spin_unlock_irqrestore(&idp->lock, flags);
170}
171
172static void idr_mark_full(struct idr_layer **pa, int id)
173{
174 struct idr_layer *p = pa[0];
175 int l = 0;
176
177 __set_bit(id & IDR_MASK, p->bitmap);
178 /*
179 * If this layer is full mark the bit in the layer above to
180 * show that this part of the radix tree is full. This may
181 * complete the layer above and require walking up the radix
182 * tree.
183 */
184 while (bitmap_full(p->bitmap, IDR_SIZE)) {
185 if (!(p = pa[++l]))
186 break;
187 id = id >> IDR_BITS;
188 __set_bit((id & IDR_MASK), p->bitmap);
189 }
190}
191
192static int __idr_pre_get(struct idr *idp, gfp_t gfp_mask)
193{
194 while (idp->id_free_cnt < MAX_IDR_FREE) {
195 struct idr_layer *new;
196 new = kmem_cache_zalloc(idr_layer_cache, gfp_mask);
197 if (new == NULL)
198 return (0);
199 move_to_free_list(idp, new);
200 }
201 return 1;
202}
203
204/**
205 * sub_alloc - try to allocate an id without growing the tree depth
206 * @idp: idr handle
207 * @starting_id: id to start search at
208 * @pa: idr_layer[MAX_IDR_LEVEL] used as backtrack buffer
209 * @gfp_mask: allocation mask for idr_layer_alloc()
210 * @layer_idr: optional idr passed to idr_layer_alloc()
211 *
212 * Allocate an id in range [@starting_id, INT_MAX] from @idp without
213 * growing its depth. Returns
214 *
215 * the allocated id >= 0 if successful,
216 * -EAGAIN if the tree needs to grow for allocation to succeed,
217 * -ENOSPC if the id space is exhausted,
218 * -ENOMEM if more idr_layers need to be allocated.
219 */
220static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa,
221 gfp_t gfp_mask, struct idr *layer_idr)
222{
223 int n, m, sh;
224 struct idr_layer *p, *new;
225 int l, id, oid;
226
227 id = *starting_id;
228 restart:
229 p = idp->top;
230 l = idp->layers;
231 pa[l--] = NULL;
232 while (1) {
233 /*
234 * We run around this while until we reach the leaf node...
235 */
236 n = (id >> (IDR_BITS*l)) & IDR_MASK;
237 m = find_next_zero_bit(p->bitmap, IDR_SIZE, n);
238 if (m == IDR_SIZE) {
239 /* no space available go back to previous layer. */
240 l++;
241 oid = id;
242 id = (id | ((1 << (IDR_BITS * l)) - 1)) + 1;
243
244 /* if already at the top layer, we need to grow */
245 if (id > idr_max(idp->layers)) {
246 *starting_id = id;
247 return -EAGAIN;
248 }
249 p = pa[l];
250 BUG_ON(!p);
251
252 /* If we need to go up one layer, continue the
253 * loop; otherwise, restart from the top.
254 */
255 sh = IDR_BITS * (l + 1);
256 if (oid >> sh == id >> sh)
257 continue;
258 else
259 goto restart;
260 }
261 if (m != n) {
262 sh = IDR_BITS*l;
263 id = ((id >> sh) ^ n ^ m) << sh;
264 }
265 if ((id >= MAX_IDR_BIT) || (id < 0))
266 return -ENOSPC;
267 if (l == 0)
268 break;
269 /*
270 * Create the layer below if it is missing.
271 */
272 if (!p->ary[m]) {
273 new = idr_layer_alloc(gfp_mask, layer_idr);
274 if (!new)
275 return -ENOMEM;
276 new->layer = l-1;
277 new->prefix = id & idr_layer_prefix_mask(new->layer);
278 rcu_assign_pointer(p->ary[m], new);
279 p->count++;
280 }
281 pa[l--] = p;
282 p = p->ary[m];
283 }
284
285 pa[l] = p;
286 return id;
287}
288
289static int idr_get_empty_slot(struct idr *idp, int starting_id,
290 struct idr_layer **pa, gfp_t gfp_mask,
291 struct idr *layer_idr)
292{
293 struct idr_layer *p, *new;
294 int layers, v, id;
295 unsigned long flags;
296
297 id = starting_id;
298build_up:
299 p = idp->top;
300 layers = idp->layers;
301 if (unlikely(!p)) {
302 if (!(p = idr_layer_alloc(gfp_mask, layer_idr)))
303 return -ENOMEM;
304 p->layer = 0;
305 layers = 1;
306 }
307 /*
308 * Add a new layer to the top of the tree if the requested
309 * id is larger than the currently allocated space.
310 */
311 while (id > idr_max(layers)) {
312 layers++;
313 if (!p->count) {
314 /* special case: if the tree is currently empty,
315 * then we grow the tree by moving the top node
316 * upwards.
317 */
318 p->layer++;
319 WARN_ON_ONCE(p->prefix);
320 continue;
321 }
322 if (!(new = idr_layer_alloc(gfp_mask, layer_idr))) {
323 /*
324 * The allocation failed. If we built part of
325 * the structure tear it down.
326 */
327 spin_lock_irqsave(&idp->lock, flags);
328 for (new = p; p && p != idp->top; new = p) {
329 p = p->ary[0];
330 new->ary[0] = NULL;
331 new->count = 0;
332 bitmap_clear(new->bitmap, 0, IDR_SIZE);
333 __move_to_free_list(idp, new);
334 }
335 spin_unlock_irqrestore(&idp->lock, flags);
336 return -ENOMEM;
337 }
338 new->ary[0] = p;
339 new->count = 1;
340 new->layer = layers-1;
341 new->prefix = id & idr_layer_prefix_mask(new->layer);
342 if (bitmap_full(p->bitmap, IDR_SIZE))
343 __set_bit(0, new->bitmap);
344 p = new;
345 }
346 rcu_assign_pointer(idp->top, p);
347 idp->layers = layers;
348 v = sub_alloc(idp, &id, pa, gfp_mask, layer_idr);
349 if (v == -EAGAIN)
350 goto build_up;
351 return(v);
352}
353
354/*
355 * @id and @pa are from a successful allocation from idr_get_empty_slot().
356 * Install the user pointer @ptr and mark the slot full.
357 */
358static void idr_fill_slot(struct idr *idr, void *ptr, int id,
359 struct idr_layer **pa)
360{
361 /* update hint used for lookup, cleared from free_layer() */
362 rcu_assign_pointer(idr->hint, pa[0]);
363
364 rcu_assign_pointer(pa[0]->ary[id & IDR_MASK], (struct idr_layer *)ptr);
365 pa[0]->count++;
366 idr_mark_full(pa, id);
367}
368
369
370/**
371 * idr_preload - preload for idr_alloc()
372 * @gfp_mask: allocation mask to use for preloading
373 *
374 * Preload per-cpu layer buffer for idr_alloc(). Can only be used from
375 * process context and each idr_preload() invocation should be matched with
376 * idr_preload_end(). Note that preemption is disabled while preloaded.
377 *
378 * The first idr_alloc() in the preloaded section can be treated as if it
379 * were invoked with @gfp_mask used for preloading. This allows using more
380 * permissive allocation masks for idrs protected by spinlocks.
381 *
382 * For example, if idr_alloc() below fails, the failure can be treated as
383 * if idr_alloc() were called with GFP_KERNEL rather than GFP_NOWAIT.
384 *
385 * idr_preload(GFP_KERNEL);
386 * spin_lock(lock);
387 *
388 * id = idr_alloc(idr, ptr, start, end, GFP_NOWAIT);
389 *
390 * spin_unlock(lock);
391 * idr_preload_end();
392 * if (id < 0)
393 * error;
394 */
395void idr_preload(gfp_t gfp_mask)
396{
397 /*
398 * Consuming preload buffer from non-process context breaks preload
399 * allocation guarantee. Disallow usage from those contexts.
400 */
401 WARN_ON_ONCE(in_interrupt());
402 might_sleep_if(gfpflags_allow_blocking(gfp_mask));
403
404 preempt_disable();
405
406 /*
407 * idr_alloc() is likely to succeed w/o full idr_layer buffer and
408 * return value from idr_alloc() needs to be checked for failure
409 * anyway. Silently give up if allocation fails. The caller can
410 * treat failures from idr_alloc() as if idr_alloc() were called
411 * with @gfp_mask which should be enough.
412 */
413 while (__this_cpu_read(idr_preload_cnt) < MAX_IDR_FREE) {
414 struct idr_layer *new;
415
416 preempt_enable();
417 new = kmem_cache_zalloc(idr_layer_cache, gfp_mask);
418 preempt_disable();
419 if (!new)
420 break;
421
422 /* link the new one to per-cpu preload list */
423 new->ary[0] = __this_cpu_read(idr_preload_head);
424 __this_cpu_write(idr_preload_head, new);
425 __this_cpu_inc(idr_preload_cnt);
426 }
427}
428EXPORT_SYMBOL(idr_preload);
429
430/**
431 * idr_alloc - allocate new idr entry
432 * @idr: the (initialized) idr
433 * @ptr: pointer to be associated with the new id 13 * @ptr: pointer to be associated with the new id
434 * @start: the minimum id (inclusive) 14 * @start: the minimum id (inclusive)
435 * @end: the maximum id (exclusive, <= 0 for max) 15 * @end: the maximum id (exclusive)
436 * @gfp_mask: memory allocation flags 16 * @gfp: memory allocation flags
437 * 17 *
438 * Allocate an id in [start, end) and associate it with @ptr. If no ID is 18 * Allocates an unused ID in the range [start, end). Returns -ENOSPC
439 * available in the specified range, returns -ENOSPC. On memory allocation 19 * if there are no unused IDs in that range.
440 * failure, returns -ENOMEM.
441 * 20 *
442 * Note that @end is treated as max when <= 0. This is to always allow 21 * Note that @end is treated as max when <= 0. This is to always allow
443 * using @start + N as @end as long as N is inside integer range. 22 * using @start + N as @end as long as N is inside integer range.
444 * 23 *
445 * The user is responsible for exclusively synchronizing all operations 24 * Simultaneous modifications to the @idr are not allowed and should be
446 * which may modify @idr. However, read-only accesses such as idr_find() 25 * prevented by the user, usually with a lock. idr_alloc() may be called
447 * or iteration can be performed under RCU read lock provided the user 26 * concurrently with read-only accesses to the @idr, such as idr_find() and
448 * destroys @ptr in RCU-safe way after removal from idr. 27 * idr_for_each_entry().
449 */ 28 */
450int idr_alloc(struct idr *idr, void *ptr, int start, int end, gfp_t gfp_mask) 29int idr_alloc(struct idr *idr, void *ptr, int start, int end, gfp_t gfp)
451{ 30{
452 int max = end > 0 ? end - 1 : INT_MAX; /* inclusive upper limit */ 31 void __rcu **slot;
453 struct idr_layer *pa[MAX_IDR_LEVEL + 1]; 32 struct radix_tree_iter iter;
454 int id;
455 33
456 might_sleep_if(gfpflags_allow_blocking(gfp_mask));
457
458 /* sanity checks */
459 if (WARN_ON_ONCE(start < 0)) 34 if (WARN_ON_ONCE(start < 0))
460 return -EINVAL; 35 return -EINVAL;
461 if (unlikely(max < start)) 36 if (WARN_ON_ONCE(radix_tree_is_internal_node(ptr)))
462 return -ENOSPC; 37 return -EINVAL;
463 38
464 /* allocate id */ 39 radix_tree_iter_init(&iter, start);
465 id = idr_get_empty_slot(idr, start, pa, gfp_mask, NULL); 40 slot = idr_get_free(&idr->idr_rt, &iter, gfp, end);
466 if (unlikely(id < 0)) 41 if (IS_ERR(slot))
467 return id; 42 return PTR_ERR(slot);
468 if (unlikely(id > max))
469 return -ENOSPC;
470 43
471 idr_fill_slot(idr, ptr, id, pa); 44 radix_tree_iter_replace(&idr->idr_rt, &iter, slot, ptr);
472 return id; 45 radix_tree_iter_tag_clear(&idr->idr_rt, &iter, IDR_FREE);
46 return iter.index;
473} 47}
474EXPORT_SYMBOL_GPL(idr_alloc); 48EXPORT_SYMBOL_GPL(idr_alloc);
475 49
476/** 50/**
477 * idr_alloc_cyclic - allocate new idr entry in a cyclical fashion 51 * idr_alloc_cyclic - allocate new idr entry in a cyclical fashion
478 * @idr: the (initialized) idr 52 * @idr: idr handle
479 * @ptr: pointer to be associated with the new id 53 * @ptr: pointer to be associated with the new id
480 * @start: the minimum id (inclusive) 54 * @start: the minimum id (inclusive)
481 * @end: the maximum id (exclusive, <= 0 for max) 55 * @end: the maximum id (exclusive)
482 * @gfp_mask: memory allocation flags 56 * @gfp: memory allocation flags
483 *
484 * Essentially the same as idr_alloc, but prefers to allocate progressively
485 * higher ids if it can. If the "cur" counter wraps, then it will start again
486 * at the "start" end of the range and allocate one that has already been used.
487 */
488int idr_alloc_cyclic(struct idr *idr, void *ptr, int start, int end,
489 gfp_t gfp_mask)
490{
491 int id;
492
493 id = idr_alloc(idr, ptr, max(start, idr->cur), end, gfp_mask);
494 if (id == -ENOSPC)
495 id = idr_alloc(idr, ptr, start, end, gfp_mask);
496
497 if (likely(id >= 0))
498 idr->cur = id + 1;
499 return id;
500}
501EXPORT_SYMBOL(idr_alloc_cyclic);
502
503static void idr_remove_warning(int id)
504{
505 WARN(1, "idr_remove called for id=%d which is not allocated.\n", id);
506}
507
508static void sub_remove(struct idr *idp, int shift, int id)
509{
510 struct idr_layer *p = idp->top;
511 struct idr_layer **pa[MAX_IDR_LEVEL + 1];
512 struct idr_layer ***paa = &pa[0];
513 struct idr_layer *to_free;
514 int n;
515
516 *paa = NULL;
517 *++paa = &idp->top;
518
519 while ((shift > 0) && p) {
520 n = (id >> shift) & IDR_MASK;
521 __clear_bit(n, p->bitmap);
522 *++paa = &p->ary[n];
523 p = p->ary[n];
524 shift -= IDR_BITS;
525 }
526 n = id & IDR_MASK;
527 if (likely(p != NULL && test_bit(n, p->bitmap))) {
528 __clear_bit(n, p->bitmap);
529 RCU_INIT_POINTER(p->ary[n], NULL);
530 to_free = NULL;
531 while(*paa && ! --((**paa)->count)){
532 if (to_free)
533 free_layer(idp, to_free);
534 to_free = **paa;
535 **paa-- = NULL;
536 }
537 if (!*paa)
538 idp->layers = 0;
539 if (to_free)
540 free_layer(idp, to_free);
541 } else
542 idr_remove_warning(id);
543}
544
545/**
546 * idr_remove - remove the given id and free its slot
547 * @idp: idr handle
548 * @id: unique key
549 */
550void idr_remove(struct idr *idp, int id)
551{
552 struct idr_layer *p;
553 struct idr_layer *to_free;
554
555 if (id < 0)
556 return;
557
558 if (id > idr_max(idp->layers)) {
559 idr_remove_warning(id);
560 return;
561 }
562
563 sub_remove(idp, (idp->layers - 1) * IDR_BITS, id);
564 if (idp->top && idp->top->count == 1 && (idp->layers > 1) &&
565 idp->top->ary[0]) {
566 /*
567 * Single child at leftmost slot: we can shrink the tree.
568 * This level is not needed anymore since when layers are
569 * inserted, they are inserted at the top of the existing
570 * tree.
571 */
572 to_free = idp->top;
573 p = idp->top->ary[0];
574 rcu_assign_pointer(idp->top, p);
575 --idp->layers;
576 to_free->count = 0;
577 bitmap_clear(to_free->bitmap, 0, IDR_SIZE);
578 free_layer(idp, to_free);
579 }
580}
581EXPORT_SYMBOL(idr_remove);
582
583static void __idr_remove_all(struct idr *idp)
584{
585 int n, id, max;
586 int bt_mask;
587 struct idr_layer *p;
588 struct idr_layer *pa[MAX_IDR_LEVEL + 1];
589 struct idr_layer **paa = &pa[0];
590
591 n = idp->layers * IDR_BITS;
592 *paa = idp->top;
593 RCU_INIT_POINTER(idp->top, NULL);
594 max = idr_max(idp->layers);
595
596 id = 0;
597 while (id >= 0 && id <= max) {
598 p = *paa;
599 while (n > IDR_BITS && p) {
600 n -= IDR_BITS;
601 p = p->ary[(id >> n) & IDR_MASK];
602 *++paa = p;
603 }
604
605 bt_mask = id;
606 id += 1 << n;
607 /* Get the highest bit that the above add changed from 0->1. */
608 while (n < fls(id ^ bt_mask)) {
609 if (*paa)
610 free_layer(idp, *paa);
611 n += IDR_BITS;
612 --paa;
613 }
614 }
615 idp->layers = 0;
616}
617
618/**
619 * idr_destroy - release all cached layers within an idr tree
620 * @idp: idr handle
621 *
622 * Free all id mappings and all idp_layers. After this function, @idp is
623 * completely unused and can be freed / recycled. The caller is
624 * responsible for ensuring that no one else accesses @idp during or after
625 * idr_destroy().
626 * 57 *
627 * A typical clean-up sequence for objects stored in an idr tree will use 58 * Allocates an ID larger than the last ID allocated if one is available.
628 * idr_for_each() to free all objects, if necessary, then idr_destroy() to 59 * If not, it will attempt to allocate the smallest ID that is larger or
629 * free up the id mappings and cached idr_layers. 60 * equal to @start.
630 */ 61 */
631void idr_destroy(struct idr *idp) 62int idr_alloc_cyclic(struct idr *idr, void *ptr, int start, int end, gfp_t gfp)
632{ 63{
633 __idr_remove_all(idp); 64 int id, curr = idr->idr_next;
634 65
635 while (idp->id_free_cnt) { 66 if (curr < start)
636 struct idr_layer *p = get_from_free_list(idp); 67 curr = start;
637 kmem_cache_free(idr_layer_cache, p);
638 }
639}
640EXPORT_SYMBOL(idr_destroy);
641 68
642void *idr_find_slowpath(struct idr *idp, int id) 69 id = idr_alloc(idr, ptr, curr, end, gfp);
643{ 70 if ((id == -ENOSPC) && (curr > start))
644 int n; 71 id = idr_alloc(idr, ptr, start, curr, gfp);
645 struct idr_layer *p;
646
647 if (id < 0)
648 return NULL;
649
650 p = rcu_dereference_raw(idp->top);
651 if (!p)
652 return NULL;
653 n = (p->layer+1) * IDR_BITS;
654 72
655 if (id > idr_max(p->layer + 1)) 73 if (id >= 0)
656 return NULL; 74 idr->idr_next = id + 1U;
657 BUG_ON(n == 0);
658 75
659 while (n > 0 && p) { 76 return id;
660 n -= IDR_BITS;
661 BUG_ON(n != p->layer*IDR_BITS);
662 p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]);
663 }
664 return((void *)p);
665} 77}
666EXPORT_SYMBOL(idr_find_slowpath); 78EXPORT_SYMBOL(idr_alloc_cyclic);
667 79
668/** 80/**
669 * idr_for_each - iterate through all stored pointers 81 * idr_for_each - iterate through all stored pointers
670 * @idp: idr handle 82 * @idr: idr handle
671 * @fn: function to be called for each pointer 83 * @fn: function to be called for each pointer
672 * @data: data passed back to callback function 84 * @data: data passed to callback function
673 * 85 *
674 * Iterate over the pointers registered with the given idr. The 86 * The callback function will be called for each entry in @idr, passing
675 * callback function will be called for each pointer currently 87 * the id, the pointer and the data pointer passed to this function.
676 * registered, passing the id, the pointer and the data pointer passed
677 * to this function. It is not safe to modify the idr tree while in
678 * the callback, so functions such as idr_get_new and idr_remove are
679 * not allowed.
680 * 88 *
681 * We check the return of @fn each time. If it returns anything other 89 * If @fn returns anything other than %0, the iteration stops and that
682 * than %0, we break out and return that value. 90 * value is returned from this function.
683 * 91 *
684 * The caller must serialize idr_for_each() vs idr_get_new() and idr_remove(). 92 * idr_for_each() can be called concurrently with idr_alloc() and
93 * idr_remove() if protected by RCU. Newly added entries may not be
94 * seen and deleted entries may be seen, but adding and removing entries
95 * will not cause other entries to be skipped, nor spurious ones to be seen.
685 */ 96 */
686int idr_for_each(struct idr *idp, 97int idr_for_each(const struct idr *idr,
687 int (*fn)(int id, void *p, void *data), void *data) 98 int (*fn)(int id, void *p, void *data), void *data)
688{ 99{
689 int n, id, max, error = 0; 100 struct radix_tree_iter iter;
690 struct idr_layer *p; 101 void __rcu **slot;
691 struct idr_layer *pa[MAX_IDR_LEVEL + 1];
692 struct idr_layer **paa = &pa[0];
693
694 n = idp->layers * IDR_BITS;
695 *paa = rcu_dereference_raw(idp->top);
696 max = idr_max(idp->layers);
697 102
698 id = 0; 103 radix_tree_for_each_slot(slot, &idr->idr_rt, &iter, 0) {
699 while (id >= 0 && id <= max) { 104 int ret = fn(iter.index, rcu_dereference_raw(*slot), data);
700 p = *paa; 105 if (ret)
701 while (n > 0 && p) { 106 return ret;
702 n -= IDR_BITS;
703 p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]);
704 *++paa = p;
705 }
706
707 if (p) {
708 error = fn(id, (void *)p, data);
709 if (error)
710 break;
711 }
712
713 id += 1 << n;
714 while (n < fls(id)) {
715 n += IDR_BITS;
716 --paa;
717 }
718 } 107 }
719 108
720 return error; 109 return 0;
721} 110}
722EXPORT_SYMBOL(idr_for_each); 111EXPORT_SYMBOL(idr_for_each);
723 112
724/** 113/**
725 * idr_get_next - lookup next object of id to given id. 114 * idr_get_next - Find next populated entry
726 * @idp: idr handle 115 * @idr: idr handle
727 * @nextidp: pointer to lookup key 116 * @nextid: Pointer to lowest possible ID to return
728 * 117 *
729 * Returns pointer to registered object with id, which is next number to 118 * Returns the next populated entry in the tree with an ID greater than
730 * given id. After being looked up, *@nextidp will be updated for the next 119 * or equal to the value pointed to by @nextid. On exit, @nextid is updated
731 * iteration. 120 * to the ID of the found value. To use in a loop, the value pointed to by
732 * 121 * nextid must be incremented by the user.
733 * This function can be called under rcu_read_lock(), given that the leaf
734 * pointers lifetimes are correctly managed.
735 */ 122 */
736void *idr_get_next(struct idr *idp, int *nextidp) 123void *idr_get_next(struct idr *idr, int *nextid)
737{ 124{
738 struct idr_layer *p, *pa[MAX_IDR_LEVEL + 1]; 125 struct radix_tree_iter iter;
739 struct idr_layer **paa = &pa[0]; 126 void __rcu **slot;
740 int id = *nextidp;
741 int n, max;
742 127
743 /* find first ent */ 128 slot = radix_tree_iter_find(&idr->idr_rt, &iter, *nextid);
744 p = *paa = rcu_dereference_raw(idp->top); 129 if (!slot)
745 if (!p)
746 return NULL; 130 return NULL;
747 n = (p->layer + 1) * IDR_BITS;
748 max = idr_max(p->layer + 1);
749
750 while (id >= 0 && id <= max) {
751 p = *paa;
752 while (n > 0 && p) {
753 n -= IDR_BITS;
754 p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]);
755 *++paa = p;
756 }
757
758 if (p) {
759 *nextidp = id;
760 return p;
761 }
762 131
763 /* 132 *nextid = iter.index;
764 * Proceed to the next layer at the current level. Unlike 133 return rcu_dereference_raw(*slot);
765 * idr_for_each(), @id isn't guaranteed to be aligned to
766 * layer boundary at this point and adding 1 << n may
767 * incorrectly skip IDs. Make sure we jump to the
768 * beginning of the next layer using round_up().
769 */
770 id = round_up(id + 1, 1 << n);
771 while (n < fls(id)) {
772 n += IDR_BITS;
773 --paa;
774 }
775 }
776 return NULL;
777} 134}
778EXPORT_SYMBOL(idr_get_next); 135EXPORT_SYMBOL(idr_get_next);
779 136
780
781/** 137/**
782 * idr_replace - replace pointer for given id 138 * idr_replace - replace pointer for given id
783 * @idp: idr handle 139 * @idr: idr handle
784 * @ptr: pointer you want associated with the id 140 * @ptr: New pointer to associate with the ID
785 * @id: lookup key 141 * @id: Lookup key
786 * 142 *
787 * Replace the pointer registered with an id and return the old value. 143 * Replace the pointer registered with an ID and return the old value.
788 * A %-ENOENT return indicates that @id was not found. 144 * This function can be called under the RCU read lock concurrently with
789 * A %-EINVAL return indicates that @id was not within valid constraints. 145 * idr_alloc() and idr_remove() (as long as the ID being removed is not
146 * the one being replaced!).
790 * 147 *
791 * The caller must serialize with writers. 148 * Returns: 0 on success. %-ENOENT indicates that @id was not found.
149 * %-EINVAL indicates that @id or @ptr were not valid.
792 */ 150 */
793void *idr_replace(struct idr *idp, void *ptr, int id) 151void *idr_replace(struct idr *idr, void *ptr, int id)
794{ 152{
795 int n; 153 struct radix_tree_node *node;
796 struct idr_layer *p, *old_p; 154 void __rcu **slot = NULL;
155 void *entry;
797 156
798 if (id < 0) 157 if (WARN_ON_ONCE(id < 0))
158 return ERR_PTR(-EINVAL);
159 if (WARN_ON_ONCE(radix_tree_is_internal_node(ptr)))
799 return ERR_PTR(-EINVAL); 160 return ERR_PTR(-EINVAL);
800 161
801 p = idp->top; 162 entry = __radix_tree_lookup(&idr->idr_rt, id, &node, &slot);
802 if (!p) 163 if (!slot || radix_tree_tag_get(&idr->idr_rt, id, IDR_FREE))
803 return ERR_PTR(-ENOENT);
804
805 if (id > idr_max(p->layer + 1))
806 return ERR_PTR(-ENOENT);
807
808 n = p->layer * IDR_BITS;
809 while ((n > 0) && p) {
810 p = p->ary[(id >> n) & IDR_MASK];
811 n -= IDR_BITS;
812 }
813
814 n = id & IDR_MASK;
815 if (unlikely(p == NULL || !test_bit(n, p->bitmap)))
816 return ERR_PTR(-ENOENT); 164 return ERR_PTR(-ENOENT);
817 165
818 old_p = p->ary[n]; 166 __radix_tree_replace(&idr->idr_rt, node, slot, ptr, NULL, NULL);
819 rcu_assign_pointer(p->ary[n], ptr);
820 167
821 return old_p; 168 return entry;
822} 169}
823EXPORT_SYMBOL(idr_replace); 170EXPORT_SYMBOL(idr_replace);
824 171
825void __init idr_init_cache(void)
826{
827 idr_layer_cache = kmem_cache_create("idr_layer_cache",
828 sizeof(struct idr_layer), 0, SLAB_PANIC, NULL);
829}
830
831/**
832 * idr_init - initialize idr handle
833 * @idp: idr handle
834 *
835 * This function is use to set up the handle (@idp) that you will pass
836 * to the rest of the functions.
837 */
838void idr_init(struct idr *idp)
839{
840 memset(idp, 0, sizeof(struct idr));
841 spin_lock_init(&idp->lock);
842}
843EXPORT_SYMBOL(idr_init);
844
845static int idr_has_entry(int id, void *p, void *data)
846{
847 return 1;
848}
849
850bool idr_is_empty(struct idr *idp)
851{
852 return !idr_for_each(idp, idr_has_entry, NULL);
853}
854EXPORT_SYMBOL(idr_is_empty);
855
856/** 172/**
857 * DOC: IDA description 173 * DOC: IDA description
858 * IDA - IDR based ID allocator
859 * 174 *
860 * This is id allocator without id -> pointer translation. Memory 175 * The IDA is an ID allocator which does not provide the ability to
861 * usage is much lower than full blown idr because each id only 176 * associate an ID with a pointer. As such, it only needs to store one
862 * occupies a bit. ida uses a custom leaf node which contains 177 * bit per ID, and so is more space efficient than an IDR. To use an IDA,
863 * IDA_BITMAP_BITS slots. 178 * define it using DEFINE_IDA() (or embed a &struct ida in a data structure,
864 * 179 * then initialise it using ida_init()). To allocate a new ID, call
865 * 2007-04-25 written by Tejun Heo <htejun@gmail.com> 180 * ida_simple_get(). To free an ID, call ida_simple_remove().
181 *
182 * If you have more complex locking requirements, use a loop around
183 * ida_pre_get() and ida_get_new() to allocate a new ID. Then use
184 * ida_remove() to free an ID. You must make sure that ida_get_new() and
185 * ida_remove() cannot be called at the same time as each other for the
186 * same IDA.
187 *
188 * You can also use ida_get_new_above() if you need an ID to be allocated
189 * above a particular number. ida_destroy() can be used to dispose of an
190 * IDA without needing to free the individual IDs in it. You can use
191 * ida_is_empty() to find out whether the IDA has any IDs currently allocated.
192 *
193 * IDs are currently limited to the range [0-INT_MAX]. If this is an awkward
194 * limitation, it should be quite straightforward to raise the maximum.
866 */ 195 */
867 196
868static void free_bitmap(struct ida *ida, struct ida_bitmap *bitmap) 197/*
869{ 198 * Developer's notes:
870 unsigned long flags; 199 *
871 200 * The IDA uses the functionality provided by the IDR & radix tree to store
872 if (!ida->free_bitmap) { 201 * bitmaps in each entry. The IDR_FREE tag means there is at least one bit
873 spin_lock_irqsave(&ida->idr.lock, flags); 202 * free, unlike the IDR where it means at least one entry is free.
874 if (!ida->free_bitmap) { 203 *
875 ida->free_bitmap = bitmap; 204 * I considered telling the radix tree that each slot is an order-10 node
876 bitmap = NULL; 205 * and storing the bit numbers in the radix tree, but the radix tree can't
877 } 206 * allow a single multiorder entry at index 0, which would significantly
878 spin_unlock_irqrestore(&ida->idr.lock, flags); 207 * increase memory consumption for the IDA. So instead we divide the index
879 } 208 * by the number of bits in the leaf bitmap before doing a radix tree lookup.
880 209 *
881 kfree(bitmap); 210 * As an optimisation, if there are only a few low bits set in any given
882} 211 * leaf, instead of allocating a 128-byte bitmap, we use the 'exceptional
883 212 * entry' functionality of the radix tree to store BITS_PER_LONG - 2 bits
884/** 213 * directly in the entry. By being really tricksy, we could store
885 * ida_pre_get - reserve resources for ida allocation 214 * BITS_PER_LONG - 1 bits, but there're diminishing returns after optimising
886 * @ida: ida handle 215 * for 0-3 allocated IDs.
887 * @gfp_mask: memory allocation flag 216 *
888 * 217 * We allow the radix tree 'exceptional' count to get out of date. Nothing
889 * This function should be called prior to locking and calling the 218 * in the IDA nor the radix tree code checks it. If it becomes important
890 * following function. It preallocates enough memory to satisfy the 219 * to maintain an accurate exceptional count, switch the rcu_assign_pointer()
891 * worst possible allocation. 220 * calls to radix_tree_iter_replace() which will correct the exceptional
892 * 221 * count.
893 * If the system is REALLY out of memory this function returns %0, 222 *
894 * otherwise %1. 223 * The IDA always requires a lock to alloc/free. If we add a 'test_bit'
224 * equivalent, it will still need locking. Going to RCU lookup would require
225 * using RCU to free bitmaps, and that's not trivial without embedding an
226 * RCU head in the bitmap, which adds a 2-pointer overhead to each 128-byte
227 * bitmap, which is excessive.
895 */ 228 */
896int ida_pre_get(struct ida *ida, gfp_t gfp_mask)
897{
898 /* allocate idr_layers */
899 if (!__idr_pre_get(&ida->idr, gfp_mask))
900 return 0;
901 229
902 /* allocate free_bitmap */ 230#define IDA_MAX (0x80000000U / IDA_BITMAP_BITS)
903 if (!ida->free_bitmap) {
904 struct ida_bitmap *bitmap;
905
906 bitmap = kmalloc(sizeof(struct ida_bitmap), gfp_mask);
907 if (!bitmap)
908 return 0;
909
910 free_bitmap(ida, bitmap);
911 }
912
913 return 1;
914}
915EXPORT_SYMBOL(ida_pre_get);
916 231
917/** 232/**
918 * ida_get_new_above - allocate new ID above or equal to a start id 233 * ida_get_new_above - allocate new ID above or equal to a start id
919 * @ida: ida handle 234 * @ida: ida handle
920 * @starting_id: id to start search at 235 * @start: id to start search at
921 * @p_id: pointer to the allocated handle 236 * @id: pointer to the allocated handle
922 * 237 *
923 * Allocate new ID above or equal to @starting_id. It should be called 238 * Allocate new ID above or equal to @start. It should be called
924 * with any required locks. 239 * with any required locks to ensure that concurrent calls to
240 * ida_get_new_above() / ida_get_new() / ida_remove() are not allowed.
241 * Consider using ida_simple_get() if you do not have complex locking
242 * requirements.
925 * 243 *
926 * If memory is required, it will return %-EAGAIN, you should unlock 244 * If memory is required, it will return %-EAGAIN, you should unlock
927 * and go back to the ida_pre_get() call. If the ida is full, it will 245 * and go back to the ida_pre_get() call. If the ida is full, it will
928 * return %-ENOSPC. 246 * return %-ENOSPC. On success, it will return 0.
929 *
930 * Note that callers must ensure that concurrent access to @ida is not possible.
931 * See ida_simple_get() for a varaint which takes care of locking.
932 * 247 *
933 * @p_id returns a value in the range @starting_id ... %0x7fffffff. 248 * @id returns a value in the range @start ... %0x7fffffff.
934 */ 249 */
935int ida_get_new_above(struct ida *ida, int starting_id, int *p_id) 250int ida_get_new_above(struct ida *ida, int start, int *id)
936{ 251{
937 struct idr_layer *pa[MAX_IDR_LEVEL + 1]; 252 struct radix_tree_root *root = &ida->ida_rt;
253 void __rcu **slot;
254 struct radix_tree_iter iter;
938 struct ida_bitmap *bitmap; 255 struct ida_bitmap *bitmap;
939 unsigned long flags; 256 unsigned long index;
940 int idr_id = starting_id / IDA_BITMAP_BITS; 257 unsigned bit, ebit;
941 int offset = starting_id % IDA_BITMAP_BITS; 258 int new;
942 int t, id; 259
943 260 index = start / IDA_BITMAP_BITS;
944 restart: 261 bit = start % IDA_BITMAP_BITS;
945 /* get vacant slot */ 262 ebit = bit + RADIX_TREE_EXCEPTIONAL_SHIFT;
946 t = idr_get_empty_slot(&ida->idr, idr_id, pa, 0, &ida->idr); 263
947 if (t < 0) 264 slot = radix_tree_iter_init(&iter, index);
948 return t == -ENOMEM ? -EAGAIN : t; 265 for (;;) {
949 266 if (slot)
950 if (t * IDA_BITMAP_BITS >= MAX_IDR_BIT) 267 slot = radix_tree_next_slot(slot, &iter,
951 return -ENOSPC; 268 RADIX_TREE_ITER_TAGGED);
952 269 if (!slot) {
953 if (t != idr_id) 270 slot = idr_get_free(root, &iter, GFP_NOWAIT, IDA_MAX);
954 offset = 0; 271 if (IS_ERR(slot)) {
955 idr_id = t; 272 if (slot == ERR_PTR(-ENOMEM))
956 273 return -EAGAIN;
957 /* if bitmap isn't there, create a new one */ 274 return PTR_ERR(slot);
958 bitmap = (void *)pa[0]->ary[idr_id & IDR_MASK]; 275 }
959 if (!bitmap) { 276 }
960 spin_lock_irqsave(&ida->idr.lock, flags); 277 if (iter.index > index) {
961 bitmap = ida->free_bitmap; 278 bit = 0;
962 ida->free_bitmap = NULL; 279 ebit = RADIX_TREE_EXCEPTIONAL_SHIFT;
963 spin_unlock_irqrestore(&ida->idr.lock, flags); 280 }
964 281 new = iter.index * IDA_BITMAP_BITS;
965 if (!bitmap) 282 bitmap = rcu_dereference_raw(*slot);
966 return -EAGAIN; 283 if (radix_tree_exception(bitmap)) {
967 284 unsigned long tmp = (unsigned long)bitmap;
968 memset(bitmap, 0, sizeof(struct ida_bitmap)); 285 ebit = find_next_zero_bit(&tmp, BITS_PER_LONG, ebit);
969 rcu_assign_pointer(pa[0]->ary[idr_id & IDR_MASK], 286 if (ebit < BITS_PER_LONG) {
970 (void *)bitmap); 287 tmp |= 1UL << ebit;
971 pa[0]->count++; 288 rcu_assign_pointer(*slot, (void *)tmp);
972 } 289 *id = new + ebit - RADIX_TREE_EXCEPTIONAL_SHIFT;
973 290 return 0;
974 /* lookup for empty slot */ 291 }
975 t = find_next_zero_bit(bitmap->bitmap, IDA_BITMAP_BITS, offset); 292 bitmap = this_cpu_xchg(ida_bitmap, NULL);
976 if (t == IDA_BITMAP_BITS) { 293 if (!bitmap)
977 /* no empty slot after offset, continue to the next chunk */ 294 return -EAGAIN;
978 idr_id++; 295 memset(bitmap, 0, sizeof(*bitmap));
979 offset = 0; 296 bitmap->bitmap[0] = tmp >> RADIX_TREE_EXCEPTIONAL_SHIFT;
980 goto restart; 297 rcu_assign_pointer(*slot, bitmap);
981 } 298 }
982
983 id = idr_id * IDA_BITMAP_BITS + t;
984 if (id >= MAX_IDR_BIT)
985 return -ENOSPC;
986 299
987 __set_bit(t, bitmap->bitmap); 300 if (bitmap) {
988 if (++bitmap->nr_busy == IDA_BITMAP_BITS) 301 bit = find_next_zero_bit(bitmap->bitmap,
989 idr_mark_full(pa, idr_id); 302 IDA_BITMAP_BITS, bit);
303 new += bit;
304 if (new < 0)
305 return -ENOSPC;
306 if (bit == IDA_BITMAP_BITS)
307 continue;
990 308
991 *p_id = id; 309 __set_bit(bit, bitmap->bitmap);
310 if (bitmap_full(bitmap->bitmap, IDA_BITMAP_BITS))
311 radix_tree_iter_tag_clear(root, &iter,
312 IDR_FREE);
313 } else {
314 new += bit;
315 if (new < 0)
316 return -ENOSPC;
317 if (ebit < BITS_PER_LONG) {
318 bitmap = (void *)((1UL << ebit) |
319 RADIX_TREE_EXCEPTIONAL_ENTRY);
320 radix_tree_iter_replace(root, &iter, slot,
321 bitmap);
322 *id = new;
323 return 0;
324 }
325 bitmap = this_cpu_xchg(ida_bitmap, NULL);
326 if (!bitmap)
327 return -EAGAIN;
328 memset(bitmap, 0, sizeof(*bitmap));
329 __set_bit(bit, bitmap->bitmap);
330 radix_tree_iter_replace(root, &iter, slot, bitmap);
331 }
992 332
993 /* Each leaf node can handle nearly a thousand slots and the 333 *id = new;
994 * whole idea of ida is to have small memory foot print. 334 return 0;
995 * Throw away extra resources one by one after each successful
996 * allocation.
997 */
998 if (ida->idr.id_free_cnt || ida->free_bitmap) {
999 struct idr_layer *p = get_from_free_list(&ida->idr);
1000 if (p)
1001 kmem_cache_free(idr_layer_cache, p);
1002 } 335 }
1003
1004 return 0;
1005} 336}
1006EXPORT_SYMBOL(ida_get_new_above); 337EXPORT_SYMBOL(ida_get_new_above);
1007 338
1008/** 339/**
1009 * ida_remove - remove the given ID 340 * ida_remove - Free the given ID
1010 * @ida: ida handle 341 * @ida: ida handle
1011 * @id: ID to free 342 * @id: ID to free
343 *
344 * This function should not be called at the same time as ida_get_new_above().
1012 */ 345 */
1013void ida_remove(struct ida *ida, int id) 346void ida_remove(struct ida *ida, int id)
1014{ 347{
1015 struct idr_layer *p = ida->idr.top; 348 unsigned long index = id / IDA_BITMAP_BITS;
1016 int shift = (ida->idr.layers - 1) * IDR_BITS; 349 unsigned offset = id % IDA_BITMAP_BITS;
1017 int idr_id = id / IDA_BITMAP_BITS;
1018 int offset = id % IDA_BITMAP_BITS;
1019 int n;
1020 struct ida_bitmap *bitmap; 350 struct ida_bitmap *bitmap;
351 unsigned long *btmp;
352 struct radix_tree_iter iter;
353 void __rcu **slot;
1021 354
1022 if (idr_id > idr_max(ida->idr.layers)) 355 slot = radix_tree_iter_lookup(&ida->ida_rt, &iter, index);
356 if (!slot)
1023 goto err; 357 goto err;
1024 358
1025 /* clear full bits while looking up the leaf idr_layer */ 359 bitmap = rcu_dereference_raw(*slot);
1026 while ((shift > 0) && p) { 360 if (radix_tree_exception(bitmap)) {
1027 n = (idr_id >> shift) & IDR_MASK; 361 btmp = (unsigned long *)slot;
1028 __clear_bit(n, p->bitmap); 362 offset += RADIX_TREE_EXCEPTIONAL_SHIFT;
1029 p = p->ary[n]; 363 if (offset >= BITS_PER_LONG)
1030 shift -= IDR_BITS; 364 goto err;
365 } else {
366 btmp = bitmap->bitmap;
1031 } 367 }
1032 368 if (!test_bit(offset, btmp))
1033 if (p == NULL)
1034 goto err;
1035
1036 n = idr_id & IDR_MASK;
1037 __clear_bit(n, p->bitmap);
1038
1039 bitmap = (void *)p->ary[n];
1040 if (!bitmap || !test_bit(offset, bitmap->bitmap))
1041 goto err; 369 goto err;
1042 370
1043 /* update bitmap and remove it if empty */ 371 __clear_bit(offset, btmp);
1044 __clear_bit(offset, bitmap->bitmap); 372 radix_tree_iter_tag_set(&ida->ida_rt, &iter, IDR_FREE);
1045 if (--bitmap->nr_busy == 0) { 373 if (radix_tree_exception(bitmap)) {
1046 __set_bit(n, p->bitmap); /* to please idr_remove() */ 374 if (rcu_dereference_raw(*slot) ==
1047 idr_remove(&ida->idr, idr_id); 375 (void *)RADIX_TREE_EXCEPTIONAL_ENTRY)
1048 free_bitmap(ida, bitmap); 376 radix_tree_iter_delete(&ida->ida_rt, &iter, slot);
377 } else if (bitmap_empty(btmp, IDA_BITMAP_BITS)) {
378 kfree(bitmap);
379 radix_tree_iter_delete(&ida->ida_rt, &iter, slot);
1049 } 380 }
1050
1051 return; 381 return;
1052
1053 err: 382 err:
1054 WARN(1, "ida_remove called for id=%d which is not allocated.\n", id); 383 WARN(1, "ida_remove called for id=%d which is not allocated.\n", id);
1055} 384}
1056EXPORT_SYMBOL(ida_remove); 385EXPORT_SYMBOL(ida_remove);
1057 386
1058/** 387/**
1059 * ida_destroy - release all cached layers within an ida tree 388 * ida_destroy - Free the contents of an ida
1060 * @ida: ida handle 389 * @ida: ida handle
390 *
391 * Calling this function releases all resources associated with an IDA. When
392 * this call returns, the IDA is empty and can be reused or freed. The caller
393 * should not allow ida_remove() or ida_get_new_above() to be called at the
394 * same time.
1061 */ 395 */
1062void ida_destroy(struct ida *ida) 396void ida_destroy(struct ida *ida)
1063{ 397{
1064 idr_destroy(&ida->idr); 398 struct radix_tree_iter iter;
1065 kfree(ida->free_bitmap); 399 void __rcu **slot;
400
401 radix_tree_for_each_slot(slot, &ida->ida_rt, &iter, 0) {
402 struct ida_bitmap *bitmap = rcu_dereference_raw(*slot);
403 if (!radix_tree_exception(bitmap))
404 kfree(bitmap);
405 radix_tree_iter_delete(&ida->ida_rt, &iter, slot);
406 }
1066} 407}
1067EXPORT_SYMBOL(ida_destroy); 408EXPORT_SYMBOL(ida_destroy);
1068 409
@@ -1141,18 +482,3 @@ void ida_simple_remove(struct ida *ida, unsigned int id)
1141 spin_unlock_irqrestore(&simple_ida_lock, flags); 482 spin_unlock_irqrestore(&simple_ida_lock, flags);
1142} 483}
1143EXPORT_SYMBOL(ida_simple_remove); 484EXPORT_SYMBOL(ida_simple_remove);
1144
1145/**
1146 * ida_init - initialize ida handle
1147 * @ida: ida handle
1148 *
1149 * This function is use to set up the handle (@ida) that you will pass
1150 * to the rest of the functions.
1151 */
1152void ida_init(struct ida *ida)
1153{
1154 memset(ida, 0, sizeof(struct ida));
1155 idr_init(&ida->idr);
1156
1157}
1158EXPORT_SYMBOL(ida_init);
generated by cgit v1.2.2 (git 2.25.0) at 2025-10-31 07:17:34 -0400