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1da177e4 LT |
1 | /* |
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 | * | |
3219b3b7 ND |
9 | * Modified by Nadia Derbey to make it RCU safe. |
10 | * | |
e15ae2dd | 11 | * Small id to pointer translation service. |
1da177e4 | 12 | * |
e15ae2dd | 13 | * It uses a radix tree like structure as a sparse array indexed |
1da177e4 | 14 | * by the id to obtain the pointer. The bitmap makes allocating |
e15ae2dd | 15 | * a new id quick. |
1da177e4 LT |
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 | ||
e15ae2dd | 22 | * You can release ids at any time. When all ids are released, most of |
125c4c70 | 23 | * the memory is returned (we keep MAX_IDR_FREE) in a local pool so we |
e15ae2dd | 24 | * don't need to go to the memory "store" during an id allocate, just |
1da177e4 LT |
25 | * so you don't need to be too concerned about locking and conflicts |
26 | * with the slab allocator. | |
27 | */ | |
28 | ||
29 | #ifndef TEST // to test in user space... | |
30 | #include <linux/slab.h> | |
31 | #include <linux/init.h> | |
8bc3bcc9 | 32 | #include <linux/export.h> |
1da177e4 | 33 | #endif |
5806f07c | 34 | #include <linux/err.h> |
1da177e4 LT |
35 | #include <linux/string.h> |
36 | #include <linux/idr.h> | |
88eca020 | 37 | #include <linux/spinlock.h> |
d5c7409f TH |
38 | #include <linux/percpu.h> |
39 | #include <linux/hardirq.h> | |
1da177e4 | 40 | |
e8c8d1bc TH |
41 | #define MAX_IDR_SHIFT (sizeof(int) * 8 - 1) |
42 | #define MAX_IDR_BIT (1U << MAX_IDR_SHIFT) | |
43 | ||
44 | /* Leave the possibility of an incomplete final layer */ | |
45 | #define MAX_IDR_LEVEL ((MAX_IDR_SHIFT + IDR_BITS - 1) / IDR_BITS) | |
46 | ||
47 | /* Number of id_layer structs to leave in free list */ | |
48 | #define MAX_IDR_FREE (MAX_IDR_LEVEL * 2) | |
49 | ||
e18b890b | 50 | static struct kmem_cache *idr_layer_cache; |
d5c7409f TH |
51 | static DEFINE_PER_CPU(struct idr_layer *, idr_preload_head); |
52 | static DEFINE_PER_CPU(int, idr_preload_cnt); | |
88eca020 | 53 | static DEFINE_SPINLOCK(simple_ida_lock); |
1da177e4 | 54 | |
326cf0f0 TH |
55 | /* the maximum ID which can be allocated given idr->layers */ |
56 | static int idr_max(int layers) | |
57 | { | |
58 | int bits = min_t(int, layers * IDR_BITS, MAX_IDR_SHIFT); | |
59 | ||
60 | return (1 << bits) - 1; | |
61 | } | |
62 | ||
54616283 TH |
63 | /* |
64 | * Prefix mask for an idr_layer at @layer. For layer 0, the prefix mask is | |
65 | * all bits except for the lower IDR_BITS. For layer 1, 2 * IDR_BITS, and | |
66 | * so on. | |
67 | */ | |
68 | static int idr_layer_prefix_mask(int layer) | |
69 | { | |
70 | return ~idr_max(layer + 1); | |
71 | } | |
72 | ||
4ae53789 | 73 | static struct idr_layer *get_from_free_list(struct idr *idp) |
1da177e4 LT |
74 | { |
75 | struct idr_layer *p; | |
c259cc28 | 76 | unsigned long flags; |
1da177e4 | 77 | |
c259cc28 | 78 | spin_lock_irqsave(&idp->lock, flags); |
1da177e4 LT |
79 | if ((p = idp->id_free)) { |
80 | idp->id_free = p->ary[0]; | |
81 | idp->id_free_cnt--; | |
82 | p->ary[0] = NULL; | |
83 | } | |
c259cc28 | 84 | spin_unlock_irqrestore(&idp->lock, flags); |
1da177e4 LT |
85 | return(p); |
86 | } | |
87 | ||
d5c7409f TH |
88 | /** |
89 | * idr_layer_alloc - allocate a new idr_layer | |
90 | * @gfp_mask: allocation mask | |
91 | * @layer_idr: optional idr to allocate from | |
92 | * | |
93 | * If @layer_idr is %NULL, directly allocate one using @gfp_mask or fetch | |
94 | * one from the per-cpu preload buffer. If @layer_idr is not %NULL, fetch | |
95 | * an idr_layer from @idr->id_free. | |
96 | * | |
97 | * @layer_idr is to maintain backward compatibility with the old alloc | |
98 | * interface - idr_pre_get() and idr_get_new*() - and will be removed | |
99 | * together with per-pool preload buffer. | |
100 | */ | |
101 | static struct idr_layer *idr_layer_alloc(gfp_t gfp_mask, struct idr *layer_idr) | |
102 | { | |
103 | struct idr_layer *new; | |
104 | ||
105 | /* this is the old path, bypass to get_from_free_list() */ | |
106 | if (layer_idr) | |
107 | return get_from_free_list(layer_idr); | |
108 | ||
109 | /* try to allocate directly from kmem_cache */ | |
110 | new = kmem_cache_zalloc(idr_layer_cache, gfp_mask); | |
111 | if (new) | |
112 | return new; | |
113 | ||
114 | /* | |
115 | * Try to fetch one from the per-cpu preload buffer if in process | |
116 | * context. See idr_preload() for details. | |
117 | */ | |
118 | if (in_interrupt()) | |
119 | return NULL; | |
120 | ||
121 | preempt_disable(); | |
122 | new = __this_cpu_read(idr_preload_head); | |
123 | if (new) { | |
124 | __this_cpu_write(idr_preload_head, new->ary[0]); | |
125 | __this_cpu_dec(idr_preload_cnt); | |
126 | new->ary[0] = NULL; | |
127 | } | |
128 | preempt_enable(); | |
129 | return new; | |
130 | } | |
131 | ||
cf481c20 ND |
132 | static void idr_layer_rcu_free(struct rcu_head *head) |
133 | { | |
134 | struct idr_layer *layer; | |
135 | ||
136 | layer = container_of(head, struct idr_layer, rcu_head); | |
137 | kmem_cache_free(idr_layer_cache, layer); | |
138 | } | |
139 | ||
0ffc2a9c | 140 | static inline void free_layer(struct idr *idr, struct idr_layer *p) |
cf481c20 | 141 | { |
0ffc2a9c TH |
142 | if (idr->hint && idr->hint == p) |
143 | RCU_INIT_POINTER(idr->hint, NULL); | |
cf481c20 ND |
144 | call_rcu(&p->rcu_head, idr_layer_rcu_free); |
145 | } | |
146 | ||
1eec0056 | 147 | /* only called when idp->lock is held */ |
4ae53789 | 148 | static void __move_to_free_list(struct idr *idp, struct idr_layer *p) |
1eec0056 SR |
149 | { |
150 | p->ary[0] = idp->id_free; | |
151 | idp->id_free = p; | |
152 | idp->id_free_cnt++; | |
153 | } | |
154 | ||
4ae53789 | 155 | static void move_to_free_list(struct idr *idp, struct idr_layer *p) |
1da177e4 | 156 | { |
c259cc28 RD |
157 | unsigned long flags; |
158 | ||
1da177e4 LT |
159 | /* |
160 | * Depends on the return element being zeroed. | |
161 | */ | |
c259cc28 | 162 | spin_lock_irqsave(&idp->lock, flags); |
4ae53789 | 163 | __move_to_free_list(idp, p); |
c259cc28 | 164 | spin_unlock_irqrestore(&idp->lock, flags); |
1da177e4 LT |
165 | } |
166 | ||
e33ac8bd TH |
167 | static void idr_mark_full(struct idr_layer **pa, int id) |
168 | { | |
169 | struct idr_layer *p = pa[0]; | |
170 | int l = 0; | |
171 | ||
1d9b2e1e | 172 | __set_bit(id & IDR_MASK, p->bitmap); |
e33ac8bd TH |
173 | /* |
174 | * If this layer is full mark the bit in the layer above to | |
175 | * show that this part of the radix tree is full. This may | |
176 | * complete the layer above and require walking up the radix | |
177 | * tree. | |
178 | */ | |
1d9b2e1e | 179 | while (bitmap_full(p->bitmap, IDR_SIZE)) { |
e33ac8bd TH |
180 | if (!(p = pa[++l])) |
181 | break; | |
182 | id = id >> IDR_BITS; | |
1d9b2e1e | 183 | __set_bit((id & IDR_MASK), p->bitmap); |
e33ac8bd TH |
184 | } |
185 | } | |
186 | ||
c8615d37 | 187 | int __idr_pre_get(struct idr *idp, gfp_t gfp_mask) |
1da177e4 | 188 | { |
125c4c70 | 189 | while (idp->id_free_cnt < MAX_IDR_FREE) { |
1da177e4 | 190 | struct idr_layer *new; |
5b019e99 | 191 | new = kmem_cache_zalloc(idr_layer_cache, gfp_mask); |
e15ae2dd | 192 | if (new == NULL) |
1da177e4 | 193 | return (0); |
4ae53789 | 194 | move_to_free_list(idp, new); |
1da177e4 LT |
195 | } |
196 | return 1; | |
197 | } | |
c8615d37 | 198 | EXPORT_SYMBOL(__idr_pre_get); |
1da177e4 | 199 | |
12d1b439 TH |
200 | /** |
201 | * sub_alloc - try to allocate an id without growing the tree depth | |
202 | * @idp: idr handle | |
203 | * @starting_id: id to start search at | |
12d1b439 | 204 | * @pa: idr_layer[MAX_IDR_LEVEL] used as backtrack buffer |
d5c7409f TH |
205 | * @gfp_mask: allocation mask for idr_layer_alloc() |
206 | * @layer_idr: optional idr passed to idr_layer_alloc() | |
12d1b439 TH |
207 | * |
208 | * Allocate an id in range [@starting_id, INT_MAX] from @idp without | |
209 | * growing its depth. Returns | |
210 | * | |
211 | * the allocated id >= 0 if successful, | |
212 | * -EAGAIN if the tree needs to grow for allocation to succeed, | |
213 | * -ENOSPC if the id space is exhausted, | |
214 | * -ENOMEM if more idr_layers need to be allocated. | |
215 | */ | |
d5c7409f TH |
216 | static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa, |
217 | gfp_t gfp_mask, struct idr *layer_idr) | |
1da177e4 LT |
218 | { |
219 | int n, m, sh; | |
220 | struct idr_layer *p, *new; | |
7aae6dd8 | 221 | int l, id, oid; |
1da177e4 LT |
222 | |
223 | id = *starting_id; | |
7aae6dd8 | 224 | restart: |
1da177e4 LT |
225 | p = idp->top; |
226 | l = idp->layers; | |
227 | pa[l--] = NULL; | |
228 | while (1) { | |
229 | /* | |
230 | * We run around this while until we reach the leaf node... | |
231 | */ | |
232 | n = (id >> (IDR_BITS*l)) & IDR_MASK; | |
1d9b2e1e | 233 | m = find_next_zero_bit(p->bitmap, IDR_SIZE, n); |
1da177e4 LT |
234 | if (m == IDR_SIZE) { |
235 | /* no space available go back to previous layer. */ | |
236 | l++; | |
7aae6dd8 | 237 | oid = id; |
e15ae2dd | 238 | id = (id | ((1 << (IDR_BITS * l)) - 1)) + 1; |
7aae6dd8 TH |
239 | |
240 | /* if already at the top layer, we need to grow */ | |
d2e7276b | 241 | if (id >= 1 << (idp->layers * IDR_BITS)) { |
1da177e4 | 242 | *starting_id = id; |
12d1b439 | 243 | return -EAGAIN; |
1da177e4 | 244 | } |
d2e7276b TH |
245 | p = pa[l]; |
246 | BUG_ON(!p); | |
7aae6dd8 TH |
247 | |
248 | /* If we need to go up one layer, continue the | |
249 | * loop; otherwise, restart from the top. | |
250 | */ | |
251 | sh = IDR_BITS * (l + 1); | |
252 | if (oid >> sh == id >> sh) | |
253 | continue; | |
254 | else | |
255 | goto restart; | |
1da177e4 LT |
256 | } |
257 | if (m != n) { | |
258 | sh = IDR_BITS*l; | |
259 | id = ((id >> sh) ^ n ^ m) << sh; | |
260 | } | |
125c4c70 | 261 | if ((id >= MAX_IDR_BIT) || (id < 0)) |
12d1b439 | 262 | return -ENOSPC; |
1da177e4 LT |
263 | if (l == 0) |
264 | break; | |
265 | /* | |
266 | * Create the layer below if it is missing. | |
267 | */ | |
268 | if (!p->ary[m]) { | |
d5c7409f | 269 | new = idr_layer_alloc(gfp_mask, layer_idr); |
4ae53789 | 270 | if (!new) |
12d1b439 | 271 | return -ENOMEM; |
6ff2d39b | 272 | new->layer = l-1; |
54616283 | 273 | new->prefix = id & idr_layer_prefix_mask(new->layer); |
3219b3b7 | 274 | rcu_assign_pointer(p->ary[m], new); |
1da177e4 LT |
275 | p->count++; |
276 | } | |
277 | pa[l--] = p; | |
278 | p = p->ary[m]; | |
279 | } | |
e33ac8bd TH |
280 | |
281 | pa[l] = p; | |
282 | return id; | |
1da177e4 LT |
283 | } |
284 | ||
e33ac8bd | 285 | static int idr_get_empty_slot(struct idr *idp, int starting_id, |
d5c7409f TH |
286 | struct idr_layer **pa, gfp_t gfp_mask, |
287 | struct idr *layer_idr) | |
1da177e4 LT |
288 | { |
289 | struct idr_layer *p, *new; | |
290 | int layers, v, id; | |
c259cc28 | 291 | unsigned long flags; |
e15ae2dd | 292 | |
1da177e4 LT |
293 | id = starting_id; |
294 | build_up: | |
295 | p = idp->top; | |
296 | layers = idp->layers; | |
297 | if (unlikely(!p)) { | |
d5c7409f | 298 | if (!(p = idr_layer_alloc(gfp_mask, layer_idr))) |
12d1b439 | 299 | return -ENOMEM; |
6ff2d39b | 300 | p->layer = 0; |
1da177e4 LT |
301 | layers = 1; |
302 | } | |
303 | /* | |
304 | * Add a new layer to the top of the tree if the requested | |
305 | * id is larger than the currently allocated space. | |
306 | */ | |
326cf0f0 | 307 | while (id > idr_max(layers)) { |
1da177e4 | 308 | layers++; |
711a49a0 MS |
309 | if (!p->count) { |
310 | /* special case: if the tree is currently empty, | |
311 | * then we grow the tree by moving the top node | |
312 | * upwards. | |
313 | */ | |
314 | p->layer++; | |
54616283 | 315 | WARN_ON_ONCE(p->prefix); |
1da177e4 | 316 | continue; |
711a49a0 | 317 | } |
d5c7409f | 318 | if (!(new = idr_layer_alloc(gfp_mask, layer_idr))) { |
1da177e4 LT |
319 | /* |
320 | * The allocation failed. If we built part of | |
321 | * the structure tear it down. | |
322 | */ | |
c259cc28 | 323 | spin_lock_irqsave(&idp->lock, flags); |
1da177e4 LT |
324 | for (new = p; p && p != idp->top; new = p) { |
325 | p = p->ary[0]; | |
326 | new->ary[0] = NULL; | |
1d9b2e1e TH |
327 | new->count = 0; |
328 | bitmap_clear(new->bitmap, 0, IDR_SIZE); | |
4ae53789 | 329 | __move_to_free_list(idp, new); |
1da177e4 | 330 | } |
c259cc28 | 331 | spin_unlock_irqrestore(&idp->lock, flags); |
12d1b439 | 332 | return -ENOMEM; |
1da177e4 LT |
333 | } |
334 | new->ary[0] = p; | |
335 | new->count = 1; | |
6ff2d39b | 336 | new->layer = layers-1; |
54616283 | 337 | new->prefix = id & idr_layer_prefix_mask(new->layer); |
1d9b2e1e TH |
338 | if (bitmap_full(p->bitmap, IDR_SIZE)) |
339 | __set_bit(0, new->bitmap); | |
1da177e4 LT |
340 | p = new; |
341 | } | |
3219b3b7 | 342 | rcu_assign_pointer(idp->top, p); |
1da177e4 | 343 | idp->layers = layers; |
d5c7409f | 344 | v = sub_alloc(idp, &id, pa, gfp_mask, layer_idr); |
12d1b439 | 345 | if (v == -EAGAIN) |
1da177e4 LT |
346 | goto build_up; |
347 | return(v); | |
348 | } | |
349 | ||
3594eb28 TH |
350 | /* |
351 | * @id and @pa are from a successful allocation from idr_get_empty_slot(). | |
352 | * Install the user pointer @ptr and mark the slot full. | |
353 | */ | |
0ffc2a9c TH |
354 | static void idr_fill_slot(struct idr *idr, void *ptr, int id, |
355 | struct idr_layer **pa) | |
e33ac8bd | 356 | { |
0ffc2a9c TH |
357 | /* update hint used for lookup, cleared from free_layer() */ |
358 | rcu_assign_pointer(idr->hint, pa[0]); | |
359 | ||
3594eb28 TH |
360 | rcu_assign_pointer(pa[0]->ary[id & IDR_MASK], (struct idr_layer *)ptr); |
361 | pa[0]->count++; | |
362 | idr_mark_full(pa, id); | |
e33ac8bd TH |
363 | } |
364 | ||
c8615d37 | 365 | int __idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id) |
1da177e4 | 366 | { |
326cf0f0 | 367 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
1da177e4 | 368 | int rv; |
e15ae2dd | 369 | |
d5c7409f | 370 | rv = idr_get_empty_slot(idp, starting_id, pa, 0, idp); |
944ca05c | 371 | if (rv < 0) |
12d1b439 | 372 | return rv == -ENOMEM ? -EAGAIN : rv; |
3594eb28 | 373 | |
0ffc2a9c | 374 | idr_fill_slot(idp, ptr, rv, pa); |
1da177e4 LT |
375 | *id = rv; |
376 | return 0; | |
377 | } | |
c8615d37 | 378 | EXPORT_SYMBOL(__idr_get_new_above); |
1da177e4 | 379 | |
d5c7409f TH |
380 | /** |
381 | * idr_preload - preload for idr_alloc() | |
382 | * @gfp_mask: allocation mask to use for preloading | |
383 | * | |
384 | * Preload per-cpu layer buffer for idr_alloc(). Can only be used from | |
385 | * process context and each idr_preload() invocation should be matched with | |
386 | * idr_preload_end(). Note that preemption is disabled while preloaded. | |
387 | * | |
388 | * The first idr_alloc() in the preloaded section can be treated as if it | |
389 | * were invoked with @gfp_mask used for preloading. This allows using more | |
390 | * permissive allocation masks for idrs protected by spinlocks. | |
391 | * | |
392 | * For example, if idr_alloc() below fails, the failure can be treated as | |
393 | * if idr_alloc() were called with GFP_KERNEL rather than GFP_NOWAIT. | |
394 | * | |
395 | * idr_preload(GFP_KERNEL); | |
396 | * spin_lock(lock); | |
397 | * | |
398 | * id = idr_alloc(idr, ptr, start, end, GFP_NOWAIT); | |
399 | * | |
400 | * spin_unlock(lock); | |
401 | * idr_preload_end(); | |
402 | * if (id < 0) | |
403 | * error; | |
404 | */ | |
405 | void idr_preload(gfp_t gfp_mask) | |
406 | { | |
407 | /* | |
408 | * Consuming preload buffer from non-process context breaks preload | |
409 | * allocation guarantee. Disallow usage from those contexts. | |
410 | */ | |
411 | WARN_ON_ONCE(in_interrupt()); | |
412 | might_sleep_if(gfp_mask & __GFP_WAIT); | |
413 | ||
414 | preempt_disable(); | |
415 | ||
416 | /* | |
417 | * idr_alloc() is likely to succeed w/o full idr_layer buffer and | |
418 | * return value from idr_alloc() needs to be checked for failure | |
419 | * anyway. Silently give up if allocation fails. The caller can | |
420 | * treat failures from idr_alloc() as if idr_alloc() were called | |
421 | * with @gfp_mask which should be enough. | |
422 | */ | |
423 | while (__this_cpu_read(idr_preload_cnt) < MAX_IDR_FREE) { | |
424 | struct idr_layer *new; | |
425 | ||
426 | preempt_enable(); | |
427 | new = kmem_cache_zalloc(idr_layer_cache, gfp_mask); | |
428 | preempt_disable(); | |
429 | if (!new) | |
430 | break; | |
431 | ||
432 | /* link the new one to per-cpu preload list */ | |
433 | new->ary[0] = __this_cpu_read(idr_preload_head); | |
434 | __this_cpu_write(idr_preload_head, new); | |
435 | __this_cpu_inc(idr_preload_cnt); | |
436 | } | |
437 | } | |
438 | EXPORT_SYMBOL(idr_preload); | |
439 | ||
440 | /** | |
441 | * idr_alloc - allocate new idr entry | |
442 | * @idr: the (initialized) idr | |
443 | * @ptr: pointer to be associated with the new id | |
444 | * @start: the minimum id (inclusive) | |
445 | * @end: the maximum id (exclusive, <= 0 for max) | |
446 | * @gfp_mask: memory allocation flags | |
447 | * | |
448 | * Allocate an id in [start, end) and associate it with @ptr. If no ID is | |
449 | * available in the specified range, returns -ENOSPC. On memory allocation | |
450 | * failure, returns -ENOMEM. | |
451 | * | |
452 | * Note that @end is treated as max when <= 0. This is to always allow | |
453 | * using @start + N as @end as long as N is inside integer range. | |
454 | * | |
455 | * The user is responsible for exclusively synchronizing all operations | |
456 | * which may modify @idr. However, read-only accesses such as idr_find() | |
457 | * or iteration can be performed under RCU read lock provided the user | |
458 | * destroys @ptr in RCU-safe way after removal from idr. | |
459 | */ | |
460 | int idr_alloc(struct idr *idr, void *ptr, int start, int end, gfp_t gfp_mask) | |
461 | { | |
462 | int max = end > 0 ? end - 1 : INT_MAX; /* inclusive upper limit */ | |
326cf0f0 | 463 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
d5c7409f TH |
464 | int id; |
465 | ||
466 | might_sleep_if(gfp_mask & __GFP_WAIT); | |
467 | ||
468 | /* sanity checks */ | |
469 | if (WARN_ON_ONCE(start < 0)) | |
470 | return -EINVAL; | |
471 | if (unlikely(max < start)) | |
472 | return -ENOSPC; | |
473 | ||
474 | /* allocate id */ | |
475 | id = idr_get_empty_slot(idr, start, pa, gfp_mask, NULL); | |
476 | if (unlikely(id < 0)) | |
477 | return id; | |
478 | if (unlikely(id > max)) | |
479 | return -ENOSPC; | |
480 | ||
0ffc2a9c | 481 | idr_fill_slot(idr, ptr, id, pa); |
d5c7409f TH |
482 | return id; |
483 | } | |
484 | EXPORT_SYMBOL_GPL(idr_alloc); | |
485 | ||
1da177e4 LT |
486 | static void idr_remove_warning(int id) |
487 | { | |
f098ad65 ND |
488 | printk(KERN_WARNING |
489 | "idr_remove called for id=%d which is not allocated.\n", id); | |
1da177e4 LT |
490 | dump_stack(); |
491 | } | |
492 | ||
493 | static void sub_remove(struct idr *idp, int shift, int id) | |
494 | { | |
495 | struct idr_layer *p = idp->top; | |
326cf0f0 | 496 | struct idr_layer **pa[MAX_IDR_LEVEL + 1]; |
1da177e4 | 497 | struct idr_layer ***paa = &pa[0]; |
cf481c20 | 498 | struct idr_layer *to_free; |
1da177e4 LT |
499 | int n; |
500 | ||
501 | *paa = NULL; | |
502 | *++paa = &idp->top; | |
503 | ||
504 | while ((shift > 0) && p) { | |
505 | n = (id >> shift) & IDR_MASK; | |
1d9b2e1e | 506 | __clear_bit(n, p->bitmap); |
1da177e4 LT |
507 | *++paa = &p->ary[n]; |
508 | p = p->ary[n]; | |
509 | shift -= IDR_BITS; | |
510 | } | |
511 | n = id & IDR_MASK; | |
1d9b2e1e TH |
512 | if (likely(p != NULL && test_bit(n, p->bitmap))) { |
513 | __clear_bit(n, p->bitmap); | |
cf481c20 ND |
514 | rcu_assign_pointer(p->ary[n], NULL); |
515 | to_free = NULL; | |
1da177e4 | 516 | while(*paa && ! --((**paa)->count)){ |
cf481c20 | 517 | if (to_free) |
0ffc2a9c | 518 | free_layer(idp, to_free); |
cf481c20 | 519 | to_free = **paa; |
1da177e4 LT |
520 | **paa-- = NULL; |
521 | } | |
e15ae2dd | 522 | if (!*paa) |
1da177e4 | 523 | idp->layers = 0; |
cf481c20 | 524 | if (to_free) |
0ffc2a9c | 525 | free_layer(idp, to_free); |
e15ae2dd | 526 | } else |
1da177e4 | 527 | idr_remove_warning(id); |
1da177e4 LT |
528 | } |
529 | ||
530 | /** | |
56083ab1 | 531 | * idr_remove - remove the given id and free its slot |
72fd4a35 RD |
532 | * @idp: idr handle |
533 | * @id: unique key | |
1da177e4 LT |
534 | */ |
535 | void idr_remove(struct idr *idp, int id) | |
536 | { | |
537 | struct idr_layer *p; | |
cf481c20 | 538 | struct idr_layer *to_free; |
1da177e4 | 539 | |
2e1c9b28 | 540 | if (id < 0) |
e8c8d1bc | 541 | return; |
1da177e4 LT |
542 | |
543 | sub_remove(idp, (idp->layers - 1) * IDR_BITS, id); | |
e15ae2dd | 544 | if (idp->top && idp->top->count == 1 && (idp->layers > 1) && |
cf481c20 ND |
545 | idp->top->ary[0]) { |
546 | /* | |
547 | * Single child at leftmost slot: we can shrink the tree. | |
548 | * This level is not needed anymore since when layers are | |
549 | * inserted, they are inserted at the top of the existing | |
550 | * tree. | |
551 | */ | |
552 | to_free = idp->top; | |
1da177e4 | 553 | p = idp->top->ary[0]; |
cf481c20 | 554 | rcu_assign_pointer(idp->top, p); |
1da177e4 | 555 | --idp->layers; |
1d9b2e1e TH |
556 | to_free->count = 0; |
557 | bitmap_clear(to_free->bitmap, 0, IDR_SIZE); | |
0ffc2a9c | 558 | free_layer(idp, to_free); |
1da177e4 | 559 | } |
125c4c70 | 560 | while (idp->id_free_cnt >= MAX_IDR_FREE) { |
4ae53789 | 561 | p = get_from_free_list(idp); |
cf481c20 ND |
562 | /* |
563 | * Note: we don't call the rcu callback here, since the only | |
564 | * layers that fall into the freelist are those that have been | |
565 | * preallocated. | |
566 | */ | |
1da177e4 | 567 | kmem_cache_free(idr_layer_cache, p); |
1da177e4 | 568 | } |
af8e2a4c | 569 | return; |
1da177e4 LT |
570 | } |
571 | EXPORT_SYMBOL(idr_remove); | |
572 | ||
fe6e24ec | 573 | void __idr_remove_all(struct idr *idp) |
23936cc0 | 574 | { |
6ace06dc | 575 | int n, id, max; |
2dcb22b3 | 576 | int bt_mask; |
23936cc0 | 577 | struct idr_layer *p; |
326cf0f0 | 578 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
23936cc0 KH |
579 | struct idr_layer **paa = &pa[0]; |
580 | ||
581 | n = idp->layers * IDR_BITS; | |
582 | p = idp->top; | |
1b23336a | 583 | rcu_assign_pointer(idp->top, NULL); |
326cf0f0 | 584 | max = idr_max(idp->layers); |
23936cc0 KH |
585 | |
586 | id = 0; | |
326cf0f0 | 587 | while (id >= 0 && id <= max) { |
23936cc0 KH |
588 | while (n > IDR_BITS && p) { |
589 | n -= IDR_BITS; | |
590 | *paa++ = p; | |
591 | p = p->ary[(id >> n) & IDR_MASK]; | |
592 | } | |
593 | ||
2dcb22b3 | 594 | bt_mask = id; |
23936cc0 | 595 | id += 1 << n; |
2dcb22b3 ID |
596 | /* Get the highest bit that the above add changed from 0->1. */ |
597 | while (n < fls(id ^ bt_mask)) { | |
cf481c20 | 598 | if (p) |
0ffc2a9c | 599 | free_layer(idp, p); |
23936cc0 KH |
600 | n += IDR_BITS; |
601 | p = *--paa; | |
602 | } | |
603 | } | |
23936cc0 KH |
604 | idp->layers = 0; |
605 | } | |
fe6e24ec | 606 | EXPORT_SYMBOL(__idr_remove_all); |
23936cc0 | 607 | |
8d3b3591 AM |
608 | /** |
609 | * idr_destroy - release all cached layers within an idr tree | |
ea24ea85 | 610 | * @idp: idr handle |
9bb26bc1 TH |
611 | * |
612 | * Free all id mappings and all idp_layers. After this function, @idp is | |
613 | * completely unused and can be freed / recycled. The caller is | |
614 | * responsible for ensuring that no one else accesses @idp during or after | |
615 | * idr_destroy(). | |
616 | * | |
617 | * A typical clean-up sequence for objects stored in an idr tree will use | |
618 | * idr_for_each() to free all objects, if necessay, then idr_destroy() to | |
619 | * free up the id mappings and cached idr_layers. | |
8d3b3591 AM |
620 | */ |
621 | void idr_destroy(struct idr *idp) | |
622 | { | |
fe6e24ec | 623 | __idr_remove_all(idp); |
9bb26bc1 | 624 | |
8d3b3591 | 625 | while (idp->id_free_cnt) { |
4ae53789 | 626 | struct idr_layer *p = get_from_free_list(idp); |
8d3b3591 AM |
627 | kmem_cache_free(idr_layer_cache, p); |
628 | } | |
629 | } | |
630 | EXPORT_SYMBOL(idr_destroy); | |
631 | ||
0ffc2a9c | 632 | void *idr_find_slowpath(struct idr *idp, int id) |
1da177e4 LT |
633 | { |
634 | int n; | |
635 | struct idr_layer *p; | |
636 | ||
2e1c9b28 | 637 | if (id < 0) |
e8c8d1bc TH |
638 | return NULL; |
639 | ||
96be753a | 640 | p = rcu_dereference_raw(idp->top); |
6ff2d39b MS |
641 | if (!p) |
642 | return NULL; | |
643 | n = (p->layer+1) * IDR_BITS; | |
1da177e4 | 644 | |
326cf0f0 | 645 | if (id > idr_max(p->layer + 1)) |
1da177e4 | 646 | return NULL; |
6ff2d39b | 647 | BUG_ON(n == 0); |
1da177e4 LT |
648 | |
649 | while (n > 0 && p) { | |
650 | n -= IDR_BITS; | |
6ff2d39b | 651 | BUG_ON(n != p->layer*IDR_BITS); |
96be753a | 652 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
1da177e4 LT |
653 | } |
654 | return((void *)p); | |
655 | } | |
0ffc2a9c | 656 | EXPORT_SYMBOL(idr_find_slowpath); |
1da177e4 | 657 | |
96d7fa42 KH |
658 | /** |
659 | * idr_for_each - iterate through all stored pointers | |
660 | * @idp: idr handle | |
661 | * @fn: function to be called for each pointer | |
662 | * @data: data passed back to callback function | |
663 | * | |
664 | * Iterate over the pointers registered with the given idr. The | |
665 | * callback function will be called for each pointer currently | |
666 | * registered, passing the id, the pointer and the data pointer passed | |
667 | * to this function. It is not safe to modify the idr tree while in | |
668 | * the callback, so functions such as idr_get_new and idr_remove are | |
669 | * not allowed. | |
670 | * | |
671 | * We check the return of @fn each time. If it returns anything other | |
56083ab1 | 672 | * than %0, we break out and return that value. |
96d7fa42 KH |
673 | * |
674 | * The caller must serialize idr_for_each() vs idr_get_new() and idr_remove(). | |
675 | */ | |
676 | int idr_for_each(struct idr *idp, | |
677 | int (*fn)(int id, void *p, void *data), void *data) | |
678 | { | |
679 | int n, id, max, error = 0; | |
680 | struct idr_layer *p; | |
326cf0f0 | 681 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
96d7fa42 KH |
682 | struct idr_layer **paa = &pa[0]; |
683 | ||
684 | n = idp->layers * IDR_BITS; | |
96be753a | 685 | p = rcu_dereference_raw(idp->top); |
326cf0f0 | 686 | max = idr_max(idp->layers); |
96d7fa42 KH |
687 | |
688 | id = 0; | |
326cf0f0 | 689 | while (id >= 0 && id <= max) { |
96d7fa42 KH |
690 | while (n > 0 && p) { |
691 | n -= IDR_BITS; | |
692 | *paa++ = p; | |
96be753a | 693 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
96d7fa42 KH |
694 | } |
695 | ||
696 | if (p) { | |
697 | error = fn(id, (void *)p, data); | |
698 | if (error) | |
699 | break; | |
700 | } | |
701 | ||
702 | id += 1 << n; | |
703 | while (n < fls(id)) { | |
704 | n += IDR_BITS; | |
705 | p = *--paa; | |
706 | } | |
707 | } | |
708 | ||
709 | return error; | |
710 | } | |
711 | EXPORT_SYMBOL(idr_for_each); | |
712 | ||
38460b48 KH |
713 | /** |
714 | * idr_get_next - lookup next object of id to given id. | |
715 | * @idp: idr handle | |
ea24ea85 | 716 | * @nextidp: pointer to lookup key |
38460b48 KH |
717 | * |
718 | * Returns pointer to registered object with id, which is next number to | |
1458ce16 NA |
719 | * given id. After being looked up, *@nextidp will be updated for the next |
720 | * iteration. | |
9f7de827 HD |
721 | * |
722 | * This function can be called under rcu_read_lock(), given that the leaf | |
723 | * pointers lifetimes are correctly managed. | |
38460b48 | 724 | */ |
38460b48 KH |
725 | void *idr_get_next(struct idr *idp, int *nextidp) |
726 | { | |
326cf0f0 | 727 | struct idr_layer *p, *pa[MAX_IDR_LEVEL + 1]; |
38460b48 KH |
728 | struct idr_layer **paa = &pa[0]; |
729 | int id = *nextidp; | |
730 | int n, max; | |
731 | ||
732 | /* find first ent */ | |
94bfa3b6 | 733 | p = rcu_dereference_raw(idp->top); |
38460b48 KH |
734 | if (!p) |
735 | return NULL; | |
9f7de827 | 736 | n = (p->layer + 1) * IDR_BITS; |
326cf0f0 | 737 | max = idr_max(p->layer + 1); |
38460b48 | 738 | |
326cf0f0 | 739 | while (id >= 0 && id <= max) { |
38460b48 KH |
740 | while (n > 0 && p) { |
741 | n -= IDR_BITS; | |
742 | *paa++ = p; | |
94bfa3b6 | 743 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
38460b48 KH |
744 | } |
745 | ||
746 | if (p) { | |
747 | *nextidp = id; | |
748 | return p; | |
749 | } | |
750 | ||
6cdae741 TH |
751 | /* |
752 | * Proceed to the next layer at the current level. Unlike | |
753 | * idr_for_each(), @id isn't guaranteed to be aligned to | |
754 | * layer boundary at this point and adding 1 << n may | |
755 | * incorrectly skip IDs. Make sure we jump to the | |
756 | * beginning of the next layer using round_up(). | |
757 | */ | |
758 | id = round_up(id + 1, 1 << n); | |
38460b48 KH |
759 | while (n < fls(id)) { |
760 | n += IDR_BITS; | |
761 | p = *--paa; | |
762 | } | |
763 | } | |
764 | return NULL; | |
765 | } | |
4d1ee80f | 766 | EXPORT_SYMBOL(idr_get_next); |
38460b48 KH |
767 | |
768 | ||
5806f07c JM |
769 | /** |
770 | * idr_replace - replace pointer for given id | |
771 | * @idp: idr handle | |
772 | * @ptr: pointer you want associated with the id | |
773 | * @id: lookup key | |
774 | * | |
775 | * Replace the pointer registered with an id and return the old value. | |
56083ab1 RD |
776 | * A %-ENOENT return indicates that @id was not found. |
777 | * A %-EINVAL return indicates that @id was not within valid constraints. | |
5806f07c | 778 | * |
cf481c20 | 779 | * The caller must serialize with writers. |
5806f07c JM |
780 | */ |
781 | void *idr_replace(struct idr *idp, void *ptr, int id) | |
782 | { | |
783 | int n; | |
784 | struct idr_layer *p, *old_p; | |
785 | ||
2e1c9b28 | 786 | if (id < 0) |
e8c8d1bc TH |
787 | return ERR_PTR(-EINVAL); |
788 | ||
5806f07c | 789 | p = idp->top; |
6ff2d39b MS |
790 | if (!p) |
791 | return ERR_PTR(-EINVAL); | |
792 | ||
793 | n = (p->layer+1) * IDR_BITS; | |
5806f07c | 794 | |
5806f07c JM |
795 | if (id >= (1 << n)) |
796 | return ERR_PTR(-EINVAL); | |
797 | ||
798 | n -= IDR_BITS; | |
799 | while ((n > 0) && p) { | |
800 | p = p->ary[(id >> n) & IDR_MASK]; | |
801 | n -= IDR_BITS; | |
802 | } | |
803 | ||
804 | n = id & IDR_MASK; | |
1d9b2e1e | 805 | if (unlikely(p == NULL || !test_bit(n, p->bitmap))) |
5806f07c JM |
806 | return ERR_PTR(-ENOENT); |
807 | ||
808 | old_p = p->ary[n]; | |
cf481c20 | 809 | rcu_assign_pointer(p->ary[n], ptr); |
5806f07c JM |
810 | |
811 | return old_p; | |
812 | } | |
813 | EXPORT_SYMBOL(idr_replace); | |
814 | ||
199f0ca5 | 815 | void __init idr_init_cache(void) |
1da177e4 | 816 | { |
199f0ca5 | 817 | idr_layer_cache = kmem_cache_create("idr_layer_cache", |
5b019e99 | 818 | sizeof(struct idr_layer), 0, SLAB_PANIC, NULL); |
1da177e4 LT |
819 | } |
820 | ||
821 | /** | |
822 | * idr_init - initialize idr handle | |
823 | * @idp: idr handle | |
824 | * | |
825 | * This function is use to set up the handle (@idp) that you will pass | |
826 | * to the rest of the functions. | |
827 | */ | |
828 | void idr_init(struct idr *idp) | |
829 | { | |
1da177e4 LT |
830 | memset(idp, 0, sizeof(struct idr)); |
831 | spin_lock_init(&idp->lock); | |
832 | } | |
833 | EXPORT_SYMBOL(idr_init); | |
72dba584 TH |
834 | |
835 | ||
56083ab1 RD |
836 | /** |
837 | * DOC: IDA description | |
72dba584 TH |
838 | * IDA - IDR based ID allocator |
839 | * | |
56083ab1 | 840 | * This is id allocator without id -> pointer translation. Memory |
72dba584 TH |
841 | * usage is much lower than full blown idr because each id only |
842 | * occupies a bit. ida uses a custom leaf node which contains | |
843 | * IDA_BITMAP_BITS slots. | |
844 | * | |
845 | * 2007-04-25 written by Tejun Heo <htejun@gmail.com> | |
846 | */ | |
847 | ||
848 | static void free_bitmap(struct ida *ida, struct ida_bitmap *bitmap) | |
849 | { | |
850 | unsigned long flags; | |
851 | ||
852 | if (!ida->free_bitmap) { | |
853 | spin_lock_irqsave(&ida->idr.lock, flags); | |
854 | if (!ida->free_bitmap) { | |
855 | ida->free_bitmap = bitmap; | |
856 | bitmap = NULL; | |
857 | } | |
858 | spin_unlock_irqrestore(&ida->idr.lock, flags); | |
859 | } | |
860 | ||
861 | kfree(bitmap); | |
862 | } | |
863 | ||
864 | /** | |
865 | * ida_pre_get - reserve resources for ida allocation | |
866 | * @ida: ida handle | |
867 | * @gfp_mask: memory allocation flag | |
868 | * | |
869 | * This function should be called prior to locking and calling the | |
870 | * following function. It preallocates enough memory to satisfy the | |
871 | * worst possible allocation. | |
872 | * | |
56083ab1 RD |
873 | * If the system is REALLY out of memory this function returns %0, |
874 | * otherwise %1. | |
72dba584 TH |
875 | */ |
876 | int ida_pre_get(struct ida *ida, gfp_t gfp_mask) | |
877 | { | |
878 | /* allocate idr_layers */ | |
c8615d37 | 879 | if (!__idr_pre_get(&ida->idr, gfp_mask)) |
72dba584 TH |
880 | return 0; |
881 | ||
882 | /* allocate free_bitmap */ | |
883 | if (!ida->free_bitmap) { | |
884 | struct ida_bitmap *bitmap; | |
885 | ||
886 | bitmap = kmalloc(sizeof(struct ida_bitmap), gfp_mask); | |
887 | if (!bitmap) | |
888 | return 0; | |
889 | ||
890 | free_bitmap(ida, bitmap); | |
891 | } | |
892 | ||
893 | return 1; | |
894 | } | |
895 | EXPORT_SYMBOL(ida_pre_get); | |
896 | ||
897 | /** | |
898 | * ida_get_new_above - allocate new ID above or equal to a start id | |
899 | * @ida: ida handle | |
ea24ea85 | 900 | * @starting_id: id to start search at |
72dba584 TH |
901 | * @p_id: pointer to the allocated handle |
902 | * | |
e3816c54 WSH |
903 | * Allocate new ID above or equal to @starting_id. It should be called |
904 | * with any required locks. | |
72dba584 | 905 | * |
56083ab1 | 906 | * If memory is required, it will return %-EAGAIN, you should unlock |
72dba584 | 907 | * and go back to the ida_pre_get() call. If the ida is full, it will |
56083ab1 | 908 | * return %-ENOSPC. |
72dba584 | 909 | * |
56083ab1 | 910 | * @p_id returns a value in the range @starting_id ... %0x7fffffff. |
72dba584 TH |
911 | */ |
912 | int ida_get_new_above(struct ida *ida, int starting_id, int *p_id) | |
913 | { | |
326cf0f0 | 914 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
72dba584 TH |
915 | struct ida_bitmap *bitmap; |
916 | unsigned long flags; | |
917 | int idr_id = starting_id / IDA_BITMAP_BITS; | |
918 | int offset = starting_id % IDA_BITMAP_BITS; | |
919 | int t, id; | |
920 | ||
921 | restart: | |
922 | /* get vacant slot */ | |
d5c7409f | 923 | t = idr_get_empty_slot(&ida->idr, idr_id, pa, 0, &ida->idr); |
944ca05c | 924 | if (t < 0) |
12d1b439 | 925 | return t == -ENOMEM ? -EAGAIN : t; |
72dba584 | 926 | |
125c4c70 | 927 | if (t * IDA_BITMAP_BITS >= MAX_IDR_BIT) |
72dba584 TH |
928 | return -ENOSPC; |
929 | ||
930 | if (t != idr_id) | |
931 | offset = 0; | |
932 | idr_id = t; | |
933 | ||
934 | /* if bitmap isn't there, create a new one */ | |
935 | bitmap = (void *)pa[0]->ary[idr_id & IDR_MASK]; | |
936 | if (!bitmap) { | |
937 | spin_lock_irqsave(&ida->idr.lock, flags); | |
938 | bitmap = ida->free_bitmap; | |
939 | ida->free_bitmap = NULL; | |
940 | spin_unlock_irqrestore(&ida->idr.lock, flags); | |
941 | ||
942 | if (!bitmap) | |
943 | return -EAGAIN; | |
944 | ||
945 | memset(bitmap, 0, sizeof(struct ida_bitmap)); | |
3219b3b7 ND |
946 | rcu_assign_pointer(pa[0]->ary[idr_id & IDR_MASK], |
947 | (void *)bitmap); | |
72dba584 TH |
948 | pa[0]->count++; |
949 | } | |
950 | ||
951 | /* lookup for empty slot */ | |
952 | t = find_next_zero_bit(bitmap->bitmap, IDA_BITMAP_BITS, offset); | |
953 | if (t == IDA_BITMAP_BITS) { | |
954 | /* no empty slot after offset, continue to the next chunk */ | |
955 | idr_id++; | |
956 | offset = 0; | |
957 | goto restart; | |
958 | } | |
959 | ||
960 | id = idr_id * IDA_BITMAP_BITS + t; | |
125c4c70 | 961 | if (id >= MAX_IDR_BIT) |
72dba584 TH |
962 | return -ENOSPC; |
963 | ||
964 | __set_bit(t, bitmap->bitmap); | |
965 | if (++bitmap->nr_busy == IDA_BITMAP_BITS) | |
966 | idr_mark_full(pa, idr_id); | |
967 | ||
968 | *p_id = id; | |
969 | ||
970 | /* Each leaf node can handle nearly a thousand slots and the | |
971 | * whole idea of ida is to have small memory foot print. | |
972 | * Throw away extra resources one by one after each successful | |
973 | * allocation. | |
974 | */ | |
975 | if (ida->idr.id_free_cnt || ida->free_bitmap) { | |
4ae53789 | 976 | struct idr_layer *p = get_from_free_list(&ida->idr); |
72dba584 TH |
977 | if (p) |
978 | kmem_cache_free(idr_layer_cache, p); | |
979 | } | |
980 | ||
981 | return 0; | |
982 | } | |
983 | EXPORT_SYMBOL(ida_get_new_above); | |
984 | ||
72dba584 TH |
985 | /** |
986 | * ida_remove - remove the given ID | |
987 | * @ida: ida handle | |
988 | * @id: ID to free | |
989 | */ | |
990 | void ida_remove(struct ida *ida, int id) | |
991 | { | |
992 | struct idr_layer *p = ida->idr.top; | |
993 | int shift = (ida->idr.layers - 1) * IDR_BITS; | |
994 | int idr_id = id / IDA_BITMAP_BITS; | |
995 | int offset = id % IDA_BITMAP_BITS; | |
996 | int n; | |
997 | struct ida_bitmap *bitmap; | |
998 | ||
999 | /* clear full bits while looking up the leaf idr_layer */ | |
1000 | while ((shift > 0) && p) { | |
1001 | n = (idr_id >> shift) & IDR_MASK; | |
1d9b2e1e | 1002 | __clear_bit(n, p->bitmap); |
72dba584 TH |
1003 | p = p->ary[n]; |
1004 | shift -= IDR_BITS; | |
1005 | } | |
1006 | ||
1007 | if (p == NULL) | |
1008 | goto err; | |
1009 | ||
1010 | n = idr_id & IDR_MASK; | |
1d9b2e1e | 1011 | __clear_bit(n, p->bitmap); |
72dba584 TH |
1012 | |
1013 | bitmap = (void *)p->ary[n]; | |
1014 | if (!test_bit(offset, bitmap->bitmap)) | |
1015 | goto err; | |
1016 | ||
1017 | /* update bitmap and remove it if empty */ | |
1018 | __clear_bit(offset, bitmap->bitmap); | |
1019 | if (--bitmap->nr_busy == 0) { | |
1d9b2e1e | 1020 | __set_bit(n, p->bitmap); /* to please idr_remove() */ |
72dba584 TH |
1021 | idr_remove(&ida->idr, idr_id); |
1022 | free_bitmap(ida, bitmap); | |
1023 | } | |
1024 | ||
1025 | return; | |
1026 | ||
1027 | err: | |
1028 | printk(KERN_WARNING | |
1029 | "ida_remove called for id=%d which is not allocated.\n", id); | |
1030 | } | |
1031 | EXPORT_SYMBOL(ida_remove); | |
1032 | ||
1033 | /** | |
1034 | * ida_destroy - release all cached layers within an ida tree | |
ea24ea85 | 1035 | * @ida: ida handle |
72dba584 TH |
1036 | */ |
1037 | void ida_destroy(struct ida *ida) | |
1038 | { | |
1039 | idr_destroy(&ida->idr); | |
1040 | kfree(ida->free_bitmap); | |
1041 | } | |
1042 | EXPORT_SYMBOL(ida_destroy); | |
1043 | ||
88eca020 RR |
1044 | /** |
1045 | * ida_simple_get - get a new id. | |
1046 | * @ida: the (initialized) ida. | |
1047 | * @start: the minimum id (inclusive, < 0x8000000) | |
1048 | * @end: the maximum id (exclusive, < 0x8000000 or 0) | |
1049 | * @gfp_mask: memory allocation flags | |
1050 | * | |
1051 | * Allocates an id in the range start <= id < end, or returns -ENOSPC. | |
1052 | * On memory allocation failure, returns -ENOMEM. | |
1053 | * | |
1054 | * Use ida_simple_remove() to get rid of an id. | |
1055 | */ | |
1056 | int ida_simple_get(struct ida *ida, unsigned int start, unsigned int end, | |
1057 | gfp_t gfp_mask) | |
1058 | { | |
1059 | int ret, id; | |
1060 | unsigned int max; | |
46cbc1d3 | 1061 | unsigned long flags; |
88eca020 RR |
1062 | |
1063 | BUG_ON((int)start < 0); | |
1064 | BUG_ON((int)end < 0); | |
1065 | ||
1066 | if (end == 0) | |
1067 | max = 0x80000000; | |
1068 | else { | |
1069 | BUG_ON(end < start); | |
1070 | max = end - 1; | |
1071 | } | |
1072 | ||
1073 | again: | |
1074 | if (!ida_pre_get(ida, gfp_mask)) | |
1075 | return -ENOMEM; | |
1076 | ||
46cbc1d3 | 1077 | spin_lock_irqsave(&simple_ida_lock, flags); |
88eca020 RR |
1078 | ret = ida_get_new_above(ida, start, &id); |
1079 | if (!ret) { | |
1080 | if (id > max) { | |
1081 | ida_remove(ida, id); | |
1082 | ret = -ENOSPC; | |
1083 | } else { | |
1084 | ret = id; | |
1085 | } | |
1086 | } | |
46cbc1d3 | 1087 | spin_unlock_irqrestore(&simple_ida_lock, flags); |
88eca020 RR |
1088 | |
1089 | if (unlikely(ret == -EAGAIN)) | |
1090 | goto again; | |
1091 | ||
1092 | return ret; | |
1093 | } | |
1094 | EXPORT_SYMBOL(ida_simple_get); | |
1095 | ||
1096 | /** | |
1097 | * ida_simple_remove - remove an allocated id. | |
1098 | * @ida: the (initialized) ida. | |
1099 | * @id: the id returned by ida_simple_get. | |
1100 | */ | |
1101 | void ida_simple_remove(struct ida *ida, unsigned int id) | |
1102 | { | |
46cbc1d3 TH |
1103 | unsigned long flags; |
1104 | ||
88eca020 | 1105 | BUG_ON((int)id < 0); |
46cbc1d3 | 1106 | spin_lock_irqsave(&simple_ida_lock, flags); |
88eca020 | 1107 | ida_remove(ida, id); |
46cbc1d3 | 1108 | spin_unlock_irqrestore(&simple_ida_lock, flags); |
88eca020 RR |
1109 | } |
1110 | EXPORT_SYMBOL(ida_simple_remove); | |
1111 | ||
72dba584 TH |
1112 | /** |
1113 | * ida_init - initialize ida handle | |
1114 | * @ida: ida handle | |
1115 | * | |
1116 | * This function is use to set up the handle (@ida) that you will pass | |
1117 | * to the rest of the functions. | |
1118 | */ | |
1119 | void ida_init(struct ida *ida) | |
1120 | { | |
1121 | memset(ida, 0, sizeof(struct ida)); | |
1122 | idr_init(&ida->idr); | |
1123 | ||
1124 | } | |
1125 | EXPORT_SYMBOL(ida_init); |