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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 | ||
59bfbcf0 TH |
109 | /* |
110 | * Try to allocate directly from kmem_cache. We want to try this | |
111 | * before preload buffer; otherwise, non-preloading idr_alloc() | |
112 | * users will end up taking advantage of preloading ones. As the | |
113 | * following is allowed to fail for preloaded cases, suppress | |
114 | * warning this time. | |
115 | */ | |
116 | new = kmem_cache_zalloc(idr_layer_cache, gfp_mask | __GFP_NOWARN); | |
d5c7409f TH |
117 | if (new) |
118 | return new; | |
119 | ||
120 | /* | |
121 | * Try to fetch one from the per-cpu preload buffer if in process | |
122 | * context. See idr_preload() for details. | |
123 | */ | |
59bfbcf0 TH |
124 | if (!in_interrupt()) { |
125 | preempt_disable(); | |
126 | new = __this_cpu_read(idr_preload_head); | |
127 | if (new) { | |
128 | __this_cpu_write(idr_preload_head, new->ary[0]); | |
129 | __this_cpu_dec(idr_preload_cnt); | |
130 | new->ary[0] = NULL; | |
131 | } | |
132 | preempt_enable(); | |
133 | if (new) | |
134 | return new; | |
d5c7409f | 135 | } |
59bfbcf0 TH |
136 | |
137 | /* | |
138 | * Both failed. Try kmem_cache again w/o adding __GFP_NOWARN so | |
139 | * that memory allocation failure warning is printed as intended. | |
140 | */ | |
141 | return kmem_cache_zalloc(idr_layer_cache, gfp_mask); | |
d5c7409f TH |
142 | } |
143 | ||
cf481c20 ND |
144 | static void idr_layer_rcu_free(struct rcu_head *head) |
145 | { | |
146 | struct idr_layer *layer; | |
147 | ||
148 | layer = container_of(head, struct idr_layer, rcu_head); | |
149 | kmem_cache_free(idr_layer_cache, layer); | |
150 | } | |
151 | ||
0ffc2a9c | 152 | static inline void free_layer(struct idr *idr, struct idr_layer *p) |
cf481c20 | 153 | { |
0ffc2a9c TH |
154 | if (idr->hint && idr->hint == p) |
155 | RCU_INIT_POINTER(idr->hint, NULL); | |
cf481c20 ND |
156 | call_rcu(&p->rcu_head, idr_layer_rcu_free); |
157 | } | |
158 | ||
1eec0056 | 159 | /* only called when idp->lock is held */ |
4ae53789 | 160 | static void __move_to_free_list(struct idr *idp, struct idr_layer *p) |
1eec0056 SR |
161 | { |
162 | p->ary[0] = idp->id_free; | |
163 | idp->id_free = p; | |
164 | idp->id_free_cnt++; | |
165 | } | |
166 | ||
4ae53789 | 167 | static void move_to_free_list(struct idr *idp, struct idr_layer *p) |
1da177e4 | 168 | { |
c259cc28 RD |
169 | unsigned long flags; |
170 | ||
1da177e4 LT |
171 | /* |
172 | * Depends on the return element being zeroed. | |
173 | */ | |
c259cc28 | 174 | spin_lock_irqsave(&idp->lock, flags); |
4ae53789 | 175 | __move_to_free_list(idp, p); |
c259cc28 | 176 | spin_unlock_irqrestore(&idp->lock, flags); |
1da177e4 LT |
177 | } |
178 | ||
e33ac8bd TH |
179 | static void idr_mark_full(struct idr_layer **pa, int id) |
180 | { | |
181 | struct idr_layer *p = pa[0]; | |
182 | int l = 0; | |
183 | ||
1d9b2e1e | 184 | __set_bit(id & IDR_MASK, p->bitmap); |
e33ac8bd TH |
185 | /* |
186 | * If this layer is full mark the bit in the layer above to | |
187 | * show that this part of the radix tree is full. This may | |
188 | * complete the layer above and require walking up the radix | |
189 | * tree. | |
190 | */ | |
1d9b2e1e | 191 | while (bitmap_full(p->bitmap, IDR_SIZE)) { |
e33ac8bd TH |
192 | if (!(p = pa[++l])) |
193 | break; | |
194 | id = id >> IDR_BITS; | |
1d9b2e1e | 195 | __set_bit((id & IDR_MASK), p->bitmap); |
e33ac8bd TH |
196 | } |
197 | } | |
198 | ||
90ae3ae5 | 199 | static int __idr_pre_get(struct idr *idp, gfp_t gfp_mask) |
1da177e4 | 200 | { |
125c4c70 | 201 | while (idp->id_free_cnt < MAX_IDR_FREE) { |
1da177e4 | 202 | struct idr_layer *new; |
5b019e99 | 203 | new = kmem_cache_zalloc(idr_layer_cache, gfp_mask); |
e15ae2dd | 204 | if (new == NULL) |
1da177e4 | 205 | return (0); |
4ae53789 | 206 | move_to_free_list(idp, new); |
1da177e4 LT |
207 | } |
208 | return 1; | |
209 | } | |
1da177e4 | 210 | |
12d1b439 TH |
211 | /** |
212 | * sub_alloc - try to allocate an id without growing the tree depth | |
213 | * @idp: idr handle | |
214 | * @starting_id: id to start search at | |
12d1b439 | 215 | * @pa: idr_layer[MAX_IDR_LEVEL] used as backtrack buffer |
d5c7409f TH |
216 | * @gfp_mask: allocation mask for idr_layer_alloc() |
217 | * @layer_idr: optional idr passed to idr_layer_alloc() | |
12d1b439 TH |
218 | * |
219 | * Allocate an id in range [@starting_id, INT_MAX] from @idp without | |
220 | * growing its depth. Returns | |
221 | * | |
222 | * the allocated id >= 0 if successful, | |
223 | * -EAGAIN if the tree needs to grow for allocation to succeed, | |
224 | * -ENOSPC if the id space is exhausted, | |
225 | * -ENOMEM if more idr_layers need to be allocated. | |
226 | */ | |
d5c7409f TH |
227 | static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa, |
228 | gfp_t gfp_mask, struct idr *layer_idr) | |
1da177e4 LT |
229 | { |
230 | int n, m, sh; | |
231 | struct idr_layer *p, *new; | |
7aae6dd8 | 232 | int l, id, oid; |
1da177e4 LT |
233 | |
234 | id = *starting_id; | |
7aae6dd8 | 235 | restart: |
1da177e4 LT |
236 | p = idp->top; |
237 | l = idp->layers; | |
238 | pa[l--] = NULL; | |
239 | while (1) { | |
240 | /* | |
241 | * We run around this while until we reach the leaf node... | |
242 | */ | |
243 | n = (id >> (IDR_BITS*l)) & IDR_MASK; | |
1d9b2e1e | 244 | m = find_next_zero_bit(p->bitmap, IDR_SIZE, n); |
1da177e4 LT |
245 | if (m == IDR_SIZE) { |
246 | /* no space available go back to previous layer. */ | |
247 | l++; | |
7aae6dd8 | 248 | oid = id; |
e15ae2dd | 249 | id = (id | ((1 << (IDR_BITS * l)) - 1)) + 1; |
7aae6dd8 TH |
250 | |
251 | /* if already at the top layer, we need to grow */ | |
3afb69cb | 252 | if (id > idr_max(idp->layers)) { |
1da177e4 | 253 | *starting_id = id; |
12d1b439 | 254 | return -EAGAIN; |
1da177e4 | 255 | } |
d2e7276b TH |
256 | p = pa[l]; |
257 | BUG_ON(!p); | |
7aae6dd8 TH |
258 | |
259 | /* If we need to go up one layer, continue the | |
260 | * loop; otherwise, restart from the top. | |
261 | */ | |
262 | sh = IDR_BITS * (l + 1); | |
263 | if (oid >> sh == id >> sh) | |
264 | continue; | |
265 | else | |
266 | goto restart; | |
1da177e4 LT |
267 | } |
268 | if (m != n) { | |
269 | sh = IDR_BITS*l; | |
270 | id = ((id >> sh) ^ n ^ m) << sh; | |
271 | } | |
125c4c70 | 272 | if ((id >= MAX_IDR_BIT) || (id < 0)) |
12d1b439 | 273 | return -ENOSPC; |
1da177e4 LT |
274 | if (l == 0) |
275 | break; | |
276 | /* | |
277 | * Create the layer below if it is missing. | |
278 | */ | |
279 | if (!p->ary[m]) { | |
d5c7409f | 280 | new = idr_layer_alloc(gfp_mask, layer_idr); |
4ae53789 | 281 | if (!new) |
12d1b439 | 282 | return -ENOMEM; |
6ff2d39b | 283 | new->layer = l-1; |
54616283 | 284 | new->prefix = id & idr_layer_prefix_mask(new->layer); |
3219b3b7 | 285 | rcu_assign_pointer(p->ary[m], new); |
1da177e4 LT |
286 | p->count++; |
287 | } | |
288 | pa[l--] = p; | |
289 | p = p->ary[m]; | |
290 | } | |
e33ac8bd TH |
291 | |
292 | pa[l] = p; | |
293 | return id; | |
1da177e4 LT |
294 | } |
295 | ||
e33ac8bd | 296 | static int idr_get_empty_slot(struct idr *idp, int starting_id, |
d5c7409f TH |
297 | struct idr_layer **pa, gfp_t gfp_mask, |
298 | struct idr *layer_idr) | |
1da177e4 LT |
299 | { |
300 | struct idr_layer *p, *new; | |
301 | int layers, v, id; | |
c259cc28 | 302 | unsigned long flags; |
e15ae2dd | 303 | |
1da177e4 LT |
304 | id = starting_id; |
305 | build_up: | |
306 | p = idp->top; | |
307 | layers = idp->layers; | |
308 | if (unlikely(!p)) { | |
d5c7409f | 309 | if (!(p = idr_layer_alloc(gfp_mask, layer_idr))) |
12d1b439 | 310 | return -ENOMEM; |
6ff2d39b | 311 | p->layer = 0; |
1da177e4 LT |
312 | layers = 1; |
313 | } | |
314 | /* | |
315 | * Add a new layer to the top of the tree if the requested | |
316 | * id is larger than the currently allocated space. | |
317 | */ | |
326cf0f0 | 318 | while (id > idr_max(layers)) { |
1da177e4 | 319 | layers++; |
711a49a0 MS |
320 | if (!p->count) { |
321 | /* special case: if the tree is currently empty, | |
322 | * then we grow the tree by moving the top node | |
323 | * upwards. | |
324 | */ | |
325 | p->layer++; | |
54616283 | 326 | WARN_ON_ONCE(p->prefix); |
1da177e4 | 327 | continue; |
711a49a0 | 328 | } |
d5c7409f | 329 | if (!(new = idr_layer_alloc(gfp_mask, layer_idr))) { |
1da177e4 LT |
330 | /* |
331 | * The allocation failed. If we built part of | |
332 | * the structure tear it down. | |
333 | */ | |
c259cc28 | 334 | spin_lock_irqsave(&idp->lock, flags); |
1da177e4 LT |
335 | for (new = p; p && p != idp->top; new = p) { |
336 | p = p->ary[0]; | |
337 | new->ary[0] = NULL; | |
1d9b2e1e TH |
338 | new->count = 0; |
339 | bitmap_clear(new->bitmap, 0, IDR_SIZE); | |
4ae53789 | 340 | __move_to_free_list(idp, new); |
1da177e4 | 341 | } |
c259cc28 | 342 | spin_unlock_irqrestore(&idp->lock, flags); |
12d1b439 | 343 | return -ENOMEM; |
1da177e4 LT |
344 | } |
345 | new->ary[0] = p; | |
346 | new->count = 1; | |
6ff2d39b | 347 | new->layer = layers-1; |
54616283 | 348 | new->prefix = id & idr_layer_prefix_mask(new->layer); |
1d9b2e1e TH |
349 | if (bitmap_full(p->bitmap, IDR_SIZE)) |
350 | __set_bit(0, new->bitmap); | |
1da177e4 LT |
351 | p = new; |
352 | } | |
3219b3b7 | 353 | rcu_assign_pointer(idp->top, p); |
1da177e4 | 354 | idp->layers = layers; |
d5c7409f | 355 | v = sub_alloc(idp, &id, pa, gfp_mask, layer_idr); |
12d1b439 | 356 | if (v == -EAGAIN) |
1da177e4 LT |
357 | goto build_up; |
358 | return(v); | |
359 | } | |
360 | ||
3594eb28 TH |
361 | /* |
362 | * @id and @pa are from a successful allocation from idr_get_empty_slot(). | |
363 | * Install the user pointer @ptr and mark the slot full. | |
364 | */ | |
0ffc2a9c TH |
365 | static void idr_fill_slot(struct idr *idr, void *ptr, int id, |
366 | struct idr_layer **pa) | |
e33ac8bd | 367 | { |
0ffc2a9c TH |
368 | /* update hint used for lookup, cleared from free_layer() */ |
369 | rcu_assign_pointer(idr->hint, pa[0]); | |
370 | ||
3594eb28 TH |
371 | rcu_assign_pointer(pa[0]->ary[id & IDR_MASK], (struct idr_layer *)ptr); |
372 | pa[0]->count++; | |
373 | idr_mark_full(pa, id); | |
e33ac8bd TH |
374 | } |
375 | ||
1da177e4 | 376 | |
d5c7409f TH |
377 | /** |
378 | * idr_preload - preload for idr_alloc() | |
379 | * @gfp_mask: allocation mask to use for preloading | |
380 | * | |
381 | * Preload per-cpu layer buffer for idr_alloc(). Can only be used from | |
382 | * process context and each idr_preload() invocation should be matched with | |
383 | * idr_preload_end(). Note that preemption is disabled while preloaded. | |
384 | * | |
385 | * The first idr_alloc() in the preloaded section can be treated as if it | |
386 | * were invoked with @gfp_mask used for preloading. This allows using more | |
387 | * permissive allocation masks for idrs protected by spinlocks. | |
388 | * | |
389 | * For example, if idr_alloc() below fails, the failure can be treated as | |
390 | * if idr_alloc() were called with GFP_KERNEL rather than GFP_NOWAIT. | |
391 | * | |
392 | * idr_preload(GFP_KERNEL); | |
393 | * spin_lock(lock); | |
394 | * | |
395 | * id = idr_alloc(idr, ptr, start, end, GFP_NOWAIT); | |
396 | * | |
397 | * spin_unlock(lock); | |
398 | * idr_preload_end(); | |
399 | * if (id < 0) | |
400 | * error; | |
401 | */ | |
402 | void idr_preload(gfp_t gfp_mask) | |
403 | { | |
404 | /* | |
405 | * Consuming preload buffer from non-process context breaks preload | |
406 | * allocation guarantee. Disallow usage from those contexts. | |
407 | */ | |
408 | WARN_ON_ONCE(in_interrupt()); | |
409 | might_sleep_if(gfp_mask & __GFP_WAIT); | |
410 | ||
411 | preempt_disable(); | |
412 | ||
413 | /* | |
414 | * idr_alloc() is likely to succeed w/o full idr_layer buffer and | |
415 | * return value from idr_alloc() needs to be checked for failure | |
416 | * anyway. Silently give up if allocation fails. The caller can | |
417 | * treat failures from idr_alloc() as if idr_alloc() were called | |
418 | * with @gfp_mask which should be enough. | |
419 | */ | |
420 | while (__this_cpu_read(idr_preload_cnt) < MAX_IDR_FREE) { | |
421 | struct idr_layer *new; | |
422 | ||
423 | preempt_enable(); | |
424 | new = kmem_cache_zalloc(idr_layer_cache, gfp_mask); | |
425 | preempt_disable(); | |
426 | if (!new) | |
427 | break; | |
428 | ||
429 | /* link the new one to per-cpu preload list */ | |
430 | new->ary[0] = __this_cpu_read(idr_preload_head); | |
431 | __this_cpu_write(idr_preload_head, new); | |
432 | __this_cpu_inc(idr_preload_cnt); | |
433 | } | |
434 | } | |
435 | EXPORT_SYMBOL(idr_preload); | |
436 | ||
437 | /** | |
438 | * idr_alloc - allocate new idr entry | |
439 | * @idr: the (initialized) idr | |
440 | * @ptr: pointer to be associated with the new id | |
441 | * @start: the minimum id (inclusive) | |
442 | * @end: the maximum id (exclusive, <= 0 for max) | |
443 | * @gfp_mask: memory allocation flags | |
444 | * | |
445 | * Allocate an id in [start, end) and associate it with @ptr. If no ID is | |
446 | * available in the specified range, returns -ENOSPC. On memory allocation | |
447 | * failure, returns -ENOMEM. | |
448 | * | |
449 | * Note that @end is treated as max when <= 0. This is to always allow | |
450 | * using @start + N as @end as long as N is inside integer range. | |
451 | * | |
452 | * The user is responsible for exclusively synchronizing all operations | |
453 | * which may modify @idr. However, read-only accesses such as idr_find() | |
454 | * or iteration can be performed under RCU read lock provided the user | |
455 | * destroys @ptr in RCU-safe way after removal from idr. | |
456 | */ | |
457 | int idr_alloc(struct idr *idr, void *ptr, int start, int end, gfp_t gfp_mask) | |
458 | { | |
459 | int max = end > 0 ? end - 1 : INT_MAX; /* inclusive upper limit */ | |
326cf0f0 | 460 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
d5c7409f TH |
461 | int id; |
462 | ||
463 | might_sleep_if(gfp_mask & __GFP_WAIT); | |
464 | ||
465 | /* sanity checks */ | |
466 | if (WARN_ON_ONCE(start < 0)) | |
467 | return -EINVAL; | |
468 | if (unlikely(max < start)) | |
469 | return -ENOSPC; | |
470 | ||
471 | /* allocate id */ | |
472 | id = idr_get_empty_slot(idr, start, pa, gfp_mask, NULL); | |
473 | if (unlikely(id < 0)) | |
474 | return id; | |
475 | if (unlikely(id > max)) | |
476 | return -ENOSPC; | |
477 | ||
0ffc2a9c | 478 | idr_fill_slot(idr, ptr, id, pa); |
d5c7409f TH |
479 | return id; |
480 | } | |
481 | EXPORT_SYMBOL_GPL(idr_alloc); | |
482 | ||
3e6628c4 JL |
483 | /** |
484 | * idr_alloc_cyclic - allocate new idr entry in a cyclical fashion | |
485 | * @idr: the (initialized) idr | |
486 | * @ptr: pointer to be associated with the new id | |
487 | * @start: the minimum id (inclusive) | |
488 | * @end: the maximum id (exclusive, <= 0 for max) | |
489 | * @gfp_mask: memory allocation flags | |
490 | * | |
491 | * Essentially the same as idr_alloc, but prefers to allocate progressively | |
492 | * higher ids if it can. If the "cur" counter wraps, then it will start again | |
493 | * at the "start" end of the range and allocate one that has already been used. | |
494 | */ | |
495 | int idr_alloc_cyclic(struct idr *idr, void *ptr, int start, int end, | |
496 | gfp_t gfp_mask) | |
497 | { | |
498 | int id; | |
499 | ||
500 | id = idr_alloc(idr, ptr, max(start, idr->cur), end, gfp_mask); | |
501 | if (id == -ENOSPC) | |
502 | id = idr_alloc(idr, ptr, start, end, gfp_mask); | |
503 | ||
504 | if (likely(id >= 0)) | |
505 | idr->cur = id + 1; | |
506 | return id; | |
507 | } | |
508 | EXPORT_SYMBOL(idr_alloc_cyclic); | |
509 | ||
1da177e4 LT |
510 | static void idr_remove_warning(int id) |
511 | { | |
dd04b452 | 512 | WARN(1, "idr_remove called for id=%d which is not allocated.\n", id); |
1da177e4 LT |
513 | } |
514 | ||
515 | static void sub_remove(struct idr *idp, int shift, int id) | |
516 | { | |
517 | struct idr_layer *p = idp->top; | |
326cf0f0 | 518 | struct idr_layer **pa[MAX_IDR_LEVEL + 1]; |
1da177e4 | 519 | struct idr_layer ***paa = &pa[0]; |
cf481c20 | 520 | struct idr_layer *to_free; |
1da177e4 LT |
521 | int n; |
522 | ||
523 | *paa = NULL; | |
524 | *++paa = &idp->top; | |
525 | ||
526 | while ((shift > 0) && p) { | |
527 | n = (id >> shift) & IDR_MASK; | |
1d9b2e1e | 528 | __clear_bit(n, p->bitmap); |
1da177e4 LT |
529 | *++paa = &p->ary[n]; |
530 | p = p->ary[n]; | |
531 | shift -= IDR_BITS; | |
532 | } | |
533 | n = id & IDR_MASK; | |
1d9b2e1e TH |
534 | if (likely(p != NULL && test_bit(n, p->bitmap))) { |
535 | __clear_bit(n, p->bitmap); | |
3f59b067 | 536 | RCU_INIT_POINTER(p->ary[n], NULL); |
cf481c20 | 537 | to_free = NULL; |
1da177e4 | 538 | while(*paa && ! --((**paa)->count)){ |
cf481c20 | 539 | if (to_free) |
0ffc2a9c | 540 | free_layer(idp, to_free); |
cf481c20 | 541 | to_free = **paa; |
1da177e4 LT |
542 | **paa-- = NULL; |
543 | } | |
e15ae2dd | 544 | if (!*paa) |
1da177e4 | 545 | idp->layers = 0; |
cf481c20 | 546 | if (to_free) |
0ffc2a9c | 547 | free_layer(idp, to_free); |
e15ae2dd | 548 | } else |
1da177e4 | 549 | idr_remove_warning(id); |
1da177e4 LT |
550 | } |
551 | ||
552 | /** | |
56083ab1 | 553 | * idr_remove - remove the given id and free its slot |
72fd4a35 RD |
554 | * @idp: idr handle |
555 | * @id: unique key | |
1da177e4 LT |
556 | */ |
557 | void idr_remove(struct idr *idp, int id) | |
558 | { | |
559 | struct idr_layer *p; | |
cf481c20 | 560 | struct idr_layer *to_free; |
1da177e4 | 561 | |
2e1c9b28 | 562 | if (id < 0) |
e8c8d1bc | 563 | return; |
1da177e4 | 564 | |
8f9f665a LJ |
565 | if (id > idr_max(idp->layers)) { |
566 | idr_remove_warning(id); | |
567 | return; | |
568 | } | |
569 | ||
1da177e4 | 570 | sub_remove(idp, (idp->layers - 1) * IDR_BITS, id); |
e15ae2dd | 571 | if (idp->top && idp->top->count == 1 && (idp->layers > 1) && |
cf481c20 ND |
572 | idp->top->ary[0]) { |
573 | /* | |
574 | * Single child at leftmost slot: we can shrink the tree. | |
575 | * This level is not needed anymore since when layers are | |
576 | * inserted, they are inserted at the top of the existing | |
577 | * tree. | |
578 | */ | |
579 | to_free = idp->top; | |
1da177e4 | 580 | p = idp->top->ary[0]; |
cf481c20 | 581 | rcu_assign_pointer(idp->top, p); |
1da177e4 | 582 | --idp->layers; |
1d9b2e1e TH |
583 | to_free->count = 0; |
584 | bitmap_clear(to_free->bitmap, 0, IDR_SIZE); | |
0ffc2a9c | 585 | free_layer(idp, to_free); |
1da177e4 | 586 | } |
125c4c70 | 587 | while (idp->id_free_cnt >= MAX_IDR_FREE) { |
4ae53789 | 588 | p = get_from_free_list(idp); |
cf481c20 ND |
589 | /* |
590 | * Note: we don't call the rcu callback here, since the only | |
591 | * layers that fall into the freelist are those that have been | |
592 | * preallocated. | |
593 | */ | |
1da177e4 | 594 | kmem_cache_free(idr_layer_cache, p); |
1da177e4 | 595 | } |
af8e2a4c | 596 | return; |
1da177e4 LT |
597 | } |
598 | EXPORT_SYMBOL(idr_remove); | |
599 | ||
90ae3ae5 | 600 | static void __idr_remove_all(struct idr *idp) |
23936cc0 | 601 | { |
6ace06dc | 602 | int n, id, max; |
2dcb22b3 | 603 | int bt_mask; |
23936cc0 | 604 | struct idr_layer *p; |
326cf0f0 | 605 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
23936cc0 KH |
606 | struct idr_layer **paa = &pa[0]; |
607 | ||
608 | n = idp->layers * IDR_BITS; | |
609 | p = idp->top; | |
3f59b067 | 610 | RCU_INIT_POINTER(idp->top, NULL); |
326cf0f0 | 611 | max = idr_max(idp->layers); |
23936cc0 KH |
612 | |
613 | id = 0; | |
326cf0f0 | 614 | while (id >= 0 && id <= max) { |
23936cc0 KH |
615 | while (n > IDR_BITS && p) { |
616 | n -= IDR_BITS; | |
617 | *paa++ = p; | |
618 | p = p->ary[(id >> n) & IDR_MASK]; | |
619 | } | |
620 | ||
2dcb22b3 | 621 | bt_mask = id; |
23936cc0 | 622 | id += 1 << n; |
2dcb22b3 ID |
623 | /* Get the highest bit that the above add changed from 0->1. */ |
624 | while (n < fls(id ^ bt_mask)) { | |
cf481c20 | 625 | if (p) |
0ffc2a9c | 626 | free_layer(idp, p); |
23936cc0 KH |
627 | n += IDR_BITS; |
628 | p = *--paa; | |
629 | } | |
630 | } | |
23936cc0 KH |
631 | idp->layers = 0; |
632 | } | |
23936cc0 | 633 | |
8d3b3591 AM |
634 | /** |
635 | * idr_destroy - release all cached layers within an idr tree | |
ea24ea85 | 636 | * @idp: idr handle |
9bb26bc1 TH |
637 | * |
638 | * Free all id mappings and all idp_layers. After this function, @idp is | |
639 | * completely unused and can be freed / recycled. The caller is | |
640 | * responsible for ensuring that no one else accesses @idp during or after | |
641 | * idr_destroy(). | |
642 | * | |
643 | * A typical clean-up sequence for objects stored in an idr tree will use | |
644 | * idr_for_each() to free all objects, if necessay, then idr_destroy() to | |
645 | * free up the id mappings and cached idr_layers. | |
8d3b3591 AM |
646 | */ |
647 | void idr_destroy(struct idr *idp) | |
648 | { | |
fe6e24ec | 649 | __idr_remove_all(idp); |
9bb26bc1 | 650 | |
8d3b3591 | 651 | while (idp->id_free_cnt) { |
4ae53789 | 652 | struct idr_layer *p = get_from_free_list(idp); |
8d3b3591 AM |
653 | kmem_cache_free(idr_layer_cache, p); |
654 | } | |
655 | } | |
656 | EXPORT_SYMBOL(idr_destroy); | |
657 | ||
0ffc2a9c | 658 | void *idr_find_slowpath(struct idr *idp, int id) |
1da177e4 LT |
659 | { |
660 | int n; | |
661 | struct idr_layer *p; | |
662 | ||
2e1c9b28 | 663 | if (id < 0) |
e8c8d1bc TH |
664 | return NULL; |
665 | ||
96be753a | 666 | p = rcu_dereference_raw(idp->top); |
6ff2d39b MS |
667 | if (!p) |
668 | return NULL; | |
669 | n = (p->layer+1) * IDR_BITS; | |
1da177e4 | 670 | |
326cf0f0 | 671 | if (id > idr_max(p->layer + 1)) |
1da177e4 | 672 | return NULL; |
6ff2d39b | 673 | BUG_ON(n == 0); |
1da177e4 LT |
674 | |
675 | while (n > 0 && p) { | |
676 | n -= IDR_BITS; | |
6ff2d39b | 677 | BUG_ON(n != p->layer*IDR_BITS); |
96be753a | 678 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
1da177e4 LT |
679 | } |
680 | return((void *)p); | |
681 | } | |
0ffc2a9c | 682 | EXPORT_SYMBOL(idr_find_slowpath); |
1da177e4 | 683 | |
96d7fa42 KH |
684 | /** |
685 | * idr_for_each - iterate through all stored pointers | |
686 | * @idp: idr handle | |
687 | * @fn: function to be called for each pointer | |
688 | * @data: data passed back to callback function | |
689 | * | |
690 | * Iterate over the pointers registered with the given idr. The | |
691 | * callback function will be called for each pointer currently | |
692 | * registered, passing the id, the pointer and the data pointer passed | |
693 | * to this function. It is not safe to modify the idr tree while in | |
694 | * the callback, so functions such as idr_get_new and idr_remove are | |
695 | * not allowed. | |
696 | * | |
697 | * We check the return of @fn each time. If it returns anything other | |
56083ab1 | 698 | * than %0, we break out and return that value. |
96d7fa42 KH |
699 | * |
700 | * The caller must serialize idr_for_each() vs idr_get_new() and idr_remove(). | |
701 | */ | |
702 | int idr_for_each(struct idr *idp, | |
703 | int (*fn)(int id, void *p, void *data), void *data) | |
704 | { | |
705 | int n, id, max, error = 0; | |
706 | struct idr_layer *p; | |
326cf0f0 | 707 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
96d7fa42 KH |
708 | struct idr_layer **paa = &pa[0]; |
709 | ||
710 | n = idp->layers * IDR_BITS; | |
96be753a | 711 | p = rcu_dereference_raw(idp->top); |
326cf0f0 | 712 | max = idr_max(idp->layers); |
96d7fa42 KH |
713 | |
714 | id = 0; | |
326cf0f0 | 715 | while (id >= 0 && id <= max) { |
96d7fa42 KH |
716 | while (n > 0 && p) { |
717 | n -= IDR_BITS; | |
718 | *paa++ = p; | |
96be753a | 719 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
96d7fa42 KH |
720 | } |
721 | ||
722 | if (p) { | |
723 | error = fn(id, (void *)p, data); | |
724 | if (error) | |
725 | break; | |
726 | } | |
727 | ||
728 | id += 1 << n; | |
729 | while (n < fls(id)) { | |
730 | n += IDR_BITS; | |
731 | p = *--paa; | |
732 | } | |
733 | } | |
734 | ||
735 | return error; | |
736 | } | |
737 | EXPORT_SYMBOL(idr_for_each); | |
738 | ||
38460b48 KH |
739 | /** |
740 | * idr_get_next - lookup next object of id to given id. | |
741 | * @idp: idr handle | |
ea24ea85 | 742 | * @nextidp: pointer to lookup key |
38460b48 KH |
743 | * |
744 | * Returns pointer to registered object with id, which is next number to | |
1458ce16 NA |
745 | * given id. After being looked up, *@nextidp will be updated for the next |
746 | * iteration. | |
9f7de827 HD |
747 | * |
748 | * This function can be called under rcu_read_lock(), given that the leaf | |
749 | * pointers lifetimes are correctly managed. | |
38460b48 | 750 | */ |
38460b48 KH |
751 | void *idr_get_next(struct idr *idp, int *nextidp) |
752 | { | |
326cf0f0 | 753 | struct idr_layer *p, *pa[MAX_IDR_LEVEL + 1]; |
38460b48 KH |
754 | struct idr_layer **paa = &pa[0]; |
755 | int id = *nextidp; | |
756 | int n, max; | |
757 | ||
758 | /* find first ent */ | |
94bfa3b6 | 759 | p = rcu_dereference_raw(idp->top); |
38460b48 KH |
760 | if (!p) |
761 | return NULL; | |
9f7de827 | 762 | n = (p->layer + 1) * IDR_BITS; |
326cf0f0 | 763 | max = idr_max(p->layer + 1); |
38460b48 | 764 | |
326cf0f0 | 765 | while (id >= 0 && id <= max) { |
38460b48 KH |
766 | while (n > 0 && p) { |
767 | n -= IDR_BITS; | |
768 | *paa++ = p; | |
94bfa3b6 | 769 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
38460b48 KH |
770 | } |
771 | ||
772 | if (p) { | |
773 | *nextidp = id; | |
774 | return p; | |
775 | } | |
776 | ||
6cdae741 TH |
777 | /* |
778 | * Proceed to the next layer at the current level. Unlike | |
779 | * idr_for_each(), @id isn't guaranteed to be aligned to | |
780 | * layer boundary at this point and adding 1 << n may | |
781 | * incorrectly skip IDs. Make sure we jump to the | |
782 | * beginning of the next layer using round_up(). | |
783 | */ | |
784 | id = round_up(id + 1, 1 << n); | |
38460b48 KH |
785 | while (n < fls(id)) { |
786 | n += IDR_BITS; | |
787 | p = *--paa; | |
788 | } | |
789 | } | |
790 | return NULL; | |
791 | } | |
4d1ee80f | 792 | EXPORT_SYMBOL(idr_get_next); |
38460b48 KH |
793 | |
794 | ||
5806f07c JM |
795 | /** |
796 | * idr_replace - replace pointer for given id | |
797 | * @idp: idr handle | |
798 | * @ptr: pointer you want associated with the id | |
799 | * @id: lookup key | |
800 | * | |
801 | * Replace the pointer registered with an id and return the old value. | |
56083ab1 RD |
802 | * A %-ENOENT return indicates that @id was not found. |
803 | * A %-EINVAL return indicates that @id was not within valid constraints. | |
5806f07c | 804 | * |
cf481c20 | 805 | * The caller must serialize with writers. |
5806f07c JM |
806 | */ |
807 | void *idr_replace(struct idr *idp, void *ptr, int id) | |
808 | { | |
809 | int n; | |
810 | struct idr_layer *p, *old_p; | |
811 | ||
2e1c9b28 | 812 | if (id < 0) |
e8c8d1bc TH |
813 | return ERR_PTR(-EINVAL); |
814 | ||
5806f07c | 815 | p = idp->top; |
6ff2d39b MS |
816 | if (!p) |
817 | return ERR_PTR(-EINVAL); | |
818 | ||
3afb69cb | 819 | if (id > idr_max(p->layer + 1)) |
5806f07c JM |
820 | return ERR_PTR(-EINVAL); |
821 | ||
3afb69cb | 822 | n = p->layer * IDR_BITS; |
5806f07c JM |
823 | while ((n > 0) && p) { |
824 | p = p->ary[(id >> n) & IDR_MASK]; | |
825 | n -= IDR_BITS; | |
826 | } | |
827 | ||
828 | n = id & IDR_MASK; | |
1d9b2e1e | 829 | if (unlikely(p == NULL || !test_bit(n, p->bitmap))) |
5806f07c JM |
830 | return ERR_PTR(-ENOENT); |
831 | ||
832 | old_p = p->ary[n]; | |
cf481c20 | 833 | rcu_assign_pointer(p->ary[n], ptr); |
5806f07c JM |
834 | |
835 | return old_p; | |
836 | } | |
837 | EXPORT_SYMBOL(idr_replace); | |
838 | ||
199f0ca5 | 839 | void __init idr_init_cache(void) |
1da177e4 | 840 | { |
199f0ca5 | 841 | idr_layer_cache = kmem_cache_create("idr_layer_cache", |
5b019e99 | 842 | sizeof(struct idr_layer), 0, SLAB_PANIC, NULL); |
1da177e4 LT |
843 | } |
844 | ||
845 | /** | |
846 | * idr_init - initialize idr handle | |
847 | * @idp: idr handle | |
848 | * | |
849 | * This function is use to set up the handle (@idp) that you will pass | |
850 | * to the rest of the functions. | |
851 | */ | |
852 | void idr_init(struct idr *idp) | |
853 | { | |
1da177e4 LT |
854 | memset(idp, 0, sizeof(struct idr)); |
855 | spin_lock_init(&idp->lock); | |
856 | } | |
857 | EXPORT_SYMBOL(idr_init); | |
72dba584 | 858 | |
05f7a7d6 AG |
859 | static int idr_has_entry(int id, void *p, void *data) |
860 | { | |
861 | return 1; | |
862 | } | |
863 | ||
864 | bool idr_is_empty(struct idr *idp) | |
865 | { | |
866 | return !idr_for_each(idp, idr_has_entry, NULL); | |
867 | } | |
868 | EXPORT_SYMBOL(idr_is_empty); | |
72dba584 | 869 | |
56083ab1 RD |
870 | /** |
871 | * DOC: IDA description | |
72dba584 TH |
872 | * IDA - IDR based ID allocator |
873 | * | |
56083ab1 | 874 | * This is id allocator without id -> pointer translation. Memory |
72dba584 TH |
875 | * usage is much lower than full blown idr because each id only |
876 | * occupies a bit. ida uses a custom leaf node which contains | |
877 | * IDA_BITMAP_BITS slots. | |
878 | * | |
879 | * 2007-04-25 written by Tejun Heo <htejun@gmail.com> | |
880 | */ | |
881 | ||
882 | static void free_bitmap(struct ida *ida, struct ida_bitmap *bitmap) | |
883 | { | |
884 | unsigned long flags; | |
885 | ||
886 | if (!ida->free_bitmap) { | |
887 | spin_lock_irqsave(&ida->idr.lock, flags); | |
888 | if (!ida->free_bitmap) { | |
889 | ida->free_bitmap = bitmap; | |
890 | bitmap = NULL; | |
891 | } | |
892 | spin_unlock_irqrestore(&ida->idr.lock, flags); | |
893 | } | |
894 | ||
895 | kfree(bitmap); | |
896 | } | |
897 | ||
898 | /** | |
899 | * ida_pre_get - reserve resources for ida allocation | |
900 | * @ida: ida handle | |
901 | * @gfp_mask: memory allocation flag | |
902 | * | |
903 | * This function should be called prior to locking and calling the | |
904 | * following function. It preallocates enough memory to satisfy the | |
905 | * worst possible allocation. | |
906 | * | |
56083ab1 RD |
907 | * If the system is REALLY out of memory this function returns %0, |
908 | * otherwise %1. | |
72dba584 TH |
909 | */ |
910 | int ida_pre_get(struct ida *ida, gfp_t gfp_mask) | |
911 | { | |
912 | /* allocate idr_layers */ | |
c8615d37 | 913 | if (!__idr_pre_get(&ida->idr, gfp_mask)) |
72dba584 TH |
914 | return 0; |
915 | ||
916 | /* allocate free_bitmap */ | |
917 | if (!ida->free_bitmap) { | |
918 | struct ida_bitmap *bitmap; | |
919 | ||
920 | bitmap = kmalloc(sizeof(struct ida_bitmap), gfp_mask); | |
921 | if (!bitmap) | |
922 | return 0; | |
923 | ||
924 | free_bitmap(ida, bitmap); | |
925 | } | |
926 | ||
927 | return 1; | |
928 | } | |
929 | EXPORT_SYMBOL(ida_pre_get); | |
930 | ||
931 | /** | |
932 | * ida_get_new_above - allocate new ID above or equal to a start id | |
933 | * @ida: ida handle | |
ea24ea85 | 934 | * @starting_id: id to start search at |
72dba584 TH |
935 | * @p_id: pointer to the allocated handle |
936 | * | |
e3816c54 WSH |
937 | * Allocate new ID above or equal to @starting_id. It should be called |
938 | * with any required locks. | |
72dba584 | 939 | * |
56083ab1 | 940 | * If memory is required, it will return %-EAGAIN, you should unlock |
72dba584 | 941 | * and go back to the ida_pre_get() call. If the ida is full, it will |
56083ab1 | 942 | * return %-ENOSPC. |
72dba584 | 943 | * |
56083ab1 | 944 | * @p_id returns a value in the range @starting_id ... %0x7fffffff. |
72dba584 TH |
945 | */ |
946 | int ida_get_new_above(struct ida *ida, int starting_id, int *p_id) | |
947 | { | |
326cf0f0 | 948 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
72dba584 TH |
949 | struct ida_bitmap *bitmap; |
950 | unsigned long flags; | |
951 | int idr_id = starting_id / IDA_BITMAP_BITS; | |
952 | int offset = starting_id % IDA_BITMAP_BITS; | |
953 | int t, id; | |
954 | ||
955 | restart: | |
956 | /* get vacant slot */ | |
d5c7409f | 957 | t = idr_get_empty_slot(&ida->idr, idr_id, pa, 0, &ida->idr); |
944ca05c | 958 | if (t < 0) |
12d1b439 | 959 | return t == -ENOMEM ? -EAGAIN : t; |
72dba584 | 960 | |
125c4c70 | 961 | if (t * IDA_BITMAP_BITS >= MAX_IDR_BIT) |
72dba584 TH |
962 | return -ENOSPC; |
963 | ||
964 | if (t != idr_id) | |
965 | offset = 0; | |
966 | idr_id = t; | |
967 | ||
968 | /* if bitmap isn't there, create a new one */ | |
969 | bitmap = (void *)pa[0]->ary[idr_id & IDR_MASK]; | |
970 | if (!bitmap) { | |
971 | spin_lock_irqsave(&ida->idr.lock, flags); | |
972 | bitmap = ida->free_bitmap; | |
973 | ida->free_bitmap = NULL; | |
974 | spin_unlock_irqrestore(&ida->idr.lock, flags); | |
975 | ||
976 | if (!bitmap) | |
977 | return -EAGAIN; | |
978 | ||
979 | memset(bitmap, 0, sizeof(struct ida_bitmap)); | |
3219b3b7 ND |
980 | rcu_assign_pointer(pa[0]->ary[idr_id & IDR_MASK], |
981 | (void *)bitmap); | |
72dba584 TH |
982 | pa[0]->count++; |
983 | } | |
984 | ||
985 | /* lookup for empty slot */ | |
986 | t = find_next_zero_bit(bitmap->bitmap, IDA_BITMAP_BITS, offset); | |
987 | if (t == IDA_BITMAP_BITS) { | |
988 | /* no empty slot after offset, continue to the next chunk */ | |
989 | idr_id++; | |
990 | offset = 0; | |
991 | goto restart; | |
992 | } | |
993 | ||
994 | id = idr_id * IDA_BITMAP_BITS + t; | |
125c4c70 | 995 | if (id >= MAX_IDR_BIT) |
72dba584 TH |
996 | return -ENOSPC; |
997 | ||
998 | __set_bit(t, bitmap->bitmap); | |
999 | if (++bitmap->nr_busy == IDA_BITMAP_BITS) | |
1000 | idr_mark_full(pa, idr_id); | |
1001 | ||
1002 | *p_id = id; | |
1003 | ||
1004 | /* Each leaf node can handle nearly a thousand slots and the | |
1005 | * whole idea of ida is to have small memory foot print. | |
1006 | * Throw away extra resources one by one after each successful | |
1007 | * allocation. | |
1008 | */ | |
1009 | if (ida->idr.id_free_cnt || ida->free_bitmap) { | |
4ae53789 | 1010 | struct idr_layer *p = get_from_free_list(&ida->idr); |
72dba584 TH |
1011 | if (p) |
1012 | kmem_cache_free(idr_layer_cache, p); | |
1013 | } | |
1014 | ||
1015 | return 0; | |
1016 | } | |
1017 | EXPORT_SYMBOL(ida_get_new_above); | |
1018 | ||
72dba584 TH |
1019 | /** |
1020 | * ida_remove - remove the given ID | |
1021 | * @ida: ida handle | |
1022 | * @id: ID to free | |
1023 | */ | |
1024 | void ida_remove(struct ida *ida, int id) | |
1025 | { | |
1026 | struct idr_layer *p = ida->idr.top; | |
1027 | int shift = (ida->idr.layers - 1) * IDR_BITS; | |
1028 | int idr_id = id / IDA_BITMAP_BITS; | |
1029 | int offset = id % IDA_BITMAP_BITS; | |
1030 | int n; | |
1031 | struct ida_bitmap *bitmap; | |
1032 | ||
8f9f665a LJ |
1033 | if (idr_id > idr_max(ida->idr.layers)) |
1034 | goto err; | |
1035 | ||
72dba584 TH |
1036 | /* clear full bits while looking up the leaf idr_layer */ |
1037 | while ((shift > 0) && p) { | |
1038 | n = (idr_id >> shift) & IDR_MASK; | |
1d9b2e1e | 1039 | __clear_bit(n, p->bitmap); |
72dba584 TH |
1040 | p = p->ary[n]; |
1041 | shift -= IDR_BITS; | |
1042 | } | |
1043 | ||
1044 | if (p == NULL) | |
1045 | goto err; | |
1046 | ||
1047 | n = idr_id & IDR_MASK; | |
1d9b2e1e | 1048 | __clear_bit(n, p->bitmap); |
72dba584 TH |
1049 | |
1050 | bitmap = (void *)p->ary[n]; | |
aef0f62e | 1051 | if (!bitmap || !test_bit(offset, bitmap->bitmap)) |
72dba584 TH |
1052 | goto err; |
1053 | ||
1054 | /* update bitmap and remove it if empty */ | |
1055 | __clear_bit(offset, bitmap->bitmap); | |
1056 | if (--bitmap->nr_busy == 0) { | |
1d9b2e1e | 1057 | __set_bit(n, p->bitmap); /* to please idr_remove() */ |
72dba584 TH |
1058 | idr_remove(&ida->idr, idr_id); |
1059 | free_bitmap(ida, bitmap); | |
1060 | } | |
1061 | ||
1062 | return; | |
1063 | ||
1064 | err: | |
dd04b452 | 1065 | WARN(1, "ida_remove called for id=%d which is not allocated.\n", id); |
72dba584 TH |
1066 | } |
1067 | EXPORT_SYMBOL(ida_remove); | |
1068 | ||
1069 | /** | |
1070 | * ida_destroy - release all cached layers within an ida tree | |
ea24ea85 | 1071 | * @ida: ida handle |
72dba584 TH |
1072 | */ |
1073 | void ida_destroy(struct ida *ida) | |
1074 | { | |
1075 | idr_destroy(&ida->idr); | |
1076 | kfree(ida->free_bitmap); | |
1077 | } | |
1078 | EXPORT_SYMBOL(ida_destroy); | |
1079 | ||
88eca020 RR |
1080 | /** |
1081 | * ida_simple_get - get a new id. | |
1082 | * @ida: the (initialized) ida. | |
1083 | * @start: the minimum id (inclusive, < 0x8000000) | |
1084 | * @end: the maximum id (exclusive, < 0x8000000 or 0) | |
1085 | * @gfp_mask: memory allocation flags | |
1086 | * | |
1087 | * Allocates an id in the range start <= id < end, or returns -ENOSPC. | |
1088 | * On memory allocation failure, returns -ENOMEM. | |
1089 | * | |
1090 | * Use ida_simple_remove() to get rid of an id. | |
1091 | */ | |
1092 | int ida_simple_get(struct ida *ida, unsigned int start, unsigned int end, | |
1093 | gfp_t gfp_mask) | |
1094 | { | |
1095 | int ret, id; | |
1096 | unsigned int max; | |
46cbc1d3 | 1097 | unsigned long flags; |
88eca020 RR |
1098 | |
1099 | BUG_ON((int)start < 0); | |
1100 | BUG_ON((int)end < 0); | |
1101 | ||
1102 | if (end == 0) | |
1103 | max = 0x80000000; | |
1104 | else { | |
1105 | BUG_ON(end < start); | |
1106 | max = end - 1; | |
1107 | } | |
1108 | ||
1109 | again: | |
1110 | if (!ida_pre_get(ida, gfp_mask)) | |
1111 | return -ENOMEM; | |
1112 | ||
46cbc1d3 | 1113 | spin_lock_irqsave(&simple_ida_lock, flags); |
88eca020 RR |
1114 | ret = ida_get_new_above(ida, start, &id); |
1115 | if (!ret) { | |
1116 | if (id > max) { | |
1117 | ida_remove(ida, id); | |
1118 | ret = -ENOSPC; | |
1119 | } else { | |
1120 | ret = id; | |
1121 | } | |
1122 | } | |
46cbc1d3 | 1123 | spin_unlock_irqrestore(&simple_ida_lock, flags); |
88eca020 RR |
1124 | |
1125 | if (unlikely(ret == -EAGAIN)) | |
1126 | goto again; | |
1127 | ||
1128 | return ret; | |
1129 | } | |
1130 | EXPORT_SYMBOL(ida_simple_get); | |
1131 | ||
1132 | /** | |
1133 | * ida_simple_remove - remove an allocated id. | |
1134 | * @ida: the (initialized) ida. | |
1135 | * @id: the id returned by ida_simple_get. | |
1136 | */ | |
1137 | void ida_simple_remove(struct ida *ida, unsigned int id) | |
1138 | { | |
46cbc1d3 TH |
1139 | unsigned long flags; |
1140 | ||
88eca020 | 1141 | BUG_ON((int)id < 0); |
46cbc1d3 | 1142 | spin_lock_irqsave(&simple_ida_lock, flags); |
88eca020 | 1143 | ida_remove(ida, id); |
46cbc1d3 | 1144 | spin_unlock_irqrestore(&simple_ida_lock, flags); |
88eca020 RR |
1145 | } |
1146 | EXPORT_SYMBOL(ida_simple_remove); | |
1147 | ||
72dba584 TH |
1148 | /** |
1149 | * ida_init - initialize ida handle | |
1150 | * @ida: ida handle | |
1151 | * | |
1152 | * This function is use to set up the handle (@ida) that you will pass | |
1153 | * to the rest of the functions. | |
1154 | */ | |
1155 | void ida_init(struct ida *ida) | |
1156 | { | |
1157 | memset(ida, 0, sizeof(struct ida)); | |
1158 | idr_init(&ida->idr); | |
1159 | ||
1160 | } | |
1161 | EXPORT_SYMBOL(ida_init); |