Commit | Line | Data |
---|---|---|
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 | ||
4ae53789 | 63 | static struct idr_layer *get_from_free_list(struct idr *idp) |
1da177e4 LT |
64 | { |
65 | struct idr_layer *p; | |
c259cc28 | 66 | unsigned long flags; |
1da177e4 | 67 | |
c259cc28 | 68 | spin_lock_irqsave(&idp->lock, flags); |
1da177e4 LT |
69 | if ((p = idp->id_free)) { |
70 | idp->id_free = p->ary[0]; | |
71 | idp->id_free_cnt--; | |
72 | p->ary[0] = NULL; | |
73 | } | |
c259cc28 | 74 | spin_unlock_irqrestore(&idp->lock, flags); |
1da177e4 LT |
75 | return(p); |
76 | } | |
77 | ||
d5c7409f TH |
78 | /** |
79 | * idr_layer_alloc - allocate a new idr_layer | |
80 | * @gfp_mask: allocation mask | |
81 | * @layer_idr: optional idr to allocate from | |
82 | * | |
83 | * If @layer_idr is %NULL, directly allocate one using @gfp_mask or fetch | |
84 | * one from the per-cpu preload buffer. If @layer_idr is not %NULL, fetch | |
85 | * an idr_layer from @idr->id_free. | |
86 | * | |
87 | * @layer_idr is to maintain backward compatibility with the old alloc | |
88 | * interface - idr_pre_get() and idr_get_new*() - and will be removed | |
89 | * together with per-pool preload buffer. | |
90 | */ | |
91 | static struct idr_layer *idr_layer_alloc(gfp_t gfp_mask, struct idr *layer_idr) | |
92 | { | |
93 | struct idr_layer *new; | |
94 | ||
95 | /* this is the old path, bypass to get_from_free_list() */ | |
96 | if (layer_idr) | |
97 | return get_from_free_list(layer_idr); | |
98 | ||
99 | /* try to allocate directly from kmem_cache */ | |
100 | new = kmem_cache_zalloc(idr_layer_cache, gfp_mask); | |
101 | if (new) | |
102 | return new; | |
103 | ||
104 | /* | |
105 | * Try to fetch one from the per-cpu preload buffer if in process | |
106 | * context. See idr_preload() for details. | |
107 | */ | |
108 | if (in_interrupt()) | |
109 | return NULL; | |
110 | ||
111 | preempt_disable(); | |
112 | new = __this_cpu_read(idr_preload_head); | |
113 | if (new) { | |
114 | __this_cpu_write(idr_preload_head, new->ary[0]); | |
115 | __this_cpu_dec(idr_preload_cnt); | |
116 | new->ary[0] = NULL; | |
117 | } | |
118 | preempt_enable(); | |
119 | return new; | |
120 | } | |
121 | ||
cf481c20 ND |
122 | static void idr_layer_rcu_free(struct rcu_head *head) |
123 | { | |
124 | struct idr_layer *layer; | |
125 | ||
126 | layer = container_of(head, struct idr_layer, rcu_head); | |
127 | kmem_cache_free(idr_layer_cache, layer); | |
128 | } | |
129 | ||
130 | static inline void free_layer(struct idr_layer *p) | |
131 | { | |
132 | call_rcu(&p->rcu_head, idr_layer_rcu_free); | |
133 | } | |
134 | ||
1eec0056 | 135 | /* only called when idp->lock is held */ |
4ae53789 | 136 | static void __move_to_free_list(struct idr *idp, struct idr_layer *p) |
1eec0056 SR |
137 | { |
138 | p->ary[0] = idp->id_free; | |
139 | idp->id_free = p; | |
140 | idp->id_free_cnt++; | |
141 | } | |
142 | ||
4ae53789 | 143 | static void move_to_free_list(struct idr *idp, struct idr_layer *p) |
1da177e4 | 144 | { |
c259cc28 RD |
145 | unsigned long flags; |
146 | ||
1da177e4 LT |
147 | /* |
148 | * Depends on the return element being zeroed. | |
149 | */ | |
c259cc28 | 150 | spin_lock_irqsave(&idp->lock, flags); |
4ae53789 | 151 | __move_to_free_list(idp, p); |
c259cc28 | 152 | spin_unlock_irqrestore(&idp->lock, flags); |
1da177e4 LT |
153 | } |
154 | ||
e33ac8bd TH |
155 | static void idr_mark_full(struct idr_layer **pa, int id) |
156 | { | |
157 | struct idr_layer *p = pa[0]; | |
158 | int l = 0; | |
159 | ||
1d9b2e1e | 160 | __set_bit(id & IDR_MASK, p->bitmap); |
e33ac8bd TH |
161 | /* |
162 | * If this layer is full mark the bit in the layer above to | |
163 | * show that this part of the radix tree is full. This may | |
164 | * complete the layer above and require walking up the radix | |
165 | * tree. | |
166 | */ | |
1d9b2e1e | 167 | while (bitmap_full(p->bitmap, IDR_SIZE)) { |
e33ac8bd TH |
168 | if (!(p = pa[++l])) |
169 | break; | |
170 | id = id >> IDR_BITS; | |
1d9b2e1e | 171 | __set_bit((id & IDR_MASK), p->bitmap); |
e33ac8bd TH |
172 | } |
173 | } | |
174 | ||
1da177e4 | 175 | /** |
56083ab1 | 176 | * idr_pre_get - reserve resources for idr allocation |
1da177e4 LT |
177 | * @idp: idr handle |
178 | * @gfp_mask: memory allocation flags | |
179 | * | |
066a9be6 NA |
180 | * This function should be called prior to calling the idr_get_new* functions. |
181 | * It preallocates enough memory to satisfy the worst possible allocation. The | |
182 | * caller should pass in GFP_KERNEL if possible. This of course requires that | |
183 | * no spinning locks be held. | |
1da177e4 | 184 | * |
56083ab1 RD |
185 | * If the system is REALLY out of memory this function returns %0, |
186 | * otherwise %1. | |
1da177e4 | 187 | */ |
fd4f2df2 | 188 | int idr_pre_get(struct idr *idp, gfp_t gfp_mask) |
1da177e4 | 189 | { |
125c4c70 | 190 | while (idp->id_free_cnt < MAX_IDR_FREE) { |
1da177e4 | 191 | struct idr_layer *new; |
5b019e99 | 192 | new = kmem_cache_zalloc(idr_layer_cache, gfp_mask); |
e15ae2dd | 193 | if (new == NULL) |
1da177e4 | 194 | return (0); |
4ae53789 | 195 | move_to_free_list(idp, new); |
1da177e4 LT |
196 | } |
197 | return 1; | |
198 | } | |
199 | EXPORT_SYMBOL(idr_pre_get); | |
200 | ||
12d1b439 TH |
201 | /** |
202 | * sub_alloc - try to allocate an id without growing the tree depth | |
203 | * @idp: idr handle | |
204 | * @starting_id: id to start search at | |
205 | * @id: pointer to the allocated handle | |
206 | * @pa: idr_layer[MAX_IDR_LEVEL] used as backtrack buffer | |
d5c7409f TH |
207 | * @gfp_mask: allocation mask for idr_layer_alloc() |
208 | * @layer_idr: optional idr passed to idr_layer_alloc() | |
12d1b439 TH |
209 | * |
210 | * Allocate an id in range [@starting_id, INT_MAX] from @idp without | |
211 | * growing its depth. Returns | |
212 | * | |
213 | * the allocated id >= 0 if successful, | |
214 | * -EAGAIN if the tree needs to grow for allocation to succeed, | |
215 | * -ENOSPC if the id space is exhausted, | |
216 | * -ENOMEM if more idr_layers need to be allocated. | |
217 | */ | |
d5c7409f TH |
218 | static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa, |
219 | gfp_t gfp_mask, struct idr *layer_idr) | |
1da177e4 LT |
220 | { |
221 | int n, m, sh; | |
222 | struct idr_layer *p, *new; | |
7aae6dd8 | 223 | int l, id, oid; |
1da177e4 LT |
224 | |
225 | id = *starting_id; | |
7aae6dd8 | 226 | restart: |
1da177e4 LT |
227 | p = idp->top; |
228 | l = idp->layers; | |
229 | pa[l--] = NULL; | |
230 | while (1) { | |
231 | /* | |
232 | * We run around this while until we reach the leaf node... | |
233 | */ | |
234 | n = (id >> (IDR_BITS*l)) & IDR_MASK; | |
1d9b2e1e | 235 | m = find_next_zero_bit(p->bitmap, IDR_SIZE, n); |
1da177e4 LT |
236 | if (m == IDR_SIZE) { |
237 | /* no space available go back to previous layer. */ | |
238 | l++; | |
7aae6dd8 | 239 | oid = id; |
e15ae2dd | 240 | id = (id | ((1 << (IDR_BITS * l)) - 1)) + 1; |
7aae6dd8 TH |
241 | |
242 | /* if already at the top layer, we need to grow */ | |
d2e7276b | 243 | if (id >= 1 << (idp->layers * IDR_BITS)) { |
1da177e4 | 244 | *starting_id = id; |
12d1b439 | 245 | return -EAGAIN; |
1da177e4 | 246 | } |
d2e7276b TH |
247 | p = pa[l]; |
248 | BUG_ON(!p); | |
7aae6dd8 TH |
249 | |
250 | /* If we need to go up one layer, continue the | |
251 | * loop; otherwise, restart from the top. | |
252 | */ | |
253 | sh = IDR_BITS * (l + 1); | |
254 | if (oid >> sh == id >> sh) | |
255 | continue; | |
256 | else | |
257 | goto restart; | |
1da177e4 LT |
258 | } |
259 | if (m != n) { | |
260 | sh = IDR_BITS*l; | |
261 | id = ((id >> sh) ^ n ^ m) << sh; | |
262 | } | |
125c4c70 | 263 | if ((id >= MAX_IDR_BIT) || (id < 0)) |
12d1b439 | 264 | return -ENOSPC; |
1da177e4 LT |
265 | if (l == 0) |
266 | break; | |
267 | /* | |
268 | * Create the layer below if it is missing. | |
269 | */ | |
270 | if (!p->ary[m]) { | |
d5c7409f | 271 | new = idr_layer_alloc(gfp_mask, layer_idr); |
4ae53789 | 272 | if (!new) |
12d1b439 | 273 | return -ENOMEM; |
6ff2d39b | 274 | new->layer = l-1; |
3219b3b7 | 275 | rcu_assign_pointer(p->ary[m], new); |
1da177e4 LT |
276 | p->count++; |
277 | } | |
278 | pa[l--] = p; | |
279 | p = p->ary[m]; | |
280 | } | |
e33ac8bd TH |
281 | |
282 | pa[l] = p; | |
283 | return id; | |
1da177e4 LT |
284 | } |
285 | ||
e33ac8bd | 286 | static int idr_get_empty_slot(struct idr *idp, int starting_id, |
d5c7409f TH |
287 | struct idr_layer **pa, gfp_t gfp_mask, |
288 | struct idr *layer_idr) | |
1da177e4 LT |
289 | { |
290 | struct idr_layer *p, *new; | |
291 | int layers, v, id; | |
c259cc28 | 292 | unsigned long flags; |
e15ae2dd | 293 | |
1da177e4 LT |
294 | id = starting_id; |
295 | build_up: | |
296 | p = idp->top; | |
297 | layers = idp->layers; | |
298 | if (unlikely(!p)) { | |
d5c7409f | 299 | if (!(p = idr_layer_alloc(gfp_mask, layer_idr))) |
12d1b439 | 300 | return -ENOMEM; |
6ff2d39b | 301 | p->layer = 0; |
1da177e4 LT |
302 | layers = 1; |
303 | } | |
304 | /* | |
305 | * Add a new layer to the top of the tree if the requested | |
306 | * id is larger than the currently allocated space. | |
307 | */ | |
326cf0f0 | 308 | while (id > idr_max(layers)) { |
1da177e4 | 309 | layers++; |
711a49a0 MS |
310 | if (!p->count) { |
311 | /* special case: if the tree is currently empty, | |
312 | * then we grow the tree by moving the top node | |
313 | * upwards. | |
314 | */ | |
315 | p->layer++; | |
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; |
1d9b2e1e TH |
337 | if (bitmap_full(p->bitmap, IDR_SIZE)) |
338 | __set_bit(0, new->bitmap); | |
1da177e4 LT |
339 | p = new; |
340 | } | |
3219b3b7 | 341 | rcu_assign_pointer(idp->top, p); |
1da177e4 | 342 | idp->layers = layers; |
d5c7409f | 343 | v = sub_alloc(idp, &id, pa, gfp_mask, layer_idr); |
12d1b439 | 344 | if (v == -EAGAIN) |
1da177e4 LT |
345 | goto build_up; |
346 | return(v); | |
347 | } | |
348 | ||
3594eb28 TH |
349 | /* |
350 | * @id and @pa are from a successful allocation from idr_get_empty_slot(). | |
351 | * Install the user pointer @ptr and mark the slot full. | |
352 | */ | |
353 | static void idr_fill_slot(void *ptr, int id, struct idr_layer **pa) | |
e33ac8bd | 354 | { |
3594eb28 TH |
355 | rcu_assign_pointer(pa[0]->ary[id & IDR_MASK], (struct idr_layer *)ptr); |
356 | pa[0]->count++; | |
357 | idr_mark_full(pa, id); | |
e33ac8bd TH |
358 | } |
359 | ||
1da177e4 | 360 | /** |
7c657f2f | 361 | * idr_get_new_above - allocate new idr entry above or equal to a start id |
1da177e4 | 362 | * @idp: idr handle |
94e2bd68 | 363 | * @ptr: pointer you want associated with the id |
ea24ea85 | 364 | * @starting_id: id to start search at |
1da177e4 LT |
365 | * @id: pointer to the allocated handle |
366 | * | |
367 | * This is the allocate id function. It should be called with any | |
368 | * required locks. | |
369 | * | |
066a9be6 | 370 | * If allocation from IDR's private freelist fails, idr_get_new_above() will |
56083ab1 | 371 | * return %-EAGAIN. The caller should retry the idr_pre_get() call to refill |
066a9be6 NA |
372 | * IDR's preallocation and then retry the idr_get_new_above() call. |
373 | * | |
56083ab1 | 374 | * If the idr is full idr_get_new_above() will return %-ENOSPC. |
1da177e4 | 375 | * |
56083ab1 | 376 | * @id returns a value in the range @starting_id ... %0x7fffffff |
1da177e4 LT |
377 | */ |
378 | int idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id) | |
379 | { | |
326cf0f0 | 380 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
1da177e4 | 381 | int rv; |
e15ae2dd | 382 | |
d5c7409f | 383 | rv = idr_get_empty_slot(idp, starting_id, pa, 0, idp); |
944ca05c | 384 | if (rv < 0) |
12d1b439 | 385 | return rv == -ENOMEM ? -EAGAIN : rv; |
3594eb28 TH |
386 | |
387 | idr_fill_slot(ptr, rv, pa); | |
1da177e4 LT |
388 | *id = rv; |
389 | return 0; | |
390 | } | |
391 | EXPORT_SYMBOL(idr_get_new_above); | |
392 | ||
d5c7409f TH |
393 | /** |
394 | * idr_preload - preload for idr_alloc() | |
395 | * @gfp_mask: allocation mask to use for preloading | |
396 | * | |
397 | * Preload per-cpu layer buffer for idr_alloc(). Can only be used from | |
398 | * process context and each idr_preload() invocation should be matched with | |
399 | * idr_preload_end(). Note that preemption is disabled while preloaded. | |
400 | * | |
401 | * The first idr_alloc() in the preloaded section can be treated as if it | |
402 | * were invoked with @gfp_mask used for preloading. This allows using more | |
403 | * permissive allocation masks for idrs protected by spinlocks. | |
404 | * | |
405 | * For example, if idr_alloc() below fails, the failure can be treated as | |
406 | * if idr_alloc() were called with GFP_KERNEL rather than GFP_NOWAIT. | |
407 | * | |
408 | * idr_preload(GFP_KERNEL); | |
409 | * spin_lock(lock); | |
410 | * | |
411 | * id = idr_alloc(idr, ptr, start, end, GFP_NOWAIT); | |
412 | * | |
413 | * spin_unlock(lock); | |
414 | * idr_preload_end(); | |
415 | * if (id < 0) | |
416 | * error; | |
417 | */ | |
418 | void idr_preload(gfp_t gfp_mask) | |
419 | { | |
420 | /* | |
421 | * Consuming preload buffer from non-process context breaks preload | |
422 | * allocation guarantee. Disallow usage from those contexts. | |
423 | */ | |
424 | WARN_ON_ONCE(in_interrupt()); | |
425 | might_sleep_if(gfp_mask & __GFP_WAIT); | |
426 | ||
427 | preempt_disable(); | |
428 | ||
429 | /* | |
430 | * idr_alloc() is likely to succeed w/o full idr_layer buffer and | |
431 | * return value from idr_alloc() needs to be checked for failure | |
432 | * anyway. Silently give up if allocation fails. The caller can | |
433 | * treat failures from idr_alloc() as if idr_alloc() were called | |
434 | * with @gfp_mask which should be enough. | |
435 | */ | |
436 | while (__this_cpu_read(idr_preload_cnt) < MAX_IDR_FREE) { | |
437 | struct idr_layer *new; | |
438 | ||
439 | preempt_enable(); | |
440 | new = kmem_cache_zalloc(idr_layer_cache, gfp_mask); | |
441 | preempt_disable(); | |
442 | if (!new) | |
443 | break; | |
444 | ||
445 | /* link the new one to per-cpu preload list */ | |
446 | new->ary[0] = __this_cpu_read(idr_preload_head); | |
447 | __this_cpu_write(idr_preload_head, new); | |
448 | __this_cpu_inc(idr_preload_cnt); | |
449 | } | |
450 | } | |
451 | EXPORT_SYMBOL(idr_preload); | |
452 | ||
453 | /** | |
454 | * idr_alloc - allocate new idr entry | |
455 | * @idr: the (initialized) idr | |
456 | * @ptr: pointer to be associated with the new id | |
457 | * @start: the minimum id (inclusive) | |
458 | * @end: the maximum id (exclusive, <= 0 for max) | |
459 | * @gfp_mask: memory allocation flags | |
460 | * | |
461 | * Allocate an id in [start, end) and associate it with @ptr. If no ID is | |
462 | * available in the specified range, returns -ENOSPC. On memory allocation | |
463 | * failure, returns -ENOMEM. | |
464 | * | |
465 | * Note that @end is treated as max when <= 0. This is to always allow | |
466 | * using @start + N as @end as long as N is inside integer range. | |
467 | * | |
468 | * The user is responsible for exclusively synchronizing all operations | |
469 | * which may modify @idr. However, read-only accesses such as idr_find() | |
470 | * or iteration can be performed under RCU read lock provided the user | |
471 | * destroys @ptr in RCU-safe way after removal from idr. | |
472 | */ | |
473 | int idr_alloc(struct idr *idr, void *ptr, int start, int end, gfp_t gfp_mask) | |
474 | { | |
475 | int max = end > 0 ? end - 1 : INT_MAX; /* inclusive upper limit */ | |
326cf0f0 | 476 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
d5c7409f TH |
477 | int id; |
478 | ||
479 | might_sleep_if(gfp_mask & __GFP_WAIT); | |
480 | ||
481 | /* sanity checks */ | |
482 | if (WARN_ON_ONCE(start < 0)) | |
483 | return -EINVAL; | |
484 | if (unlikely(max < start)) | |
485 | return -ENOSPC; | |
486 | ||
487 | /* allocate id */ | |
488 | id = idr_get_empty_slot(idr, start, pa, gfp_mask, NULL); | |
489 | if (unlikely(id < 0)) | |
490 | return id; | |
491 | if (unlikely(id > max)) | |
492 | return -ENOSPC; | |
493 | ||
494 | idr_fill_slot(ptr, id, pa); | |
495 | return id; | |
496 | } | |
497 | EXPORT_SYMBOL_GPL(idr_alloc); | |
498 | ||
1da177e4 LT |
499 | static void idr_remove_warning(int id) |
500 | { | |
f098ad65 ND |
501 | printk(KERN_WARNING |
502 | "idr_remove called for id=%d which is not allocated.\n", id); | |
1da177e4 LT |
503 | dump_stack(); |
504 | } | |
505 | ||
506 | static void sub_remove(struct idr *idp, int shift, int id) | |
507 | { | |
508 | struct idr_layer *p = idp->top; | |
326cf0f0 | 509 | struct idr_layer **pa[MAX_IDR_LEVEL + 1]; |
1da177e4 | 510 | struct idr_layer ***paa = &pa[0]; |
cf481c20 | 511 | struct idr_layer *to_free; |
1da177e4 LT |
512 | int n; |
513 | ||
514 | *paa = NULL; | |
515 | *++paa = &idp->top; | |
516 | ||
517 | while ((shift > 0) && p) { | |
518 | n = (id >> shift) & IDR_MASK; | |
1d9b2e1e | 519 | __clear_bit(n, p->bitmap); |
1da177e4 LT |
520 | *++paa = &p->ary[n]; |
521 | p = p->ary[n]; | |
522 | shift -= IDR_BITS; | |
523 | } | |
524 | n = id & IDR_MASK; | |
1d9b2e1e TH |
525 | if (likely(p != NULL && test_bit(n, p->bitmap))) { |
526 | __clear_bit(n, p->bitmap); | |
cf481c20 ND |
527 | rcu_assign_pointer(p->ary[n], NULL); |
528 | to_free = NULL; | |
1da177e4 | 529 | while(*paa && ! --((**paa)->count)){ |
cf481c20 ND |
530 | if (to_free) |
531 | free_layer(to_free); | |
532 | to_free = **paa; | |
1da177e4 LT |
533 | **paa-- = NULL; |
534 | } | |
e15ae2dd | 535 | if (!*paa) |
1da177e4 | 536 | idp->layers = 0; |
cf481c20 ND |
537 | if (to_free) |
538 | free_layer(to_free); | |
e15ae2dd | 539 | } else |
1da177e4 | 540 | idr_remove_warning(id); |
1da177e4 LT |
541 | } |
542 | ||
543 | /** | |
56083ab1 | 544 | * idr_remove - remove the given id and free its slot |
72fd4a35 RD |
545 | * @idp: idr handle |
546 | * @id: unique key | |
1da177e4 LT |
547 | */ |
548 | void idr_remove(struct idr *idp, int id) | |
549 | { | |
550 | struct idr_layer *p; | |
cf481c20 | 551 | struct idr_layer *to_free; |
1da177e4 | 552 | |
e8c8d1bc TH |
553 | if (WARN_ON_ONCE(id < 0)) |
554 | return; | |
1da177e4 LT |
555 | |
556 | sub_remove(idp, (idp->layers - 1) * IDR_BITS, id); | |
e15ae2dd | 557 | if (idp->top && idp->top->count == 1 && (idp->layers > 1) && |
cf481c20 ND |
558 | idp->top->ary[0]) { |
559 | /* | |
560 | * Single child at leftmost slot: we can shrink the tree. | |
561 | * This level is not needed anymore since when layers are | |
562 | * inserted, they are inserted at the top of the existing | |
563 | * tree. | |
564 | */ | |
565 | to_free = idp->top; | |
1da177e4 | 566 | p = idp->top->ary[0]; |
cf481c20 | 567 | rcu_assign_pointer(idp->top, p); |
1da177e4 | 568 | --idp->layers; |
1d9b2e1e TH |
569 | to_free->count = 0; |
570 | bitmap_clear(to_free->bitmap, 0, IDR_SIZE); | |
cf481c20 | 571 | free_layer(to_free); |
1da177e4 | 572 | } |
125c4c70 | 573 | while (idp->id_free_cnt >= MAX_IDR_FREE) { |
4ae53789 | 574 | p = get_from_free_list(idp); |
cf481c20 ND |
575 | /* |
576 | * Note: we don't call the rcu callback here, since the only | |
577 | * layers that fall into the freelist are those that have been | |
578 | * preallocated. | |
579 | */ | |
1da177e4 | 580 | kmem_cache_free(idr_layer_cache, p); |
1da177e4 | 581 | } |
af8e2a4c | 582 | return; |
1da177e4 LT |
583 | } |
584 | EXPORT_SYMBOL(idr_remove); | |
585 | ||
fe6e24ec | 586 | void __idr_remove_all(struct idr *idp) |
23936cc0 | 587 | { |
6ace06dc | 588 | int n, id, max; |
2dcb22b3 | 589 | int bt_mask; |
23936cc0 | 590 | struct idr_layer *p; |
326cf0f0 | 591 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
23936cc0 KH |
592 | struct idr_layer **paa = &pa[0]; |
593 | ||
594 | n = idp->layers * IDR_BITS; | |
595 | p = idp->top; | |
1b23336a | 596 | rcu_assign_pointer(idp->top, NULL); |
326cf0f0 | 597 | max = idr_max(idp->layers); |
23936cc0 KH |
598 | |
599 | id = 0; | |
326cf0f0 | 600 | while (id >= 0 && id <= max) { |
23936cc0 KH |
601 | while (n > IDR_BITS && p) { |
602 | n -= IDR_BITS; | |
603 | *paa++ = p; | |
604 | p = p->ary[(id >> n) & IDR_MASK]; | |
605 | } | |
606 | ||
2dcb22b3 | 607 | bt_mask = id; |
23936cc0 | 608 | id += 1 << n; |
2dcb22b3 ID |
609 | /* Get the highest bit that the above add changed from 0->1. */ |
610 | while (n < fls(id ^ bt_mask)) { | |
cf481c20 ND |
611 | if (p) |
612 | free_layer(p); | |
23936cc0 KH |
613 | n += IDR_BITS; |
614 | p = *--paa; | |
615 | } | |
616 | } | |
23936cc0 KH |
617 | idp->layers = 0; |
618 | } | |
fe6e24ec | 619 | EXPORT_SYMBOL(__idr_remove_all); |
23936cc0 | 620 | |
8d3b3591 AM |
621 | /** |
622 | * idr_destroy - release all cached layers within an idr tree | |
ea24ea85 | 623 | * @idp: idr handle |
9bb26bc1 TH |
624 | * |
625 | * Free all id mappings and all idp_layers. After this function, @idp is | |
626 | * completely unused and can be freed / recycled. The caller is | |
627 | * responsible for ensuring that no one else accesses @idp during or after | |
628 | * idr_destroy(). | |
629 | * | |
630 | * A typical clean-up sequence for objects stored in an idr tree will use | |
631 | * idr_for_each() to free all objects, if necessay, then idr_destroy() to | |
632 | * free up the id mappings and cached idr_layers. | |
8d3b3591 AM |
633 | */ |
634 | void idr_destroy(struct idr *idp) | |
635 | { | |
fe6e24ec | 636 | __idr_remove_all(idp); |
9bb26bc1 | 637 | |
8d3b3591 | 638 | while (idp->id_free_cnt) { |
4ae53789 | 639 | struct idr_layer *p = get_from_free_list(idp); |
8d3b3591 AM |
640 | kmem_cache_free(idr_layer_cache, p); |
641 | } | |
642 | } | |
643 | EXPORT_SYMBOL(idr_destroy); | |
644 | ||
1da177e4 LT |
645 | /** |
646 | * idr_find - return pointer for given id | |
647 | * @idp: idr handle | |
648 | * @id: lookup key | |
649 | * | |
650 | * Return the pointer given the id it has been registered with. A %NULL | |
651 | * return indicates that @id is not valid or you passed %NULL in | |
652 | * idr_get_new(). | |
653 | * | |
f9c46d6e ND |
654 | * This function can be called under rcu_read_lock(), given that the leaf |
655 | * pointers lifetimes are correctly managed. | |
1da177e4 LT |
656 | */ |
657 | void *idr_find(struct idr *idp, int id) | |
658 | { | |
659 | int n; | |
660 | struct idr_layer *p; | |
661 | ||
e8c8d1bc TH |
662 | if (WARN_ON_ONCE(id < 0)) |
663 | return NULL; | |
664 | ||
96be753a | 665 | p = rcu_dereference_raw(idp->top); |
6ff2d39b MS |
666 | if (!p) |
667 | return NULL; | |
668 | n = (p->layer+1) * IDR_BITS; | |
1da177e4 | 669 | |
326cf0f0 | 670 | if (id > idr_max(p->layer + 1)) |
1da177e4 | 671 | return NULL; |
6ff2d39b | 672 | BUG_ON(n == 0); |
1da177e4 LT |
673 | |
674 | while (n > 0 && p) { | |
675 | n -= IDR_BITS; | |
6ff2d39b | 676 | BUG_ON(n != p->layer*IDR_BITS); |
96be753a | 677 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
1da177e4 LT |
678 | } |
679 | return((void *)p); | |
680 | } | |
681 | EXPORT_SYMBOL(idr_find); | |
682 | ||
96d7fa42 KH |
683 | /** |
684 | * idr_for_each - iterate through all stored pointers | |
685 | * @idp: idr handle | |
686 | * @fn: function to be called for each pointer | |
687 | * @data: data passed back to callback function | |
688 | * | |
689 | * Iterate over the pointers registered with the given idr. The | |
690 | * callback function will be called for each pointer currently | |
691 | * registered, passing the id, the pointer and the data pointer passed | |
692 | * to this function. It is not safe to modify the idr tree while in | |
693 | * the callback, so functions such as idr_get_new and idr_remove are | |
694 | * not allowed. | |
695 | * | |
696 | * We check the return of @fn each time. If it returns anything other | |
56083ab1 | 697 | * than %0, we break out and return that value. |
96d7fa42 KH |
698 | * |
699 | * The caller must serialize idr_for_each() vs idr_get_new() and idr_remove(). | |
700 | */ | |
701 | int idr_for_each(struct idr *idp, | |
702 | int (*fn)(int id, void *p, void *data), void *data) | |
703 | { | |
704 | int n, id, max, error = 0; | |
705 | struct idr_layer *p; | |
326cf0f0 | 706 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
96d7fa42 KH |
707 | struct idr_layer **paa = &pa[0]; |
708 | ||
709 | n = idp->layers * IDR_BITS; | |
96be753a | 710 | p = rcu_dereference_raw(idp->top); |
326cf0f0 | 711 | max = idr_max(idp->layers); |
96d7fa42 KH |
712 | |
713 | id = 0; | |
326cf0f0 | 714 | while (id >= 0 && id <= max) { |
96d7fa42 KH |
715 | while (n > 0 && p) { |
716 | n -= IDR_BITS; | |
717 | *paa++ = p; | |
96be753a | 718 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
96d7fa42 KH |
719 | } |
720 | ||
721 | if (p) { | |
722 | error = fn(id, (void *)p, data); | |
723 | if (error) | |
724 | break; | |
725 | } | |
726 | ||
727 | id += 1 << n; | |
728 | while (n < fls(id)) { | |
729 | n += IDR_BITS; | |
730 | p = *--paa; | |
731 | } | |
732 | } | |
733 | ||
734 | return error; | |
735 | } | |
736 | EXPORT_SYMBOL(idr_for_each); | |
737 | ||
38460b48 KH |
738 | /** |
739 | * idr_get_next - lookup next object of id to given id. | |
740 | * @idp: idr handle | |
ea24ea85 | 741 | * @nextidp: pointer to lookup key |
38460b48 KH |
742 | * |
743 | * Returns pointer to registered object with id, which is next number to | |
1458ce16 NA |
744 | * given id. After being looked up, *@nextidp will be updated for the next |
745 | * iteration. | |
9f7de827 HD |
746 | * |
747 | * This function can be called under rcu_read_lock(), given that the leaf | |
748 | * pointers lifetimes are correctly managed. | |
38460b48 | 749 | */ |
38460b48 KH |
750 | void *idr_get_next(struct idr *idp, int *nextidp) |
751 | { | |
326cf0f0 | 752 | struct idr_layer *p, *pa[MAX_IDR_LEVEL + 1]; |
38460b48 KH |
753 | struct idr_layer **paa = &pa[0]; |
754 | int id = *nextidp; | |
755 | int n, max; | |
756 | ||
757 | /* find first ent */ | |
94bfa3b6 | 758 | p = rcu_dereference_raw(idp->top); |
38460b48 KH |
759 | if (!p) |
760 | return NULL; | |
9f7de827 | 761 | n = (p->layer + 1) * IDR_BITS; |
326cf0f0 | 762 | max = idr_max(p->layer + 1); |
38460b48 | 763 | |
326cf0f0 | 764 | while (id >= 0 && id <= max) { |
38460b48 KH |
765 | while (n > 0 && p) { |
766 | n -= IDR_BITS; | |
767 | *paa++ = p; | |
94bfa3b6 | 768 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
38460b48 KH |
769 | } |
770 | ||
771 | if (p) { | |
772 | *nextidp = id; | |
773 | return p; | |
774 | } | |
775 | ||
6cdae741 TH |
776 | /* |
777 | * Proceed to the next layer at the current level. Unlike | |
778 | * idr_for_each(), @id isn't guaranteed to be aligned to | |
779 | * layer boundary at this point and adding 1 << n may | |
780 | * incorrectly skip IDs. Make sure we jump to the | |
781 | * beginning of the next layer using round_up(). | |
782 | */ | |
783 | id = round_up(id + 1, 1 << n); | |
38460b48 KH |
784 | while (n < fls(id)) { |
785 | n += IDR_BITS; | |
786 | p = *--paa; | |
787 | } | |
788 | } | |
789 | return NULL; | |
790 | } | |
4d1ee80f | 791 | EXPORT_SYMBOL(idr_get_next); |
38460b48 KH |
792 | |
793 | ||
5806f07c JM |
794 | /** |
795 | * idr_replace - replace pointer for given id | |
796 | * @idp: idr handle | |
797 | * @ptr: pointer you want associated with the id | |
798 | * @id: lookup key | |
799 | * | |
800 | * Replace the pointer registered with an id and return the old value. | |
56083ab1 RD |
801 | * A %-ENOENT return indicates that @id was not found. |
802 | * A %-EINVAL return indicates that @id was not within valid constraints. | |
5806f07c | 803 | * |
cf481c20 | 804 | * The caller must serialize with writers. |
5806f07c JM |
805 | */ |
806 | void *idr_replace(struct idr *idp, void *ptr, int id) | |
807 | { | |
808 | int n; | |
809 | struct idr_layer *p, *old_p; | |
810 | ||
e8c8d1bc TH |
811 | if (WARN_ON_ONCE(id < 0)) |
812 | return ERR_PTR(-EINVAL); | |
813 | ||
5806f07c | 814 | p = idp->top; |
6ff2d39b MS |
815 | if (!p) |
816 | return ERR_PTR(-EINVAL); | |
817 | ||
818 | n = (p->layer+1) * IDR_BITS; | |
5806f07c | 819 | |
5806f07c JM |
820 | if (id >= (1 << n)) |
821 | return ERR_PTR(-EINVAL); | |
822 | ||
823 | n -= IDR_BITS; | |
824 | while ((n > 0) && p) { | |
825 | p = p->ary[(id >> n) & IDR_MASK]; | |
826 | n -= IDR_BITS; | |
827 | } | |
828 | ||
829 | n = id & IDR_MASK; | |
1d9b2e1e | 830 | if (unlikely(p == NULL || !test_bit(n, p->bitmap))) |
5806f07c JM |
831 | return ERR_PTR(-ENOENT); |
832 | ||
833 | old_p = p->ary[n]; | |
cf481c20 | 834 | rcu_assign_pointer(p->ary[n], ptr); |
5806f07c JM |
835 | |
836 | return old_p; | |
837 | } | |
838 | EXPORT_SYMBOL(idr_replace); | |
839 | ||
199f0ca5 | 840 | void __init idr_init_cache(void) |
1da177e4 | 841 | { |
199f0ca5 | 842 | idr_layer_cache = kmem_cache_create("idr_layer_cache", |
5b019e99 | 843 | sizeof(struct idr_layer), 0, SLAB_PANIC, NULL); |
1da177e4 LT |
844 | } |
845 | ||
846 | /** | |
847 | * idr_init - initialize idr handle | |
848 | * @idp: idr handle | |
849 | * | |
850 | * This function is use to set up the handle (@idp) that you will pass | |
851 | * to the rest of the functions. | |
852 | */ | |
853 | void idr_init(struct idr *idp) | |
854 | { | |
1da177e4 LT |
855 | memset(idp, 0, sizeof(struct idr)); |
856 | spin_lock_init(&idp->lock); | |
857 | } | |
858 | EXPORT_SYMBOL(idr_init); | |
72dba584 TH |
859 | |
860 | ||
56083ab1 RD |
861 | /** |
862 | * DOC: IDA description | |
72dba584 TH |
863 | * IDA - IDR based ID allocator |
864 | * | |
56083ab1 | 865 | * This is id allocator without id -> pointer translation. Memory |
72dba584 TH |
866 | * usage is much lower than full blown idr because each id only |
867 | * occupies a bit. ida uses a custom leaf node which contains | |
868 | * IDA_BITMAP_BITS slots. | |
869 | * | |
870 | * 2007-04-25 written by Tejun Heo <htejun@gmail.com> | |
871 | */ | |
872 | ||
873 | static void free_bitmap(struct ida *ida, struct ida_bitmap *bitmap) | |
874 | { | |
875 | unsigned long flags; | |
876 | ||
877 | if (!ida->free_bitmap) { | |
878 | spin_lock_irqsave(&ida->idr.lock, flags); | |
879 | if (!ida->free_bitmap) { | |
880 | ida->free_bitmap = bitmap; | |
881 | bitmap = NULL; | |
882 | } | |
883 | spin_unlock_irqrestore(&ida->idr.lock, flags); | |
884 | } | |
885 | ||
886 | kfree(bitmap); | |
887 | } | |
888 | ||
889 | /** | |
890 | * ida_pre_get - reserve resources for ida allocation | |
891 | * @ida: ida handle | |
892 | * @gfp_mask: memory allocation flag | |
893 | * | |
894 | * This function should be called prior to locking and calling the | |
895 | * following function. It preallocates enough memory to satisfy the | |
896 | * worst possible allocation. | |
897 | * | |
56083ab1 RD |
898 | * If the system is REALLY out of memory this function returns %0, |
899 | * otherwise %1. | |
72dba584 TH |
900 | */ |
901 | int ida_pre_get(struct ida *ida, gfp_t gfp_mask) | |
902 | { | |
903 | /* allocate idr_layers */ | |
904 | if (!idr_pre_get(&ida->idr, gfp_mask)) | |
905 | return 0; | |
906 | ||
907 | /* allocate free_bitmap */ | |
908 | if (!ida->free_bitmap) { | |
909 | struct ida_bitmap *bitmap; | |
910 | ||
911 | bitmap = kmalloc(sizeof(struct ida_bitmap), gfp_mask); | |
912 | if (!bitmap) | |
913 | return 0; | |
914 | ||
915 | free_bitmap(ida, bitmap); | |
916 | } | |
917 | ||
918 | return 1; | |
919 | } | |
920 | EXPORT_SYMBOL(ida_pre_get); | |
921 | ||
922 | /** | |
923 | * ida_get_new_above - allocate new ID above or equal to a start id | |
924 | * @ida: ida handle | |
ea24ea85 | 925 | * @starting_id: id to start search at |
72dba584 TH |
926 | * @p_id: pointer to the allocated handle |
927 | * | |
e3816c54 WSH |
928 | * Allocate new ID above or equal to @starting_id. It should be called |
929 | * with any required locks. | |
72dba584 | 930 | * |
56083ab1 | 931 | * If memory is required, it will return %-EAGAIN, you should unlock |
72dba584 | 932 | * and go back to the ida_pre_get() call. If the ida is full, it will |
56083ab1 | 933 | * return %-ENOSPC. |
72dba584 | 934 | * |
56083ab1 | 935 | * @p_id returns a value in the range @starting_id ... %0x7fffffff. |
72dba584 TH |
936 | */ |
937 | int ida_get_new_above(struct ida *ida, int starting_id, int *p_id) | |
938 | { | |
326cf0f0 | 939 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
72dba584 TH |
940 | struct ida_bitmap *bitmap; |
941 | unsigned long flags; | |
942 | int idr_id = starting_id / IDA_BITMAP_BITS; | |
943 | int offset = starting_id % IDA_BITMAP_BITS; | |
944 | int t, id; | |
945 | ||
946 | restart: | |
947 | /* get vacant slot */ | |
d5c7409f | 948 | t = idr_get_empty_slot(&ida->idr, idr_id, pa, 0, &ida->idr); |
944ca05c | 949 | if (t < 0) |
12d1b439 | 950 | return t == -ENOMEM ? -EAGAIN : t; |
72dba584 | 951 | |
125c4c70 | 952 | if (t * IDA_BITMAP_BITS >= MAX_IDR_BIT) |
72dba584 TH |
953 | return -ENOSPC; |
954 | ||
955 | if (t != idr_id) | |
956 | offset = 0; | |
957 | idr_id = t; | |
958 | ||
959 | /* if bitmap isn't there, create a new one */ | |
960 | bitmap = (void *)pa[0]->ary[idr_id & IDR_MASK]; | |
961 | if (!bitmap) { | |
962 | spin_lock_irqsave(&ida->idr.lock, flags); | |
963 | bitmap = ida->free_bitmap; | |
964 | ida->free_bitmap = NULL; | |
965 | spin_unlock_irqrestore(&ida->idr.lock, flags); | |
966 | ||
967 | if (!bitmap) | |
968 | return -EAGAIN; | |
969 | ||
970 | memset(bitmap, 0, sizeof(struct ida_bitmap)); | |
3219b3b7 ND |
971 | rcu_assign_pointer(pa[0]->ary[idr_id & IDR_MASK], |
972 | (void *)bitmap); | |
72dba584 TH |
973 | pa[0]->count++; |
974 | } | |
975 | ||
976 | /* lookup for empty slot */ | |
977 | t = find_next_zero_bit(bitmap->bitmap, IDA_BITMAP_BITS, offset); | |
978 | if (t == IDA_BITMAP_BITS) { | |
979 | /* no empty slot after offset, continue to the next chunk */ | |
980 | idr_id++; | |
981 | offset = 0; | |
982 | goto restart; | |
983 | } | |
984 | ||
985 | id = idr_id * IDA_BITMAP_BITS + t; | |
125c4c70 | 986 | if (id >= MAX_IDR_BIT) |
72dba584 TH |
987 | return -ENOSPC; |
988 | ||
989 | __set_bit(t, bitmap->bitmap); | |
990 | if (++bitmap->nr_busy == IDA_BITMAP_BITS) | |
991 | idr_mark_full(pa, idr_id); | |
992 | ||
993 | *p_id = id; | |
994 | ||
995 | /* Each leaf node can handle nearly a thousand slots and the | |
996 | * whole idea of ida is to have small memory foot print. | |
997 | * Throw away extra resources one by one after each successful | |
998 | * allocation. | |
999 | */ | |
1000 | if (ida->idr.id_free_cnt || ida->free_bitmap) { | |
4ae53789 | 1001 | struct idr_layer *p = get_from_free_list(&ida->idr); |
72dba584 TH |
1002 | if (p) |
1003 | kmem_cache_free(idr_layer_cache, p); | |
1004 | } | |
1005 | ||
1006 | return 0; | |
1007 | } | |
1008 | EXPORT_SYMBOL(ida_get_new_above); | |
1009 | ||
72dba584 TH |
1010 | /** |
1011 | * ida_remove - remove the given ID | |
1012 | * @ida: ida handle | |
1013 | * @id: ID to free | |
1014 | */ | |
1015 | void ida_remove(struct ida *ida, int id) | |
1016 | { | |
1017 | struct idr_layer *p = ida->idr.top; | |
1018 | int shift = (ida->idr.layers - 1) * IDR_BITS; | |
1019 | int idr_id = id / IDA_BITMAP_BITS; | |
1020 | int offset = id % IDA_BITMAP_BITS; | |
1021 | int n; | |
1022 | struct ida_bitmap *bitmap; | |
1023 | ||
1024 | /* clear full bits while looking up the leaf idr_layer */ | |
1025 | while ((shift > 0) && p) { | |
1026 | n = (idr_id >> shift) & IDR_MASK; | |
1d9b2e1e | 1027 | __clear_bit(n, p->bitmap); |
72dba584 TH |
1028 | p = p->ary[n]; |
1029 | shift -= IDR_BITS; | |
1030 | } | |
1031 | ||
1032 | if (p == NULL) | |
1033 | goto err; | |
1034 | ||
1035 | n = idr_id & IDR_MASK; | |
1d9b2e1e | 1036 | __clear_bit(n, p->bitmap); |
72dba584 TH |
1037 | |
1038 | bitmap = (void *)p->ary[n]; | |
1039 | if (!test_bit(offset, bitmap->bitmap)) | |
1040 | goto err; | |
1041 | ||
1042 | /* update bitmap and remove it if empty */ | |
1043 | __clear_bit(offset, bitmap->bitmap); | |
1044 | if (--bitmap->nr_busy == 0) { | |
1d9b2e1e | 1045 | __set_bit(n, p->bitmap); /* to please idr_remove() */ |
72dba584 TH |
1046 | idr_remove(&ida->idr, idr_id); |
1047 | free_bitmap(ida, bitmap); | |
1048 | } | |
1049 | ||
1050 | return; | |
1051 | ||
1052 | err: | |
1053 | printk(KERN_WARNING | |
1054 | "ida_remove called for id=%d which is not allocated.\n", id); | |
1055 | } | |
1056 | EXPORT_SYMBOL(ida_remove); | |
1057 | ||
1058 | /** | |
1059 | * ida_destroy - release all cached layers within an ida tree | |
ea24ea85 | 1060 | * @ida: ida handle |
72dba584 TH |
1061 | */ |
1062 | void ida_destroy(struct ida *ida) | |
1063 | { | |
1064 | idr_destroy(&ida->idr); | |
1065 | kfree(ida->free_bitmap); | |
1066 | } | |
1067 | EXPORT_SYMBOL(ida_destroy); | |
1068 | ||
88eca020 RR |
1069 | /** |
1070 | * ida_simple_get - get a new id. | |
1071 | * @ida: the (initialized) ida. | |
1072 | * @start: the minimum id (inclusive, < 0x8000000) | |
1073 | * @end: the maximum id (exclusive, < 0x8000000 or 0) | |
1074 | * @gfp_mask: memory allocation flags | |
1075 | * | |
1076 | * Allocates an id in the range start <= id < end, or returns -ENOSPC. | |
1077 | * On memory allocation failure, returns -ENOMEM. | |
1078 | * | |
1079 | * Use ida_simple_remove() to get rid of an id. | |
1080 | */ | |
1081 | int ida_simple_get(struct ida *ida, unsigned int start, unsigned int end, | |
1082 | gfp_t gfp_mask) | |
1083 | { | |
1084 | int ret, id; | |
1085 | unsigned int max; | |
46cbc1d3 | 1086 | unsigned long flags; |
88eca020 RR |
1087 | |
1088 | BUG_ON((int)start < 0); | |
1089 | BUG_ON((int)end < 0); | |
1090 | ||
1091 | if (end == 0) | |
1092 | max = 0x80000000; | |
1093 | else { | |
1094 | BUG_ON(end < start); | |
1095 | max = end - 1; | |
1096 | } | |
1097 | ||
1098 | again: | |
1099 | if (!ida_pre_get(ida, gfp_mask)) | |
1100 | return -ENOMEM; | |
1101 | ||
46cbc1d3 | 1102 | spin_lock_irqsave(&simple_ida_lock, flags); |
88eca020 RR |
1103 | ret = ida_get_new_above(ida, start, &id); |
1104 | if (!ret) { | |
1105 | if (id > max) { | |
1106 | ida_remove(ida, id); | |
1107 | ret = -ENOSPC; | |
1108 | } else { | |
1109 | ret = id; | |
1110 | } | |
1111 | } | |
46cbc1d3 | 1112 | spin_unlock_irqrestore(&simple_ida_lock, flags); |
88eca020 RR |
1113 | |
1114 | if (unlikely(ret == -EAGAIN)) | |
1115 | goto again; | |
1116 | ||
1117 | return ret; | |
1118 | } | |
1119 | EXPORT_SYMBOL(ida_simple_get); | |
1120 | ||
1121 | /** | |
1122 | * ida_simple_remove - remove an allocated id. | |
1123 | * @ida: the (initialized) ida. | |
1124 | * @id: the id returned by ida_simple_get. | |
1125 | */ | |
1126 | void ida_simple_remove(struct ida *ida, unsigned int id) | |
1127 | { | |
46cbc1d3 TH |
1128 | unsigned long flags; |
1129 | ||
88eca020 | 1130 | BUG_ON((int)id < 0); |
46cbc1d3 | 1131 | spin_lock_irqsave(&simple_ida_lock, flags); |
88eca020 | 1132 | ida_remove(ida, id); |
46cbc1d3 | 1133 | spin_unlock_irqrestore(&simple_ida_lock, flags); |
88eca020 RR |
1134 | } |
1135 | EXPORT_SYMBOL(ida_simple_remove); | |
1136 | ||
72dba584 TH |
1137 | /** |
1138 | * ida_init - initialize ida handle | |
1139 | * @ida: ida handle | |
1140 | * | |
1141 | * This function is use to set up the handle (@ida) that you will pass | |
1142 | * to the rest of the functions. | |
1143 | */ | |
1144 | void ida_init(struct ida *ida) | |
1145 | { | |
1146 | memset(ida, 0, sizeof(struct ida)); | |
1147 | idr_init(&ida->idr); | |
1148 | ||
1149 | } | |
1150 | EXPORT_SYMBOL(ida_init); |