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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 | |
e18b890b | 41 | static struct kmem_cache *idr_layer_cache; |
d5c7409f TH |
42 | static DEFINE_PER_CPU(struct idr_layer *, idr_preload_head); |
43 | static DEFINE_PER_CPU(int, idr_preload_cnt); | |
88eca020 | 44 | static DEFINE_SPINLOCK(simple_ida_lock); |
1da177e4 | 45 | |
4ae53789 | 46 | static struct idr_layer *get_from_free_list(struct idr *idp) |
1da177e4 LT |
47 | { |
48 | struct idr_layer *p; | |
c259cc28 | 49 | unsigned long flags; |
1da177e4 | 50 | |
c259cc28 | 51 | spin_lock_irqsave(&idp->lock, flags); |
1da177e4 LT |
52 | if ((p = idp->id_free)) { |
53 | idp->id_free = p->ary[0]; | |
54 | idp->id_free_cnt--; | |
55 | p->ary[0] = NULL; | |
56 | } | |
c259cc28 | 57 | spin_unlock_irqrestore(&idp->lock, flags); |
1da177e4 LT |
58 | return(p); |
59 | } | |
60 | ||
d5c7409f TH |
61 | /** |
62 | * idr_layer_alloc - allocate a new idr_layer | |
63 | * @gfp_mask: allocation mask | |
64 | * @layer_idr: optional idr to allocate from | |
65 | * | |
66 | * If @layer_idr is %NULL, directly allocate one using @gfp_mask or fetch | |
67 | * one from the per-cpu preload buffer. If @layer_idr is not %NULL, fetch | |
68 | * an idr_layer from @idr->id_free. | |
69 | * | |
70 | * @layer_idr is to maintain backward compatibility with the old alloc | |
71 | * interface - idr_pre_get() and idr_get_new*() - and will be removed | |
72 | * together with per-pool preload buffer. | |
73 | */ | |
74 | static struct idr_layer *idr_layer_alloc(gfp_t gfp_mask, struct idr *layer_idr) | |
75 | { | |
76 | struct idr_layer *new; | |
77 | ||
78 | /* this is the old path, bypass to get_from_free_list() */ | |
79 | if (layer_idr) | |
80 | return get_from_free_list(layer_idr); | |
81 | ||
82 | /* try to allocate directly from kmem_cache */ | |
83 | new = kmem_cache_zalloc(idr_layer_cache, gfp_mask); | |
84 | if (new) | |
85 | return new; | |
86 | ||
87 | /* | |
88 | * Try to fetch one from the per-cpu preload buffer if in process | |
89 | * context. See idr_preload() for details. | |
90 | */ | |
91 | if (in_interrupt()) | |
92 | return NULL; | |
93 | ||
94 | preempt_disable(); | |
95 | new = __this_cpu_read(idr_preload_head); | |
96 | if (new) { | |
97 | __this_cpu_write(idr_preload_head, new->ary[0]); | |
98 | __this_cpu_dec(idr_preload_cnt); | |
99 | new->ary[0] = NULL; | |
100 | } | |
101 | preempt_enable(); | |
102 | return new; | |
103 | } | |
104 | ||
cf481c20 ND |
105 | static void idr_layer_rcu_free(struct rcu_head *head) |
106 | { | |
107 | struct idr_layer *layer; | |
108 | ||
109 | layer = container_of(head, struct idr_layer, rcu_head); | |
110 | kmem_cache_free(idr_layer_cache, layer); | |
111 | } | |
112 | ||
113 | static inline void free_layer(struct idr_layer *p) | |
114 | { | |
115 | call_rcu(&p->rcu_head, idr_layer_rcu_free); | |
116 | } | |
117 | ||
1eec0056 | 118 | /* only called when idp->lock is held */ |
4ae53789 | 119 | static void __move_to_free_list(struct idr *idp, struct idr_layer *p) |
1eec0056 SR |
120 | { |
121 | p->ary[0] = idp->id_free; | |
122 | idp->id_free = p; | |
123 | idp->id_free_cnt++; | |
124 | } | |
125 | ||
4ae53789 | 126 | static void move_to_free_list(struct idr *idp, struct idr_layer *p) |
1da177e4 | 127 | { |
c259cc28 RD |
128 | unsigned long flags; |
129 | ||
1da177e4 LT |
130 | /* |
131 | * Depends on the return element being zeroed. | |
132 | */ | |
c259cc28 | 133 | spin_lock_irqsave(&idp->lock, flags); |
4ae53789 | 134 | __move_to_free_list(idp, p); |
c259cc28 | 135 | spin_unlock_irqrestore(&idp->lock, flags); |
1da177e4 LT |
136 | } |
137 | ||
e33ac8bd TH |
138 | static void idr_mark_full(struct idr_layer **pa, int id) |
139 | { | |
140 | struct idr_layer *p = pa[0]; | |
141 | int l = 0; | |
142 | ||
143 | __set_bit(id & IDR_MASK, &p->bitmap); | |
144 | /* | |
145 | * If this layer is full mark the bit in the layer above to | |
146 | * show that this part of the radix tree is full. This may | |
147 | * complete the layer above and require walking up the radix | |
148 | * tree. | |
149 | */ | |
150 | while (p->bitmap == IDR_FULL) { | |
151 | if (!(p = pa[++l])) | |
152 | break; | |
153 | id = id >> IDR_BITS; | |
154 | __set_bit((id & IDR_MASK), &p->bitmap); | |
155 | } | |
156 | } | |
157 | ||
1da177e4 | 158 | /** |
56083ab1 | 159 | * idr_pre_get - reserve resources for idr allocation |
1da177e4 LT |
160 | * @idp: idr handle |
161 | * @gfp_mask: memory allocation flags | |
162 | * | |
066a9be6 NA |
163 | * This function should be called prior to calling the idr_get_new* functions. |
164 | * It preallocates enough memory to satisfy the worst possible allocation. The | |
165 | * caller should pass in GFP_KERNEL if possible. This of course requires that | |
166 | * no spinning locks be held. | |
1da177e4 | 167 | * |
56083ab1 RD |
168 | * If the system is REALLY out of memory this function returns %0, |
169 | * otherwise %1. | |
1da177e4 | 170 | */ |
fd4f2df2 | 171 | int idr_pre_get(struct idr *idp, gfp_t gfp_mask) |
1da177e4 | 172 | { |
125c4c70 | 173 | while (idp->id_free_cnt < MAX_IDR_FREE) { |
1da177e4 | 174 | struct idr_layer *new; |
5b019e99 | 175 | new = kmem_cache_zalloc(idr_layer_cache, gfp_mask); |
e15ae2dd | 176 | if (new == NULL) |
1da177e4 | 177 | return (0); |
4ae53789 | 178 | move_to_free_list(idp, new); |
1da177e4 LT |
179 | } |
180 | return 1; | |
181 | } | |
182 | EXPORT_SYMBOL(idr_pre_get); | |
183 | ||
12d1b439 TH |
184 | /** |
185 | * sub_alloc - try to allocate an id without growing the tree depth | |
186 | * @idp: idr handle | |
187 | * @starting_id: id to start search at | |
188 | * @id: pointer to the allocated handle | |
189 | * @pa: idr_layer[MAX_IDR_LEVEL] used as backtrack buffer | |
d5c7409f TH |
190 | * @gfp_mask: allocation mask for idr_layer_alloc() |
191 | * @layer_idr: optional idr passed to idr_layer_alloc() | |
12d1b439 TH |
192 | * |
193 | * Allocate an id in range [@starting_id, INT_MAX] from @idp without | |
194 | * growing its depth. Returns | |
195 | * | |
196 | * the allocated id >= 0 if successful, | |
197 | * -EAGAIN if the tree needs to grow for allocation to succeed, | |
198 | * -ENOSPC if the id space is exhausted, | |
199 | * -ENOMEM if more idr_layers need to be allocated. | |
200 | */ | |
d5c7409f TH |
201 | static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa, |
202 | gfp_t gfp_mask, struct idr *layer_idr) | |
1da177e4 LT |
203 | { |
204 | int n, m, sh; | |
205 | struct idr_layer *p, *new; | |
7aae6dd8 | 206 | int l, id, oid; |
5ba25331 | 207 | unsigned long bm; |
1da177e4 LT |
208 | |
209 | id = *starting_id; | |
7aae6dd8 | 210 | restart: |
1da177e4 LT |
211 | p = idp->top; |
212 | l = idp->layers; | |
213 | pa[l--] = NULL; | |
214 | while (1) { | |
215 | /* | |
216 | * We run around this while until we reach the leaf node... | |
217 | */ | |
218 | n = (id >> (IDR_BITS*l)) & IDR_MASK; | |
219 | bm = ~p->bitmap; | |
220 | m = find_next_bit(&bm, IDR_SIZE, n); | |
221 | if (m == IDR_SIZE) { | |
222 | /* no space available go back to previous layer. */ | |
223 | l++; | |
7aae6dd8 | 224 | oid = id; |
e15ae2dd | 225 | id = (id | ((1 << (IDR_BITS * l)) - 1)) + 1; |
7aae6dd8 TH |
226 | |
227 | /* if already at the top layer, we need to grow */ | |
d2e7276b | 228 | if (id >= 1 << (idp->layers * IDR_BITS)) { |
1da177e4 | 229 | *starting_id = id; |
12d1b439 | 230 | return -EAGAIN; |
1da177e4 | 231 | } |
d2e7276b TH |
232 | p = pa[l]; |
233 | BUG_ON(!p); | |
7aae6dd8 TH |
234 | |
235 | /* If we need to go up one layer, continue the | |
236 | * loop; otherwise, restart from the top. | |
237 | */ | |
238 | sh = IDR_BITS * (l + 1); | |
239 | if (oid >> sh == id >> sh) | |
240 | continue; | |
241 | else | |
242 | goto restart; | |
1da177e4 LT |
243 | } |
244 | if (m != n) { | |
245 | sh = IDR_BITS*l; | |
246 | id = ((id >> sh) ^ n ^ m) << sh; | |
247 | } | |
125c4c70 | 248 | if ((id >= MAX_IDR_BIT) || (id < 0)) |
12d1b439 | 249 | return -ENOSPC; |
1da177e4 LT |
250 | if (l == 0) |
251 | break; | |
252 | /* | |
253 | * Create the layer below if it is missing. | |
254 | */ | |
255 | if (!p->ary[m]) { | |
d5c7409f | 256 | new = idr_layer_alloc(gfp_mask, layer_idr); |
4ae53789 | 257 | if (!new) |
12d1b439 | 258 | return -ENOMEM; |
6ff2d39b | 259 | new->layer = l-1; |
3219b3b7 | 260 | rcu_assign_pointer(p->ary[m], new); |
1da177e4 LT |
261 | p->count++; |
262 | } | |
263 | pa[l--] = p; | |
264 | p = p->ary[m]; | |
265 | } | |
e33ac8bd TH |
266 | |
267 | pa[l] = p; | |
268 | return id; | |
1da177e4 LT |
269 | } |
270 | ||
e33ac8bd | 271 | static int idr_get_empty_slot(struct idr *idp, int starting_id, |
d5c7409f TH |
272 | struct idr_layer **pa, gfp_t gfp_mask, |
273 | struct idr *layer_idr) | |
1da177e4 LT |
274 | { |
275 | struct idr_layer *p, *new; | |
276 | int layers, v, id; | |
c259cc28 | 277 | unsigned long flags; |
e15ae2dd | 278 | |
1da177e4 LT |
279 | id = starting_id; |
280 | build_up: | |
281 | p = idp->top; | |
282 | layers = idp->layers; | |
283 | if (unlikely(!p)) { | |
d5c7409f | 284 | if (!(p = idr_layer_alloc(gfp_mask, layer_idr))) |
12d1b439 | 285 | return -ENOMEM; |
6ff2d39b | 286 | p->layer = 0; |
1da177e4 LT |
287 | layers = 1; |
288 | } | |
289 | /* | |
290 | * Add a new layer to the top of the tree if the requested | |
291 | * id is larger than the currently allocated space. | |
292 | */ | |
125c4c70 | 293 | while ((layers < (MAX_IDR_LEVEL - 1)) && (id >= (1 << (layers*IDR_BITS)))) { |
1da177e4 | 294 | layers++; |
711a49a0 MS |
295 | if (!p->count) { |
296 | /* special case: if the tree is currently empty, | |
297 | * then we grow the tree by moving the top node | |
298 | * upwards. | |
299 | */ | |
300 | p->layer++; | |
1da177e4 | 301 | continue; |
711a49a0 | 302 | } |
d5c7409f | 303 | if (!(new = idr_layer_alloc(gfp_mask, layer_idr))) { |
1da177e4 LT |
304 | /* |
305 | * The allocation failed. If we built part of | |
306 | * the structure tear it down. | |
307 | */ | |
c259cc28 | 308 | spin_lock_irqsave(&idp->lock, flags); |
1da177e4 LT |
309 | for (new = p; p && p != idp->top; new = p) { |
310 | p = p->ary[0]; | |
311 | new->ary[0] = NULL; | |
312 | new->bitmap = new->count = 0; | |
4ae53789 | 313 | __move_to_free_list(idp, new); |
1da177e4 | 314 | } |
c259cc28 | 315 | spin_unlock_irqrestore(&idp->lock, flags); |
12d1b439 | 316 | return -ENOMEM; |
1da177e4 LT |
317 | } |
318 | new->ary[0] = p; | |
319 | new->count = 1; | |
6ff2d39b | 320 | new->layer = layers-1; |
1da177e4 LT |
321 | if (p->bitmap == IDR_FULL) |
322 | __set_bit(0, &new->bitmap); | |
323 | p = new; | |
324 | } | |
3219b3b7 | 325 | rcu_assign_pointer(idp->top, p); |
1da177e4 | 326 | idp->layers = layers; |
d5c7409f | 327 | v = sub_alloc(idp, &id, pa, gfp_mask, layer_idr); |
12d1b439 | 328 | if (v == -EAGAIN) |
1da177e4 LT |
329 | goto build_up; |
330 | return(v); | |
331 | } | |
332 | ||
3594eb28 TH |
333 | /* |
334 | * @id and @pa are from a successful allocation from idr_get_empty_slot(). | |
335 | * Install the user pointer @ptr and mark the slot full. | |
336 | */ | |
337 | static void idr_fill_slot(void *ptr, int id, struct idr_layer **pa) | |
e33ac8bd | 338 | { |
3594eb28 TH |
339 | rcu_assign_pointer(pa[0]->ary[id & IDR_MASK], (struct idr_layer *)ptr); |
340 | pa[0]->count++; | |
341 | idr_mark_full(pa, id); | |
e33ac8bd TH |
342 | } |
343 | ||
1da177e4 | 344 | /** |
7c657f2f | 345 | * idr_get_new_above - allocate new idr entry above or equal to a start id |
1da177e4 | 346 | * @idp: idr handle |
94e2bd68 | 347 | * @ptr: pointer you want associated with the id |
ea24ea85 | 348 | * @starting_id: id to start search at |
1da177e4 LT |
349 | * @id: pointer to the allocated handle |
350 | * | |
351 | * This is the allocate id function. It should be called with any | |
352 | * required locks. | |
353 | * | |
066a9be6 | 354 | * If allocation from IDR's private freelist fails, idr_get_new_above() will |
56083ab1 | 355 | * return %-EAGAIN. The caller should retry the idr_pre_get() call to refill |
066a9be6 NA |
356 | * IDR's preallocation and then retry the idr_get_new_above() call. |
357 | * | |
56083ab1 | 358 | * If the idr is full idr_get_new_above() will return %-ENOSPC. |
1da177e4 | 359 | * |
56083ab1 | 360 | * @id returns a value in the range @starting_id ... %0x7fffffff |
1da177e4 LT |
361 | */ |
362 | int idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id) | |
363 | { | |
3594eb28 | 364 | struct idr_layer *pa[MAX_IDR_LEVEL]; |
1da177e4 | 365 | int rv; |
e15ae2dd | 366 | |
d5c7409f | 367 | rv = idr_get_empty_slot(idp, starting_id, pa, 0, idp); |
944ca05c | 368 | if (rv < 0) |
12d1b439 | 369 | return rv == -ENOMEM ? -EAGAIN : rv; |
3594eb28 TH |
370 | |
371 | idr_fill_slot(ptr, rv, pa); | |
1da177e4 LT |
372 | *id = rv; |
373 | return 0; | |
374 | } | |
375 | EXPORT_SYMBOL(idr_get_new_above); | |
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 */ | |
460 | struct idr_layer *pa[MAX_IDR_LEVEL]; | |
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 | ||
478 | idr_fill_slot(ptr, id, pa); | |
479 | return id; | |
480 | } | |
481 | EXPORT_SYMBOL_GPL(idr_alloc); | |
482 | ||
1da177e4 LT |
483 | static void idr_remove_warning(int id) |
484 | { | |
f098ad65 ND |
485 | printk(KERN_WARNING |
486 | "idr_remove called for id=%d which is not allocated.\n", id); | |
1da177e4 LT |
487 | dump_stack(); |
488 | } | |
489 | ||
490 | static void sub_remove(struct idr *idp, int shift, int id) | |
491 | { | |
492 | struct idr_layer *p = idp->top; | |
125c4c70 | 493 | struct idr_layer **pa[MAX_IDR_LEVEL]; |
1da177e4 | 494 | struct idr_layer ***paa = &pa[0]; |
cf481c20 | 495 | struct idr_layer *to_free; |
1da177e4 LT |
496 | int n; |
497 | ||
498 | *paa = NULL; | |
499 | *++paa = &idp->top; | |
500 | ||
501 | while ((shift > 0) && p) { | |
502 | n = (id >> shift) & IDR_MASK; | |
503 | __clear_bit(n, &p->bitmap); | |
504 | *++paa = &p->ary[n]; | |
505 | p = p->ary[n]; | |
506 | shift -= IDR_BITS; | |
507 | } | |
508 | n = id & IDR_MASK; | |
509 | if (likely(p != NULL && test_bit(n, &p->bitmap))){ | |
510 | __clear_bit(n, &p->bitmap); | |
cf481c20 ND |
511 | rcu_assign_pointer(p->ary[n], NULL); |
512 | to_free = NULL; | |
1da177e4 | 513 | while(*paa && ! --((**paa)->count)){ |
cf481c20 ND |
514 | if (to_free) |
515 | free_layer(to_free); | |
516 | to_free = **paa; | |
1da177e4 LT |
517 | **paa-- = NULL; |
518 | } | |
e15ae2dd | 519 | if (!*paa) |
1da177e4 | 520 | idp->layers = 0; |
cf481c20 ND |
521 | if (to_free) |
522 | free_layer(to_free); | |
e15ae2dd | 523 | } else |
1da177e4 | 524 | idr_remove_warning(id); |
1da177e4 LT |
525 | } |
526 | ||
527 | /** | |
56083ab1 | 528 | * idr_remove - remove the given id and free its slot |
72fd4a35 RD |
529 | * @idp: idr handle |
530 | * @id: unique key | |
1da177e4 LT |
531 | */ |
532 | void idr_remove(struct idr *idp, int id) | |
533 | { | |
534 | struct idr_layer *p; | |
cf481c20 | 535 | struct idr_layer *to_free; |
1da177e4 LT |
536 | |
537 | /* Mask off upper bits we don't use for the search. */ | |
125c4c70 | 538 | id &= MAX_IDR_MASK; |
1da177e4 LT |
539 | |
540 | sub_remove(idp, (idp->layers - 1) * IDR_BITS, id); | |
e15ae2dd | 541 | if (idp->top && idp->top->count == 1 && (idp->layers > 1) && |
cf481c20 ND |
542 | idp->top->ary[0]) { |
543 | /* | |
544 | * Single child at leftmost slot: we can shrink the tree. | |
545 | * This level is not needed anymore since when layers are | |
546 | * inserted, they are inserted at the top of the existing | |
547 | * tree. | |
548 | */ | |
549 | to_free = idp->top; | |
1da177e4 | 550 | p = idp->top->ary[0]; |
cf481c20 | 551 | rcu_assign_pointer(idp->top, p); |
1da177e4 | 552 | --idp->layers; |
cf481c20 ND |
553 | to_free->bitmap = to_free->count = 0; |
554 | free_layer(to_free); | |
1da177e4 | 555 | } |
125c4c70 | 556 | while (idp->id_free_cnt >= MAX_IDR_FREE) { |
4ae53789 | 557 | p = get_from_free_list(idp); |
cf481c20 ND |
558 | /* |
559 | * Note: we don't call the rcu callback here, since the only | |
560 | * layers that fall into the freelist are those that have been | |
561 | * preallocated. | |
562 | */ | |
1da177e4 | 563 | kmem_cache_free(idr_layer_cache, p); |
1da177e4 | 564 | } |
af8e2a4c | 565 | return; |
1da177e4 LT |
566 | } |
567 | EXPORT_SYMBOL(idr_remove); | |
568 | ||
fe6e24ec | 569 | void __idr_remove_all(struct idr *idp) |
23936cc0 | 570 | { |
6ace06dc | 571 | int n, id, max; |
2dcb22b3 | 572 | int bt_mask; |
23936cc0 | 573 | struct idr_layer *p; |
125c4c70 | 574 | struct idr_layer *pa[MAX_IDR_LEVEL]; |
23936cc0 KH |
575 | struct idr_layer **paa = &pa[0]; |
576 | ||
577 | n = idp->layers * IDR_BITS; | |
578 | p = idp->top; | |
1b23336a | 579 | rcu_assign_pointer(idp->top, NULL); |
23936cc0 KH |
580 | max = 1 << n; |
581 | ||
582 | id = 0; | |
6ace06dc | 583 | while (id < max) { |
23936cc0 KH |
584 | while (n > IDR_BITS && p) { |
585 | n -= IDR_BITS; | |
586 | *paa++ = p; | |
587 | p = p->ary[(id >> n) & IDR_MASK]; | |
588 | } | |
589 | ||
2dcb22b3 | 590 | bt_mask = id; |
23936cc0 | 591 | id += 1 << n; |
2dcb22b3 ID |
592 | /* Get the highest bit that the above add changed from 0->1. */ |
593 | while (n < fls(id ^ bt_mask)) { | |
cf481c20 ND |
594 | if (p) |
595 | free_layer(p); | |
23936cc0 KH |
596 | n += IDR_BITS; |
597 | p = *--paa; | |
598 | } | |
599 | } | |
23936cc0 KH |
600 | idp->layers = 0; |
601 | } | |
fe6e24ec | 602 | EXPORT_SYMBOL(__idr_remove_all); |
23936cc0 | 603 | |
8d3b3591 AM |
604 | /** |
605 | * idr_destroy - release all cached layers within an idr tree | |
ea24ea85 | 606 | * @idp: idr handle |
9bb26bc1 TH |
607 | * |
608 | * Free all id mappings and all idp_layers. After this function, @idp is | |
609 | * completely unused and can be freed / recycled. The caller is | |
610 | * responsible for ensuring that no one else accesses @idp during or after | |
611 | * idr_destroy(). | |
612 | * | |
613 | * A typical clean-up sequence for objects stored in an idr tree will use | |
614 | * idr_for_each() to free all objects, if necessay, then idr_destroy() to | |
615 | * free up the id mappings and cached idr_layers. | |
8d3b3591 AM |
616 | */ |
617 | void idr_destroy(struct idr *idp) | |
618 | { | |
fe6e24ec | 619 | __idr_remove_all(idp); |
9bb26bc1 | 620 | |
8d3b3591 | 621 | while (idp->id_free_cnt) { |
4ae53789 | 622 | struct idr_layer *p = get_from_free_list(idp); |
8d3b3591 AM |
623 | kmem_cache_free(idr_layer_cache, p); |
624 | } | |
625 | } | |
626 | EXPORT_SYMBOL(idr_destroy); | |
627 | ||
1da177e4 LT |
628 | /** |
629 | * idr_find - return pointer for given id | |
630 | * @idp: idr handle | |
631 | * @id: lookup key | |
632 | * | |
633 | * Return the pointer given the id it has been registered with. A %NULL | |
634 | * return indicates that @id is not valid or you passed %NULL in | |
635 | * idr_get_new(). | |
636 | * | |
f9c46d6e ND |
637 | * This function can be called under rcu_read_lock(), given that the leaf |
638 | * pointers lifetimes are correctly managed. | |
1da177e4 LT |
639 | */ |
640 | void *idr_find(struct idr *idp, int id) | |
641 | { | |
642 | int n; | |
643 | struct idr_layer *p; | |
644 | ||
96be753a | 645 | p = rcu_dereference_raw(idp->top); |
6ff2d39b MS |
646 | if (!p) |
647 | return NULL; | |
648 | n = (p->layer+1) * IDR_BITS; | |
1da177e4 LT |
649 | |
650 | /* Mask off upper bits we don't use for the search. */ | |
125c4c70 | 651 | id &= MAX_IDR_MASK; |
1da177e4 LT |
652 | |
653 | if (id >= (1 << n)) | |
654 | return NULL; | |
6ff2d39b | 655 | BUG_ON(n == 0); |
1da177e4 LT |
656 | |
657 | while (n > 0 && p) { | |
658 | n -= IDR_BITS; | |
6ff2d39b | 659 | BUG_ON(n != p->layer*IDR_BITS); |
96be753a | 660 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
1da177e4 LT |
661 | } |
662 | return((void *)p); | |
663 | } | |
664 | EXPORT_SYMBOL(idr_find); | |
665 | ||
96d7fa42 KH |
666 | /** |
667 | * idr_for_each - iterate through all stored pointers | |
668 | * @idp: idr handle | |
669 | * @fn: function to be called for each pointer | |
670 | * @data: data passed back to callback function | |
671 | * | |
672 | * Iterate over the pointers registered with the given idr. The | |
673 | * callback function will be called for each pointer currently | |
674 | * registered, passing the id, the pointer and the data pointer passed | |
675 | * to this function. It is not safe to modify the idr tree while in | |
676 | * the callback, so functions such as idr_get_new and idr_remove are | |
677 | * not allowed. | |
678 | * | |
679 | * We check the return of @fn each time. If it returns anything other | |
56083ab1 | 680 | * than %0, we break out and return that value. |
96d7fa42 KH |
681 | * |
682 | * The caller must serialize idr_for_each() vs idr_get_new() and idr_remove(). | |
683 | */ | |
684 | int idr_for_each(struct idr *idp, | |
685 | int (*fn)(int id, void *p, void *data), void *data) | |
686 | { | |
687 | int n, id, max, error = 0; | |
688 | struct idr_layer *p; | |
125c4c70 | 689 | struct idr_layer *pa[MAX_IDR_LEVEL]; |
96d7fa42 KH |
690 | struct idr_layer **paa = &pa[0]; |
691 | ||
692 | n = idp->layers * IDR_BITS; | |
96be753a | 693 | p = rcu_dereference_raw(idp->top); |
96d7fa42 KH |
694 | max = 1 << n; |
695 | ||
696 | id = 0; | |
697 | while (id < max) { | |
698 | while (n > 0 && p) { | |
699 | n -= IDR_BITS; | |
700 | *paa++ = p; | |
96be753a | 701 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
96d7fa42 KH |
702 | } |
703 | ||
704 | if (p) { | |
705 | error = fn(id, (void *)p, data); | |
706 | if (error) | |
707 | break; | |
708 | } | |
709 | ||
710 | id += 1 << n; | |
711 | while (n < fls(id)) { | |
712 | n += IDR_BITS; | |
713 | p = *--paa; | |
714 | } | |
715 | } | |
716 | ||
717 | return error; | |
718 | } | |
719 | EXPORT_SYMBOL(idr_for_each); | |
720 | ||
38460b48 KH |
721 | /** |
722 | * idr_get_next - lookup next object of id to given id. | |
723 | * @idp: idr handle | |
ea24ea85 | 724 | * @nextidp: pointer to lookup key |
38460b48 KH |
725 | * |
726 | * Returns pointer to registered object with id, which is next number to | |
1458ce16 NA |
727 | * given id. After being looked up, *@nextidp will be updated for the next |
728 | * iteration. | |
9f7de827 HD |
729 | * |
730 | * This function can be called under rcu_read_lock(), given that the leaf | |
731 | * pointers lifetimes are correctly managed. | |
38460b48 | 732 | */ |
38460b48 KH |
733 | void *idr_get_next(struct idr *idp, int *nextidp) |
734 | { | |
125c4c70 | 735 | struct idr_layer *p, *pa[MAX_IDR_LEVEL]; |
38460b48 KH |
736 | struct idr_layer **paa = &pa[0]; |
737 | int id = *nextidp; | |
738 | int n, max; | |
739 | ||
740 | /* find first ent */ | |
94bfa3b6 | 741 | p = rcu_dereference_raw(idp->top); |
38460b48 KH |
742 | if (!p) |
743 | return NULL; | |
9f7de827 HD |
744 | n = (p->layer + 1) * IDR_BITS; |
745 | max = 1 << n; | |
38460b48 KH |
746 | |
747 | while (id < max) { | |
748 | while (n > 0 && p) { | |
749 | n -= IDR_BITS; | |
750 | *paa++ = p; | |
94bfa3b6 | 751 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
38460b48 KH |
752 | } |
753 | ||
754 | if (p) { | |
755 | *nextidp = id; | |
756 | return p; | |
757 | } | |
758 | ||
6cdae741 TH |
759 | /* |
760 | * Proceed to the next layer at the current level. Unlike | |
761 | * idr_for_each(), @id isn't guaranteed to be aligned to | |
762 | * layer boundary at this point and adding 1 << n may | |
763 | * incorrectly skip IDs. Make sure we jump to the | |
764 | * beginning of the next layer using round_up(). | |
765 | */ | |
766 | id = round_up(id + 1, 1 << n); | |
38460b48 KH |
767 | while (n < fls(id)) { |
768 | n += IDR_BITS; | |
769 | p = *--paa; | |
770 | } | |
771 | } | |
772 | return NULL; | |
773 | } | |
4d1ee80f | 774 | EXPORT_SYMBOL(idr_get_next); |
38460b48 KH |
775 | |
776 | ||
5806f07c JM |
777 | /** |
778 | * idr_replace - replace pointer for given id | |
779 | * @idp: idr handle | |
780 | * @ptr: pointer you want associated with the id | |
781 | * @id: lookup key | |
782 | * | |
783 | * Replace the pointer registered with an id and return the old value. | |
56083ab1 RD |
784 | * A %-ENOENT return indicates that @id was not found. |
785 | * A %-EINVAL return indicates that @id was not within valid constraints. | |
5806f07c | 786 | * |
cf481c20 | 787 | * The caller must serialize with writers. |
5806f07c JM |
788 | */ |
789 | void *idr_replace(struct idr *idp, void *ptr, int id) | |
790 | { | |
791 | int n; | |
792 | struct idr_layer *p, *old_p; | |
793 | ||
5806f07c | 794 | p = idp->top; |
6ff2d39b MS |
795 | if (!p) |
796 | return ERR_PTR(-EINVAL); | |
797 | ||
798 | n = (p->layer+1) * IDR_BITS; | |
5806f07c | 799 | |
125c4c70 | 800 | id &= MAX_IDR_MASK; |
5806f07c JM |
801 | |
802 | if (id >= (1 << n)) | |
803 | return ERR_PTR(-EINVAL); | |
804 | ||
805 | n -= IDR_BITS; | |
806 | while ((n > 0) && p) { | |
807 | p = p->ary[(id >> n) & IDR_MASK]; | |
808 | n -= IDR_BITS; | |
809 | } | |
810 | ||
811 | n = id & IDR_MASK; | |
812 | if (unlikely(p == NULL || !test_bit(n, &p->bitmap))) | |
813 | return ERR_PTR(-ENOENT); | |
814 | ||
815 | old_p = p->ary[n]; | |
cf481c20 | 816 | rcu_assign_pointer(p->ary[n], ptr); |
5806f07c JM |
817 | |
818 | return old_p; | |
819 | } | |
820 | EXPORT_SYMBOL(idr_replace); | |
821 | ||
199f0ca5 | 822 | void __init idr_init_cache(void) |
1da177e4 | 823 | { |
199f0ca5 | 824 | idr_layer_cache = kmem_cache_create("idr_layer_cache", |
5b019e99 | 825 | sizeof(struct idr_layer), 0, SLAB_PANIC, NULL); |
1da177e4 LT |
826 | } |
827 | ||
828 | /** | |
829 | * idr_init - initialize idr handle | |
830 | * @idp: idr handle | |
831 | * | |
832 | * This function is use to set up the handle (@idp) that you will pass | |
833 | * to the rest of the functions. | |
834 | */ | |
835 | void idr_init(struct idr *idp) | |
836 | { | |
1da177e4 LT |
837 | memset(idp, 0, sizeof(struct idr)); |
838 | spin_lock_init(&idp->lock); | |
839 | } | |
840 | EXPORT_SYMBOL(idr_init); | |
72dba584 TH |
841 | |
842 | ||
56083ab1 RD |
843 | /** |
844 | * DOC: IDA description | |
72dba584 TH |
845 | * IDA - IDR based ID allocator |
846 | * | |
56083ab1 | 847 | * This is id allocator without id -> pointer translation. Memory |
72dba584 TH |
848 | * usage is much lower than full blown idr because each id only |
849 | * occupies a bit. ida uses a custom leaf node which contains | |
850 | * IDA_BITMAP_BITS slots. | |
851 | * | |
852 | * 2007-04-25 written by Tejun Heo <htejun@gmail.com> | |
853 | */ | |
854 | ||
855 | static void free_bitmap(struct ida *ida, struct ida_bitmap *bitmap) | |
856 | { | |
857 | unsigned long flags; | |
858 | ||
859 | if (!ida->free_bitmap) { | |
860 | spin_lock_irqsave(&ida->idr.lock, flags); | |
861 | if (!ida->free_bitmap) { | |
862 | ida->free_bitmap = bitmap; | |
863 | bitmap = NULL; | |
864 | } | |
865 | spin_unlock_irqrestore(&ida->idr.lock, flags); | |
866 | } | |
867 | ||
868 | kfree(bitmap); | |
869 | } | |
870 | ||
871 | /** | |
872 | * ida_pre_get - reserve resources for ida allocation | |
873 | * @ida: ida handle | |
874 | * @gfp_mask: memory allocation flag | |
875 | * | |
876 | * This function should be called prior to locking and calling the | |
877 | * following function. It preallocates enough memory to satisfy the | |
878 | * worst possible allocation. | |
879 | * | |
56083ab1 RD |
880 | * If the system is REALLY out of memory this function returns %0, |
881 | * otherwise %1. | |
72dba584 TH |
882 | */ |
883 | int ida_pre_get(struct ida *ida, gfp_t gfp_mask) | |
884 | { | |
885 | /* allocate idr_layers */ | |
886 | if (!idr_pre_get(&ida->idr, gfp_mask)) | |
887 | return 0; | |
888 | ||
889 | /* allocate free_bitmap */ | |
890 | if (!ida->free_bitmap) { | |
891 | struct ida_bitmap *bitmap; | |
892 | ||
893 | bitmap = kmalloc(sizeof(struct ida_bitmap), gfp_mask); | |
894 | if (!bitmap) | |
895 | return 0; | |
896 | ||
897 | free_bitmap(ida, bitmap); | |
898 | } | |
899 | ||
900 | return 1; | |
901 | } | |
902 | EXPORT_SYMBOL(ida_pre_get); | |
903 | ||
904 | /** | |
905 | * ida_get_new_above - allocate new ID above or equal to a start id | |
906 | * @ida: ida handle | |
ea24ea85 | 907 | * @starting_id: id to start search at |
72dba584 TH |
908 | * @p_id: pointer to the allocated handle |
909 | * | |
e3816c54 WSH |
910 | * Allocate new ID above or equal to @starting_id. It should be called |
911 | * with any required locks. | |
72dba584 | 912 | * |
56083ab1 | 913 | * If memory is required, it will return %-EAGAIN, you should unlock |
72dba584 | 914 | * and go back to the ida_pre_get() call. If the ida is full, it will |
56083ab1 | 915 | * return %-ENOSPC. |
72dba584 | 916 | * |
56083ab1 | 917 | * @p_id returns a value in the range @starting_id ... %0x7fffffff. |
72dba584 TH |
918 | */ |
919 | int ida_get_new_above(struct ida *ida, int starting_id, int *p_id) | |
920 | { | |
125c4c70 | 921 | struct idr_layer *pa[MAX_IDR_LEVEL]; |
72dba584 TH |
922 | struct ida_bitmap *bitmap; |
923 | unsigned long flags; | |
924 | int idr_id = starting_id / IDA_BITMAP_BITS; | |
925 | int offset = starting_id % IDA_BITMAP_BITS; | |
926 | int t, id; | |
927 | ||
928 | restart: | |
929 | /* get vacant slot */ | |
d5c7409f | 930 | t = idr_get_empty_slot(&ida->idr, idr_id, pa, 0, &ida->idr); |
944ca05c | 931 | if (t < 0) |
12d1b439 | 932 | return t == -ENOMEM ? -EAGAIN : t; |
72dba584 | 933 | |
125c4c70 | 934 | if (t * IDA_BITMAP_BITS >= MAX_IDR_BIT) |
72dba584 TH |
935 | return -ENOSPC; |
936 | ||
937 | if (t != idr_id) | |
938 | offset = 0; | |
939 | idr_id = t; | |
940 | ||
941 | /* if bitmap isn't there, create a new one */ | |
942 | bitmap = (void *)pa[0]->ary[idr_id & IDR_MASK]; | |
943 | if (!bitmap) { | |
944 | spin_lock_irqsave(&ida->idr.lock, flags); | |
945 | bitmap = ida->free_bitmap; | |
946 | ida->free_bitmap = NULL; | |
947 | spin_unlock_irqrestore(&ida->idr.lock, flags); | |
948 | ||
949 | if (!bitmap) | |
950 | return -EAGAIN; | |
951 | ||
952 | memset(bitmap, 0, sizeof(struct ida_bitmap)); | |
3219b3b7 ND |
953 | rcu_assign_pointer(pa[0]->ary[idr_id & IDR_MASK], |
954 | (void *)bitmap); | |
72dba584 TH |
955 | pa[0]->count++; |
956 | } | |
957 | ||
958 | /* lookup for empty slot */ | |
959 | t = find_next_zero_bit(bitmap->bitmap, IDA_BITMAP_BITS, offset); | |
960 | if (t == IDA_BITMAP_BITS) { | |
961 | /* no empty slot after offset, continue to the next chunk */ | |
962 | idr_id++; | |
963 | offset = 0; | |
964 | goto restart; | |
965 | } | |
966 | ||
967 | id = idr_id * IDA_BITMAP_BITS + t; | |
125c4c70 | 968 | if (id >= MAX_IDR_BIT) |
72dba584 TH |
969 | return -ENOSPC; |
970 | ||
971 | __set_bit(t, bitmap->bitmap); | |
972 | if (++bitmap->nr_busy == IDA_BITMAP_BITS) | |
973 | idr_mark_full(pa, idr_id); | |
974 | ||
975 | *p_id = id; | |
976 | ||
977 | /* Each leaf node can handle nearly a thousand slots and the | |
978 | * whole idea of ida is to have small memory foot print. | |
979 | * Throw away extra resources one by one after each successful | |
980 | * allocation. | |
981 | */ | |
982 | if (ida->idr.id_free_cnt || ida->free_bitmap) { | |
4ae53789 | 983 | struct idr_layer *p = get_from_free_list(&ida->idr); |
72dba584 TH |
984 | if (p) |
985 | kmem_cache_free(idr_layer_cache, p); | |
986 | } | |
987 | ||
988 | return 0; | |
989 | } | |
990 | EXPORT_SYMBOL(ida_get_new_above); | |
991 | ||
72dba584 TH |
992 | /** |
993 | * ida_remove - remove the given ID | |
994 | * @ida: ida handle | |
995 | * @id: ID to free | |
996 | */ | |
997 | void ida_remove(struct ida *ida, int id) | |
998 | { | |
999 | struct idr_layer *p = ida->idr.top; | |
1000 | int shift = (ida->idr.layers - 1) * IDR_BITS; | |
1001 | int idr_id = id / IDA_BITMAP_BITS; | |
1002 | int offset = id % IDA_BITMAP_BITS; | |
1003 | int n; | |
1004 | struct ida_bitmap *bitmap; | |
1005 | ||
1006 | /* clear full bits while looking up the leaf idr_layer */ | |
1007 | while ((shift > 0) && p) { | |
1008 | n = (idr_id >> shift) & IDR_MASK; | |
1009 | __clear_bit(n, &p->bitmap); | |
1010 | p = p->ary[n]; | |
1011 | shift -= IDR_BITS; | |
1012 | } | |
1013 | ||
1014 | if (p == NULL) | |
1015 | goto err; | |
1016 | ||
1017 | n = idr_id & IDR_MASK; | |
1018 | __clear_bit(n, &p->bitmap); | |
1019 | ||
1020 | bitmap = (void *)p->ary[n]; | |
1021 | if (!test_bit(offset, bitmap->bitmap)) | |
1022 | goto err; | |
1023 | ||
1024 | /* update bitmap and remove it if empty */ | |
1025 | __clear_bit(offset, bitmap->bitmap); | |
1026 | if (--bitmap->nr_busy == 0) { | |
1027 | __set_bit(n, &p->bitmap); /* to please idr_remove() */ | |
1028 | idr_remove(&ida->idr, idr_id); | |
1029 | free_bitmap(ida, bitmap); | |
1030 | } | |
1031 | ||
1032 | return; | |
1033 | ||
1034 | err: | |
1035 | printk(KERN_WARNING | |
1036 | "ida_remove called for id=%d which is not allocated.\n", id); | |
1037 | } | |
1038 | EXPORT_SYMBOL(ida_remove); | |
1039 | ||
1040 | /** | |
1041 | * ida_destroy - release all cached layers within an ida tree | |
ea24ea85 | 1042 | * @ida: ida handle |
72dba584 TH |
1043 | */ |
1044 | void ida_destroy(struct ida *ida) | |
1045 | { | |
1046 | idr_destroy(&ida->idr); | |
1047 | kfree(ida->free_bitmap); | |
1048 | } | |
1049 | EXPORT_SYMBOL(ida_destroy); | |
1050 | ||
88eca020 RR |
1051 | /** |
1052 | * ida_simple_get - get a new id. | |
1053 | * @ida: the (initialized) ida. | |
1054 | * @start: the minimum id (inclusive, < 0x8000000) | |
1055 | * @end: the maximum id (exclusive, < 0x8000000 or 0) | |
1056 | * @gfp_mask: memory allocation flags | |
1057 | * | |
1058 | * Allocates an id in the range start <= id < end, or returns -ENOSPC. | |
1059 | * On memory allocation failure, returns -ENOMEM. | |
1060 | * | |
1061 | * Use ida_simple_remove() to get rid of an id. | |
1062 | */ | |
1063 | int ida_simple_get(struct ida *ida, unsigned int start, unsigned int end, | |
1064 | gfp_t gfp_mask) | |
1065 | { | |
1066 | int ret, id; | |
1067 | unsigned int max; | |
46cbc1d3 | 1068 | unsigned long flags; |
88eca020 RR |
1069 | |
1070 | BUG_ON((int)start < 0); | |
1071 | BUG_ON((int)end < 0); | |
1072 | ||
1073 | if (end == 0) | |
1074 | max = 0x80000000; | |
1075 | else { | |
1076 | BUG_ON(end < start); | |
1077 | max = end - 1; | |
1078 | } | |
1079 | ||
1080 | again: | |
1081 | if (!ida_pre_get(ida, gfp_mask)) | |
1082 | return -ENOMEM; | |
1083 | ||
46cbc1d3 | 1084 | spin_lock_irqsave(&simple_ida_lock, flags); |
88eca020 RR |
1085 | ret = ida_get_new_above(ida, start, &id); |
1086 | if (!ret) { | |
1087 | if (id > max) { | |
1088 | ida_remove(ida, id); | |
1089 | ret = -ENOSPC; | |
1090 | } else { | |
1091 | ret = id; | |
1092 | } | |
1093 | } | |
46cbc1d3 | 1094 | spin_unlock_irqrestore(&simple_ida_lock, flags); |
88eca020 RR |
1095 | |
1096 | if (unlikely(ret == -EAGAIN)) | |
1097 | goto again; | |
1098 | ||
1099 | return ret; | |
1100 | } | |
1101 | EXPORT_SYMBOL(ida_simple_get); | |
1102 | ||
1103 | /** | |
1104 | * ida_simple_remove - remove an allocated id. | |
1105 | * @ida: the (initialized) ida. | |
1106 | * @id: the id returned by ida_simple_get. | |
1107 | */ | |
1108 | void ida_simple_remove(struct ida *ida, unsigned int id) | |
1109 | { | |
46cbc1d3 TH |
1110 | unsigned long flags; |
1111 | ||
88eca020 | 1112 | BUG_ON((int)id < 0); |
46cbc1d3 | 1113 | spin_lock_irqsave(&simple_ida_lock, flags); |
88eca020 | 1114 | ida_remove(ida, id); |
46cbc1d3 | 1115 | spin_unlock_irqrestore(&simple_ida_lock, flags); |
88eca020 RR |
1116 | } |
1117 | EXPORT_SYMBOL(ida_simple_remove); | |
1118 | ||
72dba584 TH |
1119 | /** |
1120 | * ida_init - initialize ida handle | |
1121 | * @ida: ida handle | |
1122 | * | |
1123 | * This function is use to set up the handle (@ida) that you will pass | |
1124 | * to the rest of the functions. | |
1125 | */ | |
1126 | void ida_init(struct ida *ida) | |
1127 | { | |
1128 | memset(ida, 0, sizeof(struct ida)); | |
1129 | idr_init(&ida->idr); | |
1130 | ||
1131 | } | |
1132 | EXPORT_SYMBOL(ida_init); |