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1da177e4 LT |
1 | /* |
2 | * 2002-10-18 written by Jim Houston jim.houston@ccur.com | |
3 | * Copyright (C) 2002 by Concurrent Computer Corporation | |
4 | * Distributed under the GNU GPL license version 2. | |
5 | * | |
6 | * Modified by George Anzinger to reuse immediately and to use | |
7 | * find bit instructions. Also removed _irq on spinlocks. | |
8 | * | |
3219b3b7 ND |
9 | * Modified by Nadia Derbey to make it RCU safe. |
10 | * | |
e15ae2dd | 11 | * Small id to pointer translation service. |
1da177e4 | 12 | * |
e15ae2dd | 13 | * It uses a radix tree like structure as a sparse array indexed |
1da177e4 | 14 | * by the id to obtain the pointer. The bitmap makes allocating |
e15ae2dd | 15 | * a new id quick. |
1da177e4 LT |
16 | * |
17 | * You call it to allocate an id (an int) an associate with that id a | |
18 | * pointer or what ever, we treat it as a (void *). You can pass this | |
19 | * id to a user for him to pass back at a later time. You then pass | |
20 | * that id to this code and it returns your pointer. | |
21 | ||
e15ae2dd | 22 | * You can release ids at any time. When all ids are released, most of |
125c4c70 | 23 | * the memory is returned (we keep MAX_IDR_FREE) in a local pool so we |
e15ae2dd | 24 | * don't need to go to the memory "store" during an id allocate, just |
1da177e4 LT |
25 | * so you don't need to be too concerned about locking and conflicts |
26 | * with the slab allocator. | |
27 | */ | |
28 | ||
29 | #ifndef TEST // to test in user space... | |
30 | #include <linux/slab.h> | |
31 | #include <linux/init.h> | |
8bc3bcc9 | 32 | #include <linux/export.h> |
1da177e4 | 33 | #endif |
5806f07c | 34 | #include <linux/err.h> |
1da177e4 LT |
35 | #include <linux/string.h> |
36 | #include <linux/idr.h> | |
88eca020 | 37 | #include <linux/spinlock.h> |
d5c7409f TH |
38 | #include <linux/percpu.h> |
39 | #include <linux/hardirq.h> | |
1da177e4 | 40 | |
e8c8d1bc TH |
41 | #define MAX_IDR_SHIFT (sizeof(int) * 8 - 1) |
42 | #define MAX_IDR_BIT (1U << MAX_IDR_SHIFT) | |
43 | ||
44 | /* Leave the possibility of an incomplete final layer */ | |
45 | #define MAX_IDR_LEVEL ((MAX_IDR_SHIFT + IDR_BITS - 1) / IDR_BITS) | |
46 | ||
47 | /* Number of id_layer structs to leave in free list */ | |
48 | #define MAX_IDR_FREE (MAX_IDR_LEVEL * 2) | |
49 | ||
e18b890b | 50 | static struct kmem_cache *idr_layer_cache; |
d5c7409f TH |
51 | static DEFINE_PER_CPU(struct idr_layer *, idr_preload_head); |
52 | static DEFINE_PER_CPU(int, idr_preload_cnt); | |
88eca020 | 53 | static DEFINE_SPINLOCK(simple_ida_lock); |
1da177e4 | 54 | |
326cf0f0 TH |
55 | /* the maximum ID which can be allocated given idr->layers */ |
56 | static int idr_max(int layers) | |
57 | { | |
58 | int bits = min_t(int, layers * IDR_BITS, MAX_IDR_SHIFT); | |
59 | ||
60 | return (1 << bits) - 1; | |
61 | } | |
62 | ||
54616283 TH |
63 | /* |
64 | * Prefix mask for an idr_layer at @layer. For layer 0, the prefix mask is | |
65 | * all bits except for the lower IDR_BITS. For layer 1, 2 * IDR_BITS, and | |
66 | * so on. | |
67 | */ | |
68 | static int idr_layer_prefix_mask(int layer) | |
69 | { | |
70 | return ~idr_max(layer + 1); | |
71 | } | |
72 | ||
4ae53789 | 73 | static struct idr_layer *get_from_free_list(struct idr *idp) |
1da177e4 LT |
74 | { |
75 | struct idr_layer *p; | |
c259cc28 | 76 | unsigned long flags; |
1da177e4 | 77 | |
c259cc28 | 78 | spin_lock_irqsave(&idp->lock, flags); |
1da177e4 LT |
79 | if ((p = idp->id_free)) { |
80 | idp->id_free = p->ary[0]; | |
81 | idp->id_free_cnt--; | |
82 | p->ary[0] = NULL; | |
83 | } | |
c259cc28 | 84 | spin_unlock_irqrestore(&idp->lock, flags); |
1da177e4 LT |
85 | return(p); |
86 | } | |
87 | ||
d5c7409f TH |
88 | /** |
89 | * idr_layer_alloc - allocate a new idr_layer | |
90 | * @gfp_mask: allocation mask | |
91 | * @layer_idr: optional idr to allocate from | |
92 | * | |
93 | * If @layer_idr is %NULL, directly allocate one using @gfp_mask or fetch | |
94 | * one from the per-cpu preload buffer. If @layer_idr is not %NULL, fetch | |
95 | * an idr_layer from @idr->id_free. | |
96 | * | |
97 | * @layer_idr is to maintain backward compatibility with the old alloc | |
98 | * interface - idr_pre_get() and idr_get_new*() - and will be removed | |
99 | * together with per-pool preload buffer. | |
100 | */ | |
101 | static struct idr_layer *idr_layer_alloc(gfp_t gfp_mask, struct idr *layer_idr) | |
102 | { | |
103 | struct idr_layer *new; | |
104 | ||
105 | /* this is the old path, bypass to get_from_free_list() */ | |
106 | if (layer_idr) | |
107 | return get_from_free_list(layer_idr); | |
108 | ||
109 | /* try to allocate directly from kmem_cache */ | |
110 | new = kmem_cache_zalloc(idr_layer_cache, gfp_mask); | |
111 | if (new) | |
112 | return new; | |
113 | ||
114 | /* | |
115 | * Try to fetch one from the per-cpu preload buffer if in process | |
116 | * context. See idr_preload() for details. | |
117 | */ | |
118 | if (in_interrupt()) | |
119 | return NULL; | |
120 | ||
121 | preempt_disable(); | |
122 | new = __this_cpu_read(idr_preload_head); | |
123 | if (new) { | |
124 | __this_cpu_write(idr_preload_head, new->ary[0]); | |
125 | __this_cpu_dec(idr_preload_cnt); | |
126 | new->ary[0] = NULL; | |
127 | } | |
128 | preempt_enable(); | |
129 | return new; | |
130 | } | |
131 | ||
cf481c20 ND |
132 | static void idr_layer_rcu_free(struct rcu_head *head) |
133 | { | |
134 | struct idr_layer *layer; | |
135 | ||
136 | layer = container_of(head, struct idr_layer, rcu_head); | |
137 | kmem_cache_free(idr_layer_cache, layer); | |
138 | } | |
139 | ||
0ffc2a9c | 140 | static inline void free_layer(struct idr *idr, struct idr_layer *p) |
cf481c20 | 141 | { |
0ffc2a9c TH |
142 | if (idr->hint && idr->hint == p) |
143 | RCU_INIT_POINTER(idr->hint, NULL); | |
cf481c20 ND |
144 | call_rcu(&p->rcu_head, idr_layer_rcu_free); |
145 | } | |
146 | ||
1eec0056 | 147 | /* only called when idp->lock is held */ |
4ae53789 | 148 | static void __move_to_free_list(struct idr *idp, struct idr_layer *p) |
1eec0056 SR |
149 | { |
150 | p->ary[0] = idp->id_free; | |
151 | idp->id_free = p; | |
152 | idp->id_free_cnt++; | |
153 | } | |
154 | ||
4ae53789 | 155 | static void move_to_free_list(struct idr *idp, struct idr_layer *p) |
1da177e4 | 156 | { |
c259cc28 RD |
157 | unsigned long flags; |
158 | ||
1da177e4 LT |
159 | /* |
160 | * Depends on the return element being zeroed. | |
161 | */ | |
c259cc28 | 162 | spin_lock_irqsave(&idp->lock, flags); |
4ae53789 | 163 | __move_to_free_list(idp, p); |
c259cc28 | 164 | spin_unlock_irqrestore(&idp->lock, flags); |
1da177e4 LT |
165 | } |
166 | ||
e33ac8bd TH |
167 | static void idr_mark_full(struct idr_layer **pa, int id) |
168 | { | |
169 | struct idr_layer *p = pa[0]; | |
170 | int l = 0; | |
171 | ||
1d9b2e1e | 172 | __set_bit(id & IDR_MASK, p->bitmap); |
e33ac8bd TH |
173 | /* |
174 | * If this layer is full mark the bit in the layer above to | |
175 | * show that this part of the radix tree is full. This may | |
176 | * complete the layer above and require walking up the radix | |
177 | * tree. | |
178 | */ | |
1d9b2e1e | 179 | while (bitmap_full(p->bitmap, IDR_SIZE)) { |
e33ac8bd TH |
180 | if (!(p = pa[++l])) |
181 | break; | |
182 | id = id >> IDR_BITS; | |
1d9b2e1e | 183 | __set_bit((id & IDR_MASK), p->bitmap); |
e33ac8bd TH |
184 | } |
185 | } | |
186 | ||
1da177e4 | 187 | /** |
56083ab1 | 188 | * idr_pre_get - reserve resources for idr allocation |
1da177e4 LT |
189 | * @idp: idr handle |
190 | * @gfp_mask: memory allocation flags | |
191 | * | |
066a9be6 NA |
192 | * This function should be called prior to calling the idr_get_new* functions. |
193 | * It preallocates enough memory to satisfy the worst possible allocation. The | |
194 | * caller should pass in GFP_KERNEL if possible. This of course requires that | |
195 | * no spinning locks be held. | |
1da177e4 | 196 | * |
56083ab1 RD |
197 | * If the system is REALLY out of memory this function returns %0, |
198 | * otherwise %1. | |
1da177e4 | 199 | */ |
fd4f2df2 | 200 | int idr_pre_get(struct idr *idp, gfp_t gfp_mask) |
1da177e4 | 201 | { |
125c4c70 | 202 | while (idp->id_free_cnt < MAX_IDR_FREE) { |
1da177e4 | 203 | struct idr_layer *new; |
5b019e99 | 204 | new = kmem_cache_zalloc(idr_layer_cache, gfp_mask); |
e15ae2dd | 205 | if (new == NULL) |
1da177e4 | 206 | return (0); |
4ae53789 | 207 | move_to_free_list(idp, new); |
1da177e4 LT |
208 | } |
209 | return 1; | |
210 | } | |
211 | EXPORT_SYMBOL(idr_pre_get); | |
212 | ||
12d1b439 TH |
213 | /** |
214 | * sub_alloc - try to allocate an id without growing the tree depth | |
215 | * @idp: idr handle | |
216 | * @starting_id: id to start search at | |
12d1b439 | 217 | * @pa: idr_layer[MAX_IDR_LEVEL] used as backtrack buffer |
d5c7409f TH |
218 | * @gfp_mask: allocation mask for idr_layer_alloc() |
219 | * @layer_idr: optional idr passed to idr_layer_alloc() | |
12d1b439 TH |
220 | * |
221 | * Allocate an id in range [@starting_id, INT_MAX] from @idp without | |
222 | * growing its depth. Returns | |
223 | * | |
224 | * the allocated id >= 0 if successful, | |
225 | * -EAGAIN if the tree needs to grow for allocation to succeed, | |
226 | * -ENOSPC if the id space is exhausted, | |
227 | * -ENOMEM if more idr_layers need to be allocated. | |
228 | */ | |
d5c7409f TH |
229 | static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa, |
230 | gfp_t gfp_mask, struct idr *layer_idr) | |
1da177e4 LT |
231 | { |
232 | int n, m, sh; | |
233 | struct idr_layer *p, *new; | |
7aae6dd8 | 234 | int l, id, oid; |
1da177e4 LT |
235 | |
236 | id = *starting_id; | |
7aae6dd8 | 237 | restart: |
1da177e4 LT |
238 | p = idp->top; |
239 | l = idp->layers; | |
240 | pa[l--] = NULL; | |
241 | while (1) { | |
242 | /* | |
243 | * We run around this while until we reach the leaf node... | |
244 | */ | |
245 | n = (id >> (IDR_BITS*l)) & IDR_MASK; | |
1d9b2e1e | 246 | m = find_next_zero_bit(p->bitmap, IDR_SIZE, n); |
1da177e4 LT |
247 | if (m == IDR_SIZE) { |
248 | /* no space available go back to previous layer. */ | |
249 | l++; | |
7aae6dd8 | 250 | oid = id; |
e15ae2dd | 251 | id = (id | ((1 << (IDR_BITS * l)) - 1)) + 1; |
7aae6dd8 TH |
252 | |
253 | /* if already at the top layer, we need to grow */ | |
d2e7276b | 254 | if (id >= 1 << (idp->layers * IDR_BITS)) { |
1da177e4 | 255 | *starting_id = id; |
12d1b439 | 256 | return -EAGAIN; |
1da177e4 | 257 | } |
d2e7276b TH |
258 | p = pa[l]; |
259 | BUG_ON(!p); | |
7aae6dd8 TH |
260 | |
261 | /* If we need to go up one layer, continue the | |
262 | * loop; otherwise, restart from the top. | |
263 | */ | |
264 | sh = IDR_BITS * (l + 1); | |
265 | if (oid >> sh == id >> sh) | |
266 | continue; | |
267 | else | |
268 | goto restart; | |
1da177e4 LT |
269 | } |
270 | if (m != n) { | |
271 | sh = IDR_BITS*l; | |
272 | id = ((id >> sh) ^ n ^ m) << sh; | |
273 | } | |
125c4c70 | 274 | if ((id >= MAX_IDR_BIT) || (id < 0)) |
12d1b439 | 275 | return -ENOSPC; |
1da177e4 LT |
276 | if (l == 0) |
277 | break; | |
278 | /* | |
279 | * Create the layer below if it is missing. | |
280 | */ | |
281 | if (!p->ary[m]) { | |
d5c7409f | 282 | new = idr_layer_alloc(gfp_mask, layer_idr); |
4ae53789 | 283 | if (!new) |
12d1b439 | 284 | return -ENOMEM; |
6ff2d39b | 285 | new->layer = l-1; |
54616283 | 286 | new->prefix = id & idr_layer_prefix_mask(new->layer); |
3219b3b7 | 287 | rcu_assign_pointer(p->ary[m], new); |
1da177e4 LT |
288 | p->count++; |
289 | } | |
290 | pa[l--] = p; | |
291 | p = p->ary[m]; | |
292 | } | |
e33ac8bd TH |
293 | |
294 | pa[l] = p; | |
295 | return id; | |
1da177e4 LT |
296 | } |
297 | ||
e33ac8bd | 298 | static int idr_get_empty_slot(struct idr *idp, int starting_id, |
d5c7409f TH |
299 | struct idr_layer **pa, gfp_t gfp_mask, |
300 | struct idr *layer_idr) | |
1da177e4 LT |
301 | { |
302 | struct idr_layer *p, *new; | |
303 | int layers, v, id; | |
c259cc28 | 304 | unsigned long flags; |
e15ae2dd | 305 | |
1da177e4 LT |
306 | id = starting_id; |
307 | build_up: | |
308 | p = idp->top; | |
309 | layers = idp->layers; | |
310 | if (unlikely(!p)) { | |
d5c7409f | 311 | if (!(p = idr_layer_alloc(gfp_mask, layer_idr))) |
12d1b439 | 312 | return -ENOMEM; |
6ff2d39b | 313 | p->layer = 0; |
1da177e4 LT |
314 | layers = 1; |
315 | } | |
316 | /* | |
317 | * Add a new layer to the top of the tree if the requested | |
318 | * id is larger than the currently allocated space. | |
319 | */ | |
326cf0f0 | 320 | while (id > idr_max(layers)) { |
1da177e4 | 321 | layers++; |
711a49a0 MS |
322 | if (!p->count) { |
323 | /* special case: if the tree is currently empty, | |
324 | * then we grow the tree by moving the top node | |
325 | * upwards. | |
326 | */ | |
327 | p->layer++; | |
54616283 | 328 | WARN_ON_ONCE(p->prefix); |
1da177e4 | 329 | continue; |
711a49a0 | 330 | } |
d5c7409f | 331 | if (!(new = idr_layer_alloc(gfp_mask, layer_idr))) { |
1da177e4 LT |
332 | /* |
333 | * The allocation failed. If we built part of | |
334 | * the structure tear it down. | |
335 | */ | |
c259cc28 | 336 | spin_lock_irqsave(&idp->lock, flags); |
1da177e4 LT |
337 | for (new = p; p && p != idp->top; new = p) { |
338 | p = p->ary[0]; | |
339 | new->ary[0] = NULL; | |
1d9b2e1e TH |
340 | new->count = 0; |
341 | bitmap_clear(new->bitmap, 0, IDR_SIZE); | |
4ae53789 | 342 | __move_to_free_list(idp, new); |
1da177e4 | 343 | } |
c259cc28 | 344 | spin_unlock_irqrestore(&idp->lock, flags); |
12d1b439 | 345 | return -ENOMEM; |
1da177e4 LT |
346 | } |
347 | new->ary[0] = p; | |
348 | new->count = 1; | |
6ff2d39b | 349 | new->layer = layers-1; |
54616283 | 350 | new->prefix = id & idr_layer_prefix_mask(new->layer); |
1d9b2e1e TH |
351 | if (bitmap_full(p->bitmap, IDR_SIZE)) |
352 | __set_bit(0, new->bitmap); | |
1da177e4 LT |
353 | p = new; |
354 | } | |
3219b3b7 | 355 | rcu_assign_pointer(idp->top, p); |
1da177e4 | 356 | idp->layers = layers; |
d5c7409f | 357 | v = sub_alloc(idp, &id, pa, gfp_mask, layer_idr); |
12d1b439 | 358 | if (v == -EAGAIN) |
1da177e4 LT |
359 | goto build_up; |
360 | return(v); | |
361 | } | |
362 | ||
3594eb28 TH |
363 | /* |
364 | * @id and @pa are from a successful allocation from idr_get_empty_slot(). | |
365 | * Install the user pointer @ptr and mark the slot full. | |
366 | */ | |
0ffc2a9c TH |
367 | static void idr_fill_slot(struct idr *idr, void *ptr, int id, |
368 | struct idr_layer **pa) | |
e33ac8bd | 369 | { |
0ffc2a9c TH |
370 | /* update hint used for lookup, cleared from free_layer() */ |
371 | rcu_assign_pointer(idr->hint, pa[0]); | |
372 | ||
3594eb28 TH |
373 | rcu_assign_pointer(pa[0]->ary[id & IDR_MASK], (struct idr_layer *)ptr); |
374 | pa[0]->count++; | |
375 | idr_mark_full(pa, id); | |
e33ac8bd TH |
376 | } |
377 | ||
1da177e4 | 378 | /** |
7c657f2f | 379 | * idr_get_new_above - allocate new idr entry above or equal to a start id |
1da177e4 | 380 | * @idp: idr handle |
94e2bd68 | 381 | * @ptr: pointer you want associated with the id |
ea24ea85 | 382 | * @starting_id: id to start search at |
1da177e4 LT |
383 | * @id: pointer to the allocated handle |
384 | * | |
385 | * This is the allocate id function. It should be called with any | |
386 | * required locks. | |
387 | * | |
066a9be6 | 388 | * If allocation from IDR's private freelist fails, idr_get_new_above() will |
56083ab1 | 389 | * return %-EAGAIN. The caller should retry the idr_pre_get() call to refill |
066a9be6 NA |
390 | * IDR's preallocation and then retry the idr_get_new_above() call. |
391 | * | |
56083ab1 | 392 | * If the idr is full idr_get_new_above() will return %-ENOSPC. |
1da177e4 | 393 | * |
56083ab1 | 394 | * @id returns a value in the range @starting_id ... %0x7fffffff |
1da177e4 LT |
395 | */ |
396 | int idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id) | |
397 | { | |
326cf0f0 | 398 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
1da177e4 | 399 | int rv; |
e15ae2dd | 400 | |
d5c7409f | 401 | rv = idr_get_empty_slot(idp, starting_id, pa, 0, idp); |
944ca05c | 402 | if (rv < 0) |
12d1b439 | 403 | return rv == -ENOMEM ? -EAGAIN : rv; |
3594eb28 | 404 | |
0ffc2a9c | 405 | idr_fill_slot(idp, ptr, rv, pa); |
1da177e4 LT |
406 | *id = rv; |
407 | return 0; | |
408 | } | |
409 | EXPORT_SYMBOL(idr_get_new_above); | |
410 | ||
d5c7409f TH |
411 | /** |
412 | * idr_preload - preload for idr_alloc() | |
413 | * @gfp_mask: allocation mask to use for preloading | |
414 | * | |
415 | * Preload per-cpu layer buffer for idr_alloc(). Can only be used from | |
416 | * process context and each idr_preload() invocation should be matched with | |
417 | * idr_preload_end(). Note that preemption is disabled while preloaded. | |
418 | * | |
419 | * The first idr_alloc() in the preloaded section can be treated as if it | |
420 | * were invoked with @gfp_mask used for preloading. This allows using more | |
421 | * permissive allocation masks for idrs protected by spinlocks. | |
422 | * | |
423 | * For example, if idr_alloc() below fails, the failure can be treated as | |
424 | * if idr_alloc() were called with GFP_KERNEL rather than GFP_NOWAIT. | |
425 | * | |
426 | * idr_preload(GFP_KERNEL); | |
427 | * spin_lock(lock); | |
428 | * | |
429 | * id = idr_alloc(idr, ptr, start, end, GFP_NOWAIT); | |
430 | * | |
431 | * spin_unlock(lock); | |
432 | * idr_preload_end(); | |
433 | * if (id < 0) | |
434 | * error; | |
435 | */ | |
436 | void idr_preload(gfp_t gfp_mask) | |
437 | { | |
438 | /* | |
439 | * Consuming preload buffer from non-process context breaks preload | |
440 | * allocation guarantee. Disallow usage from those contexts. | |
441 | */ | |
442 | WARN_ON_ONCE(in_interrupt()); | |
443 | might_sleep_if(gfp_mask & __GFP_WAIT); | |
444 | ||
445 | preempt_disable(); | |
446 | ||
447 | /* | |
448 | * idr_alloc() is likely to succeed w/o full idr_layer buffer and | |
449 | * return value from idr_alloc() needs to be checked for failure | |
450 | * anyway. Silently give up if allocation fails. The caller can | |
451 | * treat failures from idr_alloc() as if idr_alloc() were called | |
452 | * with @gfp_mask which should be enough. | |
453 | */ | |
454 | while (__this_cpu_read(idr_preload_cnt) < MAX_IDR_FREE) { | |
455 | struct idr_layer *new; | |
456 | ||
457 | preempt_enable(); | |
458 | new = kmem_cache_zalloc(idr_layer_cache, gfp_mask); | |
459 | preempt_disable(); | |
460 | if (!new) | |
461 | break; | |
462 | ||
463 | /* link the new one to per-cpu preload list */ | |
464 | new->ary[0] = __this_cpu_read(idr_preload_head); | |
465 | __this_cpu_write(idr_preload_head, new); | |
466 | __this_cpu_inc(idr_preload_cnt); | |
467 | } | |
468 | } | |
469 | EXPORT_SYMBOL(idr_preload); | |
470 | ||
471 | /** | |
472 | * idr_alloc - allocate new idr entry | |
473 | * @idr: the (initialized) idr | |
474 | * @ptr: pointer to be associated with the new id | |
475 | * @start: the minimum id (inclusive) | |
476 | * @end: the maximum id (exclusive, <= 0 for max) | |
477 | * @gfp_mask: memory allocation flags | |
478 | * | |
479 | * Allocate an id in [start, end) and associate it with @ptr. If no ID is | |
480 | * available in the specified range, returns -ENOSPC. On memory allocation | |
481 | * failure, returns -ENOMEM. | |
482 | * | |
483 | * Note that @end is treated as max when <= 0. This is to always allow | |
484 | * using @start + N as @end as long as N is inside integer range. | |
485 | * | |
486 | * The user is responsible for exclusively synchronizing all operations | |
487 | * which may modify @idr. However, read-only accesses such as idr_find() | |
488 | * or iteration can be performed under RCU read lock provided the user | |
489 | * destroys @ptr in RCU-safe way after removal from idr. | |
490 | */ | |
491 | int idr_alloc(struct idr *idr, void *ptr, int start, int end, gfp_t gfp_mask) | |
492 | { | |
493 | int max = end > 0 ? end - 1 : INT_MAX; /* inclusive upper limit */ | |
326cf0f0 | 494 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
d5c7409f TH |
495 | int id; |
496 | ||
497 | might_sleep_if(gfp_mask & __GFP_WAIT); | |
498 | ||
499 | /* sanity checks */ | |
500 | if (WARN_ON_ONCE(start < 0)) | |
501 | return -EINVAL; | |
502 | if (unlikely(max < start)) | |
503 | return -ENOSPC; | |
504 | ||
505 | /* allocate id */ | |
506 | id = idr_get_empty_slot(idr, start, pa, gfp_mask, NULL); | |
507 | if (unlikely(id < 0)) | |
508 | return id; | |
509 | if (unlikely(id > max)) | |
510 | return -ENOSPC; | |
511 | ||
0ffc2a9c | 512 | idr_fill_slot(idr, ptr, id, pa); |
d5c7409f TH |
513 | return id; |
514 | } | |
515 | EXPORT_SYMBOL_GPL(idr_alloc); | |
516 | ||
1da177e4 LT |
517 | static void idr_remove_warning(int id) |
518 | { | |
f098ad65 ND |
519 | printk(KERN_WARNING |
520 | "idr_remove called for id=%d which is not allocated.\n", id); | |
1da177e4 LT |
521 | dump_stack(); |
522 | } | |
523 | ||
524 | static void sub_remove(struct idr *idp, int shift, int id) | |
525 | { | |
526 | struct idr_layer *p = idp->top; | |
326cf0f0 | 527 | struct idr_layer **pa[MAX_IDR_LEVEL + 1]; |
1da177e4 | 528 | struct idr_layer ***paa = &pa[0]; |
cf481c20 | 529 | struct idr_layer *to_free; |
1da177e4 LT |
530 | int n; |
531 | ||
532 | *paa = NULL; | |
533 | *++paa = &idp->top; | |
534 | ||
535 | while ((shift > 0) && p) { | |
536 | n = (id >> shift) & IDR_MASK; | |
1d9b2e1e | 537 | __clear_bit(n, p->bitmap); |
1da177e4 LT |
538 | *++paa = &p->ary[n]; |
539 | p = p->ary[n]; | |
540 | shift -= IDR_BITS; | |
541 | } | |
542 | n = id & IDR_MASK; | |
1d9b2e1e TH |
543 | if (likely(p != NULL && test_bit(n, p->bitmap))) { |
544 | __clear_bit(n, p->bitmap); | |
cf481c20 ND |
545 | rcu_assign_pointer(p->ary[n], NULL); |
546 | to_free = NULL; | |
1da177e4 | 547 | while(*paa && ! --((**paa)->count)){ |
cf481c20 | 548 | if (to_free) |
0ffc2a9c | 549 | free_layer(idp, to_free); |
cf481c20 | 550 | to_free = **paa; |
1da177e4 LT |
551 | **paa-- = NULL; |
552 | } | |
e15ae2dd | 553 | if (!*paa) |
1da177e4 | 554 | idp->layers = 0; |
cf481c20 | 555 | if (to_free) |
0ffc2a9c | 556 | free_layer(idp, to_free); |
e15ae2dd | 557 | } else |
1da177e4 | 558 | idr_remove_warning(id); |
1da177e4 LT |
559 | } |
560 | ||
561 | /** | |
56083ab1 | 562 | * idr_remove - remove the given id and free its slot |
72fd4a35 RD |
563 | * @idp: idr handle |
564 | * @id: unique key | |
1da177e4 LT |
565 | */ |
566 | void idr_remove(struct idr *idp, int id) | |
567 | { | |
568 | struct idr_layer *p; | |
cf481c20 | 569 | struct idr_layer *to_free; |
1da177e4 | 570 | |
2e1c9b28 | 571 | if (id < 0) |
e8c8d1bc | 572 | return; |
1da177e4 LT |
573 | |
574 | sub_remove(idp, (idp->layers - 1) * IDR_BITS, id); | |
e15ae2dd | 575 | if (idp->top && idp->top->count == 1 && (idp->layers > 1) && |
cf481c20 ND |
576 | idp->top->ary[0]) { |
577 | /* | |
578 | * Single child at leftmost slot: we can shrink the tree. | |
579 | * This level is not needed anymore since when layers are | |
580 | * inserted, they are inserted at the top of the existing | |
581 | * tree. | |
582 | */ | |
583 | to_free = idp->top; | |
1da177e4 | 584 | p = idp->top->ary[0]; |
cf481c20 | 585 | rcu_assign_pointer(idp->top, p); |
1da177e4 | 586 | --idp->layers; |
1d9b2e1e TH |
587 | to_free->count = 0; |
588 | bitmap_clear(to_free->bitmap, 0, IDR_SIZE); | |
0ffc2a9c | 589 | free_layer(idp, to_free); |
1da177e4 | 590 | } |
125c4c70 | 591 | while (idp->id_free_cnt >= MAX_IDR_FREE) { |
4ae53789 | 592 | p = get_from_free_list(idp); |
cf481c20 ND |
593 | /* |
594 | * Note: we don't call the rcu callback here, since the only | |
595 | * layers that fall into the freelist are those that have been | |
596 | * preallocated. | |
597 | */ | |
1da177e4 | 598 | kmem_cache_free(idr_layer_cache, p); |
1da177e4 | 599 | } |
af8e2a4c | 600 | return; |
1da177e4 LT |
601 | } |
602 | EXPORT_SYMBOL(idr_remove); | |
603 | ||
fe6e24ec | 604 | void __idr_remove_all(struct idr *idp) |
23936cc0 | 605 | { |
6ace06dc | 606 | int n, id, max; |
2dcb22b3 | 607 | int bt_mask; |
23936cc0 | 608 | struct idr_layer *p; |
326cf0f0 | 609 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
23936cc0 KH |
610 | struct idr_layer **paa = &pa[0]; |
611 | ||
612 | n = idp->layers * IDR_BITS; | |
613 | p = idp->top; | |
1b23336a | 614 | rcu_assign_pointer(idp->top, NULL); |
326cf0f0 | 615 | max = idr_max(idp->layers); |
23936cc0 KH |
616 | |
617 | id = 0; | |
326cf0f0 | 618 | while (id >= 0 && id <= max) { |
23936cc0 KH |
619 | while (n > IDR_BITS && p) { |
620 | n -= IDR_BITS; | |
621 | *paa++ = p; | |
622 | p = p->ary[(id >> n) & IDR_MASK]; | |
623 | } | |
624 | ||
2dcb22b3 | 625 | bt_mask = id; |
23936cc0 | 626 | id += 1 << n; |
2dcb22b3 ID |
627 | /* Get the highest bit that the above add changed from 0->1. */ |
628 | while (n < fls(id ^ bt_mask)) { | |
cf481c20 | 629 | if (p) |
0ffc2a9c | 630 | free_layer(idp, p); |
23936cc0 KH |
631 | n += IDR_BITS; |
632 | p = *--paa; | |
633 | } | |
634 | } | |
23936cc0 KH |
635 | idp->layers = 0; |
636 | } | |
fe6e24ec | 637 | EXPORT_SYMBOL(__idr_remove_all); |
23936cc0 | 638 | |
8d3b3591 AM |
639 | /** |
640 | * idr_destroy - release all cached layers within an idr tree | |
ea24ea85 | 641 | * @idp: idr handle |
9bb26bc1 TH |
642 | * |
643 | * Free all id mappings and all idp_layers. After this function, @idp is | |
644 | * completely unused and can be freed / recycled. The caller is | |
645 | * responsible for ensuring that no one else accesses @idp during or after | |
646 | * idr_destroy(). | |
647 | * | |
648 | * A typical clean-up sequence for objects stored in an idr tree will use | |
649 | * idr_for_each() to free all objects, if necessay, then idr_destroy() to | |
650 | * free up the id mappings and cached idr_layers. | |
8d3b3591 AM |
651 | */ |
652 | void idr_destroy(struct idr *idp) | |
653 | { | |
fe6e24ec | 654 | __idr_remove_all(idp); |
9bb26bc1 | 655 | |
8d3b3591 | 656 | while (idp->id_free_cnt) { |
4ae53789 | 657 | struct idr_layer *p = get_from_free_list(idp); |
8d3b3591 AM |
658 | kmem_cache_free(idr_layer_cache, p); |
659 | } | |
660 | } | |
661 | EXPORT_SYMBOL(idr_destroy); | |
662 | ||
0ffc2a9c | 663 | void *idr_find_slowpath(struct idr *idp, int id) |
1da177e4 LT |
664 | { |
665 | int n; | |
666 | struct idr_layer *p; | |
667 | ||
2e1c9b28 | 668 | if (id < 0) |
e8c8d1bc TH |
669 | return NULL; |
670 | ||
96be753a | 671 | p = rcu_dereference_raw(idp->top); |
6ff2d39b MS |
672 | if (!p) |
673 | return NULL; | |
674 | n = (p->layer+1) * IDR_BITS; | |
1da177e4 | 675 | |
326cf0f0 | 676 | if (id > idr_max(p->layer + 1)) |
1da177e4 | 677 | return NULL; |
6ff2d39b | 678 | BUG_ON(n == 0); |
1da177e4 LT |
679 | |
680 | while (n > 0 && p) { | |
681 | n -= IDR_BITS; | |
6ff2d39b | 682 | BUG_ON(n != p->layer*IDR_BITS); |
96be753a | 683 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
1da177e4 LT |
684 | } |
685 | return((void *)p); | |
686 | } | |
0ffc2a9c | 687 | EXPORT_SYMBOL(idr_find_slowpath); |
1da177e4 | 688 | |
96d7fa42 KH |
689 | /** |
690 | * idr_for_each - iterate through all stored pointers | |
691 | * @idp: idr handle | |
692 | * @fn: function to be called for each pointer | |
693 | * @data: data passed back to callback function | |
694 | * | |
695 | * Iterate over the pointers registered with the given idr. The | |
696 | * callback function will be called for each pointer currently | |
697 | * registered, passing the id, the pointer and the data pointer passed | |
698 | * to this function. It is not safe to modify the idr tree while in | |
699 | * the callback, so functions such as idr_get_new and idr_remove are | |
700 | * not allowed. | |
701 | * | |
702 | * We check the return of @fn each time. If it returns anything other | |
56083ab1 | 703 | * than %0, we break out and return that value. |
96d7fa42 KH |
704 | * |
705 | * The caller must serialize idr_for_each() vs idr_get_new() and idr_remove(). | |
706 | */ | |
707 | int idr_for_each(struct idr *idp, | |
708 | int (*fn)(int id, void *p, void *data), void *data) | |
709 | { | |
710 | int n, id, max, error = 0; | |
711 | struct idr_layer *p; | |
326cf0f0 | 712 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
96d7fa42 KH |
713 | struct idr_layer **paa = &pa[0]; |
714 | ||
715 | n = idp->layers * IDR_BITS; | |
96be753a | 716 | p = rcu_dereference_raw(idp->top); |
326cf0f0 | 717 | max = idr_max(idp->layers); |
96d7fa42 KH |
718 | |
719 | id = 0; | |
326cf0f0 | 720 | while (id >= 0 && id <= max) { |
96d7fa42 KH |
721 | while (n > 0 && p) { |
722 | n -= IDR_BITS; | |
723 | *paa++ = p; | |
96be753a | 724 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
96d7fa42 KH |
725 | } |
726 | ||
727 | if (p) { | |
728 | error = fn(id, (void *)p, data); | |
729 | if (error) | |
730 | break; | |
731 | } | |
732 | ||
733 | id += 1 << n; | |
734 | while (n < fls(id)) { | |
735 | n += IDR_BITS; | |
736 | p = *--paa; | |
737 | } | |
738 | } | |
739 | ||
740 | return error; | |
741 | } | |
742 | EXPORT_SYMBOL(idr_for_each); | |
743 | ||
38460b48 KH |
744 | /** |
745 | * idr_get_next - lookup next object of id to given id. | |
746 | * @idp: idr handle | |
ea24ea85 | 747 | * @nextidp: pointer to lookup key |
38460b48 KH |
748 | * |
749 | * Returns pointer to registered object with id, which is next number to | |
1458ce16 NA |
750 | * given id. After being looked up, *@nextidp will be updated for the next |
751 | * iteration. | |
9f7de827 HD |
752 | * |
753 | * This function can be called under rcu_read_lock(), given that the leaf | |
754 | * pointers lifetimes are correctly managed. | |
38460b48 | 755 | */ |
38460b48 KH |
756 | void *idr_get_next(struct idr *idp, int *nextidp) |
757 | { | |
326cf0f0 | 758 | struct idr_layer *p, *pa[MAX_IDR_LEVEL + 1]; |
38460b48 KH |
759 | struct idr_layer **paa = &pa[0]; |
760 | int id = *nextidp; | |
761 | int n, max; | |
762 | ||
763 | /* find first ent */ | |
94bfa3b6 | 764 | p = rcu_dereference_raw(idp->top); |
38460b48 KH |
765 | if (!p) |
766 | return NULL; | |
9f7de827 | 767 | n = (p->layer + 1) * IDR_BITS; |
326cf0f0 | 768 | max = idr_max(p->layer + 1); |
38460b48 | 769 | |
326cf0f0 | 770 | while (id >= 0 && id <= max) { |
38460b48 KH |
771 | while (n > 0 && p) { |
772 | n -= IDR_BITS; | |
773 | *paa++ = p; | |
94bfa3b6 | 774 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
38460b48 KH |
775 | } |
776 | ||
777 | if (p) { | |
778 | *nextidp = id; | |
779 | return p; | |
780 | } | |
781 | ||
6cdae741 TH |
782 | /* |
783 | * Proceed to the next layer at the current level. Unlike | |
784 | * idr_for_each(), @id isn't guaranteed to be aligned to | |
785 | * layer boundary at this point and adding 1 << n may | |
786 | * incorrectly skip IDs. Make sure we jump to the | |
787 | * beginning of the next layer using round_up(). | |
788 | */ | |
789 | id = round_up(id + 1, 1 << n); | |
38460b48 KH |
790 | while (n < fls(id)) { |
791 | n += IDR_BITS; | |
792 | p = *--paa; | |
793 | } | |
794 | } | |
795 | return NULL; | |
796 | } | |
4d1ee80f | 797 | EXPORT_SYMBOL(idr_get_next); |
38460b48 KH |
798 | |
799 | ||
5806f07c JM |
800 | /** |
801 | * idr_replace - replace pointer for given id | |
802 | * @idp: idr handle | |
803 | * @ptr: pointer you want associated with the id | |
804 | * @id: lookup key | |
805 | * | |
806 | * Replace the pointer registered with an id and return the old value. | |
56083ab1 RD |
807 | * A %-ENOENT return indicates that @id was not found. |
808 | * A %-EINVAL return indicates that @id was not within valid constraints. | |
5806f07c | 809 | * |
cf481c20 | 810 | * The caller must serialize with writers. |
5806f07c JM |
811 | */ |
812 | void *idr_replace(struct idr *idp, void *ptr, int id) | |
813 | { | |
814 | int n; | |
815 | struct idr_layer *p, *old_p; | |
816 | ||
2e1c9b28 | 817 | if (id < 0) |
e8c8d1bc TH |
818 | return ERR_PTR(-EINVAL); |
819 | ||
5806f07c | 820 | p = idp->top; |
6ff2d39b MS |
821 | if (!p) |
822 | return ERR_PTR(-EINVAL); | |
823 | ||
824 | n = (p->layer+1) * IDR_BITS; | |
5806f07c | 825 | |
5806f07c JM |
826 | if (id >= (1 << n)) |
827 | return ERR_PTR(-EINVAL); | |
828 | ||
829 | n -= IDR_BITS; | |
830 | while ((n > 0) && p) { | |
831 | p = p->ary[(id >> n) & IDR_MASK]; | |
832 | n -= IDR_BITS; | |
833 | } | |
834 | ||
835 | n = id & IDR_MASK; | |
1d9b2e1e | 836 | if (unlikely(p == NULL || !test_bit(n, p->bitmap))) |
5806f07c JM |
837 | return ERR_PTR(-ENOENT); |
838 | ||
839 | old_p = p->ary[n]; | |
cf481c20 | 840 | rcu_assign_pointer(p->ary[n], ptr); |
5806f07c JM |
841 | |
842 | return old_p; | |
843 | } | |
844 | EXPORT_SYMBOL(idr_replace); | |
845 | ||
199f0ca5 | 846 | void __init idr_init_cache(void) |
1da177e4 | 847 | { |
199f0ca5 | 848 | idr_layer_cache = kmem_cache_create("idr_layer_cache", |
5b019e99 | 849 | sizeof(struct idr_layer), 0, SLAB_PANIC, NULL); |
1da177e4 LT |
850 | } |
851 | ||
852 | /** | |
853 | * idr_init - initialize idr handle | |
854 | * @idp: idr handle | |
855 | * | |
856 | * This function is use to set up the handle (@idp) that you will pass | |
857 | * to the rest of the functions. | |
858 | */ | |
859 | void idr_init(struct idr *idp) | |
860 | { | |
1da177e4 LT |
861 | memset(idp, 0, sizeof(struct idr)); |
862 | spin_lock_init(&idp->lock); | |
863 | } | |
864 | EXPORT_SYMBOL(idr_init); | |
72dba584 TH |
865 | |
866 | ||
56083ab1 RD |
867 | /** |
868 | * DOC: IDA description | |
72dba584 TH |
869 | * IDA - IDR based ID allocator |
870 | * | |
56083ab1 | 871 | * This is id allocator without id -> pointer translation. Memory |
72dba584 TH |
872 | * usage is much lower than full blown idr because each id only |
873 | * occupies a bit. ida uses a custom leaf node which contains | |
874 | * IDA_BITMAP_BITS slots. | |
875 | * | |
876 | * 2007-04-25 written by Tejun Heo <htejun@gmail.com> | |
877 | */ | |
878 | ||
879 | static void free_bitmap(struct ida *ida, struct ida_bitmap *bitmap) | |
880 | { | |
881 | unsigned long flags; | |
882 | ||
883 | if (!ida->free_bitmap) { | |
884 | spin_lock_irqsave(&ida->idr.lock, flags); | |
885 | if (!ida->free_bitmap) { | |
886 | ida->free_bitmap = bitmap; | |
887 | bitmap = NULL; | |
888 | } | |
889 | spin_unlock_irqrestore(&ida->idr.lock, flags); | |
890 | } | |
891 | ||
892 | kfree(bitmap); | |
893 | } | |
894 | ||
895 | /** | |
896 | * ida_pre_get - reserve resources for ida allocation | |
897 | * @ida: ida handle | |
898 | * @gfp_mask: memory allocation flag | |
899 | * | |
900 | * This function should be called prior to locking and calling the | |
901 | * following function. It preallocates enough memory to satisfy the | |
902 | * worst possible allocation. | |
903 | * | |
56083ab1 RD |
904 | * If the system is REALLY out of memory this function returns %0, |
905 | * otherwise %1. | |
72dba584 TH |
906 | */ |
907 | int ida_pre_get(struct ida *ida, gfp_t gfp_mask) | |
908 | { | |
909 | /* allocate idr_layers */ | |
910 | if (!idr_pre_get(&ida->idr, gfp_mask)) | |
911 | return 0; | |
912 | ||
913 | /* allocate free_bitmap */ | |
914 | if (!ida->free_bitmap) { | |
915 | struct ida_bitmap *bitmap; | |
916 | ||
917 | bitmap = kmalloc(sizeof(struct ida_bitmap), gfp_mask); | |
918 | if (!bitmap) | |
919 | return 0; | |
920 | ||
921 | free_bitmap(ida, bitmap); | |
922 | } | |
923 | ||
924 | return 1; | |
925 | } | |
926 | EXPORT_SYMBOL(ida_pre_get); | |
927 | ||
928 | /** | |
929 | * ida_get_new_above - allocate new ID above or equal to a start id | |
930 | * @ida: ida handle | |
ea24ea85 | 931 | * @starting_id: id to start search at |
72dba584 TH |
932 | * @p_id: pointer to the allocated handle |
933 | * | |
e3816c54 WSH |
934 | * Allocate new ID above or equal to @starting_id. It should be called |
935 | * with any required locks. | |
72dba584 | 936 | * |
56083ab1 | 937 | * If memory is required, it will return %-EAGAIN, you should unlock |
72dba584 | 938 | * and go back to the ida_pre_get() call. If the ida is full, it will |
56083ab1 | 939 | * return %-ENOSPC. |
72dba584 | 940 | * |
56083ab1 | 941 | * @p_id returns a value in the range @starting_id ... %0x7fffffff. |
72dba584 TH |
942 | */ |
943 | int ida_get_new_above(struct ida *ida, int starting_id, int *p_id) | |
944 | { | |
326cf0f0 | 945 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
72dba584 TH |
946 | struct ida_bitmap *bitmap; |
947 | unsigned long flags; | |
948 | int idr_id = starting_id / IDA_BITMAP_BITS; | |
949 | int offset = starting_id % IDA_BITMAP_BITS; | |
950 | int t, id; | |
951 | ||
952 | restart: | |
953 | /* get vacant slot */ | |
d5c7409f | 954 | t = idr_get_empty_slot(&ida->idr, idr_id, pa, 0, &ida->idr); |
944ca05c | 955 | if (t < 0) |
12d1b439 | 956 | return t == -ENOMEM ? -EAGAIN : t; |
72dba584 | 957 | |
125c4c70 | 958 | if (t * IDA_BITMAP_BITS >= MAX_IDR_BIT) |
72dba584 TH |
959 | return -ENOSPC; |
960 | ||
961 | if (t != idr_id) | |
962 | offset = 0; | |
963 | idr_id = t; | |
964 | ||
965 | /* if bitmap isn't there, create a new one */ | |
966 | bitmap = (void *)pa[0]->ary[idr_id & IDR_MASK]; | |
967 | if (!bitmap) { | |
968 | spin_lock_irqsave(&ida->idr.lock, flags); | |
969 | bitmap = ida->free_bitmap; | |
970 | ida->free_bitmap = NULL; | |
971 | spin_unlock_irqrestore(&ida->idr.lock, flags); | |
972 | ||
973 | if (!bitmap) | |
974 | return -EAGAIN; | |
975 | ||
976 | memset(bitmap, 0, sizeof(struct ida_bitmap)); | |
3219b3b7 ND |
977 | rcu_assign_pointer(pa[0]->ary[idr_id & IDR_MASK], |
978 | (void *)bitmap); | |
72dba584 TH |
979 | pa[0]->count++; |
980 | } | |
981 | ||
982 | /* lookup for empty slot */ | |
983 | t = find_next_zero_bit(bitmap->bitmap, IDA_BITMAP_BITS, offset); | |
984 | if (t == IDA_BITMAP_BITS) { | |
985 | /* no empty slot after offset, continue to the next chunk */ | |
986 | idr_id++; | |
987 | offset = 0; | |
988 | goto restart; | |
989 | } | |
990 | ||
991 | id = idr_id * IDA_BITMAP_BITS + t; | |
125c4c70 | 992 | if (id >= MAX_IDR_BIT) |
72dba584 TH |
993 | return -ENOSPC; |
994 | ||
995 | __set_bit(t, bitmap->bitmap); | |
996 | if (++bitmap->nr_busy == IDA_BITMAP_BITS) | |
997 | idr_mark_full(pa, idr_id); | |
998 | ||
999 | *p_id = id; | |
1000 | ||
1001 | /* Each leaf node can handle nearly a thousand slots and the | |
1002 | * whole idea of ida is to have small memory foot print. | |
1003 | * Throw away extra resources one by one after each successful | |
1004 | * allocation. | |
1005 | */ | |
1006 | if (ida->idr.id_free_cnt || ida->free_bitmap) { | |
4ae53789 | 1007 | struct idr_layer *p = get_from_free_list(&ida->idr); |
72dba584 TH |
1008 | if (p) |
1009 | kmem_cache_free(idr_layer_cache, p); | |
1010 | } | |
1011 | ||
1012 | return 0; | |
1013 | } | |
1014 | EXPORT_SYMBOL(ida_get_new_above); | |
1015 | ||
72dba584 TH |
1016 | /** |
1017 | * ida_remove - remove the given ID | |
1018 | * @ida: ida handle | |
1019 | * @id: ID to free | |
1020 | */ | |
1021 | void ida_remove(struct ida *ida, int id) | |
1022 | { | |
1023 | struct idr_layer *p = ida->idr.top; | |
1024 | int shift = (ida->idr.layers - 1) * IDR_BITS; | |
1025 | int idr_id = id / IDA_BITMAP_BITS; | |
1026 | int offset = id % IDA_BITMAP_BITS; | |
1027 | int n; | |
1028 | struct ida_bitmap *bitmap; | |
1029 | ||
1030 | /* clear full bits while looking up the leaf idr_layer */ | |
1031 | while ((shift > 0) && p) { | |
1032 | n = (idr_id >> shift) & IDR_MASK; | |
1d9b2e1e | 1033 | __clear_bit(n, p->bitmap); |
72dba584 TH |
1034 | p = p->ary[n]; |
1035 | shift -= IDR_BITS; | |
1036 | } | |
1037 | ||
1038 | if (p == NULL) | |
1039 | goto err; | |
1040 | ||
1041 | n = idr_id & IDR_MASK; | |
1d9b2e1e | 1042 | __clear_bit(n, p->bitmap); |
72dba584 TH |
1043 | |
1044 | bitmap = (void *)p->ary[n]; | |
1045 | if (!test_bit(offset, bitmap->bitmap)) | |
1046 | goto err; | |
1047 | ||
1048 | /* update bitmap and remove it if empty */ | |
1049 | __clear_bit(offset, bitmap->bitmap); | |
1050 | if (--bitmap->nr_busy == 0) { | |
1d9b2e1e | 1051 | __set_bit(n, p->bitmap); /* to please idr_remove() */ |
72dba584 TH |
1052 | idr_remove(&ida->idr, idr_id); |
1053 | free_bitmap(ida, bitmap); | |
1054 | } | |
1055 | ||
1056 | return; | |
1057 | ||
1058 | err: | |
1059 | printk(KERN_WARNING | |
1060 | "ida_remove called for id=%d which is not allocated.\n", id); | |
1061 | } | |
1062 | EXPORT_SYMBOL(ida_remove); | |
1063 | ||
1064 | /** | |
1065 | * ida_destroy - release all cached layers within an ida tree | |
ea24ea85 | 1066 | * @ida: ida handle |
72dba584 TH |
1067 | */ |
1068 | void ida_destroy(struct ida *ida) | |
1069 | { | |
1070 | idr_destroy(&ida->idr); | |
1071 | kfree(ida->free_bitmap); | |
1072 | } | |
1073 | EXPORT_SYMBOL(ida_destroy); | |
1074 | ||
88eca020 RR |
1075 | /** |
1076 | * ida_simple_get - get a new id. | |
1077 | * @ida: the (initialized) ida. | |
1078 | * @start: the minimum id (inclusive, < 0x8000000) | |
1079 | * @end: the maximum id (exclusive, < 0x8000000 or 0) | |
1080 | * @gfp_mask: memory allocation flags | |
1081 | * | |
1082 | * Allocates an id in the range start <= id < end, or returns -ENOSPC. | |
1083 | * On memory allocation failure, returns -ENOMEM. | |
1084 | * | |
1085 | * Use ida_simple_remove() to get rid of an id. | |
1086 | */ | |
1087 | int ida_simple_get(struct ida *ida, unsigned int start, unsigned int end, | |
1088 | gfp_t gfp_mask) | |
1089 | { | |
1090 | int ret, id; | |
1091 | unsigned int max; | |
46cbc1d3 | 1092 | unsigned long flags; |
88eca020 RR |
1093 | |
1094 | BUG_ON((int)start < 0); | |
1095 | BUG_ON((int)end < 0); | |
1096 | ||
1097 | if (end == 0) | |
1098 | max = 0x80000000; | |
1099 | else { | |
1100 | BUG_ON(end < start); | |
1101 | max = end - 1; | |
1102 | } | |
1103 | ||
1104 | again: | |
1105 | if (!ida_pre_get(ida, gfp_mask)) | |
1106 | return -ENOMEM; | |
1107 | ||
46cbc1d3 | 1108 | spin_lock_irqsave(&simple_ida_lock, flags); |
88eca020 RR |
1109 | ret = ida_get_new_above(ida, start, &id); |
1110 | if (!ret) { | |
1111 | if (id > max) { | |
1112 | ida_remove(ida, id); | |
1113 | ret = -ENOSPC; | |
1114 | } else { | |
1115 | ret = id; | |
1116 | } | |
1117 | } | |
46cbc1d3 | 1118 | spin_unlock_irqrestore(&simple_ida_lock, flags); |
88eca020 RR |
1119 | |
1120 | if (unlikely(ret == -EAGAIN)) | |
1121 | goto again; | |
1122 | ||
1123 | return ret; | |
1124 | } | |
1125 | EXPORT_SYMBOL(ida_simple_get); | |
1126 | ||
1127 | /** | |
1128 | * ida_simple_remove - remove an allocated id. | |
1129 | * @ida: the (initialized) ida. | |
1130 | * @id: the id returned by ida_simple_get. | |
1131 | */ | |
1132 | void ida_simple_remove(struct ida *ida, unsigned int id) | |
1133 | { | |
46cbc1d3 TH |
1134 | unsigned long flags; |
1135 | ||
88eca020 | 1136 | BUG_ON((int)id < 0); |
46cbc1d3 | 1137 | spin_lock_irqsave(&simple_ida_lock, flags); |
88eca020 | 1138 | ida_remove(ida, id); |
46cbc1d3 | 1139 | spin_unlock_irqrestore(&simple_ida_lock, flags); |
88eca020 RR |
1140 | } |
1141 | EXPORT_SYMBOL(ida_simple_remove); | |
1142 | ||
72dba584 TH |
1143 | /** |
1144 | * ida_init - initialize ida handle | |
1145 | * @ida: ida handle | |
1146 | * | |
1147 | * This function is use to set up the handle (@ida) that you will pass | |
1148 | * to the rest of the functions. | |
1149 | */ | |
1150 | void ida_init(struct ida *ida) | |
1151 | { | |
1152 | memset(ida, 0, sizeof(struct ida)); | |
1153 | idr_init(&ida->idr); | |
1154 | ||
1155 | } | |
1156 | EXPORT_SYMBOL(ida_init); |