Commit | Line | Data |
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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> |
1da177e4 | 38 | |
e18b890b | 39 | static struct kmem_cache *idr_layer_cache; |
88eca020 | 40 | static DEFINE_SPINLOCK(simple_ida_lock); |
1da177e4 | 41 | |
4ae53789 | 42 | static struct idr_layer *get_from_free_list(struct idr *idp) |
1da177e4 LT |
43 | { |
44 | struct idr_layer *p; | |
c259cc28 | 45 | unsigned long flags; |
1da177e4 | 46 | |
c259cc28 | 47 | spin_lock_irqsave(&idp->lock, flags); |
1da177e4 LT |
48 | if ((p = idp->id_free)) { |
49 | idp->id_free = p->ary[0]; | |
50 | idp->id_free_cnt--; | |
51 | p->ary[0] = NULL; | |
52 | } | |
c259cc28 | 53 | spin_unlock_irqrestore(&idp->lock, flags); |
1da177e4 LT |
54 | return(p); |
55 | } | |
56 | ||
cf481c20 ND |
57 | static void idr_layer_rcu_free(struct rcu_head *head) |
58 | { | |
59 | struct idr_layer *layer; | |
60 | ||
61 | layer = container_of(head, struct idr_layer, rcu_head); | |
62 | kmem_cache_free(idr_layer_cache, layer); | |
63 | } | |
64 | ||
65 | static inline void free_layer(struct idr_layer *p) | |
66 | { | |
67 | call_rcu(&p->rcu_head, idr_layer_rcu_free); | |
68 | } | |
69 | ||
1eec0056 | 70 | /* only called when idp->lock is held */ |
4ae53789 | 71 | static void __move_to_free_list(struct idr *idp, struct idr_layer *p) |
1eec0056 SR |
72 | { |
73 | p->ary[0] = idp->id_free; | |
74 | idp->id_free = p; | |
75 | idp->id_free_cnt++; | |
76 | } | |
77 | ||
4ae53789 | 78 | static void move_to_free_list(struct idr *idp, struct idr_layer *p) |
1da177e4 | 79 | { |
c259cc28 RD |
80 | unsigned long flags; |
81 | ||
1da177e4 LT |
82 | /* |
83 | * Depends on the return element being zeroed. | |
84 | */ | |
c259cc28 | 85 | spin_lock_irqsave(&idp->lock, flags); |
4ae53789 | 86 | __move_to_free_list(idp, p); |
c259cc28 | 87 | spin_unlock_irqrestore(&idp->lock, flags); |
1da177e4 LT |
88 | } |
89 | ||
e33ac8bd TH |
90 | static void idr_mark_full(struct idr_layer **pa, int id) |
91 | { | |
92 | struct idr_layer *p = pa[0]; | |
93 | int l = 0; | |
94 | ||
95 | __set_bit(id & IDR_MASK, &p->bitmap); | |
96 | /* | |
97 | * If this layer is full mark the bit in the layer above to | |
98 | * show that this part of the radix tree is full. This may | |
99 | * complete the layer above and require walking up the radix | |
100 | * tree. | |
101 | */ | |
102 | while (p->bitmap == IDR_FULL) { | |
103 | if (!(p = pa[++l])) | |
104 | break; | |
105 | id = id >> IDR_BITS; | |
106 | __set_bit((id & IDR_MASK), &p->bitmap); | |
107 | } | |
108 | } | |
109 | ||
1da177e4 | 110 | /** |
56083ab1 | 111 | * idr_pre_get - reserve resources for idr allocation |
1da177e4 LT |
112 | * @idp: idr handle |
113 | * @gfp_mask: memory allocation flags | |
114 | * | |
066a9be6 NA |
115 | * This function should be called prior to calling the idr_get_new* functions. |
116 | * It preallocates enough memory to satisfy the worst possible allocation. The | |
117 | * caller should pass in GFP_KERNEL if possible. This of course requires that | |
118 | * no spinning locks be held. | |
1da177e4 | 119 | * |
56083ab1 RD |
120 | * If the system is REALLY out of memory this function returns %0, |
121 | * otherwise %1. | |
1da177e4 | 122 | */ |
fd4f2df2 | 123 | int idr_pre_get(struct idr *idp, gfp_t gfp_mask) |
1da177e4 | 124 | { |
125c4c70 | 125 | while (idp->id_free_cnt < MAX_IDR_FREE) { |
1da177e4 | 126 | struct idr_layer *new; |
5b019e99 | 127 | new = kmem_cache_zalloc(idr_layer_cache, gfp_mask); |
e15ae2dd | 128 | if (new == NULL) |
1da177e4 | 129 | return (0); |
4ae53789 | 130 | move_to_free_list(idp, new); |
1da177e4 LT |
131 | } |
132 | return 1; | |
133 | } | |
134 | EXPORT_SYMBOL(idr_pre_get); | |
135 | ||
e33ac8bd | 136 | static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa) |
1da177e4 LT |
137 | { |
138 | int n, m, sh; | |
139 | struct idr_layer *p, *new; | |
7aae6dd8 | 140 | int l, id, oid; |
5ba25331 | 141 | unsigned long bm; |
1da177e4 LT |
142 | |
143 | id = *starting_id; | |
7aae6dd8 | 144 | restart: |
1da177e4 LT |
145 | p = idp->top; |
146 | l = idp->layers; | |
147 | pa[l--] = NULL; | |
148 | while (1) { | |
149 | /* | |
150 | * We run around this while until we reach the leaf node... | |
151 | */ | |
152 | n = (id >> (IDR_BITS*l)) & IDR_MASK; | |
153 | bm = ~p->bitmap; | |
154 | m = find_next_bit(&bm, IDR_SIZE, n); | |
155 | if (m == IDR_SIZE) { | |
156 | /* no space available go back to previous layer. */ | |
157 | l++; | |
7aae6dd8 | 158 | oid = id; |
e15ae2dd | 159 | id = (id | ((1 << (IDR_BITS * l)) - 1)) + 1; |
7aae6dd8 TH |
160 | |
161 | /* if already at the top layer, we need to grow */ | |
d2e7276b | 162 | if (id >= 1 << (idp->layers * IDR_BITS)) { |
1da177e4 | 163 | *starting_id = id; |
944ca05c | 164 | return IDR_NEED_TO_GROW; |
1da177e4 | 165 | } |
d2e7276b TH |
166 | p = pa[l]; |
167 | BUG_ON(!p); | |
7aae6dd8 TH |
168 | |
169 | /* If we need to go up one layer, continue the | |
170 | * loop; otherwise, restart from the top. | |
171 | */ | |
172 | sh = IDR_BITS * (l + 1); | |
173 | if (oid >> sh == id >> sh) | |
174 | continue; | |
175 | else | |
176 | goto restart; | |
1da177e4 LT |
177 | } |
178 | if (m != n) { | |
179 | sh = IDR_BITS*l; | |
180 | id = ((id >> sh) ^ n ^ m) << sh; | |
181 | } | |
125c4c70 | 182 | if ((id >= MAX_IDR_BIT) || (id < 0)) |
944ca05c | 183 | return IDR_NOMORE_SPACE; |
1da177e4 LT |
184 | if (l == 0) |
185 | break; | |
186 | /* | |
187 | * Create the layer below if it is missing. | |
188 | */ | |
189 | if (!p->ary[m]) { | |
4ae53789 ND |
190 | new = get_from_free_list(idp); |
191 | if (!new) | |
1da177e4 | 192 | return -1; |
6ff2d39b | 193 | new->layer = l-1; |
3219b3b7 | 194 | rcu_assign_pointer(p->ary[m], new); |
1da177e4 LT |
195 | p->count++; |
196 | } | |
197 | pa[l--] = p; | |
198 | p = p->ary[m]; | |
199 | } | |
e33ac8bd TH |
200 | |
201 | pa[l] = p; | |
202 | return id; | |
1da177e4 LT |
203 | } |
204 | ||
e33ac8bd TH |
205 | static int idr_get_empty_slot(struct idr *idp, int starting_id, |
206 | struct idr_layer **pa) | |
1da177e4 LT |
207 | { |
208 | struct idr_layer *p, *new; | |
209 | int layers, v, id; | |
c259cc28 | 210 | unsigned long flags; |
e15ae2dd | 211 | |
1da177e4 LT |
212 | id = starting_id; |
213 | build_up: | |
214 | p = idp->top; | |
215 | layers = idp->layers; | |
216 | if (unlikely(!p)) { | |
4ae53789 | 217 | if (!(p = get_from_free_list(idp))) |
1da177e4 | 218 | return -1; |
6ff2d39b | 219 | p->layer = 0; |
1da177e4 LT |
220 | layers = 1; |
221 | } | |
222 | /* | |
223 | * Add a new layer to the top of the tree if the requested | |
224 | * id is larger than the currently allocated space. | |
225 | */ | |
125c4c70 | 226 | while ((layers < (MAX_IDR_LEVEL - 1)) && (id >= (1 << (layers*IDR_BITS)))) { |
1da177e4 | 227 | layers++; |
711a49a0 MS |
228 | if (!p->count) { |
229 | /* special case: if the tree is currently empty, | |
230 | * then we grow the tree by moving the top node | |
231 | * upwards. | |
232 | */ | |
233 | p->layer++; | |
1da177e4 | 234 | continue; |
711a49a0 | 235 | } |
4ae53789 | 236 | if (!(new = get_from_free_list(idp))) { |
1da177e4 LT |
237 | /* |
238 | * The allocation failed. If we built part of | |
239 | * the structure tear it down. | |
240 | */ | |
c259cc28 | 241 | spin_lock_irqsave(&idp->lock, flags); |
1da177e4 LT |
242 | for (new = p; p && p != idp->top; new = p) { |
243 | p = p->ary[0]; | |
244 | new->ary[0] = NULL; | |
245 | new->bitmap = new->count = 0; | |
4ae53789 | 246 | __move_to_free_list(idp, new); |
1da177e4 | 247 | } |
c259cc28 | 248 | spin_unlock_irqrestore(&idp->lock, flags); |
1da177e4 LT |
249 | return -1; |
250 | } | |
251 | new->ary[0] = p; | |
252 | new->count = 1; | |
6ff2d39b | 253 | new->layer = layers-1; |
1da177e4 LT |
254 | if (p->bitmap == IDR_FULL) |
255 | __set_bit(0, &new->bitmap); | |
256 | p = new; | |
257 | } | |
3219b3b7 | 258 | rcu_assign_pointer(idp->top, p); |
1da177e4 | 259 | idp->layers = layers; |
e33ac8bd | 260 | v = sub_alloc(idp, &id, pa); |
944ca05c | 261 | if (v == IDR_NEED_TO_GROW) |
1da177e4 LT |
262 | goto build_up; |
263 | return(v); | |
264 | } | |
265 | ||
e33ac8bd TH |
266 | static int idr_get_new_above_int(struct idr *idp, void *ptr, int starting_id) |
267 | { | |
125c4c70 | 268 | struct idr_layer *pa[MAX_IDR_LEVEL]; |
e33ac8bd TH |
269 | int id; |
270 | ||
271 | id = idr_get_empty_slot(idp, starting_id, pa); | |
272 | if (id >= 0) { | |
273 | /* | |
274 | * Successfully found an empty slot. Install the user | |
275 | * pointer and mark the slot full. | |
276 | */ | |
3219b3b7 ND |
277 | rcu_assign_pointer(pa[0]->ary[id & IDR_MASK], |
278 | (struct idr_layer *)ptr); | |
e33ac8bd TH |
279 | pa[0]->count++; |
280 | idr_mark_full(pa, id); | |
281 | } | |
282 | ||
283 | return id; | |
284 | } | |
285 | ||
1da177e4 | 286 | /** |
7c657f2f | 287 | * idr_get_new_above - allocate new idr entry above or equal to a start id |
1da177e4 | 288 | * @idp: idr handle |
94e2bd68 | 289 | * @ptr: pointer you want associated with the id |
ea24ea85 | 290 | * @starting_id: id to start search at |
1da177e4 LT |
291 | * @id: pointer to the allocated handle |
292 | * | |
293 | * This is the allocate id function. It should be called with any | |
294 | * required locks. | |
295 | * | |
066a9be6 | 296 | * If allocation from IDR's private freelist fails, idr_get_new_above() will |
56083ab1 | 297 | * return %-EAGAIN. The caller should retry the idr_pre_get() call to refill |
066a9be6 NA |
298 | * IDR's preallocation and then retry the idr_get_new_above() call. |
299 | * | |
56083ab1 | 300 | * If the idr is full idr_get_new_above() will return %-ENOSPC. |
1da177e4 | 301 | * |
56083ab1 | 302 | * @id returns a value in the range @starting_id ... %0x7fffffff |
1da177e4 LT |
303 | */ |
304 | int idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id) | |
305 | { | |
306 | int rv; | |
e15ae2dd | 307 | |
1da177e4 LT |
308 | rv = idr_get_new_above_int(idp, ptr, starting_id); |
309 | /* | |
310 | * This is a cheap hack until the IDR code can be fixed to | |
311 | * return proper error values. | |
312 | */ | |
944ca05c ND |
313 | if (rv < 0) |
314 | return _idr_rc_to_errno(rv); | |
1da177e4 LT |
315 | *id = rv; |
316 | return 0; | |
317 | } | |
318 | EXPORT_SYMBOL(idr_get_new_above); | |
319 | ||
1da177e4 LT |
320 | static void idr_remove_warning(int id) |
321 | { | |
f098ad65 ND |
322 | printk(KERN_WARNING |
323 | "idr_remove called for id=%d which is not allocated.\n", id); | |
1da177e4 LT |
324 | dump_stack(); |
325 | } | |
326 | ||
327 | static void sub_remove(struct idr *idp, int shift, int id) | |
328 | { | |
329 | struct idr_layer *p = idp->top; | |
125c4c70 | 330 | struct idr_layer **pa[MAX_IDR_LEVEL]; |
1da177e4 | 331 | struct idr_layer ***paa = &pa[0]; |
cf481c20 | 332 | struct idr_layer *to_free; |
1da177e4 LT |
333 | int n; |
334 | ||
335 | *paa = NULL; | |
336 | *++paa = &idp->top; | |
337 | ||
338 | while ((shift > 0) && p) { | |
339 | n = (id >> shift) & IDR_MASK; | |
340 | __clear_bit(n, &p->bitmap); | |
341 | *++paa = &p->ary[n]; | |
342 | p = p->ary[n]; | |
343 | shift -= IDR_BITS; | |
344 | } | |
345 | n = id & IDR_MASK; | |
346 | if (likely(p != NULL && test_bit(n, &p->bitmap))){ | |
347 | __clear_bit(n, &p->bitmap); | |
cf481c20 ND |
348 | rcu_assign_pointer(p->ary[n], NULL); |
349 | to_free = NULL; | |
1da177e4 | 350 | while(*paa && ! --((**paa)->count)){ |
cf481c20 ND |
351 | if (to_free) |
352 | free_layer(to_free); | |
353 | to_free = **paa; | |
1da177e4 LT |
354 | **paa-- = NULL; |
355 | } | |
e15ae2dd | 356 | if (!*paa) |
1da177e4 | 357 | idp->layers = 0; |
cf481c20 ND |
358 | if (to_free) |
359 | free_layer(to_free); | |
e15ae2dd | 360 | } else |
1da177e4 | 361 | idr_remove_warning(id); |
1da177e4 LT |
362 | } |
363 | ||
364 | /** | |
56083ab1 | 365 | * idr_remove - remove the given id and free its slot |
72fd4a35 RD |
366 | * @idp: idr handle |
367 | * @id: unique key | |
1da177e4 LT |
368 | */ |
369 | void idr_remove(struct idr *idp, int id) | |
370 | { | |
371 | struct idr_layer *p; | |
cf481c20 | 372 | struct idr_layer *to_free; |
1da177e4 LT |
373 | |
374 | /* Mask off upper bits we don't use for the search. */ | |
125c4c70 | 375 | id &= MAX_IDR_MASK; |
1da177e4 LT |
376 | |
377 | sub_remove(idp, (idp->layers - 1) * IDR_BITS, id); | |
e15ae2dd | 378 | if (idp->top && idp->top->count == 1 && (idp->layers > 1) && |
cf481c20 ND |
379 | idp->top->ary[0]) { |
380 | /* | |
381 | * Single child at leftmost slot: we can shrink the tree. | |
382 | * This level is not needed anymore since when layers are | |
383 | * inserted, they are inserted at the top of the existing | |
384 | * tree. | |
385 | */ | |
386 | to_free = idp->top; | |
1da177e4 | 387 | p = idp->top->ary[0]; |
cf481c20 | 388 | rcu_assign_pointer(idp->top, p); |
1da177e4 | 389 | --idp->layers; |
cf481c20 ND |
390 | to_free->bitmap = to_free->count = 0; |
391 | free_layer(to_free); | |
1da177e4 | 392 | } |
125c4c70 | 393 | while (idp->id_free_cnt >= MAX_IDR_FREE) { |
4ae53789 | 394 | p = get_from_free_list(idp); |
cf481c20 ND |
395 | /* |
396 | * Note: we don't call the rcu callback here, since the only | |
397 | * layers that fall into the freelist are those that have been | |
398 | * preallocated. | |
399 | */ | |
1da177e4 | 400 | kmem_cache_free(idr_layer_cache, p); |
1da177e4 | 401 | } |
af8e2a4c | 402 | return; |
1da177e4 LT |
403 | } |
404 | EXPORT_SYMBOL(idr_remove); | |
405 | ||
fe6e24ec | 406 | void __idr_remove_all(struct idr *idp) |
23936cc0 | 407 | { |
6ace06dc | 408 | int n, id, max; |
2dcb22b3 | 409 | int bt_mask; |
23936cc0 | 410 | struct idr_layer *p; |
125c4c70 | 411 | struct idr_layer *pa[MAX_IDR_LEVEL]; |
23936cc0 KH |
412 | struct idr_layer **paa = &pa[0]; |
413 | ||
414 | n = idp->layers * IDR_BITS; | |
415 | p = idp->top; | |
1b23336a | 416 | rcu_assign_pointer(idp->top, NULL); |
23936cc0 KH |
417 | max = 1 << n; |
418 | ||
419 | id = 0; | |
6ace06dc | 420 | while (id < max) { |
23936cc0 KH |
421 | while (n > IDR_BITS && p) { |
422 | n -= IDR_BITS; | |
423 | *paa++ = p; | |
424 | p = p->ary[(id >> n) & IDR_MASK]; | |
425 | } | |
426 | ||
2dcb22b3 | 427 | bt_mask = id; |
23936cc0 | 428 | id += 1 << n; |
2dcb22b3 ID |
429 | /* Get the highest bit that the above add changed from 0->1. */ |
430 | while (n < fls(id ^ bt_mask)) { | |
cf481c20 ND |
431 | if (p) |
432 | free_layer(p); | |
23936cc0 KH |
433 | n += IDR_BITS; |
434 | p = *--paa; | |
435 | } | |
436 | } | |
23936cc0 KH |
437 | idp->layers = 0; |
438 | } | |
fe6e24ec | 439 | EXPORT_SYMBOL(__idr_remove_all); |
23936cc0 | 440 | |
8d3b3591 AM |
441 | /** |
442 | * idr_destroy - release all cached layers within an idr tree | |
ea24ea85 | 443 | * @idp: idr handle |
9bb26bc1 TH |
444 | * |
445 | * Free all id mappings and all idp_layers. After this function, @idp is | |
446 | * completely unused and can be freed / recycled. The caller is | |
447 | * responsible for ensuring that no one else accesses @idp during or after | |
448 | * idr_destroy(). | |
449 | * | |
450 | * A typical clean-up sequence for objects stored in an idr tree will use | |
451 | * idr_for_each() to free all objects, if necessay, then idr_destroy() to | |
452 | * free up the id mappings and cached idr_layers. | |
8d3b3591 AM |
453 | */ |
454 | void idr_destroy(struct idr *idp) | |
455 | { | |
fe6e24ec | 456 | __idr_remove_all(idp); |
9bb26bc1 | 457 | |
8d3b3591 | 458 | while (idp->id_free_cnt) { |
4ae53789 | 459 | struct idr_layer *p = get_from_free_list(idp); |
8d3b3591 AM |
460 | kmem_cache_free(idr_layer_cache, p); |
461 | } | |
462 | } | |
463 | EXPORT_SYMBOL(idr_destroy); | |
464 | ||
1da177e4 LT |
465 | /** |
466 | * idr_find - return pointer for given id | |
467 | * @idp: idr handle | |
468 | * @id: lookup key | |
469 | * | |
470 | * Return the pointer given the id it has been registered with. A %NULL | |
471 | * return indicates that @id is not valid or you passed %NULL in | |
472 | * idr_get_new(). | |
473 | * | |
f9c46d6e ND |
474 | * This function can be called under rcu_read_lock(), given that the leaf |
475 | * pointers lifetimes are correctly managed. | |
1da177e4 LT |
476 | */ |
477 | void *idr_find(struct idr *idp, int id) | |
478 | { | |
479 | int n; | |
480 | struct idr_layer *p; | |
481 | ||
96be753a | 482 | p = rcu_dereference_raw(idp->top); |
6ff2d39b MS |
483 | if (!p) |
484 | return NULL; | |
485 | n = (p->layer+1) * IDR_BITS; | |
1da177e4 LT |
486 | |
487 | /* Mask off upper bits we don't use for the search. */ | |
125c4c70 | 488 | id &= MAX_IDR_MASK; |
1da177e4 LT |
489 | |
490 | if (id >= (1 << n)) | |
491 | return NULL; | |
6ff2d39b | 492 | BUG_ON(n == 0); |
1da177e4 LT |
493 | |
494 | while (n > 0 && p) { | |
495 | n -= IDR_BITS; | |
6ff2d39b | 496 | BUG_ON(n != p->layer*IDR_BITS); |
96be753a | 497 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
1da177e4 LT |
498 | } |
499 | return((void *)p); | |
500 | } | |
501 | EXPORT_SYMBOL(idr_find); | |
502 | ||
96d7fa42 KH |
503 | /** |
504 | * idr_for_each - iterate through all stored pointers | |
505 | * @idp: idr handle | |
506 | * @fn: function to be called for each pointer | |
507 | * @data: data passed back to callback function | |
508 | * | |
509 | * Iterate over the pointers registered with the given idr. The | |
510 | * callback function will be called for each pointer currently | |
511 | * registered, passing the id, the pointer and the data pointer passed | |
512 | * to this function. It is not safe to modify the idr tree while in | |
513 | * the callback, so functions such as idr_get_new and idr_remove are | |
514 | * not allowed. | |
515 | * | |
516 | * We check the return of @fn each time. If it returns anything other | |
56083ab1 | 517 | * than %0, we break out and return that value. |
96d7fa42 KH |
518 | * |
519 | * The caller must serialize idr_for_each() vs idr_get_new() and idr_remove(). | |
520 | */ | |
521 | int idr_for_each(struct idr *idp, | |
522 | int (*fn)(int id, void *p, void *data), void *data) | |
523 | { | |
524 | int n, id, max, error = 0; | |
525 | struct idr_layer *p; | |
125c4c70 | 526 | struct idr_layer *pa[MAX_IDR_LEVEL]; |
96d7fa42 KH |
527 | struct idr_layer **paa = &pa[0]; |
528 | ||
529 | n = idp->layers * IDR_BITS; | |
96be753a | 530 | p = rcu_dereference_raw(idp->top); |
96d7fa42 KH |
531 | max = 1 << n; |
532 | ||
533 | id = 0; | |
534 | while (id < max) { | |
535 | while (n > 0 && p) { | |
536 | n -= IDR_BITS; | |
537 | *paa++ = p; | |
96be753a | 538 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
96d7fa42 KH |
539 | } |
540 | ||
541 | if (p) { | |
542 | error = fn(id, (void *)p, data); | |
543 | if (error) | |
544 | break; | |
545 | } | |
546 | ||
547 | id += 1 << n; | |
548 | while (n < fls(id)) { | |
549 | n += IDR_BITS; | |
550 | p = *--paa; | |
551 | } | |
552 | } | |
553 | ||
554 | return error; | |
555 | } | |
556 | EXPORT_SYMBOL(idr_for_each); | |
557 | ||
38460b48 KH |
558 | /** |
559 | * idr_get_next - lookup next object of id to given id. | |
560 | * @idp: idr handle | |
ea24ea85 | 561 | * @nextidp: pointer to lookup key |
38460b48 KH |
562 | * |
563 | * Returns pointer to registered object with id, which is next number to | |
1458ce16 NA |
564 | * given id. After being looked up, *@nextidp will be updated for the next |
565 | * iteration. | |
9f7de827 HD |
566 | * |
567 | * This function can be called under rcu_read_lock(), given that the leaf | |
568 | * pointers lifetimes are correctly managed. | |
38460b48 | 569 | */ |
38460b48 KH |
570 | void *idr_get_next(struct idr *idp, int *nextidp) |
571 | { | |
125c4c70 | 572 | struct idr_layer *p, *pa[MAX_IDR_LEVEL]; |
38460b48 KH |
573 | struct idr_layer **paa = &pa[0]; |
574 | int id = *nextidp; | |
575 | int n, max; | |
576 | ||
577 | /* find first ent */ | |
94bfa3b6 | 578 | p = rcu_dereference_raw(idp->top); |
38460b48 KH |
579 | if (!p) |
580 | return NULL; | |
9f7de827 HD |
581 | n = (p->layer + 1) * IDR_BITS; |
582 | max = 1 << n; | |
38460b48 KH |
583 | |
584 | while (id < max) { | |
585 | while (n > 0 && p) { | |
586 | n -= IDR_BITS; | |
587 | *paa++ = p; | |
94bfa3b6 | 588 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
38460b48 KH |
589 | } |
590 | ||
591 | if (p) { | |
592 | *nextidp = id; | |
593 | return p; | |
594 | } | |
595 | ||
6cdae741 TH |
596 | /* |
597 | * Proceed to the next layer at the current level. Unlike | |
598 | * idr_for_each(), @id isn't guaranteed to be aligned to | |
599 | * layer boundary at this point and adding 1 << n may | |
600 | * incorrectly skip IDs. Make sure we jump to the | |
601 | * beginning of the next layer using round_up(). | |
602 | */ | |
603 | id = round_up(id + 1, 1 << n); | |
38460b48 KH |
604 | while (n < fls(id)) { |
605 | n += IDR_BITS; | |
606 | p = *--paa; | |
607 | } | |
608 | } | |
609 | return NULL; | |
610 | } | |
4d1ee80f | 611 | EXPORT_SYMBOL(idr_get_next); |
38460b48 KH |
612 | |
613 | ||
5806f07c JM |
614 | /** |
615 | * idr_replace - replace pointer for given id | |
616 | * @idp: idr handle | |
617 | * @ptr: pointer you want associated with the id | |
618 | * @id: lookup key | |
619 | * | |
620 | * Replace the pointer registered with an id and return the old value. | |
56083ab1 RD |
621 | * A %-ENOENT return indicates that @id was not found. |
622 | * A %-EINVAL return indicates that @id was not within valid constraints. | |
5806f07c | 623 | * |
cf481c20 | 624 | * The caller must serialize with writers. |
5806f07c JM |
625 | */ |
626 | void *idr_replace(struct idr *idp, void *ptr, int id) | |
627 | { | |
628 | int n; | |
629 | struct idr_layer *p, *old_p; | |
630 | ||
5806f07c | 631 | p = idp->top; |
6ff2d39b MS |
632 | if (!p) |
633 | return ERR_PTR(-EINVAL); | |
634 | ||
635 | n = (p->layer+1) * IDR_BITS; | |
5806f07c | 636 | |
125c4c70 | 637 | id &= MAX_IDR_MASK; |
5806f07c JM |
638 | |
639 | if (id >= (1 << n)) | |
640 | return ERR_PTR(-EINVAL); | |
641 | ||
642 | n -= IDR_BITS; | |
643 | while ((n > 0) && p) { | |
644 | p = p->ary[(id >> n) & IDR_MASK]; | |
645 | n -= IDR_BITS; | |
646 | } | |
647 | ||
648 | n = id & IDR_MASK; | |
649 | if (unlikely(p == NULL || !test_bit(n, &p->bitmap))) | |
650 | return ERR_PTR(-ENOENT); | |
651 | ||
652 | old_p = p->ary[n]; | |
cf481c20 | 653 | rcu_assign_pointer(p->ary[n], ptr); |
5806f07c JM |
654 | |
655 | return old_p; | |
656 | } | |
657 | EXPORT_SYMBOL(idr_replace); | |
658 | ||
199f0ca5 | 659 | void __init idr_init_cache(void) |
1da177e4 | 660 | { |
199f0ca5 | 661 | idr_layer_cache = kmem_cache_create("idr_layer_cache", |
5b019e99 | 662 | sizeof(struct idr_layer), 0, SLAB_PANIC, NULL); |
1da177e4 LT |
663 | } |
664 | ||
665 | /** | |
666 | * idr_init - initialize idr handle | |
667 | * @idp: idr handle | |
668 | * | |
669 | * This function is use to set up the handle (@idp) that you will pass | |
670 | * to the rest of the functions. | |
671 | */ | |
672 | void idr_init(struct idr *idp) | |
673 | { | |
1da177e4 LT |
674 | memset(idp, 0, sizeof(struct idr)); |
675 | spin_lock_init(&idp->lock); | |
676 | } | |
677 | EXPORT_SYMBOL(idr_init); | |
72dba584 TH |
678 | |
679 | ||
56083ab1 RD |
680 | /** |
681 | * DOC: IDA description | |
72dba584 TH |
682 | * IDA - IDR based ID allocator |
683 | * | |
56083ab1 | 684 | * This is id allocator without id -> pointer translation. Memory |
72dba584 TH |
685 | * usage is much lower than full blown idr because each id only |
686 | * occupies a bit. ida uses a custom leaf node which contains | |
687 | * IDA_BITMAP_BITS slots. | |
688 | * | |
689 | * 2007-04-25 written by Tejun Heo <htejun@gmail.com> | |
690 | */ | |
691 | ||
692 | static void free_bitmap(struct ida *ida, struct ida_bitmap *bitmap) | |
693 | { | |
694 | unsigned long flags; | |
695 | ||
696 | if (!ida->free_bitmap) { | |
697 | spin_lock_irqsave(&ida->idr.lock, flags); | |
698 | if (!ida->free_bitmap) { | |
699 | ida->free_bitmap = bitmap; | |
700 | bitmap = NULL; | |
701 | } | |
702 | spin_unlock_irqrestore(&ida->idr.lock, flags); | |
703 | } | |
704 | ||
705 | kfree(bitmap); | |
706 | } | |
707 | ||
708 | /** | |
709 | * ida_pre_get - reserve resources for ida allocation | |
710 | * @ida: ida handle | |
711 | * @gfp_mask: memory allocation flag | |
712 | * | |
713 | * This function should be called prior to locking and calling the | |
714 | * following function. It preallocates enough memory to satisfy the | |
715 | * worst possible allocation. | |
716 | * | |
56083ab1 RD |
717 | * If the system is REALLY out of memory this function returns %0, |
718 | * otherwise %1. | |
72dba584 TH |
719 | */ |
720 | int ida_pre_get(struct ida *ida, gfp_t gfp_mask) | |
721 | { | |
722 | /* allocate idr_layers */ | |
723 | if (!idr_pre_get(&ida->idr, gfp_mask)) | |
724 | return 0; | |
725 | ||
726 | /* allocate free_bitmap */ | |
727 | if (!ida->free_bitmap) { | |
728 | struct ida_bitmap *bitmap; | |
729 | ||
730 | bitmap = kmalloc(sizeof(struct ida_bitmap), gfp_mask); | |
731 | if (!bitmap) | |
732 | return 0; | |
733 | ||
734 | free_bitmap(ida, bitmap); | |
735 | } | |
736 | ||
737 | return 1; | |
738 | } | |
739 | EXPORT_SYMBOL(ida_pre_get); | |
740 | ||
741 | /** | |
742 | * ida_get_new_above - allocate new ID above or equal to a start id | |
743 | * @ida: ida handle | |
ea24ea85 | 744 | * @starting_id: id to start search at |
72dba584 TH |
745 | * @p_id: pointer to the allocated handle |
746 | * | |
e3816c54 WSH |
747 | * Allocate new ID above or equal to @starting_id. It should be called |
748 | * with any required locks. | |
72dba584 | 749 | * |
56083ab1 | 750 | * If memory is required, it will return %-EAGAIN, you should unlock |
72dba584 | 751 | * and go back to the ida_pre_get() call. If the ida is full, it will |
56083ab1 | 752 | * return %-ENOSPC. |
72dba584 | 753 | * |
56083ab1 | 754 | * @p_id returns a value in the range @starting_id ... %0x7fffffff. |
72dba584 TH |
755 | */ |
756 | int ida_get_new_above(struct ida *ida, int starting_id, int *p_id) | |
757 | { | |
125c4c70 | 758 | struct idr_layer *pa[MAX_IDR_LEVEL]; |
72dba584 TH |
759 | struct ida_bitmap *bitmap; |
760 | unsigned long flags; | |
761 | int idr_id = starting_id / IDA_BITMAP_BITS; | |
762 | int offset = starting_id % IDA_BITMAP_BITS; | |
763 | int t, id; | |
764 | ||
765 | restart: | |
766 | /* get vacant slot */ | |
767 | t = idr_get_empty_slot(&ida->idr, idr_id, pa); | |
944ca05c ND |
768 | if (t < 0) |
769 | return _idr_rc_to_errno(t); | |
72dba584 | 770 | |
125c4c70 | 771 | if (t * IDA_BITMAP_BITS >= MAX_IDR_BIT) |
72dba584 TH |
772 | return -ENOSPC; |
773 | ||
774 | if (t != idr_id) | |
775 | offset = 0; | |
776 | idr_id = t; | |
777 | ||
778 | /* if bitmap isn't there, create a new one */ | |
779 | bitmap = (void *)pa[0]->ary[idr_id & IDR_MASK]; | |
780 | if (!bitmap) { | |
781 | spin_lock_irqsave(&ida->idr.lock, flags); | |
782 | bitmap = ida->free_bitmap; | |
783 | ida->free_bitmap = NULL; | |
784 | spin_unlock_irqrestore(&ida->idr.lock, flags); | |
785 | ||
786 | if (!bitmap) | |
787 | return -EAGAIN; | |
788 | ||
789 | memset(bitmap, 0, sizeof(struct ida_bitmap)); | |
3219b3b7 ND |
790 | rcu_assign_pointer(pa[0]->ary[idr_id & IDR_MASK], |
791 | (void *)bitmap); | |
72dba584 TH |
792 | pa[0]->count++; |
793 | } | |
794 | ||
795 | /* lookup for empty slot */ | |
796 | t = find_next_zero_bit(bitmap->bitmap, IDA_BITMAP_BITS, offset); | |
797 | if (t == IDA_BITMAP_BITS) { | |
798 | /* no empty slot after offset, continue to the next chunk */ | |
799 | idr_id++; | |
800 | offset = 0; | |
801 | goto restart; | |
802 | } | |
803 | ||
804 | id = idr_id * IDA_BITMAP_BITS + t; | |
125c4c70 | 805 | if (id >= MAX_IDR_BIT) |
72dba584 TH |
806 | return -ENOSPC; |
807 | ||
808 | __set_bit(t, bitmap->bitmap); | |
809 | if (++bitmap->nr_busy == IDA_BITMAP_BITS) | |
810 | idr_mark_full(pa, idr_id); | |
811 | ||
812 | *p_id = id; | |
813 | ||
814 | /* Each leaf node can handle nearly a thousand slots and the | |
815 | * whole idea of ida is to have small memory foot print. | |
816 | * Throw away extra resources one by one after each successful | |
817 | * allocation. | |
818 | */ | |
819 | if (ida->idr.id_free_cnt || ida->free_bitmap) { | |
4ae53789 | 820 | struct idr_layer *p = get_from_free_list(&ida->idr); |
72dba584 TH |
821 | if (p) |
822 | kmem_cache_free(idr_layer_cache, p); | |
823 | } | |
824 | ||
825 | return 0; | |
826 | } | |
827 | EXPORT_SYMBOL(ida_get_new_above); | |
828 | ||
72dba584 TH |
829 | /** |
830 | * ida_remove - remove the given ID | |
831 | * @ida: ida handle | |
832 | * @id: ID to free | |
833 | */ | |
834 | void ida_remove(struct ida *ida, int id) | |
835 | { | |
836 | struct idr_layer *p = ida->idr.top; | |
837 | int shift = (ida->idr.layers - 1) * IDR_BITS; | |
838 | int idr_id = id / IDA_BITMAP_BITS; | |
839 | int offset = id % IDA_BITMAP_BITS; | |
840 | int n; | |
841 | struct ida_bitmap *bitmap; | |
842 | ||
843 | /* clear full bits while looking up the leaf idr_layer */ | |
844 | while ((shift > 0) && p) { | |
845 | n = (idr_id >> shift) & IDR_MASK; | |
846 | __clear_bit(n, &p->bitmap); | |
847 | p = p->ary[n]; | |
848 | shift -= IDR_BITS; | |
849 | } | |
850 | ||
851 | if (p == NULL) | |
852 | goto err; | |
853 | ||
854 | n = idr_id & IDR_MASK; | |
855 | __clear_bit(n, &p->bitmap); | |
856 | ||
857 | bitmap = (void *)p->ary[n]; | |
858 | if (!test_bit(offset, bitmap->bitmap)) | |
859 | goto err; | |
860 | ||
861 | /* update bitmap and remove it if empty */ | |
862 | __clear_bit(offset, bitmap->bitmap); | |
863 | if (--bitmap->nr_busy == 0) { | |
864 | __set_bit(n, &p->bitmap); /* to please idr_remove() */ | |
865 | idr_remove(&ida->idr, idr_id); | |
866 | free_bitmap(ida, bitmap); | |
867 | } | |
868 | ||
869 | return; | |
870 | ||
871 | err: | |
872 | printk(KERN_WARNING | |
873 | "ida_remove called for id=%d which is not allocated.\n", id); | |
874 | } | |
875 | EXPORT_SYMBOL(ida_remove); | |
876 | ||
877 | /** | |
878 | * ida_destroy - release all cached layers within an ida tree | |
ea24ea85 | 879 | * @ida: ida handle |
72dba584 TH |
880 | */ |
881 | void ida_destroy(struct ida *ida) | |
882 | { | |
883 | idr_destroy(&ida->idr); | |
884 | kfree(ida->free_bitmap); | |
885 | } | |
886 | EXPORT_SYMBOL(ida_destroy); | |
887 | ||
88eca020 RR |
888 | /** |
889 | * ida_simple_get - get a new id. | |
890 | * @ida: the (initialized) ida. | |
891 | * @start: the minimum id (inclusive, < 0x8000000) | |
892 | * @end: the maximum id (exclusive, < 0x8000000 or 0) | |
893 | * @gfp_mask: memory allocation flags | |
894 | * | |
895 | * Allocates an id in the range start <= id < end, or returns -ENOSPC. | |
896 | * On memory allocation failure, returns -ENOMEM. | |
897 | * | |
898 | * Use ida_simple_remove() to get rid of an id. | |
899 | */ | |
900 | int ida_simple_get(struct ida *ida, unsigned int start, unsigned int end, | |
901 | gfp_t gfp_mask) | |
902 | { | |
903 | int ret, id; | |
904 | unsigned int max; | |
46cbc1d3 | 905 | unsigned long flags; |
88eca020 RR |
906 | |
907 | BUG_ON((int)start < 0); | |
908 | BUG_ON((int)end < 0); | |
909 | ||
910 | if (end == 0) | |
911 | max = 0x80000000; | |
912 | else { | |
913 | BUG_ON(end < start); | |
914 | max = end - 1; | |
915 | } | |
916 | ||
917 | again: | |
918 | if (!ida_pre_get(ida, gfp_mask)) | |
919 | return -ENOMEM; | |
920 | ||
46cbc1d3 | 921 | spin_lock_irqsave(&simple_ida_lock, flags); |
88eca020 RR |
922 | ret = ida_get_new_above(ida, start, &id); |
923 | if (!ret) { | |
924 | if (id > max) { | |
925 | ida_remove(ida, id); | |
926 | ret = -ENOSPC; | |
927 | } else { | |
928 | ret = id; | |
929 | } | |
930 | } | |
46cbc1d3 | 931 | spin_unlock_irqrestore(&simple_ida_lock, flags); |
88eca020 RR |
932 | |
933 | if (unlikely(ret == -EAGAIN)) | |
934 | goto again; | |
935 | ||
936 | return ret; | |
937 | } | |
938 | EXPORT_SYMBOL(ida_simple_get); | |
939 | ||
940 | /** | |
941 | * ida_simple_remove - remove an allocated id. | |
942 | * @ida: the (initialized) ida. | |
943 | * @id: the id returned by ida_simple_get. | |
944 | */ | |
945 | void ida_simple_remove(struct ida *ida, unsigned int id) | |
946 | { | |
46cbc1d3 TH |
947 | unsigned long flags; |
948 | ||
88eca020 | 949 | BUG_ON((int)id < 0); |
46cbc1d3 | 950 | spin_lock_irqsave(&simple_ida_lock, flags); |
88eca020 | 951 | ida_remove(ida, id); |
46cbc1d3 | 952 | spin_unlock_irqrestore(&simple_ida_lock, flags); |
88eca020 RR |
953 | } |
954 | EXPORT_SYMBOL(ida_simple_remove); | |
955 | ||
72dba584 TH |
956 | /** |
957 | * ida_init - initialize ida handle | |
958 | * @ida: ida handle | |
959 | * | |
960 | * This function is use to set up the handle (@ida) that you will pass | |
961 | * to the rest of the functions. | |
962 | */ | |
963 | void ida_init(struct ida *ida) | |
964 | { | |
965 | memset(ida, 0, sizeof(struct ida)); | |
966 | idr_init(&ida->idr); | |
967 | ||
968 | } | |
969 | EXPORT_SYMBOL(ida_init); |