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 |
1da177e4 | 23 | * the memory is returned (we keep IDR_FREE_MAX) 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> | |
32 | #include <linux/module.h> | |
33 | #endif | |
5806f07c | 34 | #include <linux/err.h> |
1da177e4 LT |
35 | #include <linux/string.h> |
36 | #include <linux/idr.h> | |
37 | ||
e18b890b | 38 | static struct kmem_cache *idr_layer_cache; |
1da177e4 | 39 | |
4ae53789 | 40 | static struct idr_layer *get_from_free_list(struct idr *idp) |
1da177e4 LT |
41 | { |
42 | struct idr_layer *p; | |
c259cc28 | 43 | unsigned long flags; |
1da177e4 | 44 | |
c259cc28 | 45 | spin_lock_irqsave(&idp->lock, flags); |
1da177e4 LT |
46 | if ((p = idp->id_free)) { |
47 | idp->id_free = p->ary[0]; | |
48 | idp->id_free_cnt--; | |
49 | p->ary[0] = NULL; | |
50 | } | |
c259cc28 | 51 | spin_unlock_irqrestore(&idp->lock, flags); |
1da177e4 LT |
52 | return(p); |
53 | } | |
54 | ||
1eec0056 | 55 | /* only called when idp->lock is held */ |
4ae53789 | 56 | static void __move_to_free_list(struct idr *idp, struct idr_layer *p) |
1eec0056 SR |
57 | { |
58 | p->ary[0] = idp->id_free; | |
59 | idp->id_free = p; | |
60 | idp->id_free_cnt++; | |
61 | } | |
62 | ||
4ae53789 | 63 | static void move_to_free_list(struct idr *idp, struct idr_layer *p) |
1da177e4 | 64 | { |
c259cc28 RD |
65 | unsigned long flags; |
66 | ||
1da177e4 LT |
67 | /* |
68 | * Depends on the return element being zeroed. | |
69 | */ | |
c259cc28 | 70 | spin_lock_irqsave(&idp->lock, flags); |
4ae53789 | 71 | __move_to_free_list(idp, p); |
c259cc28 | 72 | spin_unlock_irqrestore(&idp->lock, flags); |
1da177e4 LT |
73 | } |
74 | ||
e33ac8bd TH |
75 | static void idr_mark_full(struct idr_layer **pa, int id) |
76 | { | |
77 | struct idr_layer *p = pa[0]; | |
78 | int l = 0; | |
79 | ||
80 | __set_bit(id & IDR_MASK, &p->bitmap); | |
81 | /* | |
82 | * If this layer is full mark the bit in the layer above to | |
83 | * show that this part of the radix tree is full. This may | |
84 | * complete the layer above and require walking up the radix | |
85 | * tree. | |
86 | */ | |
87 | while (p->bitmap == IDR_FULL) { | |
88 | if (!(p = pa[++l])) | |
89 | break; | |
90 | id = id >> IDR_BITS; | |
91 | __set_bit((id & IDR_MASK), &p->bitmap); | |
92 | } | |
93 | } | |
94 | ||
1da177e4 LT |
95 | /** |
96 | * idr_pre_get - reserver resources for idr allocation | |
97 | * @idp: idr handle | |
98 | * @gfp_mask: memory allocation flags | |
99 | * | |
100 | * This function should be called prior to locking and calling the | |
3219b3b7 | 101 | * idr_get_new* functions. It preallocates enough memory to satisfy |
1da177e4 LT |
102 | * the worst possible allocation. |
103 | * | |
104 | * If the system is REALLY out of memory this function returns 0, | |
105 | * otherwise 1. | |
106 | */ | |
fd4f2df2 | 107 | int idr_pre_get(struct idr *idp, gfp_t gfp_mask) |
1da177e4 LT |
108 | { |
109 | while (idp->id_free_cnt < IDR_FREE_MAX) { | |
110 | struct idr_layer *new; | |
111 | new = kmem_cache_alloc(idr_layer_cache, gfp_mask); | |
e15ae2dd | 112 | if (new == NULL) |
1da177e4 | 113 | return (0); |
4ae53789 | 114 | move_to_free_list(idp, new); |
1da177e4 LT |
115 | } |
116 | return 1; | |
117 | } | |
118 | EXPORT_SYMBOL(idr_pre_get); | |
119 | ||
e33ac8bd | 120 | static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa) |
1da177e4 LT |
121 | { |
122 | int n, m, sh; | |
123 | struct idr_layer *p, *new; | |
7aae6dd8 | 124 | int l, id, oid; |
5ba25331 | 125 | unsigned long bm; |
1da177e4 LT |
126 | |
127 | id = *starting_id; | |
7aae6dd8 | 128 | restart: |
1da177e4 LT |
129 | p = idp->top; |
130 | l = idp->layers; | |
131 | pa[l--] = NULL; | |
132 | while (1) { | |
133 | /* | |
134 | * We run around this while until we reach the leaf node... | |
135 | */ | |
136 | n = (id >> (IDR_BITS*l)) & IDR_MASK; | |
137 | bm = ~p->bitmap; | |
138 | m = find_next_bit(&bm, IDR_SIZE, n); | |
139 | if (m == IDR_SIZE) { | |
140 | /* no space available go back to previous layer. */ | |
141 | l++; | |
7aae6dd8 | 142 | oid = id; |
e15ae2dd | 143 | id = (id | ((1 << (IDR_BITS * l)) - 1)) + 1; |
7aae6dd8 TH |
144 | |
145 | /* if already at the top layer, we need to grow */ | |
1da177e4 LT |
146 | if (!(p = pa[l])) { |
147 | *starting_id = id; | |
944ca05c | 148 | return IDR_NEED_TO_GROW; |
1da177e4 | 149 | } |
7aae6dd8 TH |
150 | |
151 | /* If we need to go up one layer, continue the | |
152 | * loop; otherwise, restart from the top. | |
153 | */ | |
154 | sh = IDR_BITS * (l + 1); | |
155 | if (oid >> sh == id >> sh) | |
156 | continue; | |
157 | else | |
158 | goto restart; | |
1da177e4 LT |
159 | } |
160 | if (m != n) { | |
161 | sh = IDR_BITS*l; | |
162 | id = ((id >> sh) ^ n ^ m) << sh; | |
163 | } | |
164 | if ((id >= MAX_ID_BIT) || (id < 0)) | |
944ca05c | 165 | return IDR_NOMORE_SPACE; |
1da177e4 LT |
166 | if (l == 0) |
167 | break; | |
168 | /* | |
169 | * Create the layer below if it is missing. | |
170 | */ | |
171 | if (!p->ary[m]) { | |
4ae53789 ND |
172 | new = get_from_free_list(idp); |
173 | if (!new) | |
1da177e4 | 174 | return -1; |
3219b3b7 | 175 | rcu_assign_pointer(p->ary[m], new); |
1da177e4 LT |
176 | p->count++; |
177 | } | |
178 | pa[l--] = p; | |
179 | p = p->ary[m]; | |
180 | } | |
e33ac8bd TH |
181 | |
182 | pa[l] = p; | |
183 | return id; | |
1da177e4 LT |
184 | } |
185 | ||
e33ac8bd TH |
186 | static int idr_get_empty_slot(struct idr *idp, int starting_id, |
187 | struct idr_layer **pa) | |
1da177e4 LT |
188 | { |
189 | struct idr_layer *p, *new; | |
190 | int layers, v, id; | |
c259cc28 | 191 | unsigned long flags; |
e15ae2dd | 192 | |
1da177e4 LT |
193 | id = starting_id; |
194 | build_up: | |
195 | p = idp->top; | |
196 | layers = idp->layers; | |
197 | if (unlikely(!p)) { | |
4ae53789 | 198 | if (!(p = get_from_free_list(idp))) |
1da177e4 LT |
199 | return -1; |
200 | layers = 1; | |
201 | } | |
202 | /* | |
203 | * Add a new layer to the top of the tree if the requested | |
204 | * id is larger than the currently allocated space. | |
205 | */ | |
589777ea | 206 | while ((layers < (MAX_LEVEL - 1)) && (id >= (1 << (layers*IDR_BITS)))) { |
1da177e4 LT |
207 | layers++; |
208 | if (!p->count) | |
209 | continue; | |
4ae53789 | 210 | if (!(new = get_from_free_list(idp))) { |
1da177e4 LT |
211 | /* |
212 | * The allocation failed. If we built part of | |
213 | * the structure tear it down. | |
214 | */ | |
c259cc28 | 215 | spin_lock_irqsave(&idp->lock, flags); |
1da177e4 LT |
216 | for (new = p; p && p != idp->top; new = p) { |
217 | p = p->ary[0]; | |
218 | new->ary[0] = NULL; | |
219 | new->bitmap = new->count = 0; | |
4ae53789 | 220 | __move_to_free_list(idp, new); |
1da177e4 | 221 | } |
c259cc28 | 222 | spin_unlock_irqrestore(&idp->lock, flags); |
1da177e4 LT |
223 | return -1; |
224 | } | |
225 | new->ary[0] = p; | |
226 | new->count = 1; | |
227 | if (p->bitmap == IDR_FULL) | |
228 | __set_bit(0, &new->bitmap); | |
229 | p = new; | |
230 | } | |
3219b3b7 | 231 | rcu_assign_pointer(idp->top, p); |
1da177e4 | 232 | idp->layers = layers; |
e33ac8bd | 233 | v = sub_alloc(idp, &id, pa); |
944ca05c | 234 | if (v == IDR_NEED_TO_GROW) |
1da177e4 LT |
235 | goto build_up; |
236 | return(v); | |
237 | } | |
238 | ||
e33ac8bd TH |
239 | static int idr_get_new_above_int(struct idr *idp, void *ptr, int starting_id) |
240 | { | |
241 | struct idr_layer *pa[MAX_LEVEL]; | |
242 | int id; | |
243 | ||
244 | id = idr_get_empty_slot(idp, starting_id, pa); | |
245 | if (id >= 0) { | |
246 | /* | |
247 | * Successfully found an empty slot. Install the user | |
248 | * pointer and mark the slot full. | |
249 | */ | |
3219b3b7 ND |
250 | rcu_assign_pointer(pa[0]->ary[id & IDR_MASK], |
251 | (struct idr_layer *)ptr); | |
e33ac8bd TH |
252 | pa[0]->count++; |
253 | idr_mark_full(pa, id); | |
254 | } | |
255 | ||
256 | return id; | |
257 | } | |
258 | ||
1da177e4 | 259 | /** |
7c657f2f | 260 | * idr_get_new_above - allocate new idr entry above or equal to a start id |
1da177e4 LT |
261 | * @idp: idr handle |
262 | * @ptr: pointer you want associated with the ide | |
263 | * @start_id: id to start search at | |
264 | * @id: pointer to the allocated handle | |
265 | * | |
266 | * This is the allocate id function. It should be called with any | |
267 | * required locks. | |
268 | * | |
269 | * If memory is required, it will return -EAGAIN, you should unlock | |
270 | * and go back to the idr_pre_get() call. If the idr is full, it will | |
271 | * return -ENOSPC. | |
272 | * | |
273 | * @id returns a value in the range 0 ... 0x7fffffff | |
274 | */ | |
275 | int idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id) | |
276 | { | |
277 | int rv; | |
e15ae2dd | 278 | |
1da177e4 LT |
279 | rv = idr_get_new_above_int(idp, ptr, starting_id); |
280 | /* | |
281 | * This is a cheap hack until the IDR code can be fixed to | |
282 | * return proper error values. | |
283 | */ | |
944ca05c ND |
284 | if (rv < 0) |
285 | return _idr_rc_to_errno(rv); | |
1da177e4 LT |
286 | *id = rv; |
287 | return 0; | |
288 | } | |
289 | EXPORT_SYMBOL(idr_get_new_above); | |
290 | ||
291 | /** | |
292 | * idr_get_new - allocate new idr entry | |
293 | * @idp: idr handle | |
294 | * @ptr: pointer you want associated with the ide | |
295 | * @id: pointer to the allocated handle | |
296 | * | |
297 | * This is the allocate id function. It should be called with any | |
298 | * required locks. | |
299 | * | |
300 | * If memory is required, it will return -EAGAIN, you should unlock | |
301 | * and go back to the idr_pre_get() call. If the idr is full, it will | |
302 | * return -ENOSPC. | |
303 | * | |
304 | * @id returns a value in the range 0 ... 0x7fffffff | |
305 | */ | |
306 | int idr_get_new(struct idr *idp, void *ptr, int *id) | |
307 | { | |
308 | int rv; | |
e15ae2dd | 309 | |
1da177e4 LT |
310 | rv = idr_get_new_above_int(idp, ptr, 0); |
311 | /* | |
312 | * This is a cheap hack until the IDR code can be fixed to | |
313 | * return proper error values. | |
314 | */ | |
944ca05c ND |
315 | if (rv < 0) |
316 | return _idr_rc_to_errno(rv); | |
1da177e4 LT |
317 | *id = rv; |
318 | return 0; | |
319 | } | |
320 | EXPORT_SYMBOL(idr_get_new); | |
321 | ||
322 | static void idr_remove_warning(int id) | |
323 | { | |
f098ad65 ND |
324 | printk(KERN_WARNING |
325 | "idr_remove called for id=%d which is not allocated.\n", id); | |
1da177e4 LT |
326 | dump_stack(); |
327 | } | |
328 | ||
329 | static void sub_remove(struct idr *idp, int shift, int id) | |
330 | { | |
331 | struct idr_layer *p = idp->top; | |
332 | struct idr_layer **pa[MAX_LEVEL]; | |
333 | struct idr_layer ***paa = &pa[0]; | |
334 | int n; | |
335 | ||
336 | *paa = NULL; | |
337 | *++paa = &idp->top; | |
338 | ||
339 | while ((shift > 0) && p) { | |
340 | n = (id >> shift) & IDR_MASK; | |
341 | __clear_bit(n, &p->bitmap); | |
342 | *++paa = &p->ary[n]; | |
343 | p = p->ary[n]; | |
344 | shift -= IDR_BITS; | |
345 | } | |
346 | n = id & IDR_MASK; | |
347 | if (likely(p != NULL && test_bit(n, &p->bitmap))){ | |
348 | __clear_bit(n, &p->bitmap); | |
349 | p->ary[n] = NULL; | |
350 | while(*paa && ! --((**paa)->count)){ | |
4ae53789 | 351 | move_to_free_list(idp, **paa); |
1da177e4 LT |
352 | **paa-- = NULL; |
353 | } | |
e15ae2dd | 354 | if (!*paa) |
1da177e4 | 355 | idp->layers = 0; |
e15ae2dd | 356 | } else |
1da177e4 | 357 | idr_remove_warning(id); |
1da177e4 LT |
358 | } |
359 | ||
360 | /** | |
361 | * idr_remove - remove the given id and free it's slot | |
72fd4a35 RD |
362 | * @idp: idr handle |
363 | * @id: unique key | |
1da177e4 LT |
364 | */ |
365 | void idr_remove(struct idr *idp, int id) | |
366 | { | |
367 | struct idr_layer *p; | |
368 | ||
369 | /* Mask off upper bits we don't use for the search. */ | |
370 | id &= MAX_ID_MASK; | |
371 | ||
372 | sub_remove(idp, (idp->layers - 1) * IDR_BITS, id); | |
e15ae2dd JJ |
373 | if (idp->top && idp->top->count == 1 && (idp->layers > 1) && |
374 | idp->top->ary[0]) { // We can drop a layer | |
1da177e4 LT |
375 | |
376 | p = idp->top->ary[0]; | |
377 | idp->top->bitmap = idp->top->count = 0; | |
4ae53789 | 378 | move_to_free_list(idp, idp->top); |
1da177e4 LT |
379 | idp->top = p; |
380 | --idp->layers; | |
381 | } | |
382 | while (idp->id_free_cnt >= IDR_FREE_MAX) { | |
4ae53789 | 383 | p = get_from_free_list(idp); |
1da177e4 | 384 | kmem_cache_free(idr_layer_cache, p); |
1da177e4 | 385 | } |
af8e2a4c | 386 | return; |
1da177e4 LT |
387 | } |
388 | EXPORT_SYMBOL(idr_remove); | |
389 | ||
23936cc0 KH |
390 | /** |
391 | * idr_remove_all - remove all ids from the given idr tree | |
392 | * @idp: idr handle | |
393 | * | |
394 | * idr_destroy() only frees up unused, cached idp_layers, but this | |
395 | * function will remove all id mappings and leave all idp_layers | |
396 | * unused. | |
397 | * | |
398 | * A typical clean-up sequence for objects stored in an idr tree, will | |
399 | * use idr_for_each() to free all objects, if necessay, then | |
400 | * idr_remove_all() to remove all ids, and idr_destroy() to free | |
401 | * up the cached idr_layers. | |
402 | */ | |
403 | void idr_remove_all(struct idr *idp) | |
404 | { | |
6ace06dc | 405 | int n, id, max; |
23936cc0 KH |
406 | struct idr_layer *p; |
407 | struct idr_layer *pa[MAX_LEVEL]; | |
408 | struct idr_layer **paa = &pa[0]; | |
409 | ||
410 | n = idp->layers * IDR_BITS; | |
411 | p = idp->top; | |
412 | max = 1 << n; | |
413 | ||
414 | id = 0; | |
6ace06dc | 415 | while (id < max) { |
23936cc0 KH |
416 | while (n > IDR_BITS && p) { |
417 | n -= IDR_BITS; | |
418 | *paa++ = p; | |
419 | p = p->ary[(id >> n) & IDR_MASK]; | |
420 | } | |
421 | ||
422 | id += 1 << n; | |
423 | while (n < fls(id)) { | |
424 | if (p) { | |
425 | memset(p, 0, sizeof *p); | |
4ae53789 | 426 | move_to_free_list(idp, p); |
23936cc0 KH |
427 | } |
428 | n += IDR_BITS; | |
429 | p = *--paa; | |
430 | } | |
431 | } | |
432 | idp->top = NULL; | |
433 | idp->layers = 0; | |
434 | } | |
435 | EXPORT_SYMBOL(idr_remove_all); | |
436 | ||
8d3b3591 AM |
437 | /** |
438 | * idr_destroy - release all cached layers within an idr tree | |
439 | * idp: idr handle | |
440 | */ | |
441 | void idr_destroy(struct idr *idp) | |
442 | { | |
443 | while (idp->id_free_cnt) { | |
4ae53789 | 444 | struct idr_layer *p = get_from_free_list(idp); |
8d3b3591 AM |
445 | kmem_cache_free(idr_layer_cache, p); |
446 | } | |
447 | } | |
448 | EXPORT_SYMBOL(idr_destroy); | |
449 | ||
1da177e4 LT |
450 | /** |
451 | * idr_find - return pointer for given id | |
452 | * @idp: idr handle | |
453 | * @id: lookup key | |
454 | * | |
455 | * Return the pointer given the id it has been registered with. A %NULL | |
456 | * return indicates that @id is not valid or you passed %NULL in | |
457 | * idr_get_new(). | |
458 | * | |
459 | * The caller must serialize idr_find() vs idr_get_new() and idr_remove(). | |
460 | */ | |
461 | void *idr_find(struct idr *idp, int id) | |
462 | { | |
463 | int n; | |
464 | struct idr_layer *p; | |
465 | ||
466 | n = idp->layers * IDR_BITS; | |
467 | p = idp->top; | |
468 | ||
469 | /* Mask off upper bits we don't use for the search. */ | |
470 | id &= MAX_ID_MASK; | |
471 | ||
472 | if (id >= (1 << n)) | |
473 | return NULL; | |
474 | ||
475 | while (n > 0 && p) { | |
476 | n -= IDR_BITS; | |
477 | p = p->ary[(id >> n) & IDR_MASK]; | |
478 | } | |
479 | return((void *)p); | |
480 | } | |
481 | EXPORT_SYMBOL(idr_find); | |
482 | ||
96d7fa42 KH |
483 | /** |
484 | * idr_for_each - iterate through all stored pointers | |
485 | * @idp: idr handle | |
486 | * @fn: function to be called for each pointer | |
487 | * @data: data passed back to callback function | |
488 | * | |
489 | * Iterate over the pointers registered with the given idr. The | |
490 | * callback function will be called for each pointer currently | |
491 | * registered, passing the id, the pointer and the data pointer passed | |
492 | * to this function. It is not safe to modify the idr tree while in | |
493 | * the callback, so functions such as idr_get_new and idr_remove are | |
494 | * not allowed. | |
495 | * | |
496 | * We check the return of @fn each time. If it returns anything other | |
497 | * than 0, we break out and return that value. | |
498 | * | |
499 | * The caller must serialize idr_for_each() vs idr_get_new() and idr_remove(). | |
500 | */ | |
501 | int idr_for_each(struct idr *idp, | |
502 | int (*fn)(int id, void *p, void *data), void *data) | |
503 | { | |
504 | int n, id, max, error = 0; | |
505 | struct idr_layer *p; | |
506 | struct idr_layer *pa[MAX_LEVEL]; | |
507 | struct idr_layer **paa = &pa[0]; | |
508 | ||
509 | n = idp->layers * IDR_BITS; | |
510 | p = idp->top; | |
511 | max = 1 << n; | |
512 | ||
513 | id = 0; | |
514 | while (id < max) { | |
515 | while (n > 0 && p) { | |
516 | n -= IDR_BITS; | |
517 | *paa++ = p; | |
518 | p = p->ary[(id >> n) & IDR_MASK]; | |
519 | } | |
520 | ||
521 | if (p) { | |
522 | error = fn(id, (void *)p, data); | |
523 | if (error) | |
524 | break; | |
525 | } | |
526 | ||
527 | id += 1 << n; | |
528 | while (n < fls(id)) { | |
529 | n += IDR_BITS; | |
530 | p = *--paa; | |
531 | } | |
532 | } | |
533 | ||
534 | return error; | |
535 | } | |
536 | EXPORT_SYMBOL(idr_for_each); | |
537 | ||
5806f07c JM |
538 | /** |
539 | * idr_replace - replace pointer for given id | |
540 | * @idp: idr handle | |
541 | * @ptr: pointer you want associated with the id | |
542 | * @id: lookup key | |
543 | * | |
544 | * Replace the pointer registered with an id and return the old value. | |
545 | * A -ENOENT return indicates that @id was not found. | |
546 | * A -EINVAL return indicates that @id was not within valid constraints. | |
547 | * | |
548 | * The caller must serialize vs idr_find(), idr_get_new(), and idr_remove(). | |
549 | */ | |
550 | void *idr_replace(struct idr *idp, void *ptr, int id) | |
551 | { | |
552 | int n; | |
553 | struct idr_layer *p, *old_p; | |
554 | ||
555 | n = idp->layers * IDR_BITS; | |
556 | p = idp->top; | |
557 | ||
558 | id &= MAX_ID_MASK; | |
559 | ||
560 | if (id >= (1 << n)) | |
561 | return ERR_PTR(-EINVAL); | |
562 | ||
563 | n -= IDR_BITS; | |
564 | while ((n > 0) && p) { | |
565 | p = p->ary[(id >> n) & IDR_MASK]; | |
566 | n -= IDR_BITS; | |
567 | } | |
568 | ||
569 | n = id & IDR_MASK; | |
570 | if (unlikely(p == NULL || !test_bit(n, &p->bitmap))) | |
571 | return ERR_PTR(-ENOENT); | |
572 | ||
573 | old_p = p->ary[n]; | |
574 | p->ary[n] = ptr; | |
575 | ||
576 | return old_p; | |
577 | } | |
578 | EXPORT_SYMBOL(idr_replace); | |
579 | ||
4ba9b9d0 | 580 | static void idr_cache_ctor(struct kmem_cache *idr_layer_cache, void *idr_layer) |
1da177e4 LT |
581 | { |
582 | memset(idr_layer, 0, sizeof(struct idr_layer)); | |
583 | } | |
584 | ||
199f0ca5 | 585 | void __init idr_init_cache(void) |
1da177e4 | 586 | { |
199f0ca5 AM |
587 | idr_layer_cache = kmem_cache_create("idr_layer_cache", |
588 | sizeof(struct idr_layer), 0, SLAB_PANIC, | |
589 | idr_cache_ctor); | |
1da177e4 LT |
590 | } |
591 | ||
592 | /** | |
593 | * idr_init - initialize idr handle | |
594 | * @idp: idr handle | |
595 | * | |
596 | * This function is use to set up the handle (@idp) that you will pass | |
597 | * to the rest of the functions. | |
598 | */ | |
599 | void idr_init(struct idr *idp) | |
600 | { | |
1da177e4 LT |
601 | memset(idp, 0, sizeof(struct idr)); |
602 | spin_lock_init(&idp->lock); | |
603 | } | |
604 | EXPORT_SYMBOL(idr_init); | |
72dba584 TH |
605 | |
606 | ||
607 | /* | |
608 | * IDA - IDR based ID allocator | |
609 | * | |
610 | * this is id allocator without id -> pointer translation. Memory | |
611 | * usage is much lower than full blown idr because each id only | |
612 | * occupies a bit. ida uses a custom leaf node which contains | |
613 | * IDA_BITMAP_BITS slots. | |
614 | * | |
615 | * 2007-04-25 written by Tejun Heo <htejun@gmail.com> | |
616 | */ | |
617 | ||
618 | static void free_bitmap(struct ida *ida, struct ida_bitmap *bitmap) | |
619 | { | |
620 | unsigned long flags; | |
621 | ||
622 | if (!ida->free_bitmap) { | |
623 | spin_lock_irqsave(&ida->idr.lock, flags); | |
624 | if (!ida->free_bitmap) { | |
625 | ida->free_bitmap = bitmap; | |
626 | bitmap = NULL; | |
627 | } | |
628 | spin_unlock_irqrestore(&ida->idr.lock, flags); | |
629 | } | |
630 | ||
631 | kfree(bitmap); | |
632 | } | |
633 | ||
634 | /** | |
635 | * ida_pre_get - reserve resources for ida allocation | |
636 | * @ida: ida handle | |
637 | * @gfp_mask: memory allocation flag | |
638 | * | |
639 | * This function should be called prior to locking and calling the | |
640 | * following function. It preallocates enough memory to satisfy the | |
641 | * worst possible allocation. | |
642 | * | |
643 | * If the system is REALLY out of memory this function returns 0, | |
644 | * otherwise 1. | |
645 | */ | |
646 | int ida_pre_get(struct ida *ida, gfp_t gfp_mask) | |
647 | { | |
648 | /* allocate idr_layers */ | |
649 | if (!idr_pre_get(&ida->idr, gfp_mask)) | |
650 | return 0; | |
651 | ||
652 | /* allocate free_bitmap */ | |
653 | if (!ida->free_bitmap) { | |
654 | struct ida_bitmap *bitmap; | |
655 | ||
656 | bitmap = kmalloc(sizeof(struct ida_bitmap), gfp_mask); | |
657 | if (!bitmap) | |
658 | return 0; | |
659 | ||
660 | free_bitmap(ida, bitmap); | |
661 | } | |
662 | ||
663 | return 1; | |
664 | } | |
665 | EXPORT_SYMBOL(ida_pre_get); | |
666 | ||
667 | /** | |
668 | * ida_get_new_above - allocate new ID above or equal to a start id | |
669 | * @ida: ida handle | |
670 | * @staring_id: id to start search at | |
671 | * @p_id: pointer to the allocated handle | |
672 | * | |
673 | * Allocate new ID above or equal to @ida. It should be called with | |
674 | * any required locks. | |
675 | * | |
676 | * If memory is required, it will return -EAGAIN, you should unlock | |
677 | * and go back to the ida_pre_get() call. If the ida is full, it will | |
678 | * return -ENOSPC. | |
679 | * | |
680 | * @p_id returns a value in the range 0 ... 0x7fffffff. | |
681 | */ | |
682 | int ida_get_new_above(struct ida *ida, int starting_id, int *p_id) | |
683 | { | |
684 | struct idr_layer *pa[MAX_LEVEL]; | |
685 | struct ida_bitmap *bitmap; | |
686 | unsigned long flags; | |
687 | int idr_id = starting_id / IDA_BITMAP_BITS; | |
688 | int offset = starting_id % IDA_BITMAP_BITS; | |
689 | int t, id; | |
690 | ||
691 | restart: | |
692 | /* get vacant slot */ | |
693 | t = idr_get_empty_slot(&ida->idr, idr_id, pa); | |
944ca05c ND |
694 | if (t < 0) |
695 | return _idr_rc_to_errno(t); | |
72dba584 TH |
696 | |
697 | if (t * IDA_BITMAP_BITS >= MAX_ID_BIT) | |
698 | return -ENOSPC; | |
699 | ||
700 | if (t != idr_id) | |
701 | offset = 0; | |
702 | idr_id = t; | |
703 | ||
704 | /* if bitmap isn't there, create a new one */ | |
705 | bitmap = (void *)pa[0]->ary[idr_id & IDR_MASK]; | |
706 | if (!bitmap) { | |
707 | spin_lock_irqsave(&ida->idr.lock, flags); | |
708 | bitmap = ida->free_bitmap; | |
709 | ida->free_bitmap = NULL; | |
710 | spin_unlock_irqrestore(&ida->idr.lock, flags); | |
711 | ||
712 | if (!bitmap) | |
713 | return -EAGAIN; | |
714 | ||
715 | memset(bitmap, 0, sizeof(struct ida_bitmap)); | |
3219b3b7 ND |
716 | rcu_assign_pointer(pa[0]->ary[idr_id & IDR_MASK], |
717 | (void *)bitmap); | |
72dba584 TH |
718 | pa[0]->count++; |
719 | } | |
720 | ||
721 | /* lookup for empty slot */ | |
722 | t = find_next_zero_bit(bitmap->bitmap, IDA_BITMAP_BITS, offset); | |
723 | if (t == IDA_BITMAP_BITS) { | |
724 | /* no empty slot after offset, continue to the next chunk */ | |
725 | idr_id++; | |
726 | offset = 0; | |
727 | goto restart; | |
728 | } | |
729 | ||
730 | id = idr_id * IDA_BITMAP_BITS + t; | |
731 | if (id >= MAX_ID_BIT) | |
732 | return -ENOSPC; | |
733 | ||
734 | __set_bit(t, bitmap->bitmap); | |
735 | if (++bitmap->nr_busy == IDA_BITMAP_BITS) | |
736 | idr_mark_full(pa, idr_id); | |
737 | ||
738 | *p_id = id; | |
739 | ||
740 | /* Each leaf node can handle nearly a thousand slots and the | |
741 | * whole idea of ida is to have small memory foot print. | |
742 | * Throw away extra resources one by one after each successful | |
743 | * allocation. | |
744 | */ | |
745 | if (ida->idr.id_free_cnt || ida->free_bitmap) { | |
4ae53789 | 746 | struct idr_layer *p = get_from_free_list(&ida->idr); |
72dba584 TH |
747 | if (p) |
748 | kmem_cache_free(idr_layer_cache, p); | |
749 | } | |
750 | ||
751 | return 0; | |
752 | } | |
753 | EXPORT_SYMBOL(ida_get_new_above); | |
754 | ||
755 | /** | |
756 | * ida_get_new - allocate new ID | |
757 | * @ida: idr handle | |
758 | * @p_id: pointer to the allocated handle | |
759 | * | |
760 | * Allocate new ID. It should be called with any required locks. | |
761 | * | |
762 | * If memory is required, it will return -EAGAIN, you should unlock | |
763 | * and go back to the idr_pre_get() call. If the idr is full, it will | |
764 | * return -ENOSPC. | |
765 | * | |
766 | * @id returns a value in the range 0 ... 0x7fffffff. | |
767 | */ | |
768 | int ida_get_new(struct ida *ida, int *p_id) | |
769 | { | |
770 | return ida_get_new_above(ida, 0, p_id); | |
771 | } | |
772 | EXPORT_SYMBOL(ida_get_new); | |
773 | ||
774 | /** | |
775 | * ida_remove - remove the given ID | |
776 | * @ida: ida handle | |
777 | * @id: ID to free | |
778 | */ | |
779 | void ida_remove(struct ida *ida, int id) | |
780 | { | |
781 | struct idr_layer *p = ida->idr.top; | |
782 | int shift = (ida->idr.layers - 1) * IDR_BITS; | |
783 | int idr_id = id / IDA_BITMAP_BITS; | |
784 | int offset = id % IDA_BITMAP_BITS; | |
785 | int n; | |
786 | struct ida_bitmap *bitmap; | |
787 | ||
788 | /* clear full bits while looking up the leaf idr_layer */ | |
789 | while ((shift > 0) && p) { | |
790 | n = (idr_id >> shift) & IDR_MASK; | |
791 | __clear_bit(n, &p->bitmap); | |
792 | p = p->ary[n]; | |
793 | shift -= IDR_BITS; | |
794 | } | |
795 | ||
796 | if (p == NULL) | |
797 | goto err; | |
798 | ||
799 | n = idr_id & IDR_MASK; | |
800 | __clear_bit(n, &p->bitmap); | |
801 | ||
802 | bitmap = (void *)p->ary[n]; | |
803 | if (!test_bit(offset, bitmap->bitmap)) | |
804 | goto err; | |
805 | ||
806 | /* update bitmap and remove it if empty */ | |
807 | __clear_bit(offset, bitmap->bitmap); | |
808 | if (--bitmap->nr_busy == 0) { | |
809 | __set_bit(n, &p->bitmap); /* to please idr_remove() */ | |
810 | idr_remove(&ida->idr, idr_id); | |
811 | free_bitmap(ida, bitmap); | |
812 | } | |
813 | ||
814 | return; | |
815 | ||
816 | err: | |
817 | printk(KERN_WARNING | |
818 | "ida_remove called for id=%d which is not allocated.\n", id); | |
819 | } | |
820 | EXPORT_SYMBOL(ida_remove); | |
821 | ||
822 | /** | |
823 | * ida_destroy - release all cached layers within an ida tree | |
824 | * ida: ida handle | |
825 | */ | |
826 | void ida_destroy(struct ida *ida) | |
827 | { | |
828 | idr_destroy(&ida->idr); | |
829 | kfree(ida->free_bitmap); | |
830 | } | |
831 | EXPORT_SYMBOL(ida_destroy); | |
832 | ||
833 | /** | |
834 | * ida_init - initialize ida handle | |
835 | * @ida: ida handle | |
836 | * | |
837 | * This function is use to set up the handle (@ida) that you will pass | |
838 | * to the rest of the functions. | |
839 | */ | |
840 | void ida_init(struct ida *ida) | |
841 | { | |
842 | memset(ida, 0, sizeof(struct ida)); | |
843 | idr_init(&ida->idr); | |
844 | ||
845 | } | |
846 | EXPORT_SYMBOL(ida_init); |