Rev 5056 | Rev 6934 | Go to most recent revision | Details | Compare with Previous | Last modification | View Log | RSS feed
Rev | Author | Line No. | Line |
---|---|---|---|
1412 | serge | 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 | * |
||
9 | * Modified by Nadia Derbey to make it RCU safe. |
||
10 | * |
||
11 | * Small id to pointer translation service. |
||
12 | * |
||
13 | * It uses a radix tree like structure as a sparse array indexed |
||
14 | * by the id to obtain the pointer. The bitmap makes allocating |
||
15 | * a new id quick. |
||
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 | */ |
||
22 | |||
5270 | serge | 23 | #ifndef TEST // to test in user space... |
24 | #include |
||
3391 | Serge | 25 | #include |
5270 | serge | 26 | #endif |
27 | #include |
||
1412 | serge | 28 | #include |
29 | #include |
||
5270 | serge | 30 | #include |
1412 | serge | 31 | |
4103 | Serge | 32 | |
1412 | serge | 33 | |
34 | |||
3391 | Serge | 35 | #define MAX_IDR_SHIFT (sizeof(int) * 8 - 1) |
36 | #define MAX_IDR_BIT (1U << MAX_IDR_SHIFT) |
||
1412 | serge | 37 | |
3391 | Serge | 38 | /* Leave the possibility of an incomplete final layer */ |
39 | #define MAX_IDR_LEVEL ((MAX_IDR_SHIFT + IDR_BITS - 1) / IDR_BITS) |
||
1412 | serge | 40 | |
3391 | Serge | 41 | /* Number of id_layer structs to leave in free list */ |
42 | #define MAX_IDR_FREE (MAX_IDR_LEVEL * 2) |
||
1412 | serge | 43 | |
3391 | Serge | 44 | static struct idr_layer *idr_preload_head; |
45 | static int idr_preload_cnt; |
||
1412 | serge | 46 | |
4103 | Serge | 47 | static DEFINE_SPINLOCK(simple_ida_lock); |
1412 | serge | 48 | |
3391 | Serge | 49 | /* the maximum ID which can be allocated given idr->layers */ |
50 | static int idr_max(int layers) |
||
51 | { |
||
52 | int bits = min_t(int, layers * IDR_BITS, MAX_IDR_SHIFT); |
||
1412 | serge | 53 | |
3391 | Serge | 54 | return (1 << bits) - 1; |
55 | } |
||
1412 | serge | 56 | |
3391 | Serge | 57 | /* |
58 | * Prefix mask for an idr_layer at @layer. For layer 0, the prefix mask is |
||
59 | * all bits except for the lower IDR_BITS. For layer 1, 2 * IDR_BITS, and |
||
60 | * so on. |
||
61 | */ |
||
62 | static int idr_layer_prefix_mask(int layer) |
||
63 | { |
||
64 | return ~idr_max(layer + 1); |
||
65 | } |
||
1412 | serge | 66 | |
67 | static struct idr_layer *get_from_free_list(struct idr *idp) |
||
68 | { |
||
69 | struct idr_layer *p; |
||
70 | unsigned long flags; |
||
71 | |||
3391 | Serge | 72 | spin_lock_irqsave(&idp->lock, flags); |
1412 | serge | 73 | if ((p = idp->id_free)) { |
74 | idp->id_free = p->ary[0]; |
||
75 | idp->id_free_cnt--; |
||
76 | p->ary[0] = NULL; |
||
77 | } |
||
3391 | Serge | 78 | spin_unlock_irqrestore(&idp->lock, flags); |
1412 | serge | 79 | return(p); |
80 | } |
||
81 | |||
3391 | Serge | 82 | /** |
83 | * idr_layer_alloc - allocate a new idr_layer |
||
84 | * @gfp_mask: allocation mask |
||
85 | * @layer_idr: optional idr to allocate from |
||
86 | * |
||
87 | * If @layer_idr is %NULL, directly allocate one using @gfp_mask or fetch |
||
88 | * one from the per-cpu preload buffer. If @layer_idr is not %NULL, fetch |
||
89 | * an idr_layer from @idr->id_free. |
||
90 | * |
||
91 | * @layer_idr is to maintain backward compatibility with the old alloc |
||
92 | * interface - idr_pre_get() and idr_get_new*() - and will be removed |
||
93 | * together with per-pool preload buffer. |
||
94 | */ |
||
95 | static struct idr_layer *idr_layer_alloc(gfp_t gfp_mask, struct idr *layer_idr) |
||
96 | { |
||
97 | struct idr_layer *new; |
||
98 | |||
99 | /* this is the old path, bypass to get_from_free_list() */ |
||
100 | if (layer_idr) |
||
101 | return get_from_free_list(layer_idr); |
||
102 | |||
103 | /* try to allocate directly from kmem_cache */ |
||
104 | new = kzalloc(sizeof(struct idr_layer), gfp_mask); |
||
105 | if (new) |
||
106 | return new; |
||
107 | |||
108 | |||
109 | new = idr_preload_head; |
||
110 | if (new) { |
||
111 | idr_preload_head = new->ary[0]; |
||
112 | idr_preload_cnt--; |
||
113 | new->ary[0] = NULL; |
||
114 | } |
||
115 | preempt_enable(); |
||
116 | return new; |
||
117 | } |
||
118 | |||
1412 | serge | 119 | static void idr_layer_rcu_free(struct rcu_head *head) |
120 | { |
||
121 | struct idr_layer *layer; |
||
122 | |||
123 | layer = container_of(head, struct idr_layer, rcu_head); |
||
124 | kfree(layer); |
||
125 | } |
||
126 | |||
3391 | Serge | 127 | static inline void free_layer(struct idr *idr, struct idr_layer *p) |
1412 | serge | 128 | { |
5056 | serge | 129 | if (idr->hint == p) |
3391 | Serge | 130 | RCU_INIT_POINTER(idr->hint, NULL); |
5270 | serge | 131 | call_rcu(&p->rcu_head, idr_layer_rcu_free); |
1412 | serge | 132 | } |
133 | |||
134 | /* only called when idp->lock is held */ |
||
135 | static void __move_to_free_list(struct idr *idp, struct idr_layer *p) |
||
136 | { |
||
137 | p->ary[0] = idp->id_free; |
||
138 | idp->id_free = p; |
||
139 | idp->id_free_cnt++; |
||
140 | } |
||
141 | |||
142 | static void move_to_free_list(struct idr *idp, struct idr_layer *p) |
||
143 | { |
||
144 | unsigned long flags; |
||
145 | |||
146 | /* |
||
147 | * Depends on the return element being zeroed. |
||
148 | */ |
||
3391 | Serge | 149 | spin_lock_irqsave(&idp->lock, flags); |
1412 | serge | 150 | __move_to_free_list(idp, p); |
3391 | Serge | 151 | spin_unlock_irqrestore(&idp->lock, flags); |
1412 | serge | 152 | } |
153 | |||
154 | static void idr_mark_full(struct idr_layer **pa, int id) |
||
155 | { |
||
156 | struct idr_layer *p = pa[0]; |
||
157 | int l = 0; |
||
158 | |||
3391 | Serge | 159 | __set_bit(id & IDR_MASK, p->bitmap); |
1412 | serge | 160 | /* |
161 | * If this layer is full mark the bit in the layer above to |
||
162 | * show that this part of the radix tree is full. This may |
||
163 | * complete the layer above and require walking up the radix |
||
164 | * tree. |
||
165 | */ |
||
3391 | Serge | 166 | while (bitmap_full(p->bitmap, IDR_SIZE)) { |
1412 | serge | 167 | if (!(p = pa[++l])) |
168 | break; |
||
169 | id = id >> IDR_BITS; |
||
3391 | Serge | 170 | __set_bit((id & IDR_MASK), p->bitmap); |
1412 | serge | 171 | } |
172 | } |
||
173 | |||
5056 | serge | 174 | static int __idr_pre_get(struct idr *idp, gfp_t gfp_mask) |
1412 | serge | 175 | { |
3391 | Serge | 176 | while (idp->id_free_cnt < MAX_IDR_FREE) { |
1412 | serge | 177 | struct idr_layer *new; |
178 | new = kzalloc(sizeof(struct idr_layer), gfp_mask); |
||
179 | if (new == NULL) |
||
180 | return (0); |
||
181 | move_to_free_list(idp, new); |
||
182 | } |
||
183 | return 1; |
||
184 | } |
||
185 | |||
3391 | Serge | 186 | /** |
187 | * sub_alloc - try to allocate an id without growing the tree depth |
||
188 | * @idp: idr handle |
||
189 | * @starting_id: id to start search at |
||
190 | * @pa: idr_layer[MAX_IDR_LEVEL] used as backtrack buffer |
||
191 | * @gfp_mask: allocation mask for idr_layer_alloc() |
||
192 | * @layer_idr: optional idr passed to idr_layer_alloc() |
||
193 | * |
||
194 | * Allocate an id in range [@starting_id, INT_MAX] from @idp without |
||
195 | * growing its depth. Returns |
||
196 | * |
||
197 | * the allocated id >= 0 if successful, |
||
198 | * -EAGAIN if the tree needs to grow for allocation to succeed, |
||
199 | * -ENOSPC if the id space is exhausted, |
||
200 | * -ENOMEM if more idr_layers need to be allocated. |
||
201 | */ |
||
202 | static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa, |
||
203 | gfp_t gfp_mask, struct idr *layer_idr) |
||
1412 | serge | 204 | { |
205 | int n, m, sh; |
||
206 | struct idr_layer *p, *new; |
||
207 | int l, id, oid; |
||
208 | |||
209 | id = *starting_id; |
||
210 | restart: |
||
211 | p = idp->top; |
||
212 | l = idp->layers; |
||
213 | pa[l--] = NULL; |
||
214 | while (1) { |
||
215 | /* |
||
216 | * We run around this while until we reach the leaf node... |
||
217 | */ |
||
218 | n = (id >> (IDR_BITS*l)) & IDR_MASK; |
||
3391 | Serge | 219 | m = find_next_zero_bit(p->bitmap, IDR_SIZE, n); |
1412 | serge | 220 | if (m == IDR_SIZE) { |
221 | /* no space available go back to previous layer. */ |
||
222 | l++; |
||
223 | oid = id; |
||
224 | id = (id | ((1 << (IDR_BITS * l)) - 1)) + 1; |
||
225 | |||
226 | /* if already at the top layer, we need to grow */ |
||
5056 | serge | 227 | if (id > idr_max(idp->layers)) { |
1412 | serge | 228 | *starting_id = id; |
3391 | Serge | 229 | return -EAGAIN; |
1412 | serge | 230 | } |
3391 | Serge | 231 | p = pa[l]; |
232 | BUG_ON(!p); |
||
1412 | serge | 233 | |
234 | /* If we need to go up one layer, continue the |
||
235 | * loop; otherwise, restart from the top. |
||
236 | */ |
||
237 | sh = IDR_BITS * (l + 1); |
||
238 | if (oid >> sh == id >> sh) |
||
239 | continue; |
||
240 | else |
||
241 | goto restart; |
||
242 | } |
||
243 | if (m != n) { |
||
244 | sh = IDR_BITS*l; |
||
245 | id = ((id >> sh) ^ n ^ m) << sh; |
||
246 | } |
||
3391 | Serge | 247 | if ((id >= MAX_IDR_BIT) || (id < 0)) |
248 | return -ENOSPC; |
||
1412 | serge | 249 | if (l == 0) |
250 | break; |
||
251 | /* |
||
252 | * Create the layer below if it is missing. |
||
253 | */ |
||
254 | if (!p->ary[m]) { |
||
3391 | Serge | 255 | new = idr_layer_alloc(gfp_mask, layer_idr); |
1412 | serge | 256 | if (!new) |
3391 | Serge | 257 | return -ENOMEM; |
1412 | serge | 258 | new->layer = l-1; |
3391 | Serge | 259 | new->prefix = id & idr_layer_prefix_mask(new->layer); |
1412 | serge | 260 | rcu_assign_pointer(p->ary[m], new); |
261 | p->count++; |
||
262 | } |
||
263 | pa[l--] = p; |
||
264 | p = p->ary[m]; |
||
265 | } |
||
266 | |||
267 | pa[l] = p; |
||
268 | return id; |
||
269 | } |
||
270 | |||
271 | static int idr_get_empty_slot(struct idr *idp, int starting_id, |
||
3391 | Serge | 272 | struct idr_layer **pa, gfp_t gfp_mask, |
273 | struct idr *layer_idr) |
||
1412 | serge | 274 | { |
275 | struct idr_layer *p, *new; |
||
276 | int layers, v, id; |
||
277 | unsigned long flags; |
||
278 | |||
279 | id = starting_id; |
||
280 | build_up: |
||
281 | p = idp->top; |
||
282 | layers = idp->layers; |
||
283 | if (unlikely(!p)) { |
||
3391 | Serge | 284 | if (!(p = idr_layer_alloc(gfp_mask, layer_idr))) |
285 | return -ENOMEM; |
||
1412 | serge | 286 | p->layer = 0; |
287 | layers = 1; |
||
288 | } |
||
289 | /* |
||
290 | * Add a new layer to the top of the tree if the requested |
||
291 | * id is larger than the currently allocated space. |
||
292 | */ |
||
3391 | Serge | 293 | while (id > idr_max(layers)) { |
1412 | serge | 294 | layers++; |
295 | if (!p->count) { |
||
296 | /* special case: if the tree is currently empty, |
||
297 | * then we grow the tree by moving the top node |
||
298 | * upwards. |
||
299 | */ |
||
300 | p->layer++; |
||
3391 | Serge | 301 | WARN_ON_ONCE(p->prefix); |
1412 | serge | 302 | continue; |
303 | } |
||
3391 | Serge | 304 | if (!(new = idr_layer_alloc(gfp_mask, layer_idr))) { |
1412 | serge | 305 | /* |
306 | * The allocation failed. If we built part of |
||
307 | * the structure tear it down. |
||
308 | */ |
||
3391 | Serge | 309 | spin_lock_irqsave(&idp->lock, flags); |
1412 | serge | 310 | for (new = p; p && p != idp->top; new = p) { |
311 | p = p->ary[0]; |
||
312 | new->ary[0] = NULL; |
||
3391 | Serge | 313 | new->count = 0; |
314 | bitmap_clear(new->bitmap, 0, IDR_SIZE); |
||
1412 | serge | 315 | __move_to_free_list(idp, new); |
316 | } |
||
3391 | Serge | 317 | spin_unlock_irqrestore(&idp->lock, flags); |
318 | return -ENOMEM; |
||
1412 | serge | 319 | } |
320 | new->ary[0] = p; |
||
321 | new->count = 1; |
||
322 | new->layer = layers-1; |
||
3391 | Serge | 323 | new->prefix = id & idr_layer_prefix_mask(new->layer); |
324 | if (bitmap_full(p->bitmap, IDR_SIZE)) |
||
325 | __set_bit(0, new->bitmap); |
||
1412 | serge | 326 | p = new; |
327 | } |
||
328 | rcu_assign_pointer(idp->top, p); |
||
329 | idp->layers = layers; |
||
3391 | Serge | 330 | v = sub_alloc(idp, &id, pa, gfp_mask, layer_idr); |
331 | if (v == -EAGAIN) |
||
1412 | serge | 332 | goto build_up; |
333 | return(v); |
||
334 | } |
||
335 | |||
3391 | Serge | 336 | /* |
337 | * @id and @pa are from a successful allocation from idr_get_empty_slot(). |
||
338 | * Install the user pointer @ptr and mark the slot full. |
||
339 | */ |
||
340 | static void idr_fill_slot(struct idr *idr, void *ptr, int id, |
||
341 | struct idr_layer **pa) |
||
1412 | serge | 342 | { |
3391 | Serge | 343 | /* update hint used for lookup, cleared from free_layer() */ |
344 | rcu_assign_pointer(idr->hint, pa[0]); |
||
1412 | serge | 345 | |
3391 | Serge | 346 | rcu_assign_pointer(pa[0]->ary[id & IDR_MASK], (struct idr_layer *)ptr); |
1412 | serge | 347 | pa[0]->count++; |
348 | idr_mark_full(pa, id); |
||
349 | } |
||
350 | |||
2966 | Serge | 351 | |
1412 | serge | 352 | /** |
3391 | Serge | 353 | * idr_preload - preload for idr_alloc() |
354 | * @gfp_mask: allocation mask to use for preloading |
||
1412 | serge | 355 | * |
3391 | Serge | 356 | * Preload per-cpu layer buffer for idr_alloc(). Can only be used from |
357 | * process context and each idr_preload() invocation should be matched with |
||
358 | * idr_preload_end(). Note that preemption is disabled while preloaded. |
||
1412 | serge | 359 | * |
3391 | Serge | 360 | * The first idr_alloc() in the preloaded section can be treated as if it |
361 | * were invoked with @gfp_mask used for preloading. This allows using more |
||
362 | * permissive allocation masks for idrs protected by spinlocks. |
||
1412 | serge | 363 | * |
3391 | Serge | 364 | * For example, if idr_alloc() below fails, the failure can be treated as |
365 | * if idr_alloc() were called with GFP_KERNEL rather than GFP_NOWAIT. |
||
366 | * |
||
367 | * idr_preload(GFP_KERNEL); |
||
368 | * spin_lock(lock); |
||
369 | * |
||
370 | * id = idr_alloc(idr, ptr, start, end, GFP_NOWAIT); |
||
371 | * |
||
372 | * spin_unlock(lock); |
||
373 | * idr_preload_end(); |
||
374 | * if (id < 0) |
||
375 | * error; |
||
1412 | serge | 376 | */ |
3391 | Serge | 377 | void idr_preload(gfp_t gfp_mask) |
1412 | serge | 378 | { |
379 | |||
380 | /* |
||
3391 | Serge | 381 | * idr_alloc() is likely to succeed w/o full idr_layer buffer and |
382 | * return value from idr_alloc() needs to be checked for failure |
||
383 | * anyway. Silently give up if allocation fails. The caller can |
||
384 | * treat failures from idr_alloc() as if idr_alloc() were called |
||
385 | * with @gfp_mask which should be enough. |
||
1412 | serge | 386 | */ |
3391 | Serge | 387 | while (idr_preload_cnt < MAX_IDR_FREE) { |
388 | struct idr_layer *new; |
||
389 | |||
390 | new = kzalloc(sizeof(struct idr_layer), gfp_mask); |
||
391 | if (!new) |
||
392 | break; |
||
393 | |||
394 | /* link the new one to per-cpu preload list */ |
||
395 | new->ary[0] = idr_preload_head; |
||
396 | idr_preload_head = new; |
||
397 | idr_preload_cnt++; |
||
398 | } |
||
1412 | serge | 399 | } |
3391 | Serge | 400 | EXPORT_SYMBOL(idr_preload); |
1412 | serge | 401 | |
3391 | Serge | 402 | /** |
403 | * idr_alloc - allocate new idr entry |
||
404 | * @idr: the (initialized) idr |
||
405 | * @ptr: pointer to be associated with the new id |
||
406 | * @start: the minimum id (inclusive) |
||
407 | * @end: the maximum id (exclusive, <= 0 for max) |
||
408 | * @gfp_mask: memory allocation flags |
||
409 | * |
||
410 | * Allocate an id in [start, end) and associate it with @ptr. If no ID is |
||
411 | * available in the specified range, returns -ENOSPC. On memory allocation |
||
412 | * failure, returns -ENOMEM. |
||
413 | * |
||
414 | * Note that @end is treated as max when <= 0. This is to always allow |
||
415 | * using @start + N as @end as long as N is inside integer range. |
||
416 | * |
||
417 | * The user is responsible for exclusively synchronizing all operations |
||
418 | * which may modify @idr. However, read-only accesses such as idr_find() |
||
419 | * or iteration can be performed under RCU read lock provided the user |
||
420 | * destroys @ptr in RCU-safe way after removal from idr. |
||
421 | */ |
||
422 | int idr_alloc(struct idr *idr, void *ptr, int start, int end, gfp_t gfp_mask) |
||
423 | { |
||
424 | int max = end > 0 ? end - 1 : INT_MAX; /* inclusive upper limit */ |
||
425 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
||
426 | int id; |
||
427 | |||
428 | /* sanity checks */ |
||
429 | if (WARN_ON_ONCE(start < 0)) |
||
430 | return -EINVAL; |
||
431 | if (unlikely(max < start)) |
||
432 | return -ENOSPC; |
||
433 | |||
434 | /* allocate id */ |
||
435 | id = idr_get_empty_slot(idr, start, pa, gfp_mask, NULL); |
||
436 | if (unlikely(id < 0)) |
||
437 | return id; |
||
438 | if (unlikely(id > max)) |
||
439 | return -ENOSPC; |
||
440 | |||
441 | idr_fill_slot(idr, ptr, id, pa); |
||
442 | return id; |
||
443 | } |
||
444 | EXPORT_SYMBOL_GPL(idr_alloc); |
||
445 | |||
4103 | Serge | 446 | /** |
447 | * idr_alloc_cyclic - allocate new idr entry in a cyclical fashion |
||
448 | * @idr: the (initialized) idr |
||
449 | * @ptr: pointer to be associated with the new id |
||
450 | * @start: the minimum id (inclusive) |
||
451 | * @end: the maximum id (exclusive, <= 0 for max) |
||
452 | * @gfp_mask: memory allocation flags |
||
453 | * |
||
454 | * Essentially the same as idr_alloc, but prefers to allocate progressively |
||
455 | * higher ids if it can. If the "cur" counter wraps, then it will start again |
||
456 | * at the "start" end of the range and allocate one that has already been used. |
||
457 | */ |
||
458 | int idr_alloc_cyclic(struct idr *idr, void *ptr, int start, int end, |
||
459 | gfp_t gfp_mask) |
||
460 | { |
||
461 | int id; |
||
462 | |||
463 | id = idr_alloc(idr, ptr, max(start, idr->cur), end, gfp_mask); |
||
464 | if (id == -ENOSPC) |
||
465 | id = idr_alloc(idr, ptr, start, end, gfp_mask); |
||
466 | |||
467 | if (likely(id >= 0)) |
||
468 | idr->cur = id + 1; |
||
469 | return id; |
||
470 | } |
||
471 | EXPORT_SYMBOL(idr_alloc_cyclic); |
||
472 | |||
1412 | serge | 473 | static void idr_remove_warning(int id) |
474 | { |
||
4065 | Serge | 475 | WARN(1, "idr_remove called for id=%d which is not allocated.\n", id); |
1412 | serge | 476 | } |
477 | |||
478 | static void sub_remove(struct idr *idp, int shift, int id) |
||
479 | { |
||
480 | struct idr_layer *p = idp->top; |
||
3391 | Serge | 481 | struct idr_layer **pa[MAX_IDR_LEVEL + 1]; |
1412 | serge | 482 | struct idr_layer ***paa = &pa[0]; |
483 | struct idr_layer *to_free; |
||
484 | int n; |
||
485 | |||
486 | *paa = NULL; |
||
487 | *++paa = &idp->top; |
||
488 | |||
489 | while ((shift > 0) && p) { |
||
490 | n = (id >> shift) & IDR_MASK; |
||
3391 | Serge | 491 | __clear_bit(n, p->bitmap); |
1412 | serge | 492 | *++paa = &p->ary[n]; |
493 | p = p->ary[n]; |
||
494 | shift -= IDR_BITS; |
||
495 | } |
||
496 | n = id & IDR_MASK; |
||
3391 | Serge | 497 | if (likely(p != NULL && test_bit(n, p->bitmap))) { |
498 | __clear_bit(n, p->bitmap); |
||
5270 | serge | 499 | RCU_INIT_POINTER(p->ary[n], NULL); |
1412 | serge | 500 | to_free = NULL; |
501 | while(*paa && ! --((**paa)->count)){ |
||
502 | if (to_free) |
||
3391 | Serge | 503 | free_layer(idp, to_free); |
1412 | serge | 504 | to_free = **paa; |
505 | **paa-- = NULL; |
||
506 | } |
||
507 | if (!*paa) |
||
508 | idp->layers = 0; |
||
509 | if (to_free) |
||
3391 | Serge | 510 | free_layer(idp, to_free); |
1412 | serge | 511 | } else |
512 | idr_remove_warning(id); |
||
513 | } |
||
514 | |||
515 | /** |
||
2966 | Serge | 516 | * idr_remove - remove the given id and free its slot |
1412 | serge | 517 | * @idp: idr handle |
518 | * @id: unique key |
||
519 | */ |
||
520 | void idr_remove(struct idr *idp, int id) |
||
521 | { |
||
522 | struct idr_layer *p; |
||
523 | struct idr_layer *to_free; |
||
524 | |||
4065 | Serge | 525 | if (id < 0) |
3391 | Serge | 526 | return; |
1412 | serge | 527 | |
5056 | serge | 528 | if (id > idr_max(idp->layers)) { |
529 | idr_remove_warning(id); |
||
530 | return; |
||
531 | } |
||
532 | |||
1412 | serge | 533 | sub_remove(idp, (idp->layers - 1) * IDR_BITS, id); |
534 | if (idp->top && idp->top->count == 1 && (idp->layers > 1) && |
||
535 | idp->top->ary[0]) { |
||
536 | /* |
||
537 | * Single child at leftmost slot: we can shrink the tree. |
||
538 | * This level is not needed anymore since when layers are |
||
539 | * inserted, they are inserted at the top of the existing |
||
540 | * tree. |
||
541 | */ |
||
542 | to_free = idp->top; |
||
543 | p = idp->top->ary[0]; |
||
544 | rcu_assign_pointer(idp->top, p); |
||
545 | --idp->layers; |
||
3391 | Serge | 546 | to_free->count = 0; |
547 | bitmap_clear(to_free->bitmap, 0, IDR_SIZE); |
||
548 | free_layer(idp, to_free); |
||
1412 | serge | 549 | } |
550 | } |
||
3391 | Serge | 551 | EXPORT_SYMBOL(idr_remove); |
1412 | serge | 552 | |
5056 | serge | 553 | static void __idr_remove_all(struct idr *idp) |
1412 | serge | 554 | { |
555 | int n, id, max; |
||
2966 | Serge | 556 | int bt_mask; |
1412 | serge | 557 | struct idr_layer *p; |
3391 | Serge | 558 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
1412 | serge | 559 | struct idr_layer **paa = &pa[0]; |
560 | |||
561 | n = idp->layers * IDR_BITS; |
||
5056 | serge | 562 | *paa = idp->top; |
5270 | serge | 563 | RCU_INIT_POINTER(idp->top, NULL); |
3391 | Serge | 564 | max = idr_max(idp->layers); |
1412 | serge | 565 | |
566 | id = 0; |
||
3391 | Serge | 567 | while (id >= 0 && id <= max) { |
5056 | serge | 568 | p = *paa; |
1412 | serge | 569 | while (n > IDR_BITS && p) { |
570 | n -= IDR_BITS; |
||
571 | p = p->ary[(id >> n) & IDR_MASK]; |
||
5056 | serge | 572 | *++paa = p; |
1412 | serge | 573 | } |
574 | |||
2966 | Serge | 575 | bt_mask = id; |
1412 | serge | 576 | id += 1 << n; |
2966 | Serge | 577 | /* Get the highest bit that the above add changed from 0->1. */ |
578 | while (n < fls(id ^ bt_mask)) { |
||
5056 | serge | 579 | if (*paa) |
580 | free_layer(idp, *paa); |
||
1412 | serge | 581 | n += IDR_BITS; |
5056 | serge | 582 | --paa; |
1412 | serge | 583 | } |
584 | } |
||
585 | idp->layers = 0; |
||
586 | } |
||
587 | |||
588 | /** |
||
589 | * idr_destroy - release all cached layers within an idr tree |
||
2966 | Serge | 590 | * @idp: idr handle |
3391 | Serge | 591 | * |
592 | * Free all id mappings and all idp_layers. After this function, @idp is |
||
593 | * completely unused and can be freed / recycled. The caller is |
||
594 | * responsible for ensuring that no one else accesses @idp during or after |
||
595 | * idr_destroy(). |
||
596 | * |
||
597 | * A typical clean-up sequence for objects stored in an idr tree will use |
||
5270 | serge | 598 | * idr_for_each() to free all objects, if necessary, then idr_destroy() to |
3391 | Serge | 599 | * free up the id mappings and cached idr_layers. |
1412 | serge | 600 | */ |
601 | void idr_destroy(struct idr *idp) |
||
602 | { |
||
3391 | Serge | 603 | __idr_remove_all(idp); |
604 | |||
1412 | serge | 605 | while (idp->id_free_cnt) { |
606 | struct idr_layer *p = get_from_free_list(idp); |
||
607 | kfree(p); |
||
608 | } |
||
609 | } |
||
3391 | Serge | 610 | EXPORT_SYMBOL(idr_destroy); |
1412 | serge | 611 | |
3391 | Serge | 612 | void *idr_find_slowpath(struct idr *idp, int id) |
1412 | serge | 613 | { |
614 | int n; |
||
615 | struct idr_layer *p; |
||
616 | |||
4065 | Serge | 617 | if (id < 0) |
3391 | Serge | 618 | return NULL; |
619 | |||
620 | p = rcu_dereference_raw(idp->top); |
||
1412 | serge | 621 | if (!p) |
622 | return NULL; |
||
623 | n = (p->layer+1) * IDR_BITS; |
||
624 | |||
3391 | Serge | 625 | if (id > idr_max(p->layer + 1)) |
1412 | serge | 626 | return NULL; |
627 | BUG_ON(n == 0); |
||
628 | |||
629 | while (n > 0 && p) { |
||
630 | n -= IDR_BITS; |
||
631 | BUG_ON(n != p->layer*IDR_BITS); |
||
3391 | Serge | 632 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
1412 | serge | 633 | } |
634 | return((void *)p); |
||
635 | } |
||
3391 | Serge | 636 | EXPORT_SYMBOL(idr_find_slowpath); |
1412 | serge | 637 | |
638 | /** |
||
639 | * idr_for_each - iterate through all stored pointers |
||
640 | * @idp: idr handle |
||
641 | * @fn: function to be called for each pointer |
||
642 | * @data: data passed back to callback function |
||
643 | * |
||
644 | * Iterate over the pointers registered with the given idr. The |
||
645 | * callback function will be called for each pointer currently |
||
646 | * registered, passing the id, the pointer and the data pointer passed |
||
647 | * to this function. It is not safe to modify the idr tree while in |
||
648 | * the callback, so functions such as idr_get_new and idr_remove are |
||
649 | * not allowed. |
||
650 | * |
||
651 | * We check the return of @fn each time. If it returns anything other |
||
2966 | Serge | 652 | * than %0, we break out and return that value. |
1412 | serge | 653 | * |
654 | * The caller must serialize idr_for_each() vs idr_get_new() and idr_remove(). |
||
655 | */ |
||
656 | int idr_for_each(struct idr *idp, |
||
657 | int (*fn)(int id, void *p, void *data), void *data) |
||
658 | { |
||
659 | int n, id, max, error = 0; |
||
660 | struct idr_layer *p; |
||
3391 | Serge | 661 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
1412 | serge | 662 | struct idr_layer **paa = &pa[0]; |
663 | |||
664 | n = idp->layers * IDR_BITS; |
||
5056 | serge | 665 | *paa = rcu_dereference_raw(idp->top); |
3391 | Serge | 666 | max = idr_max(idp->layers); |
1412 | serge | 667 | |
668 | id = 0; |
||
3391 | Serge | 669 | while (id >= 0 && id <= max) { |
5056 | serge | 670 | p = *paa; |
1412 | serge | 671 | while (n > 0 && p) { |
672 | n -= IDR_BITS; |
||
3391 | Serge | 673 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
5056 | serge | 674 | *++paa = p; |
1412 | serge | 675 | } |
676 | |||
677 | if (p) { |
||
678 | error = fn(id, (void *)p, data); |
||
679 | if (error) |
||
680 | break; |
||
681 | } |
||
682 | |||
683 | id += 1 << n; |
||
684 | while (n < fls(id)) { |
||
685 | n += IDR_BITS; |
||
5056 | serge | 686 | --paa; |
1412 | serge | 687 | } |
688 | } |
||
689 | |||
690 | return error; |
||
691 | } |
||
692 | EXPORT_SYMBOL(idr_for_each); |
||
693 | |||
694 | /** |
||
695 | * idr_get_next - lookup next object of id to given id. |
||
696 | * @idp: idr handle |
||
2966 | Serge | 697 | * @nextidp: pointer to lookup key |
1412 | serge | 698 | * |
699 | * Returns pointer to registered object with id, which is next number to |
||
2966 | Serge | 700 | * given id. After being looked up, *@nextidp will be updated for the next |
701 | * iteration. |
||
3391 | Serge | 702 | * |
703 | * This function can be called under rcu_read_lock(), given that the leaf |
||
704 | * pointers lifetimes are correctly managed. |
||
1412 | serge | 705 | */ |
706 | void *idr_get_next(struct idr *idp, int *nextidp) |
||
707 | { |
||
3391 | Serge | 708 | struct idr_layer *p, *pa[MAX_IDR_LEVEL + 1]; |
1412 | serge | 709 | struct idr_layer **paa = &pa[0]; |
710 | int id = *nextidp; |
||
711 | int n, max; |
||
712 | |||
713 | /* find first ent */ |
||
5056 | serge | 714 | p = *paa = rcu_dereference_raw(idp->top); |
1412 | serge | 715 | if (!p) |
716 | return NULL; |
||
3391 | Serge | 717 | n = (p->layer + 1) * IDR_BITS; |
718 | max = idr_max(p->layer + 1); |
||
1412 | serge | 719 | |
3391 | Serge | 720 | while (id >= 0 && id <= max) { |
5056 | serge | 721 | p = *paa; |
1412 | serge | 722 | while (n > 0 && p) { |
723 | n -= IDR_BITS; |
||
3391 | Serge | 724 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
5056 | serge | 725 | *++paa = p; |
1412 | serge | 726 | } |
727 | |||
728 | if (p) { |
||
729 | *nextidp = id; |
||
730 | return p; |
||
731 | } |
||
732 | |||
3391 | Serge | 733 | /* |
734 | * Proceed to the next layer at the current level. Unlike |
||
735 | * idr_for_each(), @id isn't guaranteed to be aligned to |
||
736 | * layer boundary at this point and adding 1 << n may |
||
737 | * incorrectly skip IDs. Make sure we jump to the |
||
738 | * beginning of the next layer using round_up(). |
||
739 | */ |
||
740 | id = round_up(id + 1, 1 << n); |
||
1412 | serge | 741 | while (n < fls(id)) { |
742 | n += IDR_BITS; |
||
5056 | serge | 743 | --paa; |
1412 | serge | 744 | } |
745 | } |
||
746 | return NULL; |
||
747 | } |
||
3391 | Serge | 748 | EXPORT_SYMBOL(idr_get_next); |
1412 | serge | 749 | |
750 | |||
751 | /** |
||
752 | * idr_replace - replace pointer for given id |
||
753 | * @idp: idr handle |
||
754 | * @ptr: pointer you want associated with the id |
||
755 | * @id: lookup key |
||
756 | * |
||
757 | * Replace the pointer registered with an id and return the old value. |
||
2966 | Serge | 758 | * A %-ENOENT return indicates that @id was not found. |
759 | * A %-EINVAL return indicates that @id was not within valid constraints. |
||
1412 | serge | 760 | * |
761 | * The caller must serialize with writers. |
||
762 | */ |
||
763 | void *idr_replace(struct idr *idp, void *ptr, int id) |
||
764 | { |
||
765 | int n; |
||
766 | struct idr_layer *p, *old_p; |
||
767 | |||
4065 | Serge | 768 | if (id < 0) |
3391 | Serge | 769 | return ERR_PTR(-EINVAL); |
770 | |||
1412 | serge | 771 | p = idp->top; |
772 | if (!p) |
||
5056 | serge | 773 | return ERR_PTR(-ENOENT); |
1412 | serge | 774 | |
5056 | serge | 775 | if (id > idr_max(p->layer + 1)) |
776 | return ERR_PTR(-ENOENT); |
||
1412 | serge | 777 | |
5056 | serge | 778 | n = p->layer * IDR_BITS; |
1412 | serge | 779 | while ((n > 0) && p) { |
780 | p = p->ary[(id >> n) & IDR_MASK]; |
||
781 | n -= IDR_BITS; |
||
782 | } |
||
783 | |||
784 | n = id & IDR_MASK; |
||
3391 | Serge | 785 | if (unlikely(p == NULL || !test_bit(n, p->bitmap))) |
1412 | serge | 786 | return ERR_PTR(-ENOENT); |
787 | |||
788 | old_p = p->ary[n]; |
||
789 | rcu_assign_pointer(p->ary[n], ptr); |
||
790 | |||
791 | return old_p; |
||
792 | } |
||
793 | EXPORT_SYMBOL(idr_replace); |
||
794 | |||
4065 | Serge | 795 | void __init idr_init_cache(void) |
1412 | serge | 796 | { |
797 | //idr_layer_cache = kmem_cache_create("idr_layer_cache", |
||
798 | // sizeof(struct idr_layer), 0, SLAB_PANIC, NULL); |
||
799 | } |
||
800 | |||
801 | /** |
||
802 | * idr_init - initialize idr handle |
||
803 | * @idp: idr handle |
||
804 | * |
||
805 | * This function is use to set up the handle (@idp) that you will pass |
||
806 | * to the rest of the functions. |
||
807 | */ |
||
808 | void idr_init(struct idr *idp) |
||
809 | { |
||
810 | memset(idp, 0, sizeof(struct idr)); |
||
3391 | Serge | 811 | spin_lock_init(&idp->lock); |
1412 | serge | 812 | } |
3391 | Serge | 813 | EXPORT_SYMBOL(idr_init); |
1412 | serge | 814 | |
5056 | serge | 815 | static int idr_has_entry(int id, void *p, void *data) |
816 | { |
||
817 | return 1; |
||
818 | } |
||
1412 | serge | 819 | |
5056 | serge | 820 | bool idr_is_empty(struct idr *idp) |
821 | { |
||
822 | return !idr_for_each(idp, idr_has_entry, NULL); |
||
823 | } |
||
824 | EXPORT_SYMBOL(idr_is_empty); |
||
825 | |||
3391 | Serge | 826 | /** |
827 | * DOC: IDA description |
||
1412 | serge | 828 | * IDA - IDR based ID allocator |
829 | * |
||
2966 | Serge | 830 | * This is id allocator without id -> pointer translation. Memory |
1412 | serge | 831 | * usage is much lower than full blown idr because each id only |
832 | * occupies a bit. ida uses a custom leaf node which contains |
||
833 | * IDA_BITMAP_BITS slots. |
||
834 | * |
||
835 | * 2007-04-25 written by Tejun Heo |
||
836 | */ |
||
837 | |||
838 | static void free_bitmap(struct ida *ida, struct ida_bitmap *bitmap) |
||
839 | { |
||
840 | unsigned long flags; |
||
841 | |||
842 | if (!ida->free_bitmap) { |
||
843 | spin_lock_irqsave(&ida->idr.lock, flags); |
||
844 | if (!ida->free_bitmap) { |
||
845 | ida->free_bitmap = bitmap; |
||
846 | bitmap = NULL; |
||
847 | } |
||
848 | spin_unlock_irqrestore(&ida->idr.lock, flags); |
||
849 | } |
||
850 | |||
851 | kfree(bitmap); |
||
852 | } |
||
853 | |||
854 | /** |
||
855 | * ida_pre_get - reserve resources for ida allocation |
||
856 | * @ida: ida handle |
||
857 | * @gfp_mask: memory allocation flag |
||
858 | * |
||
859 | * This function should be called prior to locking and calling the |
||
860 | * following function. It preallocates enough memory to satisfy the |
||
861 | * worst possible allocation. |
||
862 | * |
||
2966 | Serge | 863 | * If the system is REALLY out of memory this function returns %0, |
864 | * otherwise %1. |
||
1412 | serge | 865 | */ |
866 | int ida_pre_get(struct ida *ida, gfp_t gfp_mask) |
||
867 | { |
||
868 | /* allocate idr_layers */ |
||
4103 | Serge | 869 | if (!__idr_pre_get(&ida->idr, gfp_mask)) |
1412 | serge | 870 | return 0; |
871 | |||
872 | /* allocate free_bitmap */ |
||
873 | if (!ida->free_bitmap) { |
||
874 | struct ida_bitmap *bitmap; |
||
875 | |||
3391 | Serge | 876 | bitmap = kmalloc(sizeof(struct ida_bitmap), gfp_mask); |
1412 | serge | 877 | if (!bitmap) |
878 | return 0; |
||
879 | |||
880 | free_bitmap(ida, bitmap); |
||
881 | } |
||
882 | |||
883 | return 1; |
||
884 | } |
||
885 | EXPORT_SYMBOL(ida_pre_get); |
||
886 | |||
887 | /** |
||
888 | * ida_get_new_above - allocate new ID above or equal to a start id |
||
889 | * @ida: ida handle |
||
2966 | Serge | 890 | * @starting_id: id to start search at |
1412 | serge | 891 | * @p_id: pointer to the allocated handle |
892 | * |
||
2966 | Serge | 893 | * Allocate new ID above or equal to @starting_id. It should be called |
894 | * with any required locks. |
||
1412 | serge | 895 | * |
2966 | Serge | 896 | * If memory is required, it will return %-EAGAIN, you should unlock |
1412 | serge | 897 | * and go back to the ida_pre_get() call. If the ida is full, it will |
2966 | Serge | 898 | * return %-ENOSPC. |
1412 | serge | 899 | * |
2966 | Serge | 900 | * @p_id returns a value in the range @starting_id ... %0x7fffffff. |
1412 | serge | 901 | */ |
902 | int ida_get_new_above(struct ida *ida, int starting_id, int *p_id) |
||
903 | { |
||
3391 | Serge | 904 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
1412 | serge | 905 | struct ida_bitmap *bitmap; |
906 | unsigned long flags; |
||
907 | int idr_id = starting_id / IDA_BITMAP_BITS; |
||
908 | int offset = starting_id % IDA_BITMAP_BITS; |
||
909 | int t, id; |
||
910 | |||
911 | restart: |
||
912 | /* get vacant slot */ |
||
3391 | Serge | 913 | t = idr_get_empty_slot(&ida->idr, idr_id, pa, 0, &ida->idr); |
1412 | serge | 914 | if (t < 0) |
3391 | Serge | 915 | return t == -ENOMEM ? -EAGAIN : t; |
1412 | serge | 916 | |
3391 | Serge | 917 | if (t * IDA_BITMAP_BITS >= MAX_IDR_BIT) |
1412 | serge | 918 | return -ENOSPC; |
919 | |||
920 | if (t != idr_id) |
||
921 | offset = 0; |
||
922 | idr_id = t; |
||
923 | |||
924 | /* if bitmap isn't there, create a new one */ |
||
925 | bitmap = (void *)pa[0]->ary[idr_id & IDR_MASK]; |
||
926 | if (!bitmap) { |
||
927 | spin_lock_irqsave(&ida->idr.lock, flags); |
||
928 | bitmap = ida->free_bitmap; |
||
929 | ida->free_bitmap = NULL; |
||
930 | spin_unlock_irqrestore(&ida->idr.lock, flags); |
||
931 | |||
932 | if (!bitmap) |
||
933 | return -EAGAIN; |
||
934 | |||
935 | memset(bitmap, 0, sizeof(struct ida_bitmap)); |
||
936 | rcu_assign_pointer(pa[0]->ary[idr_id & IDR_MASK], |
||
937 | (void *)bitmap); |
||
938 | pa[0]->count++; |
||
939 | } |
||
940 | |||
941 | /* lookup for empty slot */ |
||
942 | t = find_next_zero_bit(bitmap->bitmap, IDA_BITMAP_BITS, offset); |
||
943 | if (t == IDA_BITMAP_BITS) { |
||
944 | /* no empty slot after offset, continue to the next chunk */ |
||
945 | idr_id++; |
||
946 | offset = 0; |
||
947 | goto restart; |
||
948 | } |
||
949 | |||
950 | id = idr_id * IDA_BITMAP_BITS + t; |
||
3391 | Serge | 951 | if (id >= MAX_IDR_BIT) |
1412 | serge | 952 | return -ENOSPC; |
953 | |||
954 | __set_bit(t, bitmap->bitmap); |
||
955 | if (++bitmap->nr_busy == IDA_BITMAP_BITS) |
||
956 | idr_mark_full(pa, idr_id); |
||
957 | |||
958 | *p_id = id; |
||
959 | |||
960 | /* Each leaf node can handle nearly a thousand slots and the |
||
961 | * whole idea of ida is to have small memory foot print. |
||
962 | * Throw away extra resources one by one after each successful |
||
963 | * allocation. |
||
964 | */ |
||
965 | if (ida->idr.id_free_cnt || ida->free_bitmap) { |
||
966 | struct idr_layer *p = get_from_free_list(&ida->idr); |
||
967 | if (p) |
||
4065 | Serge | 968 | kfree(p); |
1412 | serge | 969 | } |
970 | |||
971 | return 0; |
||
972 | } |
||
973 | EXPORT_SYMBOL(ida_get_new_above); |
||
974 | |||
975 | /** |
||
976 | * ida_remove - remove the given ID |
||
977 | * @ida: ida handle |
||
978 | * @id: ID to free |
||
979 | */ |
||
980 | void ida_remove(struct ida *ida, int id) |
||
981 | { |
||
982 | struct idr_layer *p = ida->idr.top; |
||
983 | int shift = (ida->idr.layers - 1) * IDR_BITS; |
||
984 | int idr_id = id / IDA_BITMAP_BITS; |
||
985 | int offset = id % IDA_BITMAP_BITS; |
||
986 | int n; |
||
987 | struct ida_bitmap *bitmap; |
||
988 | |||
5056 | serge | 989 | if (idr_id > idr_max(ida->idr.layers)) |
990 | goto err; |
||
991 | |||
1412 | serge | 992 | /* clear full bits while looking up the leaf idr_layer */ |
993 | while ((shift > 0) && p) { |
||
994 | n = (idr_id >> shift) & IDR_MASK; |
||
3391 | Serge | 995 | __clear_bit(n, p->bitmap); |
1412 | serge | 996 | p = p->ary[n]; |
997 | shift -= IDR_BITS; |
||
998 | } |
||
999 | |||
1000 | if (p == NULL) |
||
1001 | goto err; |
||
1002 | |||
1003 | n = idr_id & IDR_MASK; |
||
3391 | Serge | 1004 | __clear_bit(n, p->bitmap); |
1412 | serge | 1005 | |
1006 | bitmap = (void *)p->ary[n]; |
||
5056 | serge | 1007 | if (!bitmap || !test_bit(offset, bitmap->bitmap)) |
1412 | serge | 1008 | goto err; |
1009 | |||
1010 | /* update bitmap and remove it if empty */ |
||
1011 | __clear_bit(offset, bitmap->bitmap); |
||
1012 | if (--bitmap->nr_busy == 0) { |
||
3391 | Serge | 1013 | __set_bit(n, p->bitmap); /* to please idr_remove() */ |
1412 | serge | 1014 | idr_remove(&ida->idr, idr_id); |
1015 | free_bitmap(ida, bitmap); |
||
1016 | } |
||
1017 | |||
1018 | return; |
||
1019 | |||
1020 | err: |
||
4065 | Serge | 1021 | WARN(1, "ida_remove called for id=%d which is not allocated.\n", id); |
1412 | serge | 1022 | } |
1023 | EXPORT_SYMBOL(ida_remove); |
||
1024 | |||
1025 | /** |
||
1026 | * ida_destroy - release all cached layers within an ida tree |
||
2966 | Serge | 1027 | * @ida: ida handle |
1412 | serge | 1028 | */ |
1029 | void ida_destroy(struct ida *ida) |
||
1030 | { |
||
1031 | idr_destroy(&ida->idr); |
||
1032 | kfree(ida->free_bitmap); |
||
1033 | } |
||
1034 | EXPORT_SYMBOL(ida_destroy); |
||
1035 | |||
1036 | /** |
||
4103 | Serge | 1037 | * ida_simple_get - get a new id. |
1038 | * @ida: the (initialized) ida. |
||
1039 | * @start: the minimum id (inclusive, < 0x8000000) |
||
1040 | * @end: the maximum id (exclusive, < 0x8000000 or 0) |
||
1041 | * @gfp_mask: memory allocation flags |
||
1042 | * |
||
1043 | * Allocates an id in the range start <= id < end, or returns -ENOSPC. |
||
1044 | * On memory allocation failure, returns -ENOMEM. |
||
1045 | * |
||
1046 | * Use ida_simple_remove() to get rid of an id. |
||
1047 | */ |
||
1048 | int ida_simple_get(struct ida *ida, unsigned int start, unsigned int end, |
||
1049 | gfp_t gfp_mask) |
||
1050 | { |
||
1051 | int ret, id; |
||
1052 | unsigned int max; |
||
1053 | unsigned long flags; |
||
1054 | |||
1055 | BUG_ON((int)start < 0); |
||
1056 | BUG_ON((int)end < 0); |
||
1057 | |||
1058 | if (end == 0) |
||
1059 | max = 0x80000000; |
||
1060 | else { |
||
1061 | BUG_ON(end < start); |
||
1062 | max = end - 1; |
||
1063 | } |
||
1064 | |||
1065 | again: |
||
1066 | if (!ida_pre_get(ida, gfp_mask)) |
||
1067 | return -ENOMEM; |
||
1068 | |||
1069 | spin_lock_irqsave(&simple_ida_lock, flags); |
||
1070 | ret = ida_get_new_above(ida, start, &id); |
||
1071 | if (!ret) { |
||
1072 | if (id > max) { |
||
1073 | ida_remove(ida, id); |
||
1074 | ret = -ENOSPC; |
||
1075 | } else { |
||
1076 | ret = id; |
||
1077 | } |
||
1078 | } |
||
1079 | spin_unlock_irqrestore(&simple_ida_lock, flags); |
||
1080 | |||
1081 | if (unlikely(ret == -EAGAIN)) |
||
1082 | goto again; |
||
1083 | |||
1084 | return ret; |
||
1085 | } |
||
1086 | EXPORT_SYMBOL(ida_simple_get); |
||
1087 | |||
1088 | /** |
||
1089 | * ida_simple_remove - remove an allocated id. |
||
1090 | * @ida: the (initialized) ida. |
||
1091 | * @id: the id returned by ida_simple_get. |
||
1092 | */ |
||
1093 | void ida_simple_remove(struct ida *ida, unsigned int id) |
||
1094 | { |
||
1095 | unsigned long flags; |
||
1096 | |||
1097 | BUG_ON((int)id < 0); |
||
1098 | spin_lock_irqsave(&simple_ida_lock, flags); |
||
1099 | ida_remove(ida, id); |
||
1100 | spin_unlock_irqrestore(&simple_ida_lock, flags); |
||
1101 | } |
||
1102 | EXPORT_SYMBOL(ida_simple_remove); |
||
1103 | |||
1104 | /** |
||
1412 | serge | 1105 | * ida_init - initialize ida handle |
1106 | * @ida: ida handle |
||
1107 | * |
||
1108 | * This function is use to set up the handle (@ida) that you will pass |
||
1109 | * to the rest of the functions. |
||
1110 | */ |
||
1111 | void ida_init(struct ida *ida) |
||
1112 | { |
||
1113 | memset(ida, 0, sizeof(struct ida)); |
||
1114 | idr_init(&ida->idr); |
||
1115 | |||
1116 | } |
||
1117 | EXPORT_SYMBOL(ida_init);>>>>>=>>>>>>><>><>=>>><>=>>>><>=>>=>>>>=>=>>>>><>><>>><>><> |