1/*
2 * Basic general purpose allocator for managing special purpose
3 * memory, for example, memory that is not managed by the regular
4 * kmalloc/kfree interface. Uses for this includes on-device special
5 * memory, uncached memory etc.
6 *
7 * It is safe to use the allocator in NMI handlers and other special
8 * unblockable contexts that could otherwise deadlock on locks. This
9 * is implemented by using atomic operations and retries on any
10 * conflicts. The disadvantage is that there may be livelocks in
11 * extreme cases. For better scalability, one allocator can be used
12 * for each CPU.
13 *
14 * The lockless operation only works if there is enough memory
15 * available. If new memory is added to the pool a lock has to be
16 * still taken. So any user relying on locklessness has to ensure
17 * that sufficient memory is preallocated.
18 *
19 * The basic atomic operation of this allocator is cmpxchg on long.
20 * On architectures that don't have NMI-safe cmpxchg implementation,
21 * the allocator can NOT be used in NMI handler. So code uses the
22 * allocator in NMI handler should depend on
23 * CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG.
24 *
25 * Copyright 2005 (C) Jes Sorensen <jes@trained-monkey.org>
26 *
27 * This source code is licensed under the GNU General Public License,
28 * Version 2. See the file COPYING for more details.
29 */
30
31#include <linux/slab.h>
32#include <linux/export.h>
33#include <linux/bitmap.h>
34#include <linux/rculist.h>
35#include <linux/interrupt.h>
36#include <linux/genalloc.h>
37#include <linux/of_device.h>
38#include <linux/vmalloc.h>
39
40static inline size_t chunk_size(const struct gen_pool_chunk *chunk)
41{
42 return chunk->end_addr - chunk->start_addr + 1;
43}
44
45static int set_bits_ll(unsigned long *addr, unsigned long mask_to_set)
46{
47 unsigned long val, nval;
48
49 nval = *addr;
50 do {
51 val = nval;
52 if (val & mask_to_set)
53 return -EBUSY;
54 cpu_relax();
55 } while ((nval = cmpxchg(addr, val, val | mask_to_set)) != val);
56
57 return 0;
58}
59
60static int clear_bits_ll(unsigned long *addr, unsigned long mask_to_clear)
61{
62 unsigned long val, nval;
63
64 nval = *addr;
65 do {
66 val = nval;
67 if ((val & mask_to_clear) != mask_to_clear)
68 return -EBUSY;
69 cpu_relax();
70 } while ((nval = cmpxchg(addr, val, val & ~mask_to_clear)) != val);
71
72 return 0;
73}
74
75/*
76 * bitmap_set_ll - set the specified number of bits at the specified position
77 * @map: pointer to a bitmap
78 * @start: a bit position in @map
79 * @nr: number of bits to set
80 *
81 * Set @nr bits start from @start in @map lock-lessly. Several users
82 * can set/clear the same bitmap simultaneously without lock. If two
83 * users set the same bit, one user will return remain bits, otherwise
84 * return 0.
85 */
86static int bitmap_set_ll(unsigned long *map, int start, int nr)
87{
88 unsigned long *p = map + BIT_WORD(start);
89 const int size = start + nr;
90 int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
91 unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
92
93 while (nr - bits_to_set >= 0) {
94 if (set_bits_ll(p, mask_to_set))
95 return nr;
96 nr -= bits_to_set;
97 bits_to_set = BITS_PER_LONG;
98 mask_to_set = ~0UL;
99 p++;
100 }
101 if (nr) {
102 mask_to_set &= BITMAP_LAST_WORD_MASK(size);
103 if (set_bits_ll(p, mask_to_set))
104 return nr;
105 }
106
107 return 0;
108}
109
110/*
111 * bitmap_clear_ll - clear the specified number of bits at the specified position
112 * @map: pointer to a bitmap
113 * @start: a bit position in @map
114 * @nr: number of bits to set
115 *
116 * Clear @nr bits start from @start in @map lock-lessly. Several users
117 * can set/clear the same bitmap simultaneously without lock. If two
118 * users clear the same bit, one user will return remain bits,
119 * otherwise return 0.
120 */
121static int bitmap_clear_ll(unsigned long *map, int start, int nr)
122{
123 unsigned long *p = map + BIT_WORD(start);
124 const int size = start + nr;
125 int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
126 unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
127
128 while (nr - bits_to_clear >= 0) {
129 if (clear_bits_ll(p, mask_to_clear))
130 return nr;
131 nr -= bits_to_clear;
132 bits_to_clear = BITS_PER_LONG;
133 mask_to_clear = ~0UL;
134 p++;
135 }
136 if (nr) {
137 mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
138 if (clear_bits_ll(p, mask_to_clear))
139 return nr;
140 }
141
142 return 0;
143}
144
145/**
146 * gen_pool_create - create a new special memory pool
147 * @min_alloc_order: log base 2 of number of bytes each bitmap bit represents
148 * @nid: node id of the node the pool structure should be allocated on, or -1
149 *
150 * Create a new special memory pool that can be used to manage special purpose
151 * memory not managed by the regular kmalloc/kfree interface.
152 */
153struct gen_pool *gen_pool_create(int min_alloc_order, int nid)
154{
155 struct gen_pool *pool;
156
157 pool = kmalloc_node(sizeof(struct gen_pool), GFP_KERNEL, nid);
158 if (pool != NULL) {
159 spin_lock_init(&pool->lock);
160 INIT_LIST_HEAD(&pool->chunks);
161 pool->min_alloc_order = min_alloc_order;
162 pool->algo = gen_pool_first_fit;
163 pool->data = NULL;
164 pool->name = NULL;
165 }
166 return pool;
167}
168EXPORT_SYMBOL(gen_pool_create);
169
170/**
171 * gen_pool_add_virt - add a new chunk of special memory to the pool
172 * @pool: pool to add new memory chunk to
173 * @virt: virtual starting address of memory chunk to add to pool
174 * @phys: physical starting address of memory chunk to add to pool
175 * @size: size in bytes of the memory chunk to add to pool
176 * @nid: node id of the node the chunk structure and bitmap should be
177 * allocated on, or -1
178 *
179 * Add a new chunk of special memory to the specified pool.
180 *
181 * Returns 0 on success or a -ve errno on failure.
182 */
183int gen_pool_add_virt(struct gen_pool *pool, unsigned long virt, phys_addr_t phys,
184 size_t size, int nid)
185{
186 struct gen_pool_chunk *chunk;
187 int nbits = size >> pool->min_alloc_order;
188 int nbytes = sizeof(struct gen_pool_chunk) +
189 BITS_TO_LONGS(nbits) * sizeof(long);
190
191 chunk = vzalloc_node(nbytes, nid);
192 if (unlikely(chunk == NULL))
193 return -ENOMEM;
194
195 chunk->phys_addr = phys;
196 chunk->start_addr = virt;
197 chunk->end_addr = virt + size - 1;
198 atomic_long_set(&chunk->avail, size);
199
200 spin_lock(&pool->lock);
201 list_add_rcu(&chunk->next_chunk, &pool->chunks);
202 spin_unlock(&pool->lock);
203
204 return 0;
205}
206EXPORT_SYMBOL(gen_pool_add_virt);
207
208/**
209 * gen_pool_virt_to_phys - return the physical address of memory
210 * @pool: pool to allocate from
211 * @addr: starting address of memory
212 *
213 * Returns the physical address on success, or -1 on error.
214 */
215phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long addr)
216{
217 struct gen_pool_chunk *chunk;
218 phys_addr_t paddr = -1;
219
220 rcu_read_lock();
221 list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
222 if (addr >= chunk->start_addr && addr <= chunk->end_addr) {
223 paddr = chunk->phys_addr + (addr - chunk->start_addr);
224 break;
225 }
226 }
227 rcu_read_unlock();
228
229 return paddr;
230}
231EXPORT_SYMBOL(gen_pool_virt_to_phys);
232
233/**
234 * gen_pool_destroy - destroy a special memory pool
235 * @pool: pool to destroy
236 *
237 * Destroy the specified special memory pool. Verifies that there are no
238 * outstanding allocations.
239 */
240void gen_pool_destroy(struct gen_pool *pool)
241{
242 struct list_head *_chunk, *_next_chunk;
243 struct gen_pool_chunk *chunk;
244 int order = pool->min_alloc_order;
245 int bit, end_bit;
246
247 list_for_each_safe(_chunk, _next_chunk, &pool->chunks) {
248 chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk);
249 list_del(&chunk->next_chunk);
250
251 end_bit = chunk_size(chunk) >> order;
252 bit = find_next_bit(chunk->bits, end_bit, 0);
253 BUG_ON(bit < end_bit);
254
255 vfree(chunk);
256 }
257 kfree_const(pool->name);
258 kfree(pool);
259}
260EXPORT_SYMBOL(gen_pool_destroy);
261
262/**
263 * gen_pool_alloc - allocate special memory from the pool
264 * @pool: pool to allocate from
265 * @size: number of bytes to allocate from the pool
266 *
267 * Allocate the requested number of bytes from the specified pool.
268 * Uses the pool allocation function (with first-fit algorithm by default).
269 * Can not be used in NMI handler on architectures without
270 * NMI-safe cmpxchg implementation.
271 */
272unsigned long gen_pool_alloc(struct gen_pool *pool, size_t size)
273{
274 return gen_pool_alloc_algo(pool, size, pool->algo, pool->data);
275}
276EXPORT_SYMBOL(gen_pool_alloc);
277
278/**
279 * gen_pool_alloc_algo - allocate special memory from the pool
280 * @pool: pool to allocate from
281 * @size: number of bytes to allocate from the pool
282 * @algo: algorithm passed from caller
283 * @data: data passed to algorithm
284 *
285 * Allocate the requested number of bytes from the specified pool.
286 * Uses the pool allocation function (with first-fit algorithm by default).
287 * Can not be used in NMI handler on architectures without
288 * NMI-safe cmpxchg implementation.
289 */
290unsigned long gen_pool_alloc_algo(struct gen_pool *pool, size_t size,
291 genpool_algo_t algo, void *data)
292{
293 struct gen_pool_chunk *chunk;
294 unsigned long addr = 0;
295 int order = pool->min_alloc_order;
296 int nbits, start_bit, end_bit, remain;
297
298#ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
299 BUG_ON(in_nmi());
300#endif
301
302 if (size == 0)
303 return 0;
304
305 nbits = (size + (1UL << order) - 1) >> order;
306 rcu_read_lock();
307 list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
308 if (size > atomic_long_read(&chunk->avail))
309 continue;
310
311 start_bit = 0;
312 end_bit = chunk_size(chunk) >> order;
313retry:
314 start_bit = algo(chunk->bits, end_bit, start_bit,
315 nbits, data, pool, chunk->start_addr);
316 if (start_bit >= end_bit)
317 continue;
318 remain = bitmap_set_ll(chunk->bits, start_bit, nbits);
319 if (remain) {
320 remain = bitmap_clear_ll(chunk->bits, start_bit,
321 nbits - remain);
322 BUG_ON(remain);
323 goto retry;
324 }
325
326 addr = chunk->start_addr + ((unsigned long)start_bit << order);
327 size = nbits << order;
328 atomic_long_sub(size, &chunk->avail);
329 break;
330 }
331 rcu_read_unlock();
332 return addr;
333}
334EXPORT_SYMBOL(gen_pool_alloc_algo);
335
336/**
337 * gen_pool_dma_alloc - allocate special memory from the pool for DMA usage
338 * @pool: pool to allocate from
339 * @size: number of bytes to allocate from the pool
340 * @dma: dma-view physical address return value. Use NULL if unneeded.
341 *
342 * Allocate the requested number of bytes from the specified pool.
343 * Uses the pool allocation function (with first-fit algorithm by default).
344 * Can not be used in NMI handler on architectures without
345 * NMI-safe cmpxchg implementation.
346 */
347void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size, dma_addr_t *dma)
348{
349 unsigned long vaddr;
350
351 if (!pool)
352 return NULL;
353
354 vaddr = gen_pool_alloc(pool, size);
355 if (!vaddr)
356 return NULL;
357
358 if (dma)
359 *dma = gen_pool_virt_to_phys(pool, vaddr);
360
361 return (void *)vaddr;
362}
363EXPORT_SYMBOL(gen_pool_dma_alloc);
364
365/**
366 * gen_pool_free - free allocated special memory back to the pool
367 * @pool: pool to free to
368 * @addr: starting address of memory to free back to pool
369 * @size: size in bytes of memory to free
370 *
371 * Free previously allocated special memory back to the specified
372 * pool. Can not be used in NMI handler on architectures without
373 * NMI-safe cmpxchg implementation.
374 */
375void gen_pool_free(struct gen_pool *pool, unsigned long addr, size_t size)
376{
377 struct gen_pool_chunk *chunk;
378 int order = pool->min_alloc_order;
379 int start_bit, nbits, remain;
380
381#ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
382 BUG_ON(in_nmi());
383#endif
384
385 nbits = (size + (1UL << order) - 1) >> order;
386 rcu_read_lock();
387 list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
388 if (addr >= chunk->start_addr && addr <= chunk->end_addr) {
389 BUG_ON(addr + size - 1 > chunk->end_addr);
390 start_bit = (addr - chunk->start_addr) >> order;
391 remain = bitmap_clear_ll(chunk->bits, start_bit, nbits);
392 BUG_ON(remain);
393 size = nbits << order;
394 atomic_long_add(size, &chunk->avail);
395 rcu_read_unlock();
396 return;
397 }
398 }
399 rcu_read_unlock();
400 BUG();
401}
402EXPORT_SYMBOL(gen_pool_free);
403
404/**
405 * gen_pool_for_each_chunk - call func for every chunk of generic memory pool
406 * @pool: the generic memory pool
407 * @func: func to call
408 * @data: additional data used by @func
409 *
410 * Call @func for every chunk of generic memory pool. The @func is
411 * called with rcu_read_lock held.
412 */
413void gen_pool_for_each_chunk(struct gen_pool *pool,
414 void (*func)(struct gen_pool *pool, struct gen_pool_chunk *chunk, void *data),
415 void *data)
416{
417 struct gen_pool_chunk *chunk;
418
419 rcu_read_lock();
420 list_for_each_entry_rcu(chunk, &(pool)->chunks, next_chunk)
421 func(pool, chunk, data);
422 rcu_read_unlock();
423}
424EXPORT_SYMBOL(gen_pool_for_each_chunk);
425
426/**
427 * addr_in_gen_pool - checks if an address falls within the range of a pool
428 * @pool: the generic memory pool
429 * @start: start address
430 * @size: size of the region
431 *
432 * Check if the range of addresses falls within the specified pool. Returns
433 * true if the entire range is contained in the pool and false otherwise.
434 */
435bool addr_in_gen_pool(struct gen_pool *pool, unsigned long start,
436 size_t size)
437{
438 bool found = false;
439 unsigned long end = start + size - 1;
440 struct gen_pool_chunk *chunk;
441
442 rcu_read_lock();
443 list_for_each_entry_rcu(chunk, &(pool)->chunks, next_chunk) {
444 if (start >= chunk->start_addr && start <= chunk->end_addr) {
445 if (end <= chunk->end_addr) {
446 found = true;
447 break;
448 }
449 }
450 }
451 rcu_read_unlock();
452 return found;
453}
454
455/**
456 * gen_pool_avail - get available free space of the pool
457 * @pool: pool to get available free space
458 *
459 * Return available free space of the specified pool.
460 */
461size_t gen_pool_avail(struct gen_pool *pool)
462{
463 struct gen_pool_chunk *chunk;
464 size_t avail = 0;
465
466 rcu_read_lock();
467 list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk)
468 avail += atomic_long_read(&chunk->avail);
469 rcu_read_unlock();
470 return avail;
471}
472EXPORT_SYMBOL_GPL(gen_pool_avail);
473
474/**
475 * gen_pool_size - get size in bytes of memory managed by the pool
476 * @pool: pool to get size
477 *
478 * Return size in bytes of memory managed by the pool.
479 */
480size_t gen_pool_size(struct gen_pool *pool)
481{
482 struct gen_pool_chunk *chunk;
483 size_t size = 0;
484
485 rcu_read_lock();
486 list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk)
487 size += chunk_size(chunk);
488 rcu_read_unlock();
489 return size;
490}
491EXPORT_SYMBOL_GPL(gen_pool_size);
492
493/**
494 * gen_pool_set_algo - set the allocation algorithm
495 * @pool: pool to change allocation algorithm
496 * @algo: custom algorithm function
497 * @data: additional data used by @algo
498 *
499 * Call @algo for each memory allocation in the pool.
500 * If @algo is NULL use gen_pool_first_fit as default
501 * memory allocation function.
502 */
503void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo, void *data)
504{
505 rcu_read_lock();
506
507 pool->algo = algo;
508 if (!pool->algo)
509 pool->algo = gen_pool_first_fit;
510
511 pool->data = data;
512
513 rcu_read_unlock();
514}
515EXPORT_SYMBOL(gen_pool_set_algo);
516
517/**
518 * gen_pool_first_fit - find the first available region
519 * of memory matching the size requirement (no alignment constraint)
520 * @map: The address to base the search on
521 * @size: The bitmap size in bits
522 * @start: The bitnumber to start searching at
523 * @nr: The number of zeroed bits we're looking for
524 * @data: additional data - unused
525 * @pool: pool to find the fit region memory from
526 */
527unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size,
528 unsigned long start, unsigned int nr, void *data,
529 struct gen_pool *pool, unsigned long start_addr)
530{
531 return bitmap_find_next_zero_area(map, size, start, nr, 0);
532}
533EXPORT_SYMBOL(gen_pool_first_fit);
534
535/**
536 * gen_pool_first_fit_align - find the first available region
537 * of memory matching the size requirement (alignment constraint)
538 * @map: The address to base the search on
539 * @size: The bitmap size in bits
540 * @start: The bitnumber to start searching at
541 * @nr: The number of zeroed bits we're looking for
542 * @data: data for alignment
543 * @pool: pool to get order from
544 */
545unsigned long gen_pool_first_fit_align(unsigned long *map, unsigned long size,
546 unsigned long start, unsigned int nr, void *data,
547 struct gen_pool *pool, unsigned long start_addr)
548{
549 struct genpool_data_align *alignment;
550 unsigned long align_mask, align_off;
551 int order;
552
553 alignment = data;
554 order = pool->min_alloc_order;
555 align_mask = ((alignment->align + (1UL << order) - 1) >> order) - 1;
556 align_off = (start_addr & (alignment->align - 1)) >> order;
557
558 return bitmap_find_next_zero_area_off(map, size, start, nr,
559 align_mask, align_off);
560}
561EXPORT_SYMBOL(gen_pool_first_fit_align);
562
563/**
564 * gen_pool_fixed_alloc - reserve a specific region
565 * @map: The address to base the search on
566 * @size: The bitmap size in bits
567 * @start: The bitnumber to start searching at
568 * @nr: The number of zeroed bits we're looking for
569 * @data: data for alignment
570 * @pool: pool to get order from
571 */
572unsigned long gen_pool_fixed_alloc(unsigned long *map, unsigned long size,
573 unsigned long start, unsigned int nr, void *data,
574 struct gen_pool *pool, unsigned long start_addr)
575{
576 struct genpool_data_fixed *fixed_data;
577 int order;
578 unsigned long offset_bit;
579 unsigned long start_bit;
580
581 fixed_data = data;
582 order = pool->min_alloc_order;
583 offset_bit = fixed_data->offset >> order;
584 if (WARN_ON(fixed_data->offset & ((1UL << order) - 1)))
585 return size;
586
587 start_bit = bitmap_find_next_zero_area(map, size,
588 start + offset_bit, nr, 0);
589 if (start_bit != offset_bit)
590 start_bit = size;
591 return start_bit;
592}
593EXPORT_SYMBOL(gen_pool_fixed_alloc);
594
595/**
596 * gen_pool_first_fit_order_align - find the first available region
597 * of memory matching the size requirement. The region will be aligned
598 * to the order of the size specified.
599 * @map: The address to base the search on
600 * @size: The bitmap size in bits
601 * @start: The bitnumber to start searching at
602 * @nr: The number of zeroed bits we're looking for
603 * @data: additional data - unused
604 * @pool: pool to find the fit region memory from
605 */
606unsigned long gen_pool_first_fit_order_align(unsigned long *map,
607 unsigned long size, unsigned long start,
608 unsigned int nr, void *data, struct gen_pool *pool,
609 unsigned long start_addr)
610{
611 unsigned long align_mask = roundup_pow_of_two(nr) - 1;
612
613 return bitmap_find_next_zero_area(map, size, start, nr, align_mask);
614}
615EXPORT_SYMBOL(gen_pool_first_fit_order_align);
616
617/**
618 * gen_pool_best_fit - find the best fitting region of memory
619 * macthing the size requirement (no alignment constraint)
620 * @map: The address to base the search on
621 * @size: The bitmap size in bits
622 * @start: The bitnumber to start searching at
623 * @nr: The number of zeroed bits we're looking for
624 * @data: additional data - unused
625 * @pool: pool to find the fit region memory from
626 *
627 * Iterate over the bitmap to find the smallest free region
628 * which we can allocate the memory.
629 */
630unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size,
631 unsigned long start, unsigned int nr, void *data,
632 struct gen_pool *pool, unsigned long start_addr)
633{
634 unsigned long start_bit = size;
635 unsigned long len = size + 1;
636 unsigned long index;
637
638 index = bitmap_find_next_zero_area(map, size, start, nr, 0);
639
640 while (index < size) {
641 int next_bit = find_next_bit(map, size, index + nr);
642 if ((next_bit - index) < len) {
643 len = next_bit - index;
644 start_bit = index;
645 if (len == nr)
646 return start_bit;
647 }
648 index = bitmap_find_next_zero_area(map, size,
649 next_bit + 1, nr, 0);
650 }
651
652 return start_bit;
653}
654EXPORT_SYMBOL(gen_pool_best_fit);
655
656static void devm_gen_pool_release(struct device *dev, void *res)
657{
658 gen_pool_destroy(*(struct gen_pool **)res);
659}
660
661static int devm_gen_pool_match(struct device *dev, void *res, void *data)
662{
663 struct gen_pool **p = res;
664
665 /* NULL data matches only a pool without an assigned name */
666 if (!data && !(*p)->name)
667 return 1;
668
669 if (!data || !(*p)->name)
670 return 0;
671
672 return !strcmp((*p)->name, data);
673}
674
675/**
676 * gen_pool_get - Obtain the gen_pool (if any) for a device
677 * @dev: device to retrieve the gen_pool from
678 * @name: name of a gen_pool or NULL, identifies a particular gen_pool on device
679 *
680 * Returns the gen_pool for the device if one is present, or NULL.
681 */
682struct gen_pool *gen_pool_get(struct device *dev, const char *name)
683{
684 struct gen_pool **p;
685
686 p = devres_find(dev, devm_gen_pool_release, devm_gen_pool_match,
687 (void *)name);
688 if (!p)
689 return NULL;
690 return *p;
691}
692EXPORT_SYMBOL_GPL(gen_pool_get);
693
694/**
695 * devm_gen_pool_create - managed gen_pool_create
696 * @dev: device that provides the gen_pool
697 * @min_alloc_order: log base 2 of number of bytes each bitmap bit represents
698 * @nid: node selector for allocated gen_pool, %NUMA_NO_NODE for all nodes
699 * @name: name of a gen_pool or NULL, identifies a particular gen_pool on device
700 *
701 * Create a new special memory pool that can be used to manage special purpose
702 * memory not managed by the regular kmalloc/kfree interface. The pool will be
703 * automatically destroyed by the device management code.
704 */
705struct gen_pool *devm_gen_pool_create(struct device *dev, int min_alloc_order,
706 int nid, const char *name)
707{
708 struct gen_pool **ptr, *pool;
709 const char *pool_name = NULL;
710
711 /* Check that genpool to be created is uniquely addressed on device */
712 if (gen_pool_get(dev, name))
713 return ERR_PTR(-EINVAL);
714
715 if (name) {
716 pool_name = kstrdup_const(name, GFP_KERNEL);
717 if (!pool_name)
718 return ERR_PTR(-ENOMEM);
719 }
720
721 ptr = devres_alloc(devm_gen_pool_release, sizeof(*ptr), GFP_KERNEL);
722 if (!ptr)
723 goto free_pool_name;
724
725 pool = gen_pool_create(min_alloc_order, nid);
726 if (!pool)
727 goto free_devres;
728
729 *ptr = pool;
730 pool->name = pool_name;
731 devres_add(dev, ptr);
732
733 return pool;
734
735free_devres:
736 devres_free(ptr);
737free_pool_name:
738 kfree_const(pool_name);
739
740 return ERR_PTR(-ENOMEM);
741}
742EXPORT_SYMBOL(devm_gen_pool_create);
743
744#ifdef CONFIG_OF
745/**
746 * of_gen_pool_get - find a pool by phandle property
747 * @np: device node
748 * @propname: property name containing phandle(s)
749 * @index: index into the phandle array
750 *
751 * Returns the pool that contains the chunk starting at the physical
752 * address of the device tree node pointed at by the phandle property,
753 * or NULL if not found.
754 */
755struct gen_pool *of_gen_pool_get(struct device_node *np,
756 const char *propname, int index)
757{
758 struct platform_device *pdev;
759 struct device_node *np_pool, *parent;
760 const char *name = NULL;
761 struct gen_pool *pool = NULL;
762
763 np_pool = of_parse_phandle(np, propname, index);
764 if (!np_pool)
765 return NULL;
766
767 pdev = of_find_device_by_node(np_pool);
768 if (!pdev) {
769 /* Check if named gen_pool is created by parent node device */
770 parent = of_get_parent(np_pool);
771 pdev = of_find_device_by_node(parent);
772 of_node_put(parent);
773
774 of_property_read_string(np_pool, "label", &name);
775 if (!name)
776 name = np_pool->name;
777 }
778 if (pdev)
779 pool = gen_pool_get(&pdev->dev, name);
780 of_node_put(np_pool);
781
782 return pool;
783}
784EXPORT_SYMBOL_GPL(of_gen_pool_get);
785#endif /* CONFIG_OF */
786