Version:  2.0.40 2.2.26 2.4.37 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10

Linux/lib/genalloc.c

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

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us