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.
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
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.
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.
25 * Copyright 2005 (C) Jes Sorensen <jes@trained-monkey.org>
27 * This source code is licensed under the GNU General Public License,
28 * Version 2. See the file COPYING for more details.
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>
40 static inline size_t chunk_size(const struct gen_pool_chunk *chunk)
42 return chunk->end_addr - chunk->start_addr + 1;
45 static int set_bits_ll(unsigned long *addr, unsigned long mask_to_set)
47 unsigned long val, nval;
52 if (val & mask_to_set)
55 } while ((nval = cmpxchg(addr, val, val | mask_to_set)) != val);
60 static int clear_bits_ll(unsigned long *addr, unsigned long mask_to_clear)
62 unsigned long val, nval;
67 if ((val & mask_to_clear) != mask_to_clear)
70 } while ((nval = cmpxchg(addr, val, val & ~mask_to_clear)) != val);
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
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
86 static int bitmap_set_ll(unsigned long *map, int start, int nr)
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);
93 while (nr - bits_to_set >= 0) {
94 if (set_bits_ll(p, mask_to_set))
97 bits_to_set = BITS_PER_LONG;
102 mask_to_set &= BITMAP_LAST_WORD_MASK(size);
103 if (set_bits_ll(p, mask_to_set))
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
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.
121 static int bitmap_clear_ll(unsigned long *map, int start, int nr)
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);
128 while (nr - bits_to_clear >= 0) {
129 if (clear_bits_ll(p, mask_to_clear))
132 bits_to_clear = BITS_PER_LONG;
133 mask_to_clear = ~0UL;
137 mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
138 if (clear_bits_ll(p, mask_to_clear))
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
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.
153 struct gen_pool *gen_pool_create(int min_alloc_order, int nid)
155 struct gen_pool *pool;
157 pool = kmalloc_node(sizeof(struct gen_pool), GFP_KERNEL, nid);
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;
168 EXPORT_SYMBOL(gen_pool_create);
171 * gen_pool_add_owner- 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 * @owner: private data the publisher would like to recall at alloc time
180 * Add a new chunk of special memory to the specified pool.
182 * Returns 0 on success or a -ve errno on failure.
184 int gen_pool_add_owner(struct gen_pool *pool, unsigned long virt, phys_addr_t phys,
185 size_t size, int nid, void *owner)
187 struct gen_pool_chunk *chunk;
188 int nbits = size >> pool->min_alloc_order;
189 int nbytes = sizeof(struct gen_pool_chunk) +
190 BITS_TO_LONGS(nbits) * sizeof(long);
192 chunk = vzalloc_node(nbytes, nid);
193 if (unlikely(chunk == NULL))
196 chunk->phys_addr = phys;
197 chunk->start_addr = virt;
198 chunk->end_addr = virt + size - 1;
199 chunk->owner = owner;
200 atomic_long_set(&chunk->avail, size);
202 spin_lock(&pool->lock);
203 list_add_rcu(&chunk->next_chunk, &pool->chunks);
204 spin_unlock(&pool->lock);
208 EXPORT_SYMBOL(gen_pool_add_owner);
211 * gen_pool_virt_to_phys - return the physical address of memory
212 * @pool: pool to allocate from
213 * @addr: starting address of memory
215 * Returns the physical address on success, or -1 on error.
217 phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long addr)
219 struct gen_pool_chunk *chunk;
220 phys_addr_t paddr = -1;
223 list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
224 if (addr >= chunk->start_addr && addr <= chunk->end_addr) {
225 paddr = chunk->phys_addr + (addr - chunk->start_addr);
233 EXPORT_SYMBOL(gen_pool_virt_to_phys);
236 * gen_pool_destroy - destroy a special memory pool
237 * @pool: pool to destroy
239 * Destroy the specified special memory pool. Verifies that there are no
240 * outstanding allocations.
242 void gen_pool_destroy(struct gen_pool *pool)
244 struct list_head *_chunk, *_next_chunk;
245 struct gen_pool_chunk *chunk;
246 int order = pool->min_alloc_order;
249 list_for_each_safe(_chunk, _next_chunk, &pool->chunks) {
250 chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk);
251 list_del(&chunk->next_chunk);
253 end_bit = chunk_size(chunk) >> order;
254 bit = find_next_bit(chunk->bits, end_bit, 0);
255 BUG_ON(bit < end_bit);
259 kfree_const(pool->name);
262 EXPORT_SYMBOL(gen_pool_destroy);
265 * gen_pool_alloc_algo_owner - allocate special memory from the pool
266 * @pool: pool to allocate from
267 * @size: number of bytes to allocate from the pool
268 * @algo: algorithm passed from caller
269 * @data: data passed to algorithm
270 * @owner: optionally retrieve the chunk owner
272 * Allocate the requested number of bytes from the specified pool.
273 * Uses the pool allocation function (with first-fit algorithm by default).
274 * Can not be used in NMI handler on architectures without
275 * NMI-safe cmpxchg implementation.
277 unsigned long gen_pool_alloc_algo_owner(struct gen_pool *pool, size_t size,
278 genpool_algo_t algo, void *data, void **owner)
280 struct gen_pool_chunk *chunk;
281 unsigned long addr = 0;
282 int order = pool->min_alloc_order;
283 int nbits, start_bit, end_bit, remain;
285 #ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
295 nbits = (size + (1UL << order) - 1) >> order;
297 list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
298 if (size > atomic_long_read(&chunk->avail))
302 end_bit = chunk_size(chunk) >> order;
304 start_bit = algo(chunk->bits, end_bit, start_bit,
305 nbits, data, pool, chunk->start_addr);
306 if (start_bit >= end_bit)
308 remain = bitmap_set_ll(chunk->bits, start_bit, nbits);
310 remain = bitmap_clear_ll(chunk->bits, start_bit,
316 addr = chunk->start_addr + ((unsigned long)start_bit << order);
317 size = nbits << order;
318 atomic_long_sub(size, &chunk->avail);
320 *owner = chunk->owner;
326 EXPORT_SYMBOL(gen_pool_alloc_algo_owner);
329 * gen_pool_dma_alloc - allocate special memory from the pool for DMA usage
330 * @pool: pool to allocate from
331 * @size: number of bytes to allocate from the pool
332 * @dma: dma-view physical address return value. Use NULL if unneeded.
334 * Allocate the requested number of bytes from the specified pool.
335 * Uses the pool allocation function (with first-fit algorithm by default).
336 * Can not be used in NMI handler on architectures without
337 * NMI-safe cmpxchg implementation.
339 void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size, dma_addr_t *dma)
346 vaddr = gen_pool_alloc(pool, size);
351 *dma = gen_pool_virt_to_phys(pool, vaddr);
353 return (void *)vaddr;
355 EXPORT_SYMBOL(gen_pool_dma_alloc);
358 * gen_pool_free - free allocated special memory back to the pool
359 * @pool: pool to free to
360 * @addr: starting address of memory to free back to pool
361 * @size: size in bytes of memory to free
362 * @owner: private data stashed at gen_pool_add() time
364 * Free previously allocated special memory back to the specified
365 * pool. Can not be used in NMI handler on architectures without
366 * NMI-safe cmpxchg implementation.
368 void gen_pool_free_owner(struct gen_pool *pool, unsigned long addr, size_t size,
371 struct gen_pool_chunk *chunk;
372 int order = pool->min_alloc_order;
373 int start_bit, nbits, remain;
375 #ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
382 nbits = (size + (1UL << order) - 1) >> order;
384 list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
385 if (addr >= chunk->start_addr && addr <= chunk->end_addr) {
386 BUG_ON(addr + size - 1 > chunk->end_addr);
387 start_bit = (addr - chunk->start_addr) >> order;
388 remain = bitmap_clear_ll(chunk->bits, start_bit, nbits);
390 size = nbits << order;
391 atomic_long_add(size, &chunk->avail);
393 *owner = chunk->owner;
401 EXPORT_SYMBOL(gen_pool_free_owner);
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
409 * Call @func for every chunk of generic memory pool. The @func is
410 * called with rcu_read_lock held.
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),
416 struct gen_pool_chunk *chunk;
419 list_for_each_entry_rcu(chunk, &(pool)->chunks, next_chunk)
420 func(pool, chunk, data);
423 EXPORT_SYMBOL(gen_pool_for_each_chunk);
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
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.
434 bool addr_in_gen_pool(struct gen_pool *pool, unsigned long start,
438 unsigned long end = start + size - 1;
439 struct gen_pool_chunk *chunk;
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) {
455 * gen_pool_avail - get available free space of the pool
456 * @pool: pool to get available free space
458 * Return available free space of the specified pool.
460 size_t gen_pool_avail(struct gen_pool *pool)
462 struct gen_pool_chunk *chunk;
466 list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk)
467 avail += atomic_long_read(&chunk->avail);
471 EXPORT_SYMBOL_GPL(gen_pool_avail);
474 * gen_pool_size - get size in bytes of memory managed by the pool
475 * @pool: pool to get size
477 * Return size in bytes of memory managed by the pool.
479 size_t gen_pool_size(struct gen_pool *pool)
481 struct gen_pool_chunk *chunk;
485 list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk)
486 size += chunk_size(chunk);
490 EXPORT_SYMBOL_GPL(gen_pool_size);
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
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.
502 void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo, void *data)
508 pool->algo = gen_pool_first_fit;
514 EXPORT_SYMBOL(gen_pool_set_algo);
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
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, unsigned long start_addr)
530 return bitmap_find_next_zero_area(map, size, start, nr, 0);
532 EXPORT_SYMBOL(gen_pool_first_fit);
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
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, unsigned long start_addr)
548 struct genpool_data_align *alignment;
549 unsigned long align_mask, align_off;
553 order = pool->min_alloc_order;
554 align_mask = ((alignment->align + (1UL << order) - 1) >> order) - 1;
555 align_off = (start_addr & (alignment->align - 1)) >> order;
557 return bitmap_find_next_zero_area_off(map, size, start, nr,
558 align_mask, align_off);
560 EXPORT_SYMBOL(gen_pool_first_fit_align);
563 * gen_pool_fixed_alloc - reserve a specific region
564 * @map: The address to base the search on
565 * @size: The bitmap size in bits
566 * @start: The bitnumber to start searching at
567 * @nr: The number of zeroed bits we're looking for
568 * @data: data for alignment
569 * @pool: pool to get order from
571 unsigned long gen_pool_fixed_alloc(unsigned long *map, unsigned long size,
572 unsigned long start, unsigned int nr, void *data,
573 struct gen_pool *pool, unsigned long start_addr)
575 struct genpool_data_fixed *fixed_data;
577 unsigned long offset_bit;
578 unsigned long start_bit;
581 order = pool->min_alloc_order;
582 offset_bit = fixed_data->offset >> order;
583 if (WARN_ON(fixed_data->offset & ((1UL << order) - 1)))
586 start_bit = bitmap_find_next_zero_area(map, size,
587 start + offset_bit, nr, 0);
588 if (start_bit != offset_bit)
592 EXPORT_SYMBOL(gen_pool_fixed_alloc);
595 * gen_pool_first_fit_order_align - find the first available region
596 * of memory matching the size requirement. The region will be aligned
597 * to the order of the size specified.
598 * @map: The address to base the search on
599 * @size: The bitmap size in bits
600 * @start: The bitnumber to start searching at
601 * @nr: The number of zeroed bits we're looking for
602 * @data: additional data - unused
603 * @pool: pool to find the fit region memory from
605 unsigned long gen_pool_first_fit_order_align(unsigned long *map,
606 unsigned long size, unsigned long start,
607 unsigned int nr, void *data, struct gen_pool *pool,
608 unsigned long start_addr)
610 unsigned long align_mask = roundup_pow_of_two(nr) - 1;
612 return bitmap_find_next_zero_area(map, size, start, nr, align_mask);
614 EXPORT_SYMBOL(gen_pool_first_fit_order_align);
617 * gen_pool_best_fit - find the best fitting region of memory
618 * macthing the size requirement (no alignment constraint)
619 * @map: The address to base the search on
620 * @size: The bitmap size in bits
621 * @start: The bitnumber to start searching at
622 * @nr: The number of zeroed bits we're looking for
623 * @data: additional data - unused
624 * @pool: pool to find the fit region memory from
626 * Iterate over the bitmap to find the smallest free region
627 * which we can allocate the memory.
629 unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size,
630 unsigned long start, unsigned int nr, void *data,
631 struct gen_pool *pool, unsigned long start_addr)
633 unsigned long start_bit = size;
634 unsigned long len = size + 1;
637 index = bitmap_find_next_zero_area(map, size, start, nr, 0);
639 while (index < size) {
640 int next_bit = find_next_bit(map, size, index + nr);
641 if ((next_bit - index) < len) {
642 len = next_bit - index;
647 index = bitmap_find_next_zero_area(map, size,
648 next_bit + 1, nr, 0);
653 EXPORT_SYMBOL(gen_pool_best_fit);
655 static void devm_gen_pool_release(struct device *dev, void *res)
657 gen_pool_destroy(*(struct gen_pool **)res);
660 static int devm_gen_pool_match(struct device *dev, void *res, void *data)
662 struct gen_pool **p = res;
664 /* NULL data matches only a pool without an assigned name */
665 if (!data && !(*p)->name)
668 if (!data || !(*p)->name)
671 return !strcmp((*p)->name, data);
675 * gen_pool_get - Obtain the gen_pool (if any) for a device
676 * @dev: device to retrieve the gen_pool from
677 * @name: name of a gen_pool or NULL, identifies a particular gen_pool on device
679 * Returns the gen_pool for the device if one is present, or NULL.
681 struct gen_pool *gen_pool_get(struct device *dev, const char *name)
685 p = devres_find(dev, devm_gen_pool_release, devm_gen_pool_match,
691 EXPORT_SYMBOL_GPL(gen_pool_get);
694 * devm_gen_pool_create - managed gen_pool_create
695 * @dev: device that provides the gen_pool
696 * @min_alloc_order: log base 2 of number of bytes each bitmap bit represents
697 * @nid: node selector for allocated gen_pool, %NUMA_NO_NODE for all nodes
698 * @name: name of a gen_pool or NULL, identifies a particular gen_pool on device
700 * Create a new special memory pool that can be used to manage special purpose
701 * memory not managed by the regular kmalloc/kfree interface. The pool will be
702 * automatically destroyed by the device management code.
704 struct gen_pool *devm_gen_pool_create(struct device *dev, int min_alloc_order,
705 int nid, const char *name)
707 struct gen_pool **ptr, *pool;
708 const char *pool_name = NULL;
710 /* Check that genpool to be created is uniquely addressed on device */
711 if (gen_pool_get(dev, name))
712 return ERR_PTR(-EINVAL);
715 pool_name = kstrdup_const(name, GFP_KERNEL);
717 return ERR_PTR(-ENOMEM);
720 ptr = devres_alloc(devm_gen_pool_release, sizeof(*ptr), GFP_KERNEL);
724 pool = gen_pool_create(min_alloc_order, nid);
729 pool->name = pool_name;
730 devres_add(dev, ptr);
737 kfree_const(pool_name);
739 return ERR_PTR(-ENOMEM);
741 EXPORT_SYMBOL(devm_gen_pool_create);
745 * of_gen_pool_get - find a pool by phandle property
747 * @propname: property name containing phandle(s)
748 * @index: index into the phandle array
750 * Returns the pool that contains the chunk starting at the physical
751 * address of the device tree node pointed at by the phandle property,
752 * or NULL if not found.
754 struct gen_pool *of_gen_pool_get(struct device_node *np,
755 const char *propname, int index)
757 struct platform_device *pdev;
758 struct device_node *np_pool, *parent;
759 const char *name = NULL;
760 struct gen_pool *pool = NULL;
762 np_pool = of_parse_phandle(np, propname, index);
766 pdev = of_find_device_by_node(np_pool);
768 /* Check if named gen_pool is created by parent node device */
769 parent = of_get_parent(np_pool);
770 pdev = of_find_device_by_node(parent);
773 of_property_read_string(np_pool, "label", &name);
775 name = np_pool->name;
778 pool = gen_pool_get(&pdev->dev, name);
779 of_node_put(np_pool);
783 EXPORT_SYMBOL_GPL(of_gen_pool_get);
784 #endif /* CONFIG_OF */