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Diffstat (limited to '')
| -rw-r--r-- | lib/genalloc.c | 909 |
1 files changed, 909 insertions, 0 deletions
diff --git a/lib/genalloc.c b/lib/genalloc.c new file mode 100644 index 0000000000..4fa5635bf8 --- /dev/null +++ b/lib/genalloc.c @@ -0,0 +1,909 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Basic general purpose allocator for managing special purpose + * memory, for example, memory that is not managed by the regular + * kmalloc/kfree interface. Uses for this includes on-device special + * memory, uncached memory etc. + * + * It is safe to use the allocator in NMI handlers and other special + * unblockable contexts that could otherwise deadlock on locks. This + * is implemented by using atomic operations and retries on any + * conflicts. The disadvantage is that there may be livelocks in + * extreme cases. For better scalability, one allocator can be used + * for each CPU. + * + * The lockless operation only works if there is enough memory + * available. If new memory is added to the pool a lock has to be + * still taken. So any user relying on locklessness has to ensure + * that sufficient memory is preallocated. + * + * The basic atomic operation of this allocator is cmpxchg on long. + * On architectures that don't have NMI-safe cmpxchg implementation, + * the allocator can NOT be used in NMI handler. So code uses the + * allocator in NMI handler should depend on + * CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG. + * + * Copyright 2005 (C) Jes Sorensen <jes@trained-monkey.org> + */ + +#include <linux/slab.h> +#include <linux/export.h> +#include <linux/bitmap.h> +#include <linux/rculist.h> +#include <linux/interrupt.h> +#include <linux/genalloc.h> +#include <linux/of.h> +#include <linux/of_platform.h> +#include <linux/platform_device.h> +#include <linux/vmalloc.h> + +static inline size_t chunk_size(const struct gen_pool_chunk *chunk) +{ + return chunk->end_addr - chunk->start_addr + 1; +} + +static inline int +set_bits_ll(unsigned long *addr, unsigned long mask_to_set) +{ + unsigned long val = READ_ONCE(*addr); + + do { + if (val & mask_to_set) + return -EBUSY; + cpu_relax(); + } while (!try_cmpxchg(addr, &val, val | mask_to_set)); + + return 0; +} + +static inline int +clear_bits_ll(unsigned long *addr, unsigned long mask_to_clear) +{ + unsigned long val = READ_ONCE(*addr); + + do { + if ((val & mask_to_clear) != mask_to_clear) + return -EBUSY; + cpu_relax(); + } while (!try_cmpxchg(addr, &val, val & ~mask_to_clear)); + + return 0; +} + +/* + * bitmap_set_ll - set the specified number of bits at the specified position + * @map: pointer to a bitmap + * @start: a bit position in @map + * @nr: number of bits to set + * + * Set @nr bits start from @start in @map lock-lessly. Several users + * can set/clear the same bitmap simultaneously without lock. If two + * users set the same bit, one user will return remain bits, otherwise + * return 0. + */ +static unsigned long +bitmap_set_ll(unsigned long *map, unsigned long start, unsigned long nr) +{ + unsigned long *p = map + BIT_WORD(start); + const unsigned long size = start + nr; + int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG); + unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start); + + while (nr >= bits_to_set) { + if (set_bits_ll(p, mask_to_set)) + return nr; + nr -= bits_to_set; + bits_to_set = BITS_PER_LONG; + mask_to_set = ~0UL; + p++; + } + if (nr) { + mask_to_set &= BITMAP_LAST_WORD_MASK(size); + if (set_bits_ll(p, mask_to_set)) + return nr; + } + + return 0; +} + +/* + * bitmap_clear_ll - clear the specified number of bits at the specified position + * @map: pointer to a bitmap + * @start: a bit position in @map + * @nr: number of bits to set + * + * Clear @nr bits start from @start in @map lock-lessly. Several users + * can set/clear the same bitmap simultaneously without lock. If two + * users clear the same bit, one user will return remain bits, + * otherwise return 0. + */ +static unsigned long +bitmap_clear_ll(unsigned long *map, unsigned long start, unsigned long nr) +{ + unsigned long *p = map + BIT_WORD(start); + const unsigned long size = start + nr; + int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG); + unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start); + + while (nr >= bits_to_clear) { + if (clear_bits_ll(p, mask_to_clear)) + return nr; + nr -= bits_to_clear; + bits_to_clear = BITS_PER_LONG; + mask_to_clear = ~0UL; + p++; + } + if (nr) { + mask_to_clear &= BITMAP_LAST_WORD_MASK(size); + if (clear_bits_ll(p, mask_to_clear)) + return nr; + } + + return 0; +} + +/** + * gen_pool_create - create a new special memory pool + * @min_alloc_order: log base 2 of number of bytes each bitmap bit represents + * @nid: node id of the node the pool structure should be allocated on, or -1 + * + * Create a new special memory pool that can be used to manage special purpose + * memory not managed by the regular kmalloc/kfree interface. + */ +struct gen_pool *gen_pool_create(int min_alloc_order, int nid) +{ + struct gen_pool *pool; + + pool = kmalloc_node(sizeof(struct gen_pool), GFP_KERNEL, nid); + if (pool != NULL) { + spin_lock_init(&pool->lock); + INIT_LIST_HEAD(&pool->chunks); + pool->min_alloc_order = min_alloc_order; + pool->algo = gen_pool_first_fit; + pool->data = NULL; + pool->name = NULL; + } + return pool; +} +EXPORT_SYMBOL(gen_pool_create); + +/** + * gen_pool_add_owner- add a new chunk of special memory to the pool + * @pool: pool to add new memory chunk to + * @virt: virtual starting address of memory chunk to add to pool + * @phys: physical starting address of memory chunk to add to pool + * @size: size in bytes of the memory chunk to add to pool + * @nid: node id of the node the chunk structure and bitmap should be + * allocated on, or -1 + * @owner: private data the publisher would like to recall at alloc time + * + * Add a new chunk of special memory to the specified pool. + * + * Returns 0 on success or a -ve errno on failure. + */ +int gen_pool_add_owner(struct gen_pool *pool, unsigned long virt, phys_addr_t phys, + size_t size, int nid, void *owner) +{ + struct gen_pool_chunk *chunk; + unsigned long nbits = size >> pool->min_alloc_order; + unsigned long nbytes = sizeof(struct gen_pool_chunk) + + BITS_TO_LONGS(nbits) * sizeof(long); + + chunk = vzalloc_node(nbytes, nid); + if (unlikely(chunk == NULL)) + return -ENOMEM; + + chunk->phys_addr = phys; + chunk->start_addr = virt; + chunk->end_addr = virt + size - 1; + chunk->owner = owner; + atomic_long_set(&chunk->avail, size); + + spin_lock(&pool->lock); + list_add_rcu(&chunk->next_chunk, &pool->chunks); + spin_unlock(&pool->lock); + + return 0; +} +EXPORT_SYMBOL(gen_pool_add_owner); + +/** + * gen_pool_virt_to_phys - return the physical address of memory + * @pool: pool to allocate from + * @addr: starting address of memory + * + * Returns the physical address on success, or -1 on error. + */ +phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long addr) +{ + struct gen_pool_chunk *chunk; + phys_addr_t paddr = -1; + + rcu_read_lock(); + list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) { + if (addr >= chunk->start_addr && addr <= chunk->end_addr) { + paddr = chunk->phys_addr + (addr - chunk->start_addr); + break; + } + } + rcu_read_unlock(); + + return paddr; +} +EXPORT_SYMBOL(gen_pool_virt_to_phys); + +/** + * gen_pool_destroy - destroy a special memory pool + * @pool: pool to destroy + * + * Destroy the specified special memory pool. Verifies that there are no + * outstanding allocations. + */ +void gen_pool_destroy(struct gen_pool *pool) +{ + struct list_head *_chunk, *_next_chunk; + struct gen_pool_chunk *chunk; + int order = pool->min_alloc_order; + unsigned long bit, end_bit; + + list_for_each_safe(_chunk, _next_chunk, &pool->chunks) { + chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk); + list_del(&chunk->next_chunk); + + end_bit = chunk_size(chunk) >> order; + bit = find_first_bit(chunk->bits, end_bit); + BUG_ON(bit < end_bit); + + vfree(chunk); + } + kfree_const(pool->name); + kfree(pool); +} +EXPORT_SYMBOL(gen_pool_destroy); + +/** + * gen_pool_alloc_algo_owner - allocate special memory from the pool + * @pool: pool to allocate from + * @size: number of bytes to allocate from the pool + * @algo: algorithm passed from caller + * @data: data passed to algorithm + * @owner: optionally retrieve the chunk owner + * + * Allocate the requested number of bytes from the specified pool. + * Uses the pool allocation function (with first-fit algorithm by default). + * Can not be used in NMI handler on architectures without + * NMI-safe cmpxchg implementation. + */ +unsigned long gen_pool_alloc_algo_owner(struct gen_pool *pool, size_t size, + genpool_algo_t algo, void *data, void **owner) +{ + struct gen_pool_chunk *chunk; + unsigned long addr = 0; + int order = pool->min_alloc_order; + unsigned long nbits, start_bit, end_bit, remain; + +#ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG + BUG_ON(in_nmi()); +#endif + + if (owner) + *owner = NULL; + + if (size == 0) + return 0; + + nbits = (size + (1UL << order) - 1) >> order; + rcu_read_lock(); + list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) { + if (size > atomic_long_read(&chunk->avail)) + continue; + + start_bit = 0; + end_bit = chunk_size(chunk) >> order; +retry: + start_bit = algo(chunk->bits, end_bit, start_bit, + nbits, data, pool, chunk->start_addr); + if (start_bit >= end_bit) + continue; + remain = bitmap_set_ll(chunk->bits, start_bit, nbits); + if (remain) { + remain = bitmap_clear_ll(chunk->bits, start_bit, + nbits - remain); + BUG_ON(remain); + goto retry; + } + + addr = chunk->start_addr + ((unsigned long)start_bit << order); + size = nbits << order; + atomic_long_sub(size, &chunk->avail); + if (owner) + *owner = chunk->owner; + break; + } + rcu_read_unlock(); + return addr; +} +EXPORT_SYMBOL(gen_pool_alloc_algo_owner); + +/** + * gen_pool_dma_alloc - allocate special memory from the pool for DMA usage + * @pool: pool to allocate from + * @size: number of bytes to allocate from the pool + * @dma: dma-view physical address return value. Use %NULL if unneeded. + * + * Allocate the requested number of bytes from the specified pool. + * Uses the pool allocation function (with first-fit algorithm by default). + * Can not be used in NMI handler on architectures without + * NMI-safe cmpxchg implementation. + * + * Return: virtual address of the allocated memory, or %NULL on failure + */ +void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size, dma_addr_t *dma) +{ + return gen_pool_dma_alloc_algo(pool, size, dma, pool->algo, pool->data); +} +EXPORT_SYMBOL(gen_pool_dma_alloc); + +/** + * gen_pool_dma_alloc_algo - allocate special memory from the pool for DMA + * usage with the given pool algorithm + * @pool: pool to allocate from + * @size: number of bytes to allocate from the pool + * @dma: DMA-view physical address return value. Use %NULL if unneeded. + * @algo: algorithm passed from caller + * @data: data passed to algorithm + * + * Allocate the requested number of bytes from the specified pool. Uses the + * given pool allocation function. Can not be used in NMI handler on + * architectures without NMI-safe cmpxchg implementation. + * + * Return: virtual address of the allocated memory, or %NULL on failure + */ +void *gen_pool_dma_alloc_algo(struct gen_pool *pool, size_t size, + dma_addr_t *dma, genpool_algo_t algo, void *data) +{ + unsigned long vaddr; + + if (!pool) + return NULL; + + vaddr = gen_pool_alloc_algo(pool, size, algo, data); + if (!vaddr) + return NULL; + + if (dma) + *dma = gen_pool_virt_to_phys(pool, vaddr); + + return (void *)vaddr; +} +EXPORT_SYMBOL(gen_pool_dma_alloc_algo); + +/** + * gen_pool_dma_alloc_align - allocate special memory from the pool for DMA + * usage with the given alignment + * @pool: pool to allocate from + * @size: number of bytes to allocate from the pool + * @dma: DMA-view physical address return value. Use %NULL if unneeded. + * @align: alignment in bytes for starting address + * + * Allocate the requested number bytes from the specified pool, with the given + * alignment restriction. Can not be used in NMI handler on architectures + * without NMI-safe cmpxchg implementation. + * + * Return: virtual address of the allocated memory, or %NULL on failure + */ +void *gen_pool_dma_alloc_align(struct gen_pool *pool, size_t size, + dma_addr_t *dma, int align) +{ + struct genpool_data_align data = { .align = align }; + + return gen_pool_dma_alloc_algo(pool, size, dma, + gen_pool_first_fit_align, &data); +} +EXPORT_SYMBOL(gen_pool_dma_alloc_align); + +/** + * gen_pool_dma_zalloc - allocate special zeroed memory from the pool for + * DMA usage + * @pool: pool to allocate from + * @size: number of bytes to allocate from the pool + * @dma: dma-view physical address return value. Use %NULL if unneeded. + * + * Allocate the requested number of zeroed bytes from the specified pool. + * Uses the pool allocation function (with first-fit algorithm by default). + * Can not be used in NMI handler on architectures without + * NMI-safe cmpxchg implementation. + * + * Return: virtual address of the allocated zeroed memory, or %NULL on failure + */ +void *gen_pool_dma_zalloc(struct gen_pool *pool, size_t size, dma_addr_t *dma) +{ + return gen_pool_dma_zalloc_algo(pool, size, dma, pool->algo, pool->data); +} +EXPORT_SYMBOL(gen_pool_dma_zalloc); + +/** + * gen_pool_dma_zalloc_algo - allocate special zeroed memory from the pool for + * DMA usage with the given pool algorithm + * @pool: pool to allocate from + * @size: number of bytes to allocate from the pool + * @dma: DMA-view physical address return value. Use %NULL if unneeded. + * @algo: algorithm passed from caller + * @data: data passed to algorithm + * + * Allocate the requested number of zeroed bytes from the specified pool. Uses + * the given pool allocation function. Can not be used in NMI handler on + * architectures without NMI-safe cmpxchg implementation. + * + * Return: virtual address of the allocated zeroed memory, or %NULL on failure + */ +void *gen_pool_dma_zalloc_algo(struct gen_pool *pool, size_t size, + dma_addr_t *dma, genpool_algo_t algo, void *data) +{ + void *vaddr = gen_pool_dma_alloc_algo(pool, size, dma, algo, data); + + if (vaddr) + memset(vaddr, 0, size); + + return vaddr; +} +EXPORT_SYMBOL(gen_pool_dma_zalloc_algo); + +/** + * gen_pool_dma_zalloc_align - allocate special zeroed memory from the pool for + * DMA usage with the given alignment + * @pool: pool to allocate from + * @size: number of bytes to allocate from the pool + * @dma: DMA-view physical address return value. Use %NULL if unneeded. + * @align: alignment in bytes for starting address + * + * Allocate the requested number of zeroed bytes from the specified pool, + * with the given alignment restriction. Can not be used in NMI handler on + * architectures without NMI-safe cmpxchg implementation. + * + * Return: virtual address of the allocated zeroed memory, or %NULL on failure + */ +void *gen_pool_dma_zalloc_align(struct gen_pool *pool, size_t size, + dma_addr_t *dma, int align) +{ + struct genpool_data_align data = { .align = align }; + + return gen_pool_dma_zalloc_algo(pool, size, dma, + gen_pool_first_fit_align, &data); +} +EXPORT_SYMBOL(gen_pool_dma_zalloc_align); + +/** + * gen_pool_free_owner - free allocated special memory back to the pool + * @pool: pool to free to + * @addr: starting address of memory to free back to pool + * @size: size in bytes of memory to free + * @owner: private data stashed at gen_pool_add() time + * + * Free previously allocated special memory back to the specified + * pool. Can not be used in NMI handler on architectures without + * NMI-safe cmpxchg implementation. + */ +void gen_pool_free_owner(struct gen_pool *pool, unsigned long addr, size_t size, + void **owner) +{ + struct gen_pool_chunk *chunk; + int order = pool->min_alloc_order; + unsigned long start_bit, nbits, remain; + +#ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG + BUG_ON(in_nmi()); +#endif + + if (owner) + *owner = NULL; + + nbits = (size + (1UL << order) - 1) >> order; + rcu_read_lock(); + list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) { + if (addr >= chunk->start_addr && addr <= chunk->end_addr) { + BUG_ON(addr + size - 1 > chunk->end_addr); + start_bit = (addr - chunk->start_addr) >> order; + remain = bitmap_clear_ll(chunk->bits, start_bit, nbits); + BUG_ON(remain); + size = nbits << order; + atomic_long_add(size, &chunk->avail); + if (owner) + *owner = chunk->owner; + rcu_read_unlock(); + return; + } + } + rcu_read_unlock(); + BUG(); +} +EXPORT_SYMBOL(gen_pool_free_owner); + +/** + * gen_pool_for_each_chunk - call func for every chunk of generic memory pool + * @pool: the generic memory pool + * @func: func to call + * @data: additional data used by @func + * + * Call @func for every chunk of generic memory pool. The @func is + * called with rcu_read_lock held. + */ +void gen_pool_for_each_chunk(struct gen_pool *pool, + void (*func)(struct gen_pool *pool, struct gen_pool_chunk *chunk, void *data), + void *data) +{ + struct gen_pool_chunk *chunk; + + rcu_read_lock(); + list_for_each_entry_rcu(chunk, &(pool)->chunks, next_chunk) + func(pool, chunk, data); + rcu_read_unlock(); +} +EXPORT_SYMBOL(gen_pool_for_each_chunk); + +/** + * gen_pool_has_addr - checks if an address falls within the range of a pool + * @pool: the generic memory pool + * @start: start address + * @size: size of the region + * + * Check if the range of addresses falls within the specified pool. Returns + * true if the entire range is contained in the pool and false otherwise. + */ +bool gen_pool_has_addr(struct gen_pool *pool, unsigned long start, + size_t size) +{ + bool found = false; + unsigned long end = start + size - 1; + struct gen_pool_chunk *chunk; + + rcu_read_lock(); + list_for_each_entry_rcu(chunk, &(pool)->chunks, next_chunk) { + if (start >= chunk->start_addr && start <= chunk->end_addr) { + if (end <= chunk->end_addr) { + found = true; + break; + } + } + } + rcu_read_unlock(); + return found; +} +EXPORT_SYMBOL(gen_pool_has_addr); + +/** + * gen_pool_avail - get available free space of the pool + * @pool: pool to get available free space + * + * Return available free space of the specified pool. + */ +size_t gen_pool_avail(struct gen_pool *pool) +{ + struct gen_pool_chunk *chunk; + size_t avail = 0; + + rcu_read_lock(); + list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) + avail += atomic_long_read(&chunk->avail); + rcu_read_unlock(); + return avail; +} +EXPORT_SYMBOL_GPL(gen_pool_avail); + +/** + * gen_pool_size - get size in bytes of memory managed by the pool + * @pool: pool to get size + * + * Return size in bytes of memory managed by the pool. + */ +size_t gen_pool_size(struct gen_pool *pool) +{ + struct gen_pool_chunk *chunk; + size_t size = 0; + + rcu_read_lock(); + list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) + size += chunk_size(chunk); + rcu_read_unlock(); + return size; +} +EXPORT_SYMBOL_GPL(gen_pool_size); + +/** + * gen_pool_set_algo - set the allocation algorithm + * @pool: pool to change allocation algorithm + * @algo: custom algorithm function + * @data: additional data used by @algo + * + * Call @algo for each memory allocation in the pool. + * If @algo is NULL use gen_pool_first_fit as default + * memory allocation function. + */ +void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo, void *data) +{ + rcu_read_lock(); + + pool->algo = algo; + if (!pool->algo) + pool->algo = gen_pool_first_fit; + + pool->data = data; + + rcu_read_unlock(); +} +EXPORT_SYMBOL(gen_pool_set_algo); + +/** + * gen_pool_first_fit - find the first available region + * of memory matching the size requirement (no alignment constraint) + * @map: The address to base the search on + * @size: The bitmap size in bits + * @start: The bitnumber to start searching at + * @nr: The number of zeroed bits we're looking for + * @data: additional data - unused + * @pool: pool to find the fit region memory from + * @start_addr: not used in this function + */ +unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size, + unsigned long start, unsigned int nr, void *data, + struct gen_pool *pool, unsigned long start_addr) +{ + return bitmap_find_next_zero_area(map, size, start, nr, 0); +} +EXPORT_SYMBOL(gen_pool_first_fit); + +/** + * gen_pool_first_fit_align - find the first available region + * of memory matching the size requirement (alignment constraint) + * @map: The address to base the search on + * @size: The bitmap size in bits + * @start: The bitnumber to start searching at + * @nr: The number of zeroed bits we're looking for + * @data: data for alignment + * @pool: pool to get order from + * @start_addr: start addr of alloction chunk + */ +unsigned long gen_pool_first_fit_align(unsigned long *map, unsigned long size, + unsigned long start, unsigned int nr, void *data, + struct gen_pool *pool, unsigned long start_addr) +{ + struct genpool_data_align *alignment; + unsigned long align_mask, align_off; + int order; + + alignment = data; + order = pool->min_alloc_order; + align_mask = ((alignment->align + (1UL << order) - 1) >> order) - 1; + align_off = (start_addr & (alignment->align - 1)) >> order; + + return bitmap_find_next_zero_area_off(map, size, start, nr, + align_mask, align_off); +} +EXPORT_SYMBOL(gen_pool_first_fit_align); + +/** + * gen_pool_fixed_alloc - reserve a specific region + * @map: The address to base the search on + * @size: The bitmap size in bits + * @start: The bitnumber to start searching at + * @nr: The number of zeroed bits we're looking for + * @data: data for alignment + * @pool: pool to get order from + * @start_addr: not used in this function + */ +unsigned long gen_pool_fixed_alloc(unsigned long *map, unsigned long size, + unsigned long start, unsigned int nr, void *data, + struct gen_pool *pool, unsigned long start_addr) +{ + struct genpool_data_fixed *fixed_data; + int order; + unsigned long offset_bit; + unsigned long start_bit; + + fixed_data = data; + order = pool->min_alloc_order; + offset_bit = fixed_data->offset >> order; + if (WARN_ON(fixed_data->offset & ((1UL << order) - 1))) + return size; + + start_bit = bitmap_find_next_zero_area(map, size, + start + offset_bit, nr, 0); + if (start_bit != offset_bit) + start_bit = size; + return start_bit; +} +EXPORT_SYMBOL(gen_pool_fixed_alloc); + +/** + * gen_pool_first_fit_order_align - find the first available region + * of memory matching the size requirement. The region will be aligned + * to the order of the size specified. + * @map: The address to base the search on + * @size: The bitmap size in bits + * @start: The bitnumber to start searching at + * @nr: The number of zeroed bits we're looking for + * @data: additional data - unused + * @pool: pool to find the fit region memory from + * @start_addr: not used in this function + */ +unsigned long gen_pool_first_fit_order_align(unsigned long *map, + unsigned long size, unsigned long start, + unsigned int nr, void *data, struct gen_pool *pool, + unsigned long start_addr) +{ + unsigned long align_mask = roundup_pow_of_two(nr) - 1; + + return bitmap_find_next_zero_area(map, size, start, nr, align_mask); +} +EXPORT_SYMBOL(gen_pool_first_fit_order_align); + +/** + * gen_pool_best_fit - find the best fitting region of memory + * matching the size requirement (no alignment constraint) + * @map: The address to base the search on + * @size: The bitmap size in bits + * @start: The bitnumber to start searching at + * @nr: The number of zeroed bits we're looking for + * @data: additional data - unused + * @pool: pool to find the fit region memory from + * @start_addr: not used in this function + * + * Iterate over the bitmap to find the smallest free region + * which we can allocate the memory. + */ +unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size, + unsigned long start, unsigned int nr, void *data, + struct gen_pool *pool, unsigned long start_addr) +{ + unsigned long start_bit = size; + unsigned long len = size + 1; + unsigned long index; + + index = bitmap_find_next_zero_area(map, size, start, nr, 0); + + while (index < size) { + unsigned long next_bit = find_next_bit(map, size, index + nr); + if ((next_bit - index) < len) { + len = next_bit - index; + start_bit = index; + if (len == nr) + return start_bit; + } + index = bitmap_find_next_zero_area(map, size, + next_bit + 1, nr, 0); + } + + return start_bit; +} +EXPORT_SYMBOL(gen_pool_best_fit); + +static void devm_gen_pool_release(struct device *dev, void *res) +{ + gen_pool_destroy(*(struct gen_pool **)res); +} + +static int devm_gen_pool_match(struct device *dev, void *res, void *data) +{ + struct gen_pool **p = res; + + /* NULL data matches only a pool without an assigned name */ + if (!data && !(*p)->name) + return 1; + + if (!data || !(*p)->name) + return 0; + + return !strcmp((*p)->name, data); +} + +/** + * gen_pool_get - Obtain the gen_pool (if any) for a device + * @dev: device to retrieve the gen_pool from + * @name: name of a gen_pool or NULL, identifies a particular gen_pool on device + * + * Returns the gen_pool for the device if one is present, or NULL. + */ +struct gen_pool *gen_pool_get(struct device *dev, const char *name) +{ + struct gen_pool **p; + + p = devres_find(dev, devm_gen_pool_release, devm_gen_pool_match, + (void *)name); + if (!p) + return NULL; + return *p; +} +EXPORT_SYMBOL_GPL(gen_pool_get); + +/** + * devm_gen_pool_create - managed gen_pool_create + * @dev: device that provides the gen_pool + * @min_alloc_order: log base 2 of number of bytes each bitmap bit represents + * @nid: node selector for allocated gen_pool, %NUMA_NO_NODE for all nodes + * @name: name of a gen_pool or NULL, identifies a particular gen_pool on device + * + * Create a new special memory pool that can be used to manage special purpose + * memory not managed by the regular kmalloc/kfree interface. The pool will be + * automatically destroyed by the device management code. + */ +struct gen_pool *devm_gen_pool_create(struct device *dev, int min_alloc_order, + int nid, const char *name) +{ + struct gen_pool **ptr, *pool; + const char *pool_name = NULL; + + /* Check that genpool to be created is uniquely addressed on device */ + if (gen_pool_get(dev, name)) + return ERR_PTR(-EINVAL); + + if (name) { + pool_name = kstrdup_const(name, GFP_KERNEL); + if (!pool_name) + return ERR_PTR(-ENOMEM); + } + + ptr = devres_alloc(devm_gen_pool_release, sizeof(*ptr), GFP_KERNEL); + if (!ptr) + goto free_pool_name; + + pool = gen_pool_create(min_alloc_order, nid); + if (!pool) + goto free_devres; + + *ptr = pool; + pool->name = pool_name; + devres_add(dev, ptr); + + return pool; + +free_devres: + devres_free(ptr); +free_pool_name: + kfree_const(pool_name); + + return ERR_PTR(-ENOMEM); +} +EXPORT_SYMBOL(devm_gen_pool_create); + +#ifdef CONFIG_OF +/** + * of_gen_pool_get - find a pool by phandle property + * @np: device node + * @propname: property name containing phandle(s) + * @index: index into the phandle array + * + * Returns the pool that contains the chunk starting at the physical + * address of the device tree node pointed at by the phandle property, + * or NULL if not found. + */ +struct gen_pool *of_gen_pool_get(struct device_node *np, + const char *propname, int index) +{ + struct platform_device *pdev; + struct device_node *np_pool, *parent; + const char *name = NULL; + struct gen_pool *pool = NULL; + + np_pool = of_parse_phandle(np, propname, index); + if (!np_pool) + return NULL; + + pdev = of_find_device_by_node(np_pool); + if (!pdev) { + /* Check if named gen_pool is created by parent node device */ + parent = of_get_parent(np_pool); + pdev = of_find_device_by_node(parent); + of_node_put(parent); + + of_property_read_string(np_pool, "label", &name); + if (!name) + name = of_node_full_name(np_pool); + } + if (pdev) + pool = gen_pool_get(&pdev->dev, name); + of_node_put(np_pool); + + return pool; +} +EXPORT_SYMBOL_GPL(of_gen_pool_get); +#endif /* CONFIG_OF */ |