OSCL-LXR linux-6.0.1/​lib/​genalloc.c	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // 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_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 int set_bits_ll(unsigned long *addr, unsigned long mask_to_set)
 {
     unsigned long val, nval;
 
     nval = *addr;
     do {
         val = nval;
         if (val & mask_to_set)
             return -EBUSY;
         cpu_relax();
     } while ((nval = cmpxchg(addr, val, val | mask_to_set)) != val);
 
     return 0;
 }
 
 static int clear_bits_ll(unsigned long *addr, unsigned long mask_to_clear)
 {
     unsigned long val, nval;
 
     nval = *addr;
     do {
         val = nval;
         if ((val & mask_to_clear) != mask_to_clear)
             return -EBUSY;
         cpu_relax();
     } while ((nval = cmpxchg(addr, val, val & ~mask_to_clear)) != val);
 
     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 = np_pool->name;
     }
     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 */

This page was automatically generated by the 2.1.0 LXR engine. The LXR team