This commit adds a gen_pool_alloc_aligned() function to the generic allocator API. It allows specifying alignment for the allocated block. This feature uses the bitmap_find_next_zero_area_off() function. It also fixes possible issue with bitmap's last element being not fully allocated (ie. space allocated for chunk->bits is not a multiple of sizeof(long)). It also makes some other smaller changes: - moves structure definitions out of the header file, - adds __must_check to functions returning value, - makes gen_pool_add() return -ENOMEM rater than -1 on error, - changes list_for_each to list_for_each_entry, and - makes use of bitmap_clear(). Signed-off-by: Michal Nazarewicz <mina86@xxxxxxxxxx> --- include/linux/genalloc.h | 46 ++++++------ lib/genalloc.c | 182 ++++++++++++++++++++++++++------------------- 2 files changed, 129 insertions(+), 99 deletions(-) diff --git a/include/linux/genalloc.h b/include/linux/genalloc.h index 9869ef3..8ac7337 100644 --- a/include/linux/genalloc.h +++ b/include/linux/genalloc.h @@ -8,29 +8,31 @@ * Version 2. See the file COPYING for more details. */ +struct gen_pool; -/* - * General purpose special memory pool descriptor. - */ -struct gen_pool { - rwlock_t lock; - struct list_head chunks; /* list of chunks in this pool */ - int min_alloc_order; /* minimum allocation order */ -}; +struct gen_pool *__must_check gen_pool_create(unsigned order, int nid); -/* - * General purpose special memory pool chunk descriptor. +int __must_check gen_pool_add(struct gen_pool *pool, unsigned long addr, + size_t size, int nid); + +void gen_pool_destroy(struct gen_pool *pool); + +unsigned long __must_check +gen_pool_alloc_aligned(struct gen_pool *pool, size_t size, + unsigned alignment_order); + +/** + * gen_pool_alloc() - allocate special memory from the pool + * @pool: Pool to allocate from. + * @size: Number of bytes to allocate from the pool. + * + * Allocate the requested number of bytes from the specified pool. + * Uses a first-fit algorithm. */ -struct gen_pool_chunk { - spinlock_t lock; - struct list_head next_chunk; /* next chunk in pool */ - unsigned long start_addr; /* starting address of memory chunk */ - unsigned long end_addr; /* ending address of memory chunk */ - unsigned long bits[0]; /* bitmap for allocating memory chunk */ -}; +static inline unsigned long __must_check +gen_pool_alloc(struct gen_pool *pool, size_t size) +{ + return gen_pool_alloc_aligned(pool, size, 0); +} -extern struct gen_pool *gen_pool_create(int, int); -extern int gen_pool_add(struct gen_pool *, unsigned long, size_t, int); -extern void gen_pool_destroy(struct gen_pool *); -extern unsigned long gen_pool_alloc(struct gen_pool *, size_t); -extern void gen_pool_free(struct gen_pool *, unsigned long, size_t); +void gen_pool_free(struct gen_pool *pool, unsigned long addr, size_t size); diff --git a/lib/genalloc.c b/lib/genalloc.c index 1923f14..0761079 100644 --- a/lib/genalloc.c +++ b/lib/genalloc.c @@ -16,53 +16,80 @@ #include <linux/genalloc.h> +/* General purpose special memory pool descriptor. */ +struct gen_pool { + rwlock_t lock; /* protects chunks list */ + struct list_head chunks; /* list of chunks in this pool */ + unsigned order; /* minimum allocation order */ +}; + +/* General purpose special memory pool chunk descriptor. */ +struct gen_pool_chunk { + spinlock_t lock; /* protects bits */ + struct list_head next_chunk; /* next chunk in pool */ + unsigned long start; /* start of memory chunk */ + unsigned long size; /* number of bits */ + unsigned long bits[0]; /* bitmap for allocating memory chunk */ +}; + + /** - * 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 + * gen_pool_create() - create a new special memory pool + * @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. This will be also used for other allocations. * * 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 *__must_check gen_pool_create(unsigned order, int nid) { struct gen_pool *pool; - pool = kmalloc_node(sizeof(struct gen_pool), GFP_KERNEL, nid); - if (pool != NULL) { + if (WARN_ON(order >= BITS_PER_LONG)) + return NULL; + + pool = kmalloc_node(sizeof *pool, GFP_KERNEL, nid); + if (pool) { rwlock_init(&pool->lock); INIT_LIST_HEAD(&pool->chunks); - pool->min_alloc_order = min_alloc_order; + pool->order = order; } return pool; } EXPORT_SYMBOL(gen_pool_create); /** - * gen_pool_add - add a new chunk of special memory to the pool - * @pool: pool to add new memory chunk to - * @addr: 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 + * gen_pool_add() - add a new chunk of special memory to the pool + * @pool: Pool to add new memory chunk to. + * @addr: Starting address of memory chunk to add to pool. + * @size: Size in bytes of the memory chunk to add to pool. * * Add a new chunk of special memory to the specified pool. */ -int gen_pool_add(struct gen_pool *pool, unsigned long addr, size_t size, - int nid) +int __must_check +gen_pool_add(struct gen_pool *pool, unsigned long addr, size_t size, int nid) { struct gen_pool_chunk *chunk; - int nbits = size >> pool->min_alloc_order; - int nbytes = sizeof(struct gen_pool_chunk) + - (nbits + BITS_PER_BYTE - 1) / BITS_PER_BYTE; + size_t nbytes; + + if (WARN_ON(!addr || addr + size < addr || + (addr & ((1 << pool->order) - 1)))) + return -EINVAL; - chunk = kmalloc_node(nbytes, GFP_KERNEL | __GFP_ZERO, nid); - if (unlikely(chunk == NULL)) - return -1; + size = size >> pool->order; + if (WARN_ON(!size)) + return -EINVAL; + + nbytes = sizeof *chunk + BITS_TO_LONGS(size) * sizeof *chunk->bits; + chunk = kzalloc_node(nbytes, GFP_KERNEL, nid); + if (!chunk) + return -ENOMEM; spin_lock_init(&chunk->lock); - chunk->start_addr = addr; - chunk->end_addr = addr + size; + chunk->start = addr >> pool->order; + chunk->size = size; write_lock(&pool->lock); list_add(&chunk->next_chunk, &pool->chunks); @@ -73,115 +100,116 @@ int gen_pool_add(struct gen_pool *pool, unsigned long addr, size_t size, EXPORT_SYMBOL(gen_pool_add); /** - * gen_pool_destroy - destroy a special memory pool - * @pool: pool to destroy + * 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; - int bit, end_bit; - + int bit; - list_for_each_safe(_chunk, _next_chunk, &pool->chunks) { - chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk); + while (!list_empty(&pool->chunks)) { + chunk = list_entry(pool->chunks.next, struct gen_pool_chunk, + next_chunk); list_del(&chunk->next_chunk); - end_bit = (chunk->end_addr - chunk->start_addr) >> order; - bit = find_next_bit(chunk->bits, end_bit, 0); - BUG_ON(bit < end_bit); + bit = find_next_bit(chunk->bits, chunk->size, 0); + BUG_ON(bit < chunk->size); kfree(chunk); } kfree(pool); - return; } EXPORT_SYMBOL(gen_pool_destroy); /** - * gen_pool_alloc - allocate special memory from the pool - * @pool: pool to allocate from - * @size: number of bytes to allocate from the pool + * gen_pool_alloc_aligned() - allocate special memory from the pool + * @pool: Pool to allocate from. + * @size: Number of bytes to allocate from the pool. + * @alignment_order: Order the allocated space should be + * aligned to (eg. 20 means allocated space + * must be aligned to 1MiB). * * Allocate the requested number of bytes from the specified pool. * Uses a first-fit algorithm. */ -unsigned long gen_pool_alloc(struct gen_pool *pool, size_t size) +unsigned long __must_check +gen_pool_alloc_aligned(struct gen_pool *pool, size_t size, + unsigned alignment_order) { - struct list_head *_chunk; + unsigned long addr, align_mask = 0, flags, start; struct gen_pool_chunk *chunk; - unsigned long addr, flags; - int order = pool->min_alloc_order; - int nbits, start_bit, end_bit; if (size == 0) return 0; - nbits = (size + (1UL << order) - 1) >> order; + if (alignment_order > pool->order) + align_mask = (1 << (alignment_order - pool->order)) - 1; - read_lock(&pool->lock); - list_for_each(_chunk, &pool->chunks) { - chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk); + size = (size + (1UL << pool->order) - 1) >> pool->order; - end_bit = (chunk->end_addr - chunk->start_addr) >> order; + read_lock(&pool->lock); + list_for_each_entry(chunk, &pool->chunks, next_chunk) { + if (chunk->size < size) + continue; spin_lock_irqsave(&chunk->lock, flags); - start_bit = bitmap_find_next_zero_area(chunk->bits, end_bit, 0, - nbits, 0); - if (start_bit >= end_bit) { + start = bitmap_find_next_zero_area_off(chunk->bits, chunk->size, + 0, size, align_mask, + chunk->start); + if (start >= chunk->size) { spin_unlock_irqrestore(&chunk->lock, flags); continue; } - addr = chunk->start_addr + ((unsigned long)start_bit << order); - - bitmap_set(chunk->bits, start_bit, nbits); + bitmap_set(chunk->bits, start, size); spin_unlock_irqrestore(&chunk->lock, flags); - read_unlock(&pool->lock); - return addr; + addr = (chunk->start + start) << pool->order; + goto done; } + + addr = 0; +done: read_unlock(&pool->lock); - return 0; + return addr; } -EXPORT_SYMBOL(gen_pool_alloc); +EXPORT_SYMBOL(gen_pool_alloc_aligned); /** - * gen_pool_free - 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 + * gen_pool_free() - 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. * * Free previously allocated special memory back to the specified pool. */ void gen_pool_free(struct gen_pool *pool, unsigned long addr, size_t size) { - struct list_head *_chunk; struct gen_pool_chunk *chunk; unsigned long flags; - int order = pool->min_alloc_order; - int bit, nbits; - nbits = (size + (1UL << order) - 1) >> order; + if (!size) + return; - read_lock(&pool->lock); - list_for_each(_chunk, &pool->chunks) { - chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk); + addr = addr >> pool->order; + size = (size + (1UL << pool->order) - 1) >> pool->order; + + BUG_ON(addr + size < addr); - if (addr >= chunk->start_addr && addr < chunk->end_addr) { - BUG_ON(addr + size > chunk->end_addr); + read_lock(&pool->lock); + list_for_each_entry(chunk, &pool->chunks, next_chunk) + if (addr >= chunk->start && + addr + size <= chunk->start + chunk->size) { spin_lock_irqsave(&chunk->lock, flags); - bit = (addr - chunk->start_addr) >> order; - while (nbits--) - __clear_bit(bit++, chunk->bits); + bitmap_clear(chunk->bits, addr - chunk->start, size); spin_unlock_irqrestore(&chunk->lock, flags); - break; + goto done; } - } - BUG_ON(nbits > 0); + BUG_ON(1); +done: read_unlock(&pool->lock); } EXPORT_SYMBOL(gen_pool_free); -- 1.7.2.3 -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html