diff options
Diffstat (limited to 'mm/dmapool.c')
| -rw-r--r-- | mm/dmapool.c | 40 |
1 files changed, 30 insertions, 10 deletions
diff --git a/mm/dmapool.c b/mm/dmapool.c index 744d541df866..e2ea4543abb4 100644 --- a/mm/dmapool.c +++ b/mm/dmapool.c @@ -1,19 +1,39 @@ +/* + * DMA Pool allocator + * + * Copyright 2001 David Brownell + * Copyright 2007 Intel Corporation + * Author: Matthew Wilcox <willy@linux.intel.com> + * + * This software may be redistributed and/or modified under the terms of + * the GNU General Public License ("GPL") version 2 as published by the + * Free Software Foundation. + * + * This allocator returns small blocks of a given size which are DMA-able by + * the given device. It uses the dma_alloc_coherent page allocator to get + * new pages, then splits them up into blocks of the required size. + * Many older drivers still have their own code to do this. + * + * The current design of this allocator is fairly simple. The pool is + * represented by the 'struct dma_pool' which keeps a doubly-linked list of + * allocated pages. Each page in the page_list is split into blocks of at + * least 'size' bytes. + */ #include <linux/device.h> -#include <linux/mm.h> -#include <asm/io.h> /* Needed for i386 to build */ #include <linux/dma-mapping.h> #include <linux/dmapool.h> -#include <linux/slab.h> +#include <linux/kernel.h> +#include <linux/list.h> #include <linux/module.h> +#include <linux/mutex.h> #include <linux/poison.h> #include <linux/sched.h> - -/* - * Pool allocator ... wraps the dma_alloc_coherent page allocator, so - * small blocks are easily used by drivers for bus mastering controllers. - * This should probably be sharing the guts of the slab allocator. - */ +#include <linux/slab.h> +#include <linux/spinlock.h> +#include <linux/string.h> +#include <linux/types.h> +#include <linux/wait.h> struct dma_pool { /* the pool */ struct list_head page_list; @@ -265,7 +285,7 @@ EXPORT_SYMBOL(dma_pool_destroy); * * This returns the kernel virtual address of a currently unused block, * and reports its dma address through the handle. - * If such a memory block can't be allocated, null is returned. + * If such a memory block can't be allocated, %NULL is returned. */ void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags, dma_addr_t *handle) |