On Fri, Aug 24, 2012 at 11:29:02AM +0300, Hiroshi Doyu wrote:
> struct page **pages is necessary to align with non atomic path in
> __iommu_get_pages(). atomic_pool() has the intialized **pages instead
> of just *page.
>
> Signed-off-by: Hiroshi Doyu <hd...@nvidia.com>
> ---
> arch/arm/mm/dma-mapping.c | 17 +++++++++++++----
> 1 files changed, 13 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
> index 601da7a..b14ee64 100644
> --- a/arch/arm/mm/dma-mapping.c
> +++ b/arch/arm/mm/dma-mapping.c
> @@ -296,7 +296,7 @@ struct dma_pool {
> unsigned long *bitmap;
> unsigned long nr_pages;
> void *vaddr;
> - struct page *page;
> + struct page **pages;
> };
>
> static struct dma_pool atomic_pool = {
> @@ -335,12 +335,16 @@ static int __init atomic_pool_init(void)
> unsigned long nr_pages = pool->size >> PAGE_SHIFT;
> unsigned long *bitmap;
> struct page *page;
> + struct page **pages;
> void *ptr;
> int bitmap_size = BITS_TO_LONGS(nr_pages) * sizeof(long);
> + size_t size = nr_pages * sizeof(struct page *);
>
> - bitmap = kzalloc(bitmap_size, GFP_KERNEL);
> + size += bitmap_size;
> + bitmap = kzalloc(size, GFP_KERNEL);
> if (!bitmap)
> goto no_bitmap;
> + pages = (void *)bitmap + bitmap_size;
So you stuck a bitmap field in front of the array then?
Why not just define a structure where this is clearly defined
instead of doing the casting.
>
> if (IS_ENABLED(CONFIG_CMA))
> ptr = __alloc_from_contiguous(NULL, pool->size, prot, &page);
> @@ -348,9 +352,14 @@ static int __init atomic_pool_init(void)
> ptr = __alloc_remap_buffer(NULL, pool->size, GFP_KERNEL, prot,
> &page, NULL);
> if (ptr) {
> + int i;
> +
> + for (i = 0; i < nr_pages; i++)
> + pages[i] = page + i;
> +
> spin_lock_init(&pool->lock);
> pool->vaddr = ptr;
> - pool->page = page;
> + pool->pages = pages;
> pool->bitmap = bitmap;
> pool->nr_pages = nr_pages;
> pr_info("DMA: preallocated %u KiB pool for atomic coherent
> allocations\n",
> @@ -481,7 +490,7 @@ static void *__alloc_from_pool(size_t size, struct page
> **ret_page)
> if (pageno < pool->nr_pages) {
> bitmap_set(pool->bitmap, pageno, count);
> ptr = pool->vaddr + PAGE_SIZE * pageno;
> - *ret_page = pool->page + pageno;
> + *ret_page = pool->pages[pageno];
> } else {
> pr_err_once("ERROR: %u KiB atomic DMA coherent pool is too
> small!\n"
> "Please increase it with coherent_pool= kernel
> parameter!\n",
> --
> 1.7.5.4
>
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