Re: [PATCH 21/34] AMD IOMMU: add address allocation anddeallocation functions

[FUJITA Tomonori]

On Thu, 26 Jun 2008 21:27:57 +0200
Joerg Roedel <joerg.roedel@xxxxxxx> wrote:

> This patch adds the address allocator to the AMD IOMMU code.
> 
> Signed-off-by: Joerg Roedel <joerg.roedel@xxxxxxx>
> ---
>  arch/x86/kernel/amd_iommu.c |   48 +++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 48 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
> index 1d70f5e..69d8d02 100644
> --- a/arch/x86/kernel/amd_iommu.c
> +++ b/arch/x86/kernel/amd_iommu.c
> @@ -266,3 +266,51 @@ static int init_unity_mappings_for_device(struct dma_ops_domain *dma_dom,
>  	return 0;
>  }
>  
> +static unsigned long dma_mask_to_pages(unsigned long mask)
> +{
> +	return (mask >> PAGE_SHIFT) +
> +		(PAGE_ALIGN(mask & ~PAGE_MASK) >> PAGE_SHIFT);
> +}
> +
> +static unsigned long dma_ops_alloc_addresses(struct device *dev,
> +					     struct dma_ops_domain *dom,
> +					     unsigned int pages)
> +{
> +	unsigned long limit = dma_mask_to_pages(*dev->dma_mask);
> +	unsigned long address;
> +	unsigned long size = dom->aperture_size >> PAGE_SHIFT;
> +	unsigned long boundary_size;
> +
> +	boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1,
> +			PAGE_SIZE) >> PAGE_SHIFT;
> +	limit = limit < size ? limit : size;
> +
> +	if (dom->next_bit >= limit)
> +		dom->next_bit = 0;
> +
> +	address = iommu_area_alloc(dom->bitmap, limit, dom->next_bit, pages,
> +			0 , boundary_size, 0);
> +	if (address == -1)
> +		address = iommu_area_alloc(dom->bitmap, limit, 0, pages,
> +				0, boundary_size, 0);
> +
> +	if (likely(address != -1)) {
> +		set_bit_string(dom->bitmap, address, pages);

Is set_bit_string() necessary here? iommu_area_alloc calls it internally.
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