linux-kernel - Re: [PATCH 4/5] swiotlb: map_page fix for highmem systems

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Date:	Wed, 25 Mar 2009 11:58:26 +0900
From:	FUJITA Tomonori <fujita.tomonori@....ntt.co.jp>
To:	beckyb@...nel.crashing.org
Cc:	linux-kernel@...r.kernel.org, mingo@...e.hu,
	fujita.tomonori@....ntt.co.jp, ian.campbell@...rix.com,
	jeremy@...p.org
Subject: Re: [PATCH 4/5] swiotlb: map_page fix for highmem systems

On Tue, 24 Mar 2009 16:28:45 -0500
Becky Bruce <beckyb@...nel.crashing.org> wrote:

> The current code calls virt_to_phys() on address that might
> be in highmem, which is bad.  This wasn't needed, anyway, because
> we already have the physical address we need. Get rid of the
> now-unused virtual address as well.
> 
> Signed-off-by: Becky Bruce <beckyb@...nel.crashing.org>
> ---
>  lib/swiotlb.c |    3 +--
>  1 files changed, 1 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/swiotlb.c b/lib/swiotlb.c
> index c152f17..b33180e 100644
> --- a/lib/swiotlb.c
> +++ b/lib/swiotlb.c
> @@ -640,7 +640,6 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page,
>  			    struct dma_attrs *attrs)
>  {
>  	phys_addr_t phys = page_to_phys(page) + offset;
> -	void *ptr = page_address(page) + offset;
>  	dma_addr_t dev_addr = swiotlb_phys_to_bus(dev, phys);
>  	void *map;
>  
> @@ -651,7 +650,7 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page,
>  	 * buffering it.
>  	 */
>  	if (!address_needs_mapping(dev, dev_addr, size) &&
> -	    !range_needs_mapping(virt_to_phys(ptr), size))
> +	    !range_needs_mapping(phys, size))
>  		return dev_addr;

Acked-by: FUJITA Tomonori <fujita.tomonori@....ntt.co.jp>
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