[PATCH] x86: dma-mapping: fix broken allocation when dma_mask has been provided

[PATCH] x86: dma-mapping: fix broken allocation when dma_mask has been provided

[Marek Szyprowski]

Commit 0a2b9a6ea93 ("X86: integrate CMA with DMA-mapping subsystem")
broke memory allocation with dma_mask. This patch fixes possible kernel
ops caused by lack of resetting page variable when jumping to 'again' label.

Reported-by: Konrad Rzeszutek Wilk <konrad@darnok.org>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 arch/x86/kernel/pci-dma.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index 62c9457..c0f420f 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -100,7 +100,7 @@ void *dma_generic_alloc_coherent(struct device *dev, size_t size,
 				 struct dma_attrs *attrs)
 {
 	unsigned long dma_mask;
-	struct page *page = NULL;
+	struct page *page;
 	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
 	dma_addr_t addr;
 
@@ -108,6 +108,7 @@ void *dma_generic_alloc_coherent(struct device *dev, size_t size,
 
 	flag |= __GFP_ZERO;
 again:
+	page = NULL;
 	if (!(flag & GFP_ATOMIC))
 		page = dma_alloc_from_contiguous(dev, count, get_order(size));
 	if (!page)
-- 
1.7.1.569.g6f426

Re: [PATCH] x86: dma-mapping: fix broken allocation when dma_mask has been provided

[Michal Nazarewicz]

On Wed, 13 Jun 2012 07:57:26 +0200, Marek Szyprowski <m.szyprowski@samsung.com> wrote:

> Commit 0a2b9a6ea93 ("X86: integrate CMA with DMA-mapping subsystem")
> broke memory allocation with dma_mask. This patch fixes possible kernel
> ops caused by lack of resetting page variable when jumping to 'again' label.
>
> Reported-by: Konrad Rzeszutek Wilk <konrad@darnok.org>
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>

Acked-by: Michal Nazarewicz <mina86@mina86.com>

> ---
>  arch/x86/kernel/pci-dma.c |    3 ++-
>  1 files changed, 2 insertions(+), 1 deletions(-)
>
> diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
> index 62c9457..c0f420f 100644
> --- a/arch/x86/kernel/pci-dma.c
> +++ b/arch/x86/kernel/pci-dma.c
> @@ -100,7 +100,7 @@ void *dma_generic_alloc_coherent(struct device *dev, size_t size,
>  				 struct dma_attrs *attrs)
>  {
>  	unsigned long dma_mask;
> -	struct page *page = NULL;
> +	struct page *page;
>  	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
>  	dma_addr_t addr;
>@@ -108,6 +108,7 @@ void *dma_generic_alloc_coherent(struct device *dev, size_t size,
> 	flag |= __GFP_ZERO;
>  again:
> +	page = NULL;
>  	if (!(flag & GFP_ATOMIC))
>  		page = dma_alloc_from_contiguous(dev, count, get_order(size));
>  	if (!page)


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