2012-06-13 06:00:54

by Marek Szyprowski

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

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 <[email protected]>
Signed-off-by: Marek Szyprowski <[email protected]>
---
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

2012-06-13 07:56:10

by Michal Nazarewicz

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

On Wed, 13 Jun 2012 07:57:26 +0200, Marek Szyprowski <[email protected]> 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 <[email protected]>
> Signed-off-by: Marek Szyprowski <[email protected]>

Acked-by: Michal Nazarewicz <[email protected]>

> ---
> 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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