Messages in this thread | | | Date | Fri, 5 Sep 2008 12:40:49 +0200 | From | Joerg Roedel <> | Subject | Re: [PATCH] x86: fix nommu_alloc_coherent allocation with NULL device argument |
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I agree with this patch in principle. It fixes the problem. But I think we should evaluate if we can change the dma_mask of the fallback_dev to 24 bit.
On Fri, Sep 05, 2008 at 05:58:47PM +0900, FUJITA Tomonori wrote: > We need to use __GFP_DMA for NULL device argument (fallback_dev) with > pci-nommu. It's a hack for ISA (and some old code) so we need to use > GFP_DMA. > > Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> > --- > arch/x86/kernel/pci-nommu.c | 5 +---- > include/asm-x86/dma-mapping.h | 2 ++ > 2 files changed, 3 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/kernel/pci-nommu.c b/arch/x86/kernel/pci-nommu.c > index 73853d3..526b2db 100644 > --- a/arch/x86/kernel/pci-nommu.c > +++ b/arch/x86/kernel/pci-nommu.c > @@ -83,7 +83,6 @@ nommu_alloc_coherent(struct device *hwdev, size_t size, > if (hwdev->dma_mask == NULL) > return NULL; > > - gfp &= ~(__GFP_DMA | __GFP_HIGHMEM | __GFP_DMA32); > gfp |= __GFP_ZERO; > > dma_mask = hwdev->coherent_dma_mask; > @@ -96,14 +95,12 @@ nommu_alloc_coherent(struct device *hwdev, size_t size, > node = dev_to_node(hwdev); > > #ifdef CONFIG_X86_64 > - if (dma_mask <= DMA_32BIT_MASK) > + if (dma_mask <= DMA_32BIT_MASK && !(gfp & GFP_DMA)) > gfp |= GFP_DMA32; > #endif > - > /* No alloc-free penalty for ISA devices */ > if (dma_mask == DMA_24BIT_MASK) > gfp |= GFP_DMA; > -
Please leave these spare lines where they are. They increase the readability of the code imho.
> again: > page = alloc_pages_node(node, gfp, get_order(size)); > if (!page) > diff --git a/include/asm-x86/dma-mapping.h b/include/asm-x86/dma-mapping.h > index 3a9a6f5..de4495e 100644 > --- a/include/asm-x86/dma-mapping.h > +++ b/include/asm-x86/dma-mapping.h > @@ -246,6 +246,8 @@ dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_handle, > struct dma_mapping_ops *ops = get_dma_ops(dev); > void *memory; > > + gfp &= ~(__GFP_DMA | __GFP_HIGHMEM | __GFP_DMA32); > + > if (dma_alloc_from_coherent(dev, size, dma_handle, &memory)) > return memory; > > -- > 1.5.4.2 > >
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