Messages in this thread | | | Date | Mon, 31 Oct 2011 10:36:10 +0000 | From | Russell King - ARM Linux <> | Subject | Re: [RFC PATCH] arm: dma: Drop GFP_COMP for DMA memory allocations |
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On Fri, Oct 28, 2011 at 03:18:52PM -0600, Stephen Warren wrote: > I believe the patch below was once posted to solve this for ARM, but never > got picked up. Evidently, AVR32 did pick it up. I'm wondering if we should > pick this up for ARM now, or if there's some other solution?
Well, Nick did talk about a solution using GFP_USERMAP in one of those threads, which doesn't seem to have gone anywhere. So I guess we need this patch.
> diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c > index 82a093c..93b86e6 100644 > --- a/arch/arm/mm/dma-mapping.c > +++ b/arch/arm/mm/dma-mapping.c > @@ -308,6 +308,13 @@ __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp, > struct page *page; > void *addr; > > + /* Following is a work-around (a.k.a. hack) to prevent pages > + * with __GFP_COMP being passed to split_page() which cannot > + * handle them. The real problem is that this flag probably > + * should be 0 on ARM as it is not supported on this > + * platform--see CONFIG_HUGETLB_PAGE. */
I don't think this comment makes sense anymore - HUGETLB_PAGE doesn't have any help text.
> + gfp &= ~(__GFP_COMP); > + > *handle = ~0; > size = PAGE_ALIGN(size); > > -- > 1.7.0.4 > >
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