From: FUJITA Tomonori Date: Thu, 23 Oct 2008 11:46:55 +0000 (+0900) Subject: x86: use GFP_DMA for 24bit coherent_dma_mask X-Git-Tag: v2.6.28-rc3~88^2~3 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=75bebb7f0c2a709812cccb4d3151a21b012c5cad;p=linux-2.6-omap-h63xx.git x86: use GFP_DMA for 24bit coherent_dma_mask dma_alloc_coherent (include/asm-x86/dma-mapping.h) avoids GFP_DMA allocation first and if the allocated address is not fit for the device's coherent_dma_mask, then dma_alloc_coherent does GFP_DMA allocation. This is because dma_alloc_coherent avoids precious GFP_DMA zone if possible. This is also how the old dma_alloc_coherent (arch/x86/kernel/pci-dma.c) works. However, if the coherent_dma_mask of a device is 24bit, there is no point to go into the above GFP_DMA retry mechanism. We had better use GFP_DMA in the first place. Signed-off-by: FUJITA Tomonori Tested-by: Takashi Iwai Signed-off-by: Ingo Molnar --- diff --git a/arch/x86/include/asm/dma-mapping.h b/arch/x86/include/asm/dma-mapping.h index 4a5397bfce2..7f225a4b2a2 100644 --- a/arch/x86/include/asm/dma-mapping.h +++ b/arch/x86/include/asm/dma-mapping.h @@ -255,9 +255,11 @@ static inline unsigned long dma_alloc_coherent_mask(struct device *dev, static inline gfp_t dma_alloc_coherent_gfp_flags(struct device *dev, gfp_t gfp) { -#ifdef CONFIG_X86_64 unsigned long dma_mask = dma_alloc_coherent_mask(dev, gfp); + if (dma_mask <= DMA_24BIT_MASK) + gfp |= GFP_DMA; +#ifdef CONFIG_X86_64 if (dma_mask <= DMA_32BIT_MASK && !(gfp & GFP_DMA)) gfp |= GFP_DMA32; #endif