Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 75bebb7f authored by FUJITA Tomonori's avatar FUJITA Tomonori Committed by Ingo Molnar
Browse files

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: default avatarFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Tested-by: default avatarTakashi Iwai <tiwai@suse.de>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent a2b89b59

arch/x86/include/asm/dma-mapping.h

+3 −1
Original line number Diff line number Diff line
@@ -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