Messages in this thread | | | Date | Fri, 23 Oct 2009 13:48:25 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH] x86: adjust GFP mask handling for coherent allocations |
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* Jan Beulich <JBeulich@novell.com> wrote:
> Rather than forcing GFP flags and DMA mask to be inconsistent, GFP > flags should be determined even for the fallback device through > dma_alloc_coherent_mask()/dma_alloc_coherent_gfp_flags(). This > restores 64-bit behavior as it was prior to commits > 8965eb19386fdf5ccd0ef8b02593eb8560aa3416 and > 4a367f3a9dbf2e7ffcee4702203479809236ee6e (not sure why there are two of > them), where GFP_DMA was forced on for 32-bit, but not for 64-bit, with > the slight adjustment that afaict even 32-bit doesn't need this without > CONFIG_ISA. > > Signed-off-by: Jan Beulich <jbeulich@novell.com> > Cc: Takashi Iwai <tiwai@suse.de> > Cc: Jesse Barnes <jbarnes@virtuousgeek.org> > > --- > arch/x86/include/asm/dma-mapping.h | 4 +--- > arch/x86/kernel/pci-dma.c | 8 +++++--- > 2 files changed, 6 insertions(+), 6 deletions(-) > > --- linux-2.6.32-rc5/arch/x86/include/asm/dma-mapping.h 2009-10-19 13:09:44.000000000 +0200 > +++ 2.6.32-rc5-x86-dma-mask-gfp/arch/x86/include/asm/dma-mapping.h 2009-10-22 10:54:08.000000000 +0200 > @@ -124,10 +124,8 @@ dma_alloc_coherent(struct device *dev, s > if (dma_alloc_from_coherent(dev, size, dma_handle, &memory)) > return memory; > > - if (!dev) { > + if (!dev) > dev = &x86_dma_fallback_dev; > - gfp |= GFP_DMA; > - } > > if (!is_device_dma_capable(dev)) > return NULL; > --- linux-2.6.32-rc5/arch/x86/kernel/pci-dma.c 2009-10-19 13:09:45.000000000 +0200 > +++ 2.6.32-rc5-x86-dma-mask-gfp/arch/x86/kernel/pci-dma.c 2009-10-22 10:56:46.000000000 +0200 > @@ -45,12 +45,14 @@ int iommu_pass_through __read_mostly; > dma_addr_t bad_dma_address __read_mostly = 0; > EXPORT_SYMBOL(bad_dma_address); > > -/* Dummy device used for NULL arguments (normally ISA). Better would > - be probably a smaller DMA mask, but this is bug-to-bug compatible > - to older i386. */ > +/* Dummy device used for NULL arguments (normally ISA). */ > struct device x86_dma_fallback_dev = { > .init_name = "fallback device", > +#ifdef CONFIG_ISA > + .coherent_dma_mask = DMA_BIT_MASK(24), > +#else > .coherent_dma_mask = DMA_BIT_MASK(32), > +#endif > .dma_mask = &x86_dma_fallback_dev.coherent_dma_mask, > }; > EXPORT_SYMBOL(x86_dma_fallback_dev);
makes sense (although there were a few odd ends in various ISA sound driver details so this should go on the .33 not .32), but please introduce a cleaner construct, like a new DMA_ISA_BIT_MASK() or so.
Thanks,
Ingo
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