Messages in this thread | | | Date | Fri, 30 Jan 2009 07:54:07 +0900 | From | Yasunori Goto <> | Subject | Re: [PATCH -tip 1/3] IA64: fix swiotlb alloc_coherent for non DMA_64BIT_MASK devices |
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> On Thu, 29 Jan 2009 20:41:07 +0900 > Yasunori Goto <y-goto@jp.fujitsu.com> wrote: > > > > Before the dma ops unification, IA64 always uses GFP_DMA for > > > dma_alloc_coherent like: > > > > > > #define dma_alloc_coherent(dev, size, handle, gfp) \ > > > platform_dma_alloc_coherent(dev, size, handle, (gfp) | GFP_DMA) > > > > > > This GFP_DMA enforcement doesn't make sense for IOMMUs since they can > > > do address translation to give addresses that devices can access > > > to. The IOMMU drivers ignore the zone flag. However, this is still > > > necessary for swiotlb since it can't do address translation. > > > > > > We don't always need to use GFP_DMA for swiotlb. We need GFP_DMA for > > > devices incapable of 64bit DMA. > > > > > > This patch is sorta updated version of: > > > > > > http://marc.info/?l=linux-kernel&m=122638215612705&w=2 > > > > > > Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> > > > Cc: Yasunori Goto <y-goto@jp.fujitsu.com> > > > --- > > > arch/ia64/kernel/pci-swiotlb.c | 10 +++++++++- > > > 1 files changed, 9 insertions(+), 1 deletions(-) > > > > > > diff --git a/arch/ia64/kernel/pci-swiotlb.c b/arch/ia64/kernel/pci-swiotlb.c > > > index 717ad4f..573f02c 100644 > > > --- a/arch/ia64/kernel/pci-swiotlb.c > > > +++ b/arch/ia64/kernel/pci-swiotlb.c > > > @@ -13,8 +13,16 @@ > > > int swiotlb __read_mostly; > > > EXPORT_SYMBOL(swiotlb); > > > > > > +static void *ia64_swiotlb_alloc_coherent(struct device *dev, size_t size, > > > + dma_addr_t *dma_handle, gfp_t gfp) > > > +{ > > > + if (dev->coherent_dma_mask != DMA_64BIT_MASK) > > > + gfp |= GFP_DMA; > > > + return swiotlb_alloc_coherent(dev, size, dma_handle, gfp); > > > +} > > > + > > > struct dma_map_ops swiotlb_dma_ops = { > > > - .alloc_coherent = swiotlb_alloc_coherent, > > > + .alloc_coherent = ia64_swiotlb_alloc_coherent, > > > .free_coherent = swiotlb_free_coherent, > > > .map_page = swiotlb_map_page, > > > .unmap_page = swiotlb_unmap_page, > > > -- > > > 1.6.0.6 > > > > > > Though I may be misunderstanding something, this initialization seems to be > > called only when CONFIG_IA64_DIG_VTD is on. > > Hmm, what's 'this initialization'? > > This patch always sets swiotlb_dma_ops.alloc_coherent to > ia64_swiotlb_alloc_coherent.
I tested your patch, but, ia64_swiotlb_alloc_coherent() was not called with CONFIG_GENERIC.
swiotlb_dma_ops is set by pci_swiotlb_init(). However, it seems to be not called when CONFIG_IA64_DIG/Generic configuration.
> > > This patch is sorta updated version of: > > > > > > http://marc.info/?l=linux-kernel&m=122638215612705&w=2 > > >
This old version is effective even CONFIG_GENERIC/CONFIG_IA64_DIG.
Bye.
> > > > CONFIG_IA64_DIG_VTD > > platform_dma_init() -> pci_iommu_alloc() -> pci_swiotlb_init() > > > > CONFIG_IA64_DIG/CONFIG_IA64_GENERIC > > platform_dma_init() -> swiotlb_dma_init() > > > > Is it intended? > > Do you wish GFP_DMA should be always ON when generic config?
-- Yasunori Goto
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