On Mon, Jan 09, 2012 at 04:49:21PM +0100, Marek Szyprowski wrote: > This patch add a complete implementation of DMA-mapping API for > devices that have IOMMU support. All DMA-mapping calls are supported. > > This patch contains some of the code kindly provided by Krishna Reddy > <vdumpa@xxxxxxxxxx> and Andrzej Pietrasiewicz <andrzej.p@xxxxxxxxxxx> > > Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> > Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx> > > --- > > Hello, > > This is the corrected version of the previous patch from the "[PATCH 0/8 > v4] ARM: DMA-mapping framework redesign" thread which can be found here: > http://www.spinics.net/lists/linux-mm/msg27382.html > > Previous version had very nasty bug which causes memory trashing if > DMA-mapping managed to allocate pages larger than 4KiB. The problem was > in __iommu_alloc_buffer() function which did not check how many pages > has been left to allocate. This patch seems to be incomplete. If the standard DMA API is used (the one which exists in current kernels) and NEED_SG_DMA_LENGTH is enabled, then where do we set the DMA length in the scatterlist? > diff --git a/arch/arm/include/asm/dma-iommu.h b/arch/arm/include/asm/dma-iommu.h > new file mode 100644 > index 0000000..6668b41 > --- /dev/null > +++ b/arch/arm/include/asm/dma-iommu.h > @@ -0,0 +1,36 @@ > +#ifndef ASMARM_DMA_IOMMU_H > +#define ASMARM_DMA_IOMMU_H > + > +#ifdef __KERNEL__ > + > +#include <linux/mm_types.h> > +#include <linux/scatterlist.h> > +#include <linux/dma-debug.h> > +#include <linux/kmemcheck.h> > + > +#include <asm/memory.h> I can't see anything in here which needs asm/memory.h - if files which include this need it, please include it in there so we can see why it's needed. > + > +struct dma_iommu_mapping { > + /* iommu specific data */ > + struct iommu_domain *domain; > + > + void *bitmap; > + size_t bits; > + unsigned int order; > + dma_addr_t base; > + > + spinlock_t lock; > + struct kref kref; > +}; > + > +struct dma_iommu_mapping * > +arm_iommu_create_mapping(struct bus_type *bus, dma_addr_t base, size_t size, > + int order); > + > +void arm_iommu_release_mapping(struct dma_iommu_mapping *mapping); > + > +int arm_iommu_attach_device(struct device *dev, > + struct dma_iommu_mapping *mapping); > + > +#endif /* __KERNEL__ */ > +#endif > diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c > index 4845c09..2287b01 100644 > --- a/arch/arm/mm/dma-mapping.c > +++ b/arch/arm/mm/dma-mapping.c > @@ -27,6 +27,9 @@ > #include <asm/sizes.h> > #include <asm/mach/arch.h> > > +#include <linux/iommu.h> linux/ includes should be grouped together. > diff --git a/arch/arm/mm/vmregion.h b/arch/arm/mm/vmregion.h > index 15e9f04..6bbc402 100644 > --- a/arch/arm/mm/vmregion.h > +++ b/arch/arm/mm/vmregion.h > @@ -17,7 +17,7 @@ struct arm_vmregion { > struct list_head vm_list; > unsigned long vm_start; > unsigned long vm_end; > - struct page *vm_pages; > + void *priv; I want to think about that - I may wish to export the vm_pages via the new dma-mappings file to provide additional information. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>