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authorMuli Ben-Yehuda <mulix@mulix.org>2006-01-11 22:44:42 +0100
committerLinus Torvalds <torvalds@g5.osdl.org>2006-01-11 19:04:55 -0800
commit17a941d854a3f7b0bb916fdeee4c9ffdcc19d8d3 (patch)
treeb6b3b55318336adf769bf57141a01a9defbbb202 /Documentation/nommu-mmap.txt
parent8a6fdd3e912e0ce6f723431d66baf704bf8a1d26 (diff)
[PATCH] x86_64: Use function pointers to call DMA mapping functions
AK: I hacked Muli's original patch a lot and there were a lot of changes - all bugs are probably to blame on me now. There were also some changes in the fall back behaviour for swiotlb - in particular it doesn't try to use GFP_DMA now anymore. Also all DMA mapping operations use the same core dma_alloc_coherent code with proper fallbacks now. And various other changes and cleanups. Known problems: iommu=force swiotlb=force together breaks needs more testing. This patch cleans up x86_64's DMA mapping dispatching code. Right now we have three possible IOMMU types: AGP GART, swiotlb and nommu, and in the future we will also have Xen's x86_64 swiotlb and other HW IOMMUs for x86_64. In order to support all of them cleanly, this patch: - introduces a struct dma_mapping_ops with function pointers for each of the DMA mapping operations of gart (AMD HW IOMMU), swiotlb (software IOMMU) and nommu (no IOMMU). - gets rid of: if (swiotlb) return swiotlb_xxx(); - PCI_DMA_BUS_IS_PHYS is now checked against the dma_ops being set This makes swiotlb faster by avoiding double copying in some cases. Signed-Off-By: Muli Ben-Yehuda <mulix@mulix.org> Signed-Off-By: Jon D. Mason <jdmason@us.ibm.com> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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