2013/11/20 Konrad Rzeszutek Wilk <konrad.w...@oracle.com>: > On Wed, Nov 20, 2013 at 08:32:19AM +0900, Akinobu Mita wrote: >> The DMA Contiguous Memory Allocator support on x86 is disabled when >> swiotlb config option is enabled. So DMA CMA is always disabled on >> x86_64 because swiotlb is always enabled. This attempts to support >> for DMA CMA with enabling swiotlb config option. >> >> The contiguous memory allocator on x86 is integrated in the function >> dma_generic_alloc_coherent() which is .alloc callback in nommu_dma_ops >> for dma_alloc_coherent(). >> >> x86_swiotlb_alloc_coherent() which is .alloc callback in swiotlb_dma_ops >> tries to allocate with dma_generic_alloc_coherent() firstly and then >> swiotlb_alloc_coherent() is called as a fallback. >> >> The main part of supporting DMA CMA with swiotlb is that changing >> x86_swiotlb_free_coherent() which is .free callback in swiotlb_dma_ops >> for dma_free_coherent() so that it can distinguish memory allocated by >> dma_generic_alloc_coherent() from one allocated by swiotlb_alloc_coherent() >> and release it with dma_generic_free_coherent() which can handle contiguous >> memory. This change requires making is_swiotlb_buffer() global function. >> >> This also needs to change .free callback in the dma_map_ops for amd_gart >> and sta2x11, because these dma_ops are also using >> dma_generic_alloc_coherent(). >> >> Cc: Marek Szyprowski <m.szyprow...@samsung.com> >> Cc: Konrad Rzeszutek Wilk <konrad.w...@oracle.com> >> Cc: Thomas Gleixner <t...@linutronix.de> >> Cc: Ingo Molnar <mi...@redhat.com> >> Cc: "H. Peter Anvin" <h...@zytor.com> >> Cc: x...@kernel.org >> Signed-off-by: Akinobu Mita <akinobu.m...@gmail.com> >> --- >> arch/x86/Kconfig | 2 +- >> arch/x86/include/asm/swiotlb.h | 7 +++++++ >> arch/x86/kernel/amd_gart_64.c | 2 +- >> arch/x86/kernel/pci-swiotlb.c | 9 ++++++--- >> arch/x86/pci/sta2x11-fixup.c | 6 ++---- >> include/linux/swiotlb.h | 2 ++ >> lib/swiotlb.c | 2 +- > > Looks OK, but before this goes anywhere I need to run regression tests > on IA64 and the other users of SWIOTLB.
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