• Akinobu Mita's avatar
    x86: enable DMA CMA with swiotlb · 9c5a3621
    Akinobu Mita authored
    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().
    Signed-off-by: default avatarAkinobu Mita <akinobu.mita@gmail.com>
    Acked-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
    Acked-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
    Cc: David Woodhouse <dwmw2@infradead.org>
    Cc: Don Dutile <ddutile@redhat.com>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: "H. Peter Anvin" <hpa@zytor.com>
    Cc: Andi Kleen <andi@firstfloor.org>
    Cc: Yinghai Lu <yinghai@kernel.org>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    9c5a3621
pci-swiotlb.c 2.68 KB