Re: [PATCH] x86: restore the old swiotlb alloc_coherent behavior

[Ingo Molnar <mingo@elte.hu>]

* FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> wrote:

> This restores the old swiotlb alloc_coherent behavior (before the
> alloc_coherent rewrite):
> 
> http://lkml.org/lkml/2008/8/12/200
> 
> The old alloc_coherent avoids GFP_DMA allocation first and if the
> allocated address is not fit for the device's coherent_dma_mask, then
> dma_alloc_coherent does GFP_DMA allocation. If it fails,
> alloc_coherent calls swiotlb_alloc_coherent (in short, we rarely used
> swiotlb_alloc_coherent).
> 
> After the alloc_coherent rewrite, dma_alloc_coherent
> (include/asm-x86/dma-mapping.h) directly calls swiotlb_alloc_coherent.
> It means that we possibly can't handle a device having dma_masks >
> 24bit < 32bits since swiotlb_alloc_coherent doesn't have the above
> GFP_DMA retry mechanism.
> 
> This patch fixes x86's swiotlb alloc_coherent to use the GFP_DMA retry
> mechanism, which dma_generic_alloc_coherent() provides now
> (pci-nommu.c and GART IOMMU driver also use
> dma_generic_alloc_coherent).
> 
> Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
> ---
>  arch/x86/kernel/pci-swiotlb_64.c |   14 +++++++++++++-
>  1 files changed, 13 insertions(+), 1 deletions(-)

applied to tip/core/urgent (to after the two other iommu related 
patches) - thanks Fujita!

	Ingo