Re: [PATCH 22/34] dma-mapping: add an arch_dma_supported hook

Randy Dunlap
2018-02-02T17:47:23Z

On 01/12/2018 12:42 AM, Christoph Hellwig wrote:
> To implement the x86 forbid_dac and iommu_sac_force we want an arch hook
> so that it can apply the global options across all dma_map_ops
> implementations.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
> arch/x86/include/asm/dma-mapping.h | 3 +++
> arch/x86/kernel/pci-dma.c | 19 ++++++++++++-------
> include/linux/dma-mapping.h | 11 +++++++++++
> 3 files changed, 26 insertions(+), 7 deletions(-)

> diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
> index 88bcb1a8211d..d67742dad904 100644
> --- a/include/linux/dma-mapping.h
> +++ b/include/linux/dma-mapping.h
> @@ -576,6 +576,14 @@ static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
> return 0;
> }
>
> +/*
> + * This is a hack for the legacy x86 forbid_dac and iommu_sac_force. Please
> + * don't use this is new code.

in new code.

> + */
> +#ifndef arch_dma_supported
> +#define arch_dma_supported(dev, mask) (1)
> +#endif

--
~Randy