Re: [PATCH v8 08/19] arm/xen: get_dma_ops: return xen_dma_ops if weare running as xen_initial_domain

From: Stefano Stabellini
Date: Fri Oct 18 2013 - 08:23:39 EST


Russell,
are you OK with this patch?


On Thu, 17 Oct 2013, Stefano Stabellini wrote:
> We can't simply override arm_dma_ops with xen_dma_ops because devices
> are allowed to have their own dma_ops and they take precedence over
> arm_dma_ops. When running on Xen as initial domain, we always want
> xen_dma_ops to be the one in use.
>
> Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
> Suggested-by: Catalin Marinas <catalin.marinas@xxxxxxx>
> CC: will.deacon@xxxxxxx
> CC: linux@xxxxxxxxxxxxxxxx
>
> Changes in v7:
> - return xen_dma_ops only if we are the initial domain;
> - rename __get_dma_ops to __generic_dma_ops.
> ---
> arch/arm/include/asm/dma-mapping.h | 13 ++++++++++++-
> 1 files changed, 12 insertions(+), 1 deletions(-)
>
> diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
> index 01b5a3d..f5945d4 100644
> --- a/arch/arm/include/asm/dma-mapping.h
> +++ b/arch/arm/include/asm/dma-mapping.h
> @@ -12,17 +12,28 @@
> #include <asm/memory.h>
> #include <asm/cacheflush.h>
>
> +#include <xen/xen.h>
> +#include <asm/xen/hypervisor.h>
> +
> #define DMA_ERROR_CODE (~0)
> extern struct dma_map_ops arm_dma_ops;
> extern struct dma_map_ops arm_coherent_dma_ops;
>
> -static inline struct dma_map_ops *get_dma_ops(struct device *dev)
> +static inline struct dma_map_ops *__generic_dma_ops(struct device *dev)
> {
> if (dev && dev->archdata.dma_ops)
> return dev->archdata.dma_ops;
> return &arm_dma_ops;
> }
>
> +static inline struct dma_map_ops *get_dma_ops(struct device *dev)
> +{
> + if (xen_initial_domain())
> + return xen_dma_ops;
> + else
> + return __generic_dma_ops(dev);
> +}
> +
> static inline void set_dma_ops(struct device *dev, struct dma_map_ops *ops)
> {
> BUG_ON(!dev);
> --
> 1.7.2.5
>
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