Re: [ppc64] support for dma-mapping

[Hollis Blanchard]

On Feb 12, 2004, at 3:51 PM, Dave Boutcher wrote:
[snip]
> include/asm-ppc64/dma-mapping.h
>
> +static inline int
> +dma_supported(struct device *dev, u64 mask)
> +{
> +	if (dev->bus == &pci_bus_type) return 
> pci_dma_supported(to_pci_dev(dev), mask);
> +	if (dev->bus == &vio_bus_type) return 
> vio_dma_supported(to_vio_dev(dev), mask);
> +	BUG();
> +}

The thing is that there is such an obvious cleanup here:

+static inline int
+dma_supported(struct device *dev, u64 mask)
+{
+	if (dev->bus)
+		return dev->bus->dma_supported(dev, mask);
+	BUG();
+}

This would require modifying include/linux/device.h for struct bus_type 
(impacting PCI and USB at least). In fact I'm sure the original author 
of include/asm-generic/dma-mapping.h knew that even when they wrote it:

static inline int
dma_supported(struct device *dev, u64 mask)
{
    BUG_ON(dev->bus != &pci_bus_type);
    return pci_dma_supported(to_pci_dev(dev), mask);
}

It's just begging to be generalized.

--
Hollis Blanchard
IBM Linux Technology Center

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