Re: dmapool (was: Re: Linux 2.6.3-rc2)

[David Brownell]

> +static inline int
> +dma_supported(struct device *dev, u64 mask)
> +{
> +	BUG();
> +	return 0;
> +}

dma_supported() in particular shouldn't BUG(); this should work:

   if (use_dma && dma_supported(dev, ~(u32)0)) {
       ... set up for DMA ...
   } else {
       ... just use PIO instead ...
   }

Likewise the other routines that have clearly defined fault paths
should probably just use those instead of BUG().  Examples of this
type would be dma_alloc_coherent(), dma_map_sg() and maybe also
dma_get_cache_alignment().


Of course the API still lacks clean fault reporting for the single
shot mapping calls -- like maybe an arch-settable

  #define DMA_ADDR_INVALID (~(dma_addr_t)0)

return value -- but that'd be a different patch.

- Dave



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