Re: [PATCH v2 -mm 1/2] add the device argument to dma_mapping_error

[Andrew Morton <akpm@linux-foundation.org>]

On Mon, 19 May 2008 15:31:28 +0900 FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> wrote:

> dma_mapping_error doesn't take a pointer to the device unlike other
> DMA operations. So we can't have dma_mapping_ops per device.
> 
> Note that POWER already has dma_mapping_ops per device but all the
> POWER IOMMUs use the same dma_mapping_error function. x86 IOMMUs use
> different dma_mapping_error functions. So dma_mapping_error needs the
> device argument.

This patch continues to turn my hair grey.

I'm currently staring at this, in include/linux/ssb/ssb.h:

static inline int ssb_dma_mapping_error(struct ssb_device *dev, dma_addr_t addr)
{
	switch (dev->bus->bustype) {
	case SSB_BUSTYPE_PCI:
		return pci_dma_mapping_error(dev->dev, addr);
	case SSB_BUSTYPE_SSB:
		return dma_mapping_error(dev->dev, addr);
	default:
		__ssb_dma_not_implemented(dev);
	}
	return -ENOSYS;
}

How do I go from an ssb_device* to a pci_dev*?

Dunno.  I think I'll cheat and do:

static inline int ssb_dma_mapping_error(struct ssb_device *dev, dma_addr_t addr)
{
	switch (dev->bus->bustype) {
	case SSB_BUSTYPE_PCI:
		return dma_mapping_error(dev->dev, addr);
	case SSB_BUSTYPE_SSB:
		return dma_mapping_error(dev->dev, addr);
	default:
		__ssb_dma_not_implemented(dev);
	}
	return -ENOSYS;
}

please take a look, see if we can do better?