Re: libata & no PCI: dma_[un]map_single undefined

[Jeff Garzik <jeff@garzik.org>]

On Tue, Jun 05, 2007 at 12:22:18PM +0100, Alan Cox wrote:
> > NAK
> > 
> > We have generic devices and generic DMA mapping.  libata already uses
> > the generic stuff.  Now fix the platform...
> 
> Nice theory but your generic helpers rely on the map functions working
> even for generic hardware that doesn't need them, so at the very least
> there is some clean up required.

Sure there is some clean up needed -- on the arch side.

Even !PCI dma_xxx wrappers that do nothing more than return a dma
mapping error are a valid platform implementation.

Even !HAS_DMA (s/390?) arches should be using the aforementioned
return-error wrappers, mimicing the implementation of PCI functions
in linux/pci.h for the !PCI case.

libata core for DMA mapping is already generic enough such that, #ifdefs
are not needed in the code.


OTOH.....  further work in libata _is_ need for I/O accessors, to
isolate those from the core code.

	Jeff