Re: [PATCH 2.6.24-rc1] fix sg_phys to use dma_addr_t

From: Jens Axboe
Date: Thu Oct 25 2007 - 04:54:33 EST


On Thu, Oct 25 2007, Rolf Eike Beer wrote:
> Am Donnerstag, 25. Oktober 2007 schrieb Arjan van de Ven:
> > > Signed-off-by: Hugh Dickins <hugh@xxxxxxxxxxx>
> > > ---
> > > Whether this is a complete patch, suitable for all architectures,
> > > I'm not sure: it builds, boots and runs correctly on the x86_32 box
> > > in question, but you'll be a lot wiser than me about using dma_addr_t
> > > for everyone. (Seems a bit of a shame to include <asm/types.h> here,
> > > when I think all arches already get to include it one way or another,
> > > typically via asm/scatterlist.h; but I guess it's safest to repeat
> > > it.)
> >
> > there is a problem with this... sg_phys doesn't return an actual *dma*
> > address.... at least not an address you can give to the device.
> > Using dma_addr_t is thus a bit misleading.....
>
> Ok, then: how do I actually get such an address?

You use the dma mapping api, Documentation/DMA-mapping.txt

--
Jens Axboe

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