Jens Axboe wrote:
quoted text > 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@veritas.com>
> > > > ---
> > > > 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
quoted text > > > > for everyone. (Seems a bit of a shame to include <asm/types.h> her=
e,
quoted text > > > > when I think all arches already get to include it one way or anothe=
r,
quoted text > > > > 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
Which comes back always to the same point: if I get a buffer from userspace=
to=20
use for DMA: what can I do then? I need to convert a given list of (physica=
l,=20
pinned) pages to DMA addresses.
Eike
