Re: [RFC][PATCH] SPI subsystem

[Arjan van de Ven]

On Mon, 2005-10-03 at 11:57 +0100, Mark Underwood wrote:

> > > > > Hmm, using local variables for messages, so DMA adapter drivers have
> > > > > to check if this is non-kmalloc'ed space (how?)
> > > > 
> > > > They can't check that.  It turns out that most current Linuxes
> > > > have no issues DMAing a few bytes from the stack.
> > >
> > > Will the DMA remapping calls work with data from the stack?
> > 
> > On "most current Linuxes" yes.  All I know about, in fact.
> > But it's not guaranteed.
> 
> OK. Thanks

please NEVER EVER do dma from or to a stack variable. It's not allowed
on all architectures and it is really really bad practice in general
anyway. 

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