Re: [PATCH V3 3/4] dmaselftest: add memcpy selftest support functions

[Sinan Kaya]

On 11/9/2015 8:48 AM, Timur Tabi wrote:
> Sinan Kaya wrote:
> > > And why kmalloc anyway?  Why not leave it on the stack?
> > >
> > >      char src[] = "hello world";
> > >
> > > ?
> >
> > I need to call dma_map_single on this address to convert it to a DMA
> > address. That's why.
>
> And you can't do that with an object that's on the stack?

no, pasting from here.

https://www.kernel.org/doc/Documentation/DMA-API-HOWTO.txt

under 'What memory is DMA'able?'

This rule also means that you may use neither kernel image addresses
(items in data/text/bss segments), nor module image addresses, nor
stack addresses for DMA.

--
Sinan Kaya
Qualcomm Technologies, Inc. on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a 
Linux Foundation Collaborative Project
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