[PATCH V3 3/4] dmaselftest: add memcpy selftest support functions
arnd at arndb.de
Tue Nov 10 02:13:24 PST 2015
On Monday 09 November 2015 23:49:54 Sinan Kaya wrote:
> 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.
> 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.
Correct. I think this is just because of cache line alignment that
is guaranteed for kmalloc but not for anything on the stack.
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