Subject: Re: powerpc: DMA coherent allocations broken for CONFIG_NOT_COHERENT_CACHE

From: Benjamin Herrenschmidt <[email-masked]>
Date: Mon, 25 May 2009 14:19:41 +1000

On Mon, 2009-05-25 at 02:43 +0100, Arnd Bergmann wrote:
> I might be missing too much context here, but can't we make drivers
> that
> need this allocate an uncached memory range at setup time and call
> dma_declare_coherent_memory() on that to make a later
> dma_alloc_coherent()
> succeed without GFP_KERNEL?

That isn't that much different, and still needs a dedicated allocator
which is pretty much what I'm trying to get rid of.

It would make everybody's life easier if we just banned those
allocations from atomic contexts :-)

Cheers,
Ben.