Re: [PATCH] dma/pool: do not complain if DMA pool is not allocated

Christoph Hellwig
2022-08-11T07:35:03Z

On Fri, Aug 05, 2022 at 07:37:16PM +0200, Michal Hocko wrote:
> GFP_DMA is a misnomer. It doesn't really say that the allocation should
> be done for actual DMA. GFP_DMA really says allocate from ZONE_DMA.

Yes. But in practice that either is to do DMA of some form, including
the s390 variant not using the dma api, or completely stupid cargo
cult code.

> It
> is my understanding that all actual DMA users should use a dedicated dma
> allocation APIs which should do the right thing wrt. address constrains.

Yes. And we were at a point where we got to that, but it seems somewhat
recently a lot of people added completely stupid GFP_DMA kmallocs in the
all over the crypto drivers. Sigh...