Re: [kernel-hardening] [PATCH 09/38] usercopy: Mark kmalloc caches as usercopy caches

[Christoph Hellwig]

On Wed, Jan 29, 2020 at 06:07:14PM +0100, Christian Borntraeger wrote:
> > DMA can be done to NORMAL memory as well.
> 
> Exactly. 
> I think iucv uses GFP_DMA because z/VM needs those buffers to reside below 2GB (which is ZONA_DMA for s390).

The normal way to allocate memory with addressing limits would be to
use dma_alloc_coherent and friends.  Any chance to switch iucv over to
that?  Or is there no device associated with it?