Subject: Re: powerpc/npu-dma: Remove NPU DMA ops

From: Michael Ellerman <[email-masked]>
Date: Thu, 8 Nov 2018 08:27:45 +1100 (AEDT)

On Tue, 2018-10-30 at 11:02:03 UTC, Alistair Popple wrote:
> The NPU IOMMU is setup to mirror the parent PCIe device IOMMU
> setup. Therefore it does not make sense to call dma operations such as
> dma_map_page, etc. directly on these devices. The existing dma-ops
> simply print a warning if they are ever called, however this is
> unnecessary and the warnings are likely to go unnoticed.
> 
> It is instead simpler to remove these operations and let the generic
> DMA code print warnings (eg. via a NULL pointer deref) in cases of
> buggy drivers attempting dma operations on NVLink devices.
> 
> Signed-off-by: Alistair Popple <[email-masked]>

Applied to powerpc fixes, thanks.

https://git.kernel.org/powerpc/c/3182215dd0b2120fb942ed88430cfb

cheers