Re: [PATCH] Changing the AMD IOMMU API path to work in an atomic context which is necessary for any custom drivers using the IOMMU API while holding a spinlock.

[Christoph Hellwig]

On Fri, Aug 24, 2018 at 11:55:53PM +0100, Tom Murphy wrote:
> We were going to do this by using the iommu-dma api and replacing all the
> existing calls to the DMA api functions in the amd driver with their
> iommu-dma equivalent like in this driver:
> https://elixir.bootlin.com/linux/latest/source/arch/arm64/mm/dma-mapping.c#L810

FYI, I have a a wip branch to move the arm64 wrappers for both
swiotlb and dma-iommu here:

http://git.infradead.org/users/hch/misc.git/shortlog/refs/heads/dma-maybe-coherent

Maybe you could try to base on top of that.

> To do this we need the map/unmap callbacks to be spinlock-safe.

You probably want to send the patch together with the one(s) making use
of it.