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 04:24:49PM +0100, Robin Murphy wrote:
> Although IIRC the AMD driver is in fact the only one whose map/unmap
> callbacks aren't already spinlock-safe (or at least it was last time I was
> looking). Stuff like iommu-dma is already relying on this in order to
> implement streaming DMA API calls (which may be in atomic context) on top of
> the corresponding IOMMU API operations.

True.  That should be mentioned in the spinlock, though - and once
it is done the calling conventions should be documented.