Fence wait in mmu_interval_notifier_ops::invalidate

Wed Dec 9 16:37:31 UTC 2020

On Wed, Dec 09, 2020 at 05:36:16PM +0100, Thomas Hellström (Intel) wrote:
> Jason, Christian
> 
> In most implementations of the callback mentioned in the subject there's a
> fence wait.
> What exactly is it needed for?

Invalidate must stop DMA before returning, so presumably drivers using
a dma fence are relying on a dma fence mechanism to stop DMA.

Jason