[PATCH v2 1/7] drm/i915: Drop user contexts on driver remove

[Janusz Krzysztofik]

On Mon, 2020-07-06 at 07:59 +0100, Chris Wilson wrote:
> Quoting Janusz Krzysztofik (2020-07-06 07:29:05)
> > Contexts associated with open device file descriptors together with
> > their assigned address spaces are now closed on device file close.
> > On address space closure its underlying DMA mappings are revoked.
> > When the device is removed while being open, DMA API may then issue
> > a warning on device associated DMA mappings still active.  Moreover,
> > subsequent attempts to revoke those mappings while late closing the
> > device file descriptor may be judged by intel-iommu code as bugs and
> > result in kernel panic.
> 
> As I said originally, you are tackling this at the wrong layer, as
> evidenced imo by that you need multiple patches to do the same thing and
> you still haven't found all the places that hold dma/iommu mappings --
> because they are not tracked on behalf of a user.

Are they tracked at all?

Thanks,
Janusz

> -Chris