[PATCH] iommu/io-pgtable: Abstract iommu_iotlb_gather access

[Geert Uytterhoeven]

Hi Robin,

On Fri, Aug 20, 2021 at 3:22 PM Robin Murphy <robin.murphy at arm.com> wrote:
> Previously io-pgtable merely passed the iommu_iotlb_gather pointer
> through to helpers, but now it has grown its own direct dereference.
> This turns out to break the build for !IOMMU_API configs where the
> structure only has a dummy definition. It will probably also crash
> drivers who don't use the gather mechanism and simply pass in NULL.
>
> Wrap this dereference in a suitable helper which can both be stubbed
> out for !IOMMU_API and encapsulate a NULL check otherwise.
>
> Fixes: 7a7c5badf858 ("iommu: Indicate queued flushes via gather data")

Is this the right Fixes tag?

The build issue was introduced by:
Fixes: a8e5f04458c4e496 ("iommu/io-pgtable: Remove non-strict quirk")

> Reported-by: kernel test robot <lkp at intel.com>
> Signed-off-by: Robin Murphy <robin.murphy at arm.com>

Thanks, this fixes the build issues I was seeing.

Tested-by: Geert Uytterhoeven <geert+renesas at glider.be>

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds