Re: [PATCH 2/5] iommu/of: Use device_iommu_mapped()

Joerg Roedel
2018-12-06T15:35:15Z

Hi Robin,

On Wed, Dec 05, 2018 at 05:17:54PM +0000, Robin Murphy wrote:
> FWIW, this check (and its ACPI equivalent in patch #3) is specifically
> asking "has .add_device() already been called?", rather than the more
> general "is this device managed by an IOMMU?" (to which the exact answer at
> this point is "yes, provided we return successfully from here").
>
> I have no objection to the change as-is - especially if that usage is within
> the intended scope of this API - I just wanted to call it out in case you're
> also planning to introduce something else which would be even more
> appropriate for that.

Yes, the purpose of the device_iommu_mapped() functions is to check
whether the device has been initialized by the IOMMU driver that handles
it, if any.

So it answers the question: Can I use the device in an IOMMU-API call?
And it is more readable than the dev->iommu_group checks everywhere :)

Regards,

Joerg