[dpdk-dev] [PATCH v6] vfio: Support for no-IOMMU mode

[Thomas Monjalon]

2016-01-28 14:16, Burakov, Anatoly:
> Hi Thomas,
> 
> > 2016-01-28 11:57, Anatoly Burakov:
> > > +#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 5, 0)
> > 
> > Why not #ifndef VFIO_NOIOMMU_IOMMU?
> > It would avoid some backport issue.
> 
> I don't see how it could. Versions post-4.5 will have VFIO_NOIOMMU_IOMMU, so no issue there. Pre-4.5 versions, whether they do or do not have VFIO_NOIOMMU_IOMMU defined, will have RTE_VFIO_NOIOMMU defined as 8 regardless.

Are we sure it will ever be backported as 8?
Anyway I think it's better to avoid version number checks.
What happens if the feature is reverted from 4.5 as it was from 4.4?