Messages in this thread | | | Date | Mon, 4 Oct 2021 12:44:18 +0100 | From | Will Deacon <> | Subject | Re: [PATCH 0/5] iommu: Some IOVA code reorganisation |
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On Fri, Sep 24, 2021 at 06:01:52PM +0800, John Garry wrote: > The IOVA domain structure is a bit overloaded, holding: > - IOVA tree management > - FQ control > - IOVA rcache memories > > Indeed only a couple of IOVA users use the rcache, and only dma-iommu.c > uses the FQ feature. > > This series separates out that structure. In addition, it moves the FQ > code into dma-iommu.c . This is not strictly necessary, but it does make > it easier for the FQ domain lookup the rcache domain. > > The rcache code stays where it is, as it may be reworked in future, so > there is not much point in relocating and then discarding. > > This topic was initially discussed and suggested (I think) by Robin here: > https://lore.kernel.org/linux-iommu/1d06eda1-9961-d023-f5e7-fe87e768f067@arm.com/
It would be useful to have Robin's Ack on patches 2-4. The implementation looks straightforward to me, but the thread above isn't very clear about what is being suggested.
To play devil's advocate: there aren't many direct users of the iovad code: either they'll die out entirely (and everybody will use the dma-iommu code) and it's fine having the flush queue code where it is, or we'll get more users and the likelihood of somebody else wanting flush queues increases.
Will
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