Re: [Qemu-devel] [RFC PATCH v2 06/13] spapr_iommu: Implement free_table() helper

[David Gibson]

On Fri, Aug 15, 2014 at 08:12:28PM +1000, Alexey Kardashevskiy wrote:
> Every sPAPRTCETable object holds an IOMMU memory region which holds
> a referenced to the sPAPRTCETable instance. So if we want to free
> an sPAPRTCETable instance, calling object_unref() will not be enough
> as embedded memory region will hold the reference and we need to break
> the loop.
> 
> This adds a spapr_tce_free_table() helper which destroys the embedded
> memory region and then calls object_unref() on the sPAPRTCETable instance
> which will succeed now. The helper adds a new child under unique name
> derived from LIOBN.
> 
> As we are here, fix spapr_tce_new_table() callers.
> At the moment spapr_tce_new_table() references sPAPRTCETable twice -
> once in object_new() and second time in object_property_add_child().
> The callers of spapr_tce_new_table() should take care of correct
> referencing.

So I've been trying to determine if there's any way to avoid this by
not constructing the reference loop in the first place, but all the
qom is breaking my brain.

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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