Subject: Re: [RFC PATCH V3 06/17] ppc/pnv: allocate pe->iommu_table dynamically

From: Wei Yang <[email-masked]>
Date: Wed, 25 Jun 2014 13:27:58 +0800

On Wed, Jun 25, 2014 at 02:12:34PM +1000, Alexey Kardashevskiy wrote:
>On 06/25/2014 11:12 AM, Wei Yang wrote:
>> On Tue, Jun 24, 2014 at 08:06:32PM +1000, Alexey Kardashevskiy wrote:
>>> On 06/10/2014 11:56 AM, Wei Yang wrote:
>>>> Current iommu_table of a PE is a static field. This will have a problem when
>>>> iommu_free_table is called.
>>>
>>> What kind of problem? This table is per PE and PE is not going anywhere.
>>>
>> 
>> Yes, for Bus PE, they will always sit in the system. When VF PE introduced,
>> they could be released on the fly. When they are released, so do the iommu
>> table for the PE.
>
>iommu_table is a part of PE struct. When PE is released, iommu_table will
>go with it as well. Why to make is a pointer? I would understand it if you
>added reference counting there but no - iommu_table's lifetime is equal to
>PE lifetime.
>

Yes, iommu_talbe's life time equals to PE lifetime, so when releasing a PE we
need to release the iommu table. Currently, there is one function to release
the iommu table, iommu_free_table() which takes a pointer of the iommu_table
and release it.

If the iommu table in PE is just a part of PE, it will have some problem to
release it with iommu_free_table(). That's why I make it a pointer in PE
structure.

>-- 
>Alexey

-- 
Richard Yang
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