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

From: Alexey Kardashevskiy <[email-masked]>
Date: Wed, 25 Jun 2014 17:50:08 +1000

On 06/25/2014 03:27 PM, Wei Yang wrote:
> 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.

So you are saying that you want to release PE by one kfree() and release
iommu_table by another kfree (embedded into iommu_free_table()). For me
that means that PE and iommu_table have different lifetime.

And I cannot find the exact place in this patchset where you call
iommu_free_table(), what do I miss?

-- 
Alexey