Re: [PATCH v5 10/33] iommu, irq: Allocate irq_desc for dmar_msi with local node

[Jiang Liu <jiang.liu@linux.intel.com>]

On 2014/2/22 7:18, Yinghai Lu wrote:
> On Thu, Feb 20, 2014 at 11:43 PM, Jiang Liu <jiang.liu@linux.intel.com> wrote:
>>
>>
>> On 2014/1/3 8:05, Yinghai Lu wrote:
>>> iommu irq's irq_desc should be on local node ram.
>>>
>>> Fix the return value checking problem.
>>>   create_irq() will return -1 when fail to allocate.
>>>   create_irq_nr() will return 0 when fail to allocate.
>>> here only check !irq, so need to change it to use create_irq_nr instead.
>>>
>>> -v2: According to Sebastian, add cc to stable.
>>>
>>> Signed-off-by: Yinghai Lu <yinghai@kernel.org>
>>> Cc: Joerg Roedel <joro@8bytes.org>
>>> Cc: Donald Dutile <ddutile@redhat.com>
>>> Acked-by: Donald Dutile <ddutile@redhat.com>
>>> Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
>>> Cc: stable@vger.kernel.org
>>> ---
>>>  drivers/iommu/dmar.c | 2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
>>> index 8b452c9..f4eaa50 100644
>>> --- a/drivers/iommu/dmar.c
>>> +++ b/drivers/iommu/dmar.c
>>> @@ -1277,7 +1277,7 @@ int dmar_set_interrupt(struct intel_iommu *iommu)
>>>       if (iommu->irq)
>>>               return 0;
>>>
>>> -     irq = create_irq();
>>> +     irq = create_irq_nr(0, iommu->node);
>> Hi Yinghai,
>>         How about create_irq_nrq(1, iommu->node) here to clearly state
>> that 0 is not a valid irq number for dmar here?
> 
> Should be the same. that 0 or 1 will be from in __create_irqs().
> 
> And we have
>         if (from < nr_irqs_gsi)
>                 from = nr_irqs_gsi;
> in __create_irqs().
Hi Yinghai,
	Seems there is no such protection on IA64 side. I feel create_irq_nr()
returns 0 for error is a little risky, 0 may be
a valid IRQ number on other platforms(no sure about this).
Thanks!
> 
> Thanks
> 
> Yinghai
>