Re: [PATCH 2/2] powerpc/iommu: check dev->iommu_group before remove a device from iommu_group

[Wei Yang <weiyang@linux.vnet.ibm.com>]

On Fri, Aug 16, 2013 at 08:15:36PM +1000, Alexey Kardashevskiy wrote:
>On 08/16/2013 08:08 PM, Wei Yang wrote:
>> ---
>>  arch/powerpc/kernel/iommu.c |    3 ++-
>>  1 files changed, 2 insertions(+), 1 deletions(-)
>> 
>> diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
>> index b20ff17..5abf7c3 100644
>> --- a/arch/powerpc/kernel/iommu.c
>> +++ b/arch/powerpc/kernel/iommu.c
>> @@ -1149,7 +1149,8 @@ static int iommu_bus_notifier(struct notifier_block *nb,
>>  	case BUS_NOTIFY_ADD_DEVICE:
>>  		return iommu_add_device(dev);
>>  	case BUS_NOTIFY_DEL_DEVICE:
>> -		iommu_del_device(dev);
>> +		if (dev->iommu_group)
>> +			iommu_del_device(dev);
>>  		return 0;
>>  	default:
>>  		return 0;
>> 
>
>This one seems redundant, no?

Sorry for the late.

Yes, these two patches have the same purpose to guard the system, while in two
different places.  One is in powernv platform, the other is in the generic iommu 
driver.

The one in powernv platform is used to correct the original logic.

The one in generic iommu driver is to keep system safe in case other platform to
call iommu_group_remove_device() without the check.

>
>
>-- 
>Alexey

-- 
Richard Yang
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