Re: [PATCH] powerpc: iommu: fix build when neither PCI or IBMVIO is set

[Randy Dunlap <rdunlap@infradead.org>]

On March 2, 2021 3:08:43 AM PST, Michael Ellerman <mpe@ellerman.id.au> wrote:
>Randy Dunlap <rdunlap@infradead.org> writes:
>> When neither CONFIG_PCI nor CONFIG_IBMVIO is enabled:
>>
>> ../arch/powerpc/kernel/iommu.c:178:30: error:
>'fail_iommu_bus_notifier' defined but not used
>[-Werror=unused-variable]
>>   178 | static struct notifier_block fail_iommu_bus_notifier = {
>>
>> If only that struct is bounded by 2 #if defined() phrases (PCI &&
>IBMVIO):
>>
>> ../arch/powerpc/kernel/iommu.c:162:12: error: 'fail_iommu_bus_notify'
>defined but not used [-Werror=unused-function]
>>   162 | static int fail_iommu_bus_notify(struct notifier_block *nb,
>>
>> If that function is also guarded by 2 #if defined() phrases:
>>
>> In file included from ../include/linux/dma-mapping.h:7,
>>                  from ../arch/powerpc/kernel/iommu.c:19:
>> ../include/linux/device.h:131:26: error: 'dev_attr_fail_iommu'
>defined but not used [-Werror=unused-variable]
>>   131 |  struct device_attribute dev_attr_##_name = __ATTR_RW(_name)
>> ../arch/powerpc/kernel/iommu.c:160:8: note: in expansion of macro
>'DEVICE_ATTR_RW'
>>   160 | static DEVICE_ATTR_RW(fail_iommu);
>>
>> and the snowball continues to grow.
>> Next I got this one:
>>
>> ../arch/powerpc/kernel/iommu.c: In function 'iommu_range_alloc':
>> ../arch/powerpc/kernel/iommu.c:234:6: error: implicit declaration of
>function 'should_fail_iommu'; did you mean 'should_failslab'?
>[-Werror=implicit-function-declaration]
>>   234 |  if (should_fail_iommu(dev))
>>
>> and
>>
>> ../arch/powerpc/kernel/iommu.c: In function 'should_fail_iommu':
>> ../arch/powerpc/kernel/iommu.c:122:50: error: 'fail_iommu' undeclared
>(first use in this function)
>>   122 |  return dev->archdata.fail_iommu && should_fail(&fail_iommu,
>1);
>>
>> So combine CONFIG_FAIL_IOMMU && (CONFIG_PCI || CONFIG_IBMVIO)
>> to decide on building some of this code/data.
>
>Couldn't we just make FAIL_IOMMU depend on PCI || IBMVIO?
>
>cheers

Yes, I thought of that about 5 seconds after hitting Send. But I can't do it just now -- am away from computer.


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