Hi Mpe,
Thanks for looking into this patch.
Michael Ellerman writes:
> Shivaprasad G Bhat writes:
>> papr_scm and ndtest share common PDSM payload structs like
>> nd_papr_pdsm_health. Presently these structs are duplicated across
>> papr_pdsm.h
>> and ndtest.h header files. Since 'ndtest' is essentially arch independent
>> and can
>> run on platforms other than PPC64, a way needs to be deviced to avoid
>> redundancy
>> and duplication of PDSM structs in future.
>>
>> So the patch proposes moving the PDSM header from arch/powerpc/include/uapi/
>> to
>> the generic include/uapi/linux directory. Also, there are some #defines
>> common
>> between papr_scm and ndtest which are not exported to the user space. So,
>> move
>> them to a header file which can be shared across ndtest and papr_scm via
>> newly
>> introduced include/linux/papr_scm.h.
>>
>> Signed-off-by: Shivaprasad G Bhat
>> Signed-off-by: Vaibhav Jain
>> Suggested-by: "Aneesh Kumar K.V"
>> ---
>> Changelog:
>>
>> Since v1:
>> Link:
>> https://patchwork.kernel.org/project/linux-nvdimm/patch/162505488483.72147.12741153746322191381.stgit@56e104a48989/
>> * Removed dependency on this patch for the other patches
>>
>> MAINTAINERS |2
>> arch/powerpc/include/uapi/asm/papr_pdsm.h | 165
>> -
>> arch/powerpc/platforms/pseries/papr_scm.c | 43
>> include/linux/papr_scm.h | 48
>> include/uapi/linux/papr_pdsm.h| 165
>> +
>
> This doesn't make sense to me.
>
> Anything with papr (or PAPR) in the name is fundamentally powerpc
> specific, it doesn't belong in a generic header, or in a generic
> location.
>
> What's the actual problem you're trying to solve?
>
The ndtest module (tools/testing/nvdimm/test/ndtest.c) is implemented in
an arch independed way to enable testing of PAPR PDSMs on non ppc64
platforms like x86_64. It uses the same PDSM structs as used by papr_scm
to communicate with libndctl userspace.
Since papr_scm is ppc64 arch specific we were so far duplicating the
PDSM structures between ndtest and papr_scm. The patch tries to solve
this duplication by moving the shared structs to arch independent common
include dirs.
Secondly, PDSMs describes how userspace can use NVDIMM_FAMILY_PAPR to
interact with NVDIMMs. So potentially a new NVDIMM beyond powerpc arch
can add its support and would need access to the same structs used by
papr_scm and ndtest. In that context it would make sense to move PDSM
headers to generic include dirs.
> If it's just including papr_scm bits into ndtest.c then that should be
> as simple as:
>
> #ifdef __powerpc__
> #include
> #endif
>
> Shouldn't it?
>
No, as ndtest implements support for NVDIMM_FAMILY_PAPR and would need
access to PDSM related structs which presently are only available for
powerpc.
> cheers
>
--
Cheers
~ Vaibhav
