Re: [PATCH V3 16/20] cxl/mem: Preserve cxl root decoder during mem probe

Neeraj Kumar
2025-10-06T04:55:10Z

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On 24/09/25 02:38PM, Alison Schofield wrote:
>On Wed, Sep 17, 2025 at 07:11:12PM +0530, Neeraj Kumar wrote:
>> Saved root decoder info is required for cxl region persistency
>
>It seem there must be a more detailed story here.
>Saving the root decoder in struct cxl_memdev does not sound
>persistent. Please add more detail on how this step fits
>into the grander scheme.
>

Yes it has story. For region creation using cxl_create_region()
we need to know the root decoder.

In current case cxl root decocer is provided from ndctl using device
attribute create_region_store(). And saving root decoder (cxlrd) in
cxl_memdev(cxlmd) helps to get root decoder during region creation.

Actually, cxl_memdev instance is saved in struct cxl_nvdimm(cxl_nvd). So
after parsing region information from nvdimm driver we recreate region
and thus cxlmd is available from cxl_nvd along with saved cxlrd

I will elaborate commit message with above information

Regards,
Neeraj

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