Change Details

Factor the NFIT table walking logic into a handful of helper functions which pass back a temporarily malloc'd array of pointers. The complexity tradeoff of embedded-walks vs factored-out-walks in the existing logic is mostly neutral, but the complexity win will come with upcoming namespace support where we would need to do three nested walks to correlate each SPA with many NVDIMM Region Mapping Structures, and then each of those regions with an NVDIMM Control Region Structure. Notably, this change allows us to modify the way in which NVDIMM devices are enumerated. Previously, we would create an NVDIMM device for each child of the ACPI NVDIMM root device. On many systems (and allowed by the spec), these child devices only represent a slot where an NVDIMM could possibly be plugged in. With this change, we have the acpi_nfit_get_dimm_ids() function which walks SPAs, to regions, to control regions to find actually present NVDIMMs.

Factor the NFIT table walking logic into a handful of helper functions which pass back a temporarily malloc'd array of pointers. The complexity tradeoff of embedded-walks vs factored-out-walks in the existing logic is mostly neutral, but the complexity win will come with upcoming namespace support where we would need to do three nested walks to correlate each SPA with many NVDIMM Region Mapping Structures, and then each of those regions with an NVDIMM Control Region Structure. Notably, this change allows us to modify the way in which NVDIMM devices are enumerated. Previously, we would create an NVDIMM device for each child of the ACPI NVDIMM root device. On many systems (and allowed by the spec), these child devices only represent a slot where an NVDIMM could possibly be plugged in. With this change, we have the acpi_nfit_get_dimm_ids() function which walks SPAs, to regions, to control regions to find actually present NVDIMMs.

Factor the NFIT table walking logic into a handful of helper functions which pass back a temporarily malloc'd array of pointers. The complexity tradeoff of embedded-walks vs factored-out-walks in the existing logic is mostly neutral, but the complexity win will come with upcoming namespace support where we would need to do three nested walks to correlate each SPA with many NVDIMM Region Mapping Structures, and then each of those regions with an NVDIMM Control Region Structure. Notably, this change allows us to modify the way in which NVDIMM devices are enumerated. Previously, we would create an NVDIMM device for each child of the ACPI NVDIMM root device. On many systems (and allowed by the spec), these child devices only represent a slot where an NVDIMM could possibly be plugged in. With this change, we have the acpi_nfit_get_dimm_ids() function which walks SPAs, to regions, to control regions to find actually present NVDIMMs.