Re: [Linux-nvdimm] [PATCH v2 08/20] libnd, nd_acpi: regions (block-data-window, persistent memory, volatile memory)

-----Original Message----- From: Linux-nvdimm [mailto:linux-nvdimm-bounces@lists.01.org] On Behalf Of Dan Williams Sent: Tuesday, April 28, 2015 1:25 PM Subject: [Linux-nvdimm] [PATCH v2 08/20] libnd, nd_acpi: regions (block- data-window, persistent memory, volatile memory) A "region" device represents the maximum capacity of a BLK range (mmio block-data-window(s)), or a PMEM range (DAX-capable persistent memory or volatile memory), without regard for aliasing. Aliasing, in the dimm-local address space (DPA), is resolved by metadata on a dimm to designate which exclusive interface will access the aliased DPA ranges. Support for the per-dimm metadata/label arrvies is in a subsequent patch. The name format of "region" devices is "regionN" where, like dimms, N is a global ida index assigned at discovery time. This id is not reliable across reboots nor in the presence of hotplug. Look to attributes of the region or static id-data of the sub-namespace to generate a persistent name.

+++ b/drivers/block/nd/region_devs.c

+static noinline struct nd_region *nd_region_create(struct nd_bus *nd_bus, + struct nd_region_desc *ndr_desc, struct device_type *dev_type) +{ + struct nd_region *nd_region; + struct device *dev; + u16 i; + + for (i = 0; i < ndr_desc->num_mappings; i++) { + struct nd_mapping *nd_mapping = &ndr_desc->nd_mapping[i]; + struct nd_dimm *nd_dimm = nd_mapping->nd_dimm; + + if ((nd_mapping->start | nd_mapping->size) % SZ_4K) { + dev_err(&nd_bus->dev, "%pf: %s mapping%d is not 4K aligned\n", + __builtin_return_address(0),

+ dev_name(&nd_dimm->dev), i); + + return NULL; + } + } + + nd_region = kzalloc(sizeof(struct nd_region) + + sizeof(struct nd_mapping) * ndr_desc->num_mappings, + GFP_KERNEL); + if (!nd_region) + return NULL; + nd_region->id = ida_simple_get(&region_ida, 0, 0, GFP_KERNEL); + if (nd_region->id < 0) { + kfree(nd_region); + return NULL; + } + + memcpy(nd_region->mapping, ndr_desc->nd_mapping, + sizeof(struct nd_mapping) * ndr_desc->num_mappings); + for (i = 0; i < ndr_desc->num_mappings; i++) { + struct nd_mapping *nd_mapping = &ndr_desc->nd_mapping[i]; + struct nd_dimm *nd_dimm = nd_mapping->nd_dimm; + + get_device(&nd_dimm->dev); + } + nd_region->ndr_mappings = ndr_desc->num_mappings; + nd_region->provider_data = ndr_desc->provider_data; + dev = &nd_region->dev; + dev_set_name(dev, "region%d", nd_region->id);