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

Elliott, Robert (Server Storage)
2015-04-29T15:54:45Z

> -----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),

Please use "KiB" rather than the unclear "K".

Same comment for a dev_dbg print in patch 14.

> + 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);

Could this include "nd" in the name, like "ndregion%d"?

The other dev_set_name calls in this patch set use:
btt%d
ndbus%d
nmem%d
namespace%d.%d

which are a bit more distinctive.

---
Robert Elliott, HP Server Storage