libnvdimm: Add sysfs numa_node to NVDIMM devices

Add support of sysfs 'numa_node' to I/O-related NVDIMM devices
under /sys/bus/nd/devices, regionN, namespaceN.0, and bttN.x.

An example of numa_node values on a 2-socket system with a single
NVDIMM range on each socket is shown below.
  /sys/bus/nd/devices
  |-- btt0.0/numa_node:0
  |-- btt1.0/numa_node:1
  |-- btt1.1/numa_node:1
  |-- namespace0.0/numa_node:0
  |-- namespace1.0/numa_node:1
  |-- region0/numa_node:0
  |-- region1/numa_node:1

These numa_node files are then linked under the block class of
their device names.
  /sys/class/block/pmem0/device/numa_node:0
  /sys/class/block/pmem1s/device/numa_node:1

This enables numactl(8) to accept 'block:' and 'file:' paths of
pmem and btt devices as shown in the examples below.
  numactl --preferred block:pmem0 --show
  numactl --preferred file:/dev/pmem1s --show

Signed-off-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/libnvdimm.h b/include/linux/libnvdimm.h
index 30b3deaafd51..75e3af01ee32 100644
--- a/include/linux/libnvdimm.h
+++ b/include/linux/libnvdimm.h
@@ -38,6 +38,7 @@ enum {
 extern struct attribute_group nvdimm_bus_attribute_group;
 extern struct attribute_group nvdimm_attribute_group;
 extern struct attribute_group nd_device_attribute_group;
+extern struct attribute_group nd_numa_attribute_group;
 extern struct attribute_group nd_region_attribute_group;
 extern struct attribute_group nd_mapping_attribute_group;