MFC 348757,351225: acpi and nvdimm location_str updates

[scottph]

Summary

348757:
nvdimm: Provide nvdimm location information

Provide the acpi handle path as the location string for the nvdimm
children of the nvdimm_root device.

351225:
Don't set the string "unknown" as a device's location_str

Return an empty string when the location is unknown instead of the
string "unknown". This ensures that all location entries are of
the form key=val.

Sponsored by: Intel Corporation

[emaste]

It looks like Phabricator will report that there are property changes on the directory but does not show the details - you can confirm that svn diff shows this metadata change:

Index: .
===================================================================
--- .   (revision 349048)
+++ .   (working copy)

Property changes on: .
___________________________________________________________________
Modified: svn:mergeinfo
## -0,0 +0,1 ##
   Merged /head:r348757

[imp]

sys/dev/nvdimm/nvdimm.c

574

Don't do this. All entries must be foo=bar for the parser to be happy. If it is unknown, report nothing: *buf = '\0';

[emaste]

sys/dev/nvdimm/nvdimm.c

574

Note that this review is for the MFC, the change is already in head, review D20528.

Path forward is to make the change in head, then MFC both together.

[scottph]

sys/dev/nvdimm/nvdimm.c

574

@imp, thanks for pointing that out. I was following acpi's method https://svnweb.freebsd.org/base/head/sys/dev/acpica/acpi.c?revision=347984&view=markup#l853

I'll send a change for both of these and then squash that into this MFC.

[scottph]

Index: stable/12

and also:

• stable/12 (revision 351512)

+++ stable/12 (working copy)

Property changes on: stable/12

---

Modified: svn:mergeinfo

1. -0,0 +0,1 ## Merged /head:r348757,351225