Pull libnvdimm fixes from Dan Williams:
"Several fixes to the DSM (ACPI device specific method) marshaling
implementation.
I consider these urgent enough to send for 4.9 consideration since
they fix the kernel's handling of ARS (Address Range Scrub) commands.
Especially for platforms without machine-check-recovery capabilities,
successful execution of ARS commands enables the platform to
potentially break out of an infinite reboot problem if a media error
is present in the boot path. There is also a one line fix for a
device-dax read-only mapping regression.
Commits 9a901f5495 ("acpi, nfit: fix extended status translations
for ACPI DSMs") and 325896ffdf ("device-dax: fix private mapping
restriction, permit read-only") are true regression fixes for changes
introduced this cycle.
Commit efda1b5d87 ("acpi, nfit, libnvdimm: fix / harden ars_status
output length handling") fixes the kernel's handling of zero-length
results, this never would have worked in the past, but we only just
recently discovered a BIOS implementation that emits this arguably
spec non-compliant result.
The remaining two commits are additional fall out from thinking
through the implications of a zero / truncated length result of the
ARS Status command.
In order to mitigate the risk that these changes introduce yet more
regressions they are backstopped by a new unit test in commit
a7de92dac9 ("tools/testing/nvdimm: unit test acpi_nfit_ctl()") that
mocks up inputs to acpi_nfit_ctl()"
* 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
device-dax: fix private mapping restriction, permit read-only
tools/testing/nvdimm: unit test acpi_nfit_ctl()
acpi, nfit: fix bus vs dimm confusion in xlat_status
acpi, nfit: validate ars_status output buffer size
acpi, nfit, libnvdimm: fix / harden ars_status output length handling
acpi, nfit: fix extended status translations for ACPI DSMs
810ac7b755