Merge branch 'for-5.1/nfit/ars' into libnvdimm-for-next

Merge several updates to the ARS implementation. Highlights include:

* Support retrieval of short-ARS results if the ARS state is "requires
  continuation", and even if the "no_init_ars" module parameter is
  specified.
* Allow busy-polling of the kernel ARS state by allowing root to reset
  the exponential back-off timer.
* Filter potentially stale ARS results by tracking query-ARS relative to
  the previous start-ARS.

drivers/acpi/nfit/nfit.h

@@ -214,6 +214,13 @@ struct nfit_mem {
 	int family;
 };
 
+enum scrub_flags {
+	ARS_BUSY,
+	ARS_CANCEL,
+	ARS_VALID,
+	ARS_POLL,
+};
+
 struct acpi_nfit_desc {
 	struct nvdimm_bus_descriptor nd_desc;
 	struct acpi_table_header acpi_header;
@@ -227,7 +234,6 @@ struct acpi_nfit_desc {
 	struct list_head idts;
 	struct nvdimm_bus *nvdimm_bus;
 	struct device *dev;
-	u8 ars_start_flags;
 	struct nd_cmd_ars_status *ars_status;
 	struct nfit_spa *scrub_spa;
 	struct delayed_work dwork;
@@ -236,8 +242,7 @@ struct acpi_nfit_desc {
 	unsigned int max_ars;
 	unsigned int scrub_count;
 	unsigned int scrub_mode;
-	unsigned int scrub_busy:1;
-	unsigned int cancel:1;
+	unsigned long scrub_flags;
 	unsigned long dimm_cmd_force_en;
 	unsigned long bus_cmd_force_en;
 	unsigned long bus_nfit_cmd_force_en;