libnvdimm 4.20-rc3

- Address Range Scrub overflow continuation handling has been broken
   since it was initially merged. It was only recently that error injection
   and platform-BIOS support enabled this corner case to be exercised.
 
 - The recent attempt to provide more isolation for the kernel Address
   Range Scrub state machine from userapace initiated sessions triggers a
   lockdep report. Revert and try again at the next merge window.
 
 - Fix a kasan reported buffer overflow in libnvdimm unit test
   infrastrucutre (nfit_test)
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Merge tag 'libnvdimm-fixes-4.20-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

Pull libnvdimm fixes from Dan Williams:
 "A small batch of fixes for v4.20-rc3.

  The overflow continuation fix addresses something that has been broken
  for several releases. Arguably it could wait even longer, but it's a
  one line fix and this finishes the last of the known address range
  scrub bug reports. The revert addresses a lockdep regression. The unit
  tests are not critical to fix, but no reason to hold this fix back.

  Summary:

   - Address Range Scrub overflow continuation handling has been broken
     since it was initially merged. It was only recently that error
     injection and platform-BIOS support enabled this corner case to be
     exercised.

   - The recent attempt to provide more isolation for the kernel Address
     Range Scrub state machine from userapace initiated sessions
     triggers a lockdep report. Revert and try again at the next merge
     window.

   - Fix a kasan reported buffer overflow in libnvdimm unit test
     infrastrucutre (nfit_test)"

* tag 'libnvdimm-fixes-4.20-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  Revert "acpi, nfit: Further restrict userspace ARS start requests"
  acpi, nfit: Fix ARS overflow continuation
  tools/testing/nvdimm: Fix the array size for dimm devices.

drivers/acpi/nfit/core.c

@@ -2928,9 +2928,9 @@ static int acpi_nfit_query_poison(struct acpi_nfit_desc *acpi_desc)
 		return rc;
 
 	if (ars_status_process_records(acpi_desc))
-		return -ENOMEM;
+		dev_err(acpi_desc->dev, "Failed to process ARS records\n");
 
-	return 0;
+	return rc;
 }
 
 static int ars_register(struct acpi_nfit_desc *acpi_desc,
@@ -3341,8 +3341,6 @@ static int acpi_nfit_clear_to_send(struct nvdimm_bus_descriptor *nd_desc,
 		struct nvdimm *nvdimm, unsigned int cmd)
 {
 	struct acpi_nfit_desc *acpi_desc = to_acpi_nfit_desc(nd_desc);
-	struct nfit_spa *nfit_spa;
-	int rc = 0;
 
 	if (nvdimm)
 		return 0;
@@ -3355,17 +3353,10 @@ static int acpi_nfit_clear_to_send(struct nvdimm_bus_descriptor *nd_desc,
 	 * just needs guarantees that any ARS it initiates are not
 	 * interrupted by any intervening start requests from userspace.
 	 */
-	mutex_lock(&acpi_desc->init_mutex);
-	list_for_each_entry(nfit_spa, &acpi_desc->spas, list)
-		if (acpi_desc->scrub_spa
-				|| test_bit(ARS_REQ_SHORT, &nfit_spa->ars_state)
-				|| test_bit(ARS_REQ_LONG, &nfit_spa->ars_state)) {
-			rc = -EBUSY;
-			break;
-		}
-	mutex_unlock(&acpi_desc->init_mutex);
+	if (work_busy(&acpi_desc->dwork.work))
+		return -EBUSY;
 
-	return rc;
+	return 0;
 }
 
 int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc,

tools/testing/nvdimm/test/nfit.c

@@ -140,8 +140,8 @@ static u32 handle[] = {
 	[6] = NFIT_DIMM_HANDLE(1, 0, 0, 0, 1),
 };
 
-static unsigned long dimm_fail_cmd_flags[NUM_DCR];
-static int dimm_fail_cmd_code[NUM_DCR];
+static unsigned long dimm_fail_cmd_flags[ARRAY_SIZE(handle)];
+static int dimm_fail_cmd_code[ARRAY_SIZE(handle)];
 
 static const struct nd_intel_smart smart_def = {
 	.flags = ND_INTEL_SMART_HEALTH_VALID
@@ -205,7 +205,7 @@ struct nfit_test {
 		unsigned long deadline;
 		spinlock_t lock;
 	} ars_state;
-	struct device *dimm_dev[NUM_DCR];
+	struct device *dimm_dev[ARRAY_SIZE(handle)];
 	struct nd_intel_smart *smart;
 	struct nd_intel_smart_threshold *smart_threshold;
 	struct badrange badrange;
@@ -2680,7 +2680,7 @@ static int nfit_test_probe(struct platform_device *pdev)
 		u32 nfit_handle = __to_nfit_memdev(nfit_mem)->device_handle;
 		int i;
 
-		for (i = 0; i < NUM_DCR; i++)
+		for (i = 0; i < ARRAY_SIZE(handle); i++)
 			if (nfit_handle == handle[i])
 				dev_set_drvdata(nfit_test->dimm_dev[i],
 						nfit_mem);