libnvdimm/region: Introduce NDD_LABELING

The NDD_ALIASING flag is used to indicate where pmem capacity might
alias with blk capacity and require labeling. It is also used to
indicate whether the DIMM supports labeling. Separate this latter
capability into its own flag so that the NDD_ALIASING flag is scoped to
true aliased configurations.

To my knowledge aliased configurations only exist in the ACPI spec,
there are no known platforms that ship this support in production.

This clarity allows namespace-capacity alignment constraints around
interleave-ways to be relaxed.

Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Link: https://lore.kernel.org/r/158041477856.3889308.4212605617834097674.stgit@dwillia2-desk3.amr.corp.intel.comSigned-off-by: Dan Williams <dan.j.williams@intel.com>

arch/powerpc/platforms/pseries/papr_scm.c

@@ -328,7 +328,7 @@ static int papr_scm_nvdimm_init(struct papr_scm_priv *p)
 	}
 
 	dimm_flags = 0;
-	set_bit(NDD_ALIASING, &dimm_flags);
+	set_bit(NDD_LABELING, &dimm_flags);
 
 	p->nvdimm = nvdimm_create(p->bus, p, NULL, dimm_flags,
 				  PAPR_SCM_DIMM_CMD_MASK, 0, NULL);

drivers/acpi/nfit/core.c

@@ -2026,8 +2026,10 @@ static int acpi_nfit_register_dimms(struct acpi_nfit_desc *acpi_desc)
 			continue;
 		}
 
-		if (nfit_mem->bdw && nfit_mem->memdev_pmem)
+		if (nfit_mem->bdw && nfit_mem->memdev_pmem) {
 			set_bit(NDD_ALIASING, &flags);
+			set_bit(NDD_LABELING, &flags);
+		}
 
 		/* collate flags across all memdevs for this dimm */
 		list_for_each_entry(nfit_memdev, &acpi_desc->memdevs, list) {

drivers/nvdimm/dimm.c

@@ -99,7 +99,7 @@ static int nvdimm_probe(struct device *dev)
 	if (ndd->ns_current >= 0) {
 		rc = nd_label_reserve_dpa(ndd);
 		if (rc == 0)
-			nvdimm_set_aliasing(dev);
+			nvdimm_set_labeling(dev);
 	}
 	nvdimm_bus_unlock(dev);
 

drivers/nvdimm/dimm_devs.c

@@ -32,7 +32,7 @@ int nvdimm_check_config_data(struct device *dev)
 
 	if (!nvdimm->cmd_mask ||
 	    !test_bit(ND_CMD_GET_CONFIG_DATA, &nvdimm->cmd_mask)) {
-		if (test_bit(NDD_ALIASING, &nvdimm->flags))
+		if (test_bit(NDD_LABELING, &nvdimm->flags))
 			return -ENXIO;
 		else
 			return -ENOTTY;
@@ -173,11 +173,11 @@ int nvdimm_set_config_data(struct nvdimm_drvdata *ndd, size_t offset,
 	return rc;
 }
 
-void nvdimm_set_aliasing(struct device *dev)
+void nvdimm_set_labeling(struct device *dev)
 {
 	struct nvdimm *nvdimm = to_nvdimm(dev);
 
-	set_bit(NDD_ALIASING, &nvdimm->flags);
+	set_bit(NDD_LABELING, &nvdimm->flags);
 }
 
 void nvdimm_set_locked(struct device *dev)
@@ -312,8 +312,9 @@ static ssize_t flags_show(struct device *dev,
 {
 	struct nvdimm *nvdimm = to_nvdimm(dev);
 
-	return sprintf(buf, "%s%s\n",
+	return sprintf(buf, "%s%s%s\n",
 			test_bit(NDD_ALIASING, &nvdimm->flags) ? "alias " : "",
+			test_bit(NDD_LABELING, &nvdimm->flags) ? "label " : "",
 			test_bit(NDD_LOCKED, &nvdimm->flags) ? "lock " : "");
 }
 static DEVICE_ATTR_RO(flags);

drivers/nvdimm/namespace_devs.c

@@ -2538,7 +2538,7 @@ static int init_active_labels(struct nd_region *nd_region)
 		if (!ndd) {
 			if (test_bit(NDD_LOCKED, &nvdimm->flags))
 				/* fail, label data may be unreadable */;
-			else if (test_bit(NDD_ALIASING, &nvdimm->flags))
+			else if (test_bit(NDD_LABELING, &nvdimm->flags))
 				/* fail, labels needed to disambiguate dpa */;
 			else
 				return 0;

drivers/nvdimm/nd.h

@@ -252,7 +252,7 @@ int nvdimm_set_config_data(struct nvdimm_drvdata *ndd, size_t offset,
 		void *buf, size_t len);
 long nvdimm_clear_poison(struct device *dev, phys_addr_t phys,
 		unsigned int len);
-void nvdimm_set_aliasing(struct device *dev);
+void nvdimm_set_labeling(struct device *dev);
 void nvdimm_set_locked(struct device *dev);
 void nvdimm_clear_locked(struct device *dev);
 int nvdimm_security_setup_events(struct device *dev);

drivers/nvdimm/region_devs.c

@@ -195,16 +195,16 @@ EXPORT_SYMBOL_GPL(nd_blk_region_set_provider_data);
 int nd_region_to_nstype(struct nd_region *nd_region)
 {
 	if (is_memory(&nd_region->dev)) {
-		u16 i, alias;
+		u16 i, label;
 
-		for (i = 0, alias = 0; i < nd_region->ndr_mappings; i++) {
+		for (i = 0, label = 0; i < nd_region->ndr_mappings; i++) {
 			struct nd_mapping *nd_mapping = &nd_region->mapping[i];
 			struct nvdimm *nvdimm = nd_mapping->nvdimm;
 
-			if (test_bit(NDD_ALIASING, &nvdimm->flags))
-				alias++;
+			if (test_bit(NDD_LABELING, &nvdimm->flags))
+				label++;
 		}
-		if (alias)
+		if (label)
 			return ND_DEVICE_NAMESPACE_PMEM;
 		else
 			return ND_DEVICE_NAMESPACE_IO;

include/linux/libnvdimm.h

@@ -37,6 +37,8 @@ enum {
 	NDD_WORK_PENDING = 4,
 	/* ignore / filter NSLABEL_FLAG_LOCAL for this DIMM, i.e. no aliasing */
 	NDD_NOBLK = 5,
+	/* dimm supports namespace labels */
+	NDD_LABELING = 6,
 
 	/* need to set a limit somewhere, but yes, this is likely overkill */
 	ND_IOCTL_MAX_BUFLEN = SZ_4M,