libnvdimm: convert NDD_ flags to use bitops, introduce NDD_LOCKED

This is a preparation patch for handling locked nvdimm label regions, a
new concept as introduced by the latest DSM document on pmem.io [1]. A
future patch will leverage nvdimm_set_locked() at DIMM probe time to
flag regions that can not be enabled. There should be no functional
difference resulting from this change.

[1]: http://pmem.io/documents/NVDIMM_DSM_Interface_Example-V1.3.pdfSigned-off-by: NDan Williams <dan.j.williams@intel.com>

drivers/acpi/nfit/core.c

@@ -1512,7 +1512,7 @@ static int acpi_nfit_register_dimms(struct acpi_nfit_desc *acpi_desc)
 		}
 
 		if (nfit_mem->bdw && nfit_mem->memdev_pmem)
-			flags |= NDD_ALIASING;
+			set_bit(NDD_ALIASING, &flags);
 
 		/* collate flags across all memdevs for this dimm */
 		list_for_each_entry(nfit_memdev, &acpi_desc->memdevs, list) {
@@ -1527,7 +1527,7 @@ static int acpi_nfit_register_dimms(struct acpi_nfit_desc *acpi_desc)
 
 		mem_flags = __to_nfit_memdev(nfit_mem)->flags;
 		if (mem_flags & ACPI_NFIT_MEM_NOT_ARMED)
-			flags |= NDD_UNARMED;
+			set_bit(NDD_UNARMED, &flags);
 
 		rc = acpi_nfit_add_dimm(acpi_desc, nfit_mem, device_handle);
 		if (rc)

drivers/nvdimm/dimm_devs.c

@@ -34,7 +34,7 @@ int nvdimm_check_config_data(struct device *dev)
 
 	if (!nvdimm->cmd_mask ||
 	    !test_bit(ND_CMD_GET_CONFIG_DATA, &nvdimm->cmd_mask)) {
-		if (nvdimm->flags & NDD_ALIASING)
+		if (test_bit(NDD_ALIASING, &nvdimm->flags))
 			return -ENXIO;
 		else
 			return -ENOTTY;
@@ -188,7 +188,14 @@ void nvdimm_set_aliasing(struct device *dev)
 {
 	struct nvdimm *nvdimm = to_nvdimm(dev);
 
-	nvdimm->flags |= NDD_ALIASING;
+	set_bit(NDD_ALIASING, &nvdimm->flags);
+}
+
+void nvdimm_set_locked(struct device *dev)
+{
+	struct nvdimm *nvdimm = to_nvdimm(dev);
+
+	set_bit(NDD_LOCKED, &nvdimm->flags);
 }
 
 static void nvdimm_release(struct device *dev)

drivers/nvdimm/namespace_devs.c

@@ -2240,7 +2240,7 @@ static int init_active_labels(struct nd_region *nd_region)
 		 * being activated if it aliases DPA.
 		 */
 		if (!ndd) {
-			if ((nvdimm->flags & NDD_ALIASING) == 0)
+			if (!test_bit(NDD_ALIASING, &nvdimm->flags))
 				return 0;
 			dev_dbg(&nd_region->dev, "%s: is disabled, failing probe\n",
 					dev_name(&nd_mapping->nvdimm->dev));

drivers/nvdimm/nd.h

@@ -240,6 +240,7 @@ int nvdimm_set_config_data(struct nvdimm_drvdata *ndd, size_t offset,
 long nvdimm_clear_poison(struct device *dev, phys_addr_t phys,
 		unsigned int len);
 void nvdimm_set_aliasing(struct device *dev);
+void nvdimm_set_locked(struct device *dev);
 struct nd_btt *to_nd_btt(struct device *dev);
 
 struct nd_gen_sb {

drivers/nvdimm/region_devs.c

@@ -222,7 +222,7 @@ int nd_region_to_nstype(struct nd_region *nd_region)
 			struct nd_mapping *nd_mapping = &nd_region->mapping[i];
 			struct nvdimm *nvdimm = nd_mapping->nvdimm;
 
-			if (nvdimm->flags & NDD_ALIASING)
+			if (test_bit(NDD_ALIASING, &nvdimm->flags))
 				alias++;
 		}
 		if (alias)
@@ -881,7 +881,7 @@ static struct nd_region *nd_region_create(struct nvdimm_bus *nvdimm_bus,
 			return NULL;
 		}
 
-		if (nvdimm->flags & NDD_UNARMED)
+		if (test_bit(NDD_UNARMED, &nvdimm->flags))
 			ro = 1;
 	}
 

include/linux/libnvdimm.h

@@ -20,9 +20,11 @@
 
 enum {
 	/* when a dimm supports both PMEM and BLK access a label is required */
-	NDD_ALIASING = 1 << 0,
+	NDD_ALIASING = 0,
 	/* unarmed memory devices may not persist writes */
-	NDD_UNARMED = 1 << 1,
+	NDD_UNARMED = 1,
+	/* locked memory devices should not be accessed */
+	NDD_LOCKED = 2,
 
 	/* need to set a limit somewhere, but yes, this is likely overkill */
 	ND_IOCTL_MAX_BUFLEN = SZ_4M,