[PATCH 8/9] libnvdimm, label: add address abstraction identifiers

[Dan Williams <dan.j.williams@xxxxxxxxx>]

Starting with v1.2 labels, 'address abstractions' can be hinted via an
address abstraction id that implies an info-block format. The standard
address abstraction in the specification is the v2 format of the
Block-Translation-Table (BTT). Support for that is saved for a later
patch, for now we add support for the Linux supported address
abstractions BTT (v1), PFN, and DAX.

The new 'holder_class' attribute for namespace devices is added for
tooling to specify the 'abstraction_guid' to store in the namespace label.
For v1.1 labels this field is undefined and any setting of
'holder_class' away from the default 'none' value will only have effect
until the driver is unloaded. Setting 'holder_class' requires that
whatever device tries to claim the namespace must be of the specified
class.

Cc: Vishal Verma <vishal.l.verma@xxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
 drivers/nvdimm/btt_devs.c       |    8 ++++
 drivers/nvdimm/claim.c          |   28 +++++++++++++++
 drivers/nvdimm/core.c           |    3 ++
 drivers/nvdimm/dax_devs.c       |    8 ++++
 drivers/nvdimm/label.c          |   58 +++++++++++++++++++++++++++++++
 drivers/nvdimm/label.h          |    5 +++
 drivers/nvdimm/namespace_devs.c |   74 +++++++++++++++++++++++++++++++++++++++
 drivers/nvdimm/nd.h             |    1 +
 drivers/nvdimm/pfn_devs.c       |    8 ++++
 include/linux/nd.h              |   10 +++++
 10 files changed, 203 insertions(+)

diff --git a/drivers/nvdimm/btt_devs.c b/drivers/nvdimm/btt_devs.c
index 4c989bb9a8a0..31d875a91569 100644
--- a/drivers/nvdimm/btt_devs.c
+++ b/drivers/nvdimm/btt_devs.c
@@ -295,6 +295,14 @@ int nd_btt_probe(struct device *dev, struct nd_namespace_common *ndns)
 	if (ndns->force_raw)
 		return -ENODEV;
 
+	switch (ndns->claim_class) {
+	case NVDIMM_CCLASS_NONE:
+	case NVDIMM_CCLASS_BTT:
+		break;
+	default:
+		return -ENODEV;
+	}
+
 	nvdimm_bus_lock(&ndns->dev);
 	btt_dev = __nd_btt_create(nd_region, 0, NULL, ndns);
 	nvdimm_bus_unlock(&ndns->dev);
diff --git a/drivers/nvdimm/claim.c b/drivers/nvdimm/claim.c
index 7ceb5fa4f2a1..de9b1cce242e 100644
--- a/drivers/nvdimm/claim.c
+++ b/drivers/nvdimm/claim.c
@@ -184,6 +184,34 @@ ssize_t nd_namespace_store(struct device *dev,
 	}
 
 	ndns = to_ndns(found);
+
+	switch (ndns->claim_class) {
+	case NVDIMM_CCLASS_NONE:
+		break;
+	case NVDIMM_CCLASS_BTT:
+		if (!is_nd_btt(dev)) {
+			len = -EBUSY;
+			goto out_attach;
+		}
+		break;
+	case NVDIMM_CCLASS_PFN:
+		if (!is_nd_pfn(dev)) {
+			len = -EBUSY;
+			goto out_attach;
+		}
+		break;
+	case NVDIMM_CCLASS_DAX:
+		if (!is_nd_dax(dev)) {
+			len = -EBUSY;
+			goto out_attach;
+		}
+		break;
+	default:
+		len = -EBUSY;
+		goto out_attach;
+		break;
+	}
+
 	if (__nvdimm_namespace_capacity(ndns) < SZ_16M) {
 		dev_dbg(dev, "%s too small to host\n", name);
 		len = -ENXIO;
diff --git a/drivers/nvdimm/core.c b/drivers/nvdimm/core.c
index 2dee908e4bae..ed0bf174d128 100644
--- a/drivers/nvdimm/core.c
+++ b/drivers/nvdimm/core.c
@@ -699,6 +699,9 @@ static __init int libnvdimm_init(void)
 	rc = nd_region_init();
 	if (rc)
 		goto err_region;
+
+	nd_label_init();
+
 	return 0;
  err_region:
 	nvdimm_exit();
diff --git a/drivers/nvdimm/dax_devs.c b/drivers/nvdimm/dax_devs.c
index c1b6556aea6e..59f676381ae5 100644
--- a/drivers/nvdimm/dax_devs.c
+++ b/drivers/nvdimm/dax_devs.c
@@ -111,6 +111,14 @@ int nd_dax_probe(struct device *dev, struct nd_namespace_common *ndns)
 	if (ndns->force_raw)
 		return -ENODEV;
 
+	switch (ndns->claim_class) {
+	case NVDIMM_CCLASS_NONE:
+	case NVDIMM_CCLASS_DAX:
+		break;
+	default:
+		return -ENODEV;
+	}
+
 	nvdimm_bus_lock(&ndns->dev);
 	nd_dax = nd_dax_alloc(nd_region);
 	nd_pfn = &nd_dax->nd_pfn;
diff --git a/drivers/nvdimm/label.c b/drivers/nvdimm/label.c
index c503362a03c7..837bf21c8555 100644
--- a/drivers/nvdimm/label.c
+++ b/drivers/nvdimm/label.c
@@ -12,6 +12,7 @@
  */
 #include <linux/device.h>
 #include <linux/ndctl.h>
+#include <linux/uuid.h>
 #include <linux/slab.h>
 #include <linux/io.h>
 #include <linux/nd.h>
@@ -19,6 +20,10 @@
 #include "label.h"
 #include "nd.h"
 
+static guid_t nvdimm_btt_guid;
+static guid_t nvdimm_pfn_guid;
+static guid_t nvdimm_dax_guid;
+
 static u32 best_seq(u32 a, u32 b)
 {
 	a &= NSINDEX_SEQ_MASK;
@@ -565,10 +570,44 @@ static unsigned long nd_label_offset(struct nvdimm_drvdata *ndd,
 		- (unsigned long) to_namespace_index(ndd, 0);
 }
 
+enum nvdimm_claim_class to_nvdimm_cclass(guid_t *guid)
+{
+	if (guid_equal(guid, &nvdimm_btt_guid))
+		return NVDIMM_CCLASS_BTT;
+	else if (guid_equal(guid, &nvdimm_pfn_guid))
+		return NVDIMM_CCLASS_PFN;
+	else if (guid_equal(guid, &nvdimm_dax_guid))
+		return NVDIMM_CCLASS_DAX;
+	else if (guid_equal(guid, &guid_null))
+		return NVDIMM_CCLASS_NONE;
+
+	return NVDIMM_CCLASS_UNKNOWN;
+}
+
+static const guid_t *to_abstraction_guid(enum nvdimm_claim_class claim_class,
+	guid_t *target)
+{
+	if (claim_class == NVDIMM_CCLASS_BTT)
+		return &nvdimm_btt_guid;
+	else if (claim_class == NVDIMM_CCLASS_PFN)
+		return &nvdimm_pfn_guid;
+	else if (claim_class == NVDIMM_CCLASS_DAX)
+		return &nvdimm_dax_guid;
+	else if (claim_class == NVDIMM_CCLASS_UNKNOWN) {
+		/*
+		 * If we're modifying a namespace for which we don't
+		 * know the claim_class, don't touch the existing guid.
+		 */
+		return target;
+	} else
+		return &guid_null;
+}
+
 static int __pmem_label_update(struct nd_region *nd_region,
 		struct nd_mapping *nd_mapping, struct nd_namespace_pmem *nspm,
 		int pos)
 {
+	struct nd_namespace_common *ndns = &nspm->nsio.common;
 	struct nd_interleave_set *nd_set = nd_region->nd_set;
 	struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
 	struct nd_label_ent *label_ent, *victim = NULL;
@@ -616,6 +655,10 @@ static int __pmem_label_update(struct nd_region *nd_region,
 	nd_label->slot = __cpu_to_le32(slot);
 	if (namespace_label_has(ndd, type_guid))
 		guid_copy(&nd_label->type_guid, &nd_set->type_guid);
+	if (namespace_label_has(ndd, abstraction_guid))
+		guid_copy(&nd_label->abstraction_guid,
+				to_abstraction_guid(ndns->claim_class,
+					&nd_label->abstraction_guid));
 	if (namespace_label_has(ndd, checksum)) {
 		u64 sum;
 
@@ -711,6 +754,7 @@ static int __blk_label_update(struct nd_region *nd_region,
 {
 	int i, alloc, victims, nfree, old_num_resources, nlabel, rc = -ENXIO;
 	struct nd_interleave_set *nd_set = nd_region->nd_set;
+	struct nd_namespace_common *ndns = &nsblk->common;
 	struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
 	struct nd_namespace_label *nd_label;
 	struct nd_label_ent *label_ent, *e;
@@ -848,6 +892,11 @@ static int __blk_label_update(struct nd_region *nd_region,
 		nd_label->slot = __cpu_to_le32(slot);
 		if (namespace_label_has(ndd, type_guid))
 			guid_copy(&nd_label->type_guid, &nd_set->type_guid);
+		if (namespace_label_has(ndd, abstraction_guid))
+			guid_copy(&nd_label->abstraction_guid,
+					to_abstraction_guid(ndns->claim_class,
+						&nd_label->abstraction_guid));
+
 		if (namespace_label_has(ndd, checksum)) {
 			u64 sum;
 
@@ -1101,3 +1150,12 @@ int nd_blk_namespace_label_update(struct nd_region *nd_region,
 
 	return __blk_label_update(nd_region, nd_mapping, nsblk, count);
 }
+
+int __init nd_label_init(void)
+{
+	WARN_ON(guid_parse(NVDIMM_BTT_GUID, &nvdimm_btt_guid));
+	WARN_ON(guid_parse(NVDIMM_PFN_GUID, &nvdimm_pfn_guid));
+	WARN_ON(guid_parse(NVDIMM_DAX_GUID, &nvdimm_dax_guid));
+
+	return 0;
+}
diff --git a/drivers/nvdimm/label.h b/drivers/nvdimm/label.h
index f39bfb31f72f..7c8e2cc9e73e 100644
--- a/drivers/nvdimm/label.h
+++ b/drivers/nvdimm/label.h
@@ -112,6 +112,10 @@ struct nd_namespace_label {
 	__le64 checksum;
 };
 
+#define NVDIMM_BTT_GUID "8aed63a2-29a2-4c66-8b12-f05d15d3922a"
+#define NVDIMM_PFN_GUID "266400ba-fb9f-4677-bcb0-968f11d0d225"
+#define NVDIMM_DAX_GUID "97a86d9c-3cdd-4eda-986f-5068b4f80088"
+
 /**
  * struct nd_label_id - identifier string for dpa allocation
  * @id: "{blk|pmem}-<namespace uuid>"
@@ -142,6 +146,7 @@ struct nd_namespace_label *nd_label_active(struct nvdimm_drvdata *ndd, int n);
 u32 nd_label_alloc_slot(struct nvdimm_drvdata *ndd);
 bool nd_label_free_slot(struct nvdimm_drvdata *ndd, u32 slot);
 u32 nd_label_nfree(struct nvdimm_drvdata *ndd);
+enum nvdimm_claim_class to_nvdimm_cclass(guid_t *guid);
 struct nd_region;
 struct nd_namespace_pmem;
 struct nd_namespace_blk;
diff --git a/drivers/nvdimm/namespace_devs.c b/drivers/nvdimm/namespace_devs.c
index 7aba9a569c8e..f05d9b0672bf 100644
--- a/drivers/nvdimm/namespace_devs.c
+++ b/drivers/nvdimm/namespace_devs.c
@@ -1425,6 +1425,69 @@ static ssize_t holder_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(holder);
 
+static ssize_t __holder_class_store(struct device *dev, const char *buf)
+{
+	struct nd_namespace_common *ndns = to_ndns(dev);
+
+	if (dev->driver || ndns->claim)
+		return -EBUSY;
+
+	if (strcmp(buf, "btt") == 0 || strcmp(buf, "btt\n") == 0)
+		ndns->claim_class = NVDIMM_CCLASS_BTT;
+	else if (strcmp(buf, "pfn") == 0 || strcmp(buf, "pfn\n") == 0)
+		ndns->claim_class = NVDIMM_CCLASS_PFN;
+	else if (strcmp(buf, "dax") == 0 || strcmp(buf, "dax\n") == 0)
+		ndns->claim_class = NVDIMM_CCLASS_DAX;
+	else if (strcmp(buf, "") == 0 || strcmp(buf, "\n") == 0)
+		ndns->claim_class = NVDIMM_CCLASS_NONE;
+	else
+		return -EINVAL;
+
+	return 0;
+}
+
+static ssize_t holder_class_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t len)
+{
+	struct nd_region *nd_region = to_nd_region(dev->parent);
+	ssize_t rc;
+
+	device_lock(dev);
+	nvdimm_bus_lock(dev);
+	wait_nvdimm_bus_probe_idle(dev);
+	rc = __holder_class_store(dev, buf);
+	if (rc >= 0)
+		rc = nd_namespace_label_update(nd_region, dev);
+	dev_dbg(dev, "%s: %s(%zd)\n", __func__, rc < 0 ? "fail " : "", rc);
+	nvdimm_bus_unlock(dev);
+	device_unlock(dev);
+
+	return rc < 0 ? rc : len;
+}
+
+static ssize_t holder_class_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct nd_namespace_common *ndns = to_ndns(dev);
+	ssize_t rc;
+
+	device_lock(dev);
+	if (ndns->claim_class == NVDIMM_CCLASS_NONE)
+		rc = sprintf(buf, "\n");
+	else if (ndns->claim_class == NVDIMM_CCLASS_BTT)
+		rc = sprintf(buf, "btt\n");
+	else if (ndns->claim_class == NVDIMM_CCLASS_PFN)
+		rc = sprintf(buf, "pfn\n");
+	else if (ndns->claim_class == NVDIMM_CCLASS_DAX)
+		rc = sprintf(buf, "dax\n");
+	else
+		rc = sprintf(buf, "<unknown>\n");
+	device_unlock(dev);
+
+	return rc;
+}
+static DEVICE_ATTR_RW(holder_class);
+
 static ssize_t mode_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
 {
@@ -1483,6 +1546,7 @@ static struct attribute *nd_namespace_attributes[] = {
 	&dev_attr_force_raw.attr,
 	&dev_attr_sector_size.attr,
 	&dev_attr_dpa_extents.attr,
+	&dev_attr_holder_class.attr,
 	NULL,
 };
 
@@ -1506,6 +1570,7 @@ static umode_t namespace_visible(struct kobject *kobj,
 
 	if (a == &dev_attr_nstype.attr || a == &dev_attr_size.attr
 			|| a == &dev_attr_holder.attr
+			|| a == &dev_attr_holder_class.attr
 			|| a == &dev_attr_force_raw.attr
 			|| a == &dev_attr_mode.attr)
 		return a->mode;
@@ -1827,6 +1892,7 @@ struct device *create_namespace_pmem(struct nd_region *nd_region,
 	/* Calculate total size and populate namespace properties from label0 */
 	for (i = 0; i < nd_region->ndr_mappings; i++) {
 		struct nd_namespace_label *label0;
+		struct nvdimm_drvdata *ndd;
 
 		nd_mapping = &nd_region->mapping[i];
 		label_ent = list_first_entry_or_null(&nd_mapping->labels,
@@ -1847,6 +1913,11 @@ struct device *create_namespace_pmem(struct nd_region *nd_region,
 		nspm->uuid = kmemdup((void __force *) label0->uuid,
 				NSLABEL_UUID_LEN, GFP_KERNEL);
 		nspm->lbasize = __le64_to_cpu(label0->lbasize);
+		ndd = to_ndd(nd_mapping);
+		if (namespace_label_has(ndd, abstraction_guid))
+			nspm->nsio.common.claim_class
+				= to_nvdimm_cclass(&label0->abstraction_guid);
+
 	}
 
 	if (!nspm->alt_name || !nspm->uuid) {
@@ -2091,6 +2162,9 @@ struct device *create_namespace_blk(struct nd_region *nd_region,
 	nsblk->lbasize = __le64_to_cpu(nd_label->lbasize);
 	nsblk->uuid = kmemdup(nd_label->uuid, NSLABEL_UUID_LEN,
 			GFP_KERNEL);
+	if (namespace_label_has(ndd, abstraction_guid))
+		nsblk->common.claim_class
+			= to_nvdimm_cclass(&nd_label->abstraction_guid);
 	if (!nsblk->uuid)
 		goto blk_err;
 	memcpy(name, nd_label->name, NSLABEL_NAME_LEN);
diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
index 17cecb38dfc9..8cabd836df0e 100644
--- a/drivers/nvdimm/nd.h
+++ b/drivers/nvdimm/nd.h
@@ -235,6 +235,7 @@ ssize_t nd_sector_size_store(struct device *dev, const char *buf,
 		unsigned long *current_lbasize, const unsigned long *supported);
 int __init nvdimm_init(void);
 int __init nd_region_init(void);
+int __init nd_label_init(void);
 void nvdimm_exit(void);
 void nd_region_exit(void);
 struct nvdimm;
diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c
index a6c403600d19..5e4041276d6f 100644
--- a/drivers/nvdimm/pfn_devs.c
+++ b/drivers/nvdimm/pfn_devs.c
@@ -471,6 +471,14 @@ int nd_pfn_probe(struct device *dev, struct nd_namespace_common *ndns)
 	if (ndns->force_raw)
 		return -ENODEV;
 
+	switch (ndns->claim_class) {
+	case NVDIMM_CCLASS_NONE:
+	case NVDIMM_CCLASS_PFN:
+		break;
+	default:
+		return -ENODEV;
+	}
+
 	nvdimm_bus_lock(&ndns->dev);
 	nd_pfn = nd_pfn_alloc(nd_region);
 	pfn_dev = nd_pfn_devinit(nd_pfn, ndns);
diff --git a/include/linux/nd.h b/include/linux/nd.h
index d8f5023b49ae..96069c543890 100644
--- a/include/linux/nd.h
+++ b/include/linux/nd.h
@@ -21,6 +21,14 @@ enum nvdimm_event {
 	NVDIMM_REVALIDATE_POISON,
 };
 
+enum nvdimm_claim_class {
+	NVDIMM_CCLASS_NONE,
+	NVDIMM_CCLASS_BTT,
+	NVDIMM_CCLASS_PFN,
+	NVDIMM_CCLASS_DAX,
+	NVDIMM_CCLASS_UNKNOWN,
+};
+
 struct nd_device_driver {
 	struct device_driver drv;
 	unsigned long type;
@@ -41,12 +49,14 @@ static inline struct nd_device_driver *to_nd_device_driver(
  * @force_raw: ignore other personalities for the namespace (e.g. btt)
  * @dev: device model node
  * @claim: when set a another personality has taken ownership of the namespace
+ * @claim_class: restrict claim type to a given class
  * @rw_bytes: access the raw namespace capacity with byte-aligned transfers
  */
 struct nd_namespace_common {
 	int force_raw;
 	struct device dev;
 	struct device *claim;
+	enum nvdimm_claim_class claim_class;
 	int (*rw_bytes)(struct nd_namespace_common *, resource_size_t offset,
 			void *buf, size_t size, int rw, unsigned long flags);
 };

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