libnvdimm, label: add address abstraction identifiers

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@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 10 insertions, 0 deletions

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);
 };