libnvdimm, pfn: fix pfn seed creation

Similar to btt, plant a new pfn seed when the existing one is activated.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

drivers/nvdimm/namespace_devs.c

@@ -1707,6 +1707,18 @@ void nd_region_create_blk_seed(struct nd_region *nd_region)
 		nd_device_register(nd_region->ns_seed);
 }
 
+void nd_region_create_pfn_seed(struct nd_region *nd_region)
+{
+	WARN_ON(!is_nvdimm_bus_locked(&nd_region->dev));
+	nd_region->pfn_seed = nd_pfn_create(nd_region);
+	/*
+	 * Seed creation failures are not fatal, provisioning is simply
+	 * disabled until memory becomes available
+	 */
+	if (!nd_region->pfn_seed)
+		dev_err(&nd_region->dev, "failed to create pfn namespace\n");
+}
+
 void nd_region_create_btt_seed(struct nd_region *nd_region)
 {
 	WARN_ON(!is_nvdimm_bus_locked(&nd_region->dev));

drivers/nvdimm/nd-core.h

@@ -52,6 +52,7 @@ void nd_region_probe_success(struct nvdimm_bus *nvdimm_bus, struct device *dev);
 struct nd_region;
 void nd_region_create_blk_seed(struct nd_region *nd_region);
 void nd_region_create_btt_seed(struct nd_region *nd_region);
+void nd_region_create_pfn_seed(struct nd_region *nd_region);
 void nd_region_disable(struct nvdimm_bus *nvdimm_bus, struct device *dev);
 int nvdimm_bus_create_ndctl(struct nvdimm_bus *nvdimm_bus);
 void nvdimm_bus_destroy_ndctl(struct nvdimm_bus *nvdimm_bus);

drivers/nvdimm/region_devs.c

@@ -490,6 +490,13 @@ static void nd_region_notify_driver_action(struct nvdimm_bus *nvdimm_bus,
 			nd_region_create_blk_seed(nd_region);
 		nvdimm_bus_unlock(dev);
 	}
+	if (is_nd_pfn(dev) && probe) {
+		nd_region = to_nd_region(dev->parent);
+		nvdimm_bus_lock(dev);
+		if (nd_region->pfn_seed == dev)
+			nd_region_create_pfn_seed(nd_region);
+		nvdimm_bus_unlock(dev);
+	}
 }
 
 void nd_region_probe_success(struct nvdimm_bus *nvdimm_bus, struct device *dev)