libnvdimm: infrastructure for btt devices

NVDIMM namespaces, in addition to accepting "struct bio" based requests,
also have the capability to perform byte-aligned accesses.  By default
only the bio/block interface is used.  However, if another driver can
make effective use of the byte-aligned capability it can claim namespace
interface and use the byte-aligned ->rw_bytes() interface.

The BTT driver is the initial first consumer of this mechanism to allow
adding atomic sector update semantics to a pmem or blk namespace.  This
patch is the sysfs infrastructure to allow configuring a BTT instance
for a namespace.  Enabling that BTT and performing i/o is in a
subsequent patch.

Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/nvdimm/label.c b/drivers/nvdimm/label.c
index 3414800..96526dc 100644
--- a/drivers/nvdimm/label.c
+++ b/drivers/nvdimm/label.c
@@ -666,7 +666,7 @@
 
 	/* don't allow updates that consume the last label */
 	if (nfree - alloc < 0 || nfree - alloc + victims < 1) {
-		dev_info(&nsblk->dev, "insufficient label space\n");
+		dev_info(&nsblk->common.dev, "insufficient label space\n");
 		kfree(victim_map);
 		return -ENOSPC;
 	}
@@ -762,7 +762,8 @@
 			continue;
 		res = to_resource(ndd, nd_label);
 		res->flags &= ~DPA_RESOURCE_ADJUSTED;
-		dev_vdbg(&nsblk->dev, "assign label[%d] slot: %d\n", l, slot);
+		dev_vdbg(&nsblk->common.dev, "assign label[%d] slot: %d\n",
+				l, slot);
 		nd_mapping->labels[l++] = nd_label;
 	}
 	nd_mapping->labels[l] = NULL;