libnvdimm/labels: Add blk isetcookie set / validation helpers

In preparation for LIBNVDIMM to manage labels on CXL devices deploy
helpers that abstract the label type from the implementation. The CXL
label format is mostly similar to the EFI label format with concepts /
fields added, like dynamic region creation and label type guids, and
other concepts removed like BLK-mode and interleave-set-cookie ids.

Given BLK-mode is not even supported on CXL push hide the BLK-mode
specific details inside the helpers.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/162982115185.1124374.13459190993792729776.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/nvdimm/label.c

@@ -898,6 +898,33 @@ static struct resource *to_resource(struct nvdimm_drvdata *ndd,
 	return NULL;
 }
 
+static void nsl_set_blk_isetcookie(struct nvdimm_drvdata *ndd,
+				   struct nd_namespace_label *nd_label,
+				   u64 isetcookie)
+{
+	if (namespace_label_has(ndd, type_guid)) {
+		nsl_set_isetcookie(ndd, nd_label, isetcookie);
+		return;
+	}
+	nsl_set_isetcookie(ndd, nd_label, 0); /* N/A */
+}
+
+bool nsl_validate_blk_isetcookie(struct nvdimm_drvdata *ndd,
+				 struct nd_namespace_label *nd_label,
+				 u64 isetcookie)
+{
+	if (!namespace_label_has(ndd, type_guid))
+		return true;
+
+	if (nsl_get_isetcookie(ndd, nd_label) != isetcookie) {
+		dev_dbg(ndd->dev, "expect cookie %#llx got %#llx\n", isetcookie,
+			nsl_get_isetcookie(ndd, nd_label));
+		return false;
+	}
+
+	return true;
+}
+
 /*
  * 1/ Account all the labels that can be freed after this update
  * 2/ Allocate and write the label to the staging (next) index
@@ -1042,12 +1069,11 @@ static int __blk_label_update(struct nd_region *nd_region,
 				nsl_set_nlabel(ndd, nd_label, 0xffff);
 				nsl_set_position(ndd, nd_label, 0xffff);
 			}
-			nsl_set_isetcookie(ndd, nd_label, nd_set->cookie2);
 		} else {
 			nsl_set_nlabel(ndd, nd_label, 0); /* N/A */
 			nsl_set_position(ndd, nd_label, 0); /* N/A */
-			nsl_set_isetcookie(ndd, nd_label, 0); /* N/A */
 		}
+		nsl_set_blk_isetcookie(ndd, nd_label, nd_set->cookie2);
 
 		nsl_set_dpa(ndd, nd_label, res->start);
 		nsl_set_rawsize(ndd, nd_label, resource_size(res));

drivers/nvdimm/namespace_devs.c

@@ -2272,14 +2272,9 @@ static struct device *create_namespace_blk(struct nd_region *nd_region,
 					&nd_label->type_guid);
 			return ERR_PTR(-EAGAIN);
 		}
-
-		if (nd_label->isetcookie != __cpu_to_le64(nd_set->cookie2)) {
-			dev_dbg(ndd->dev, "expect cookie %#llx got %#llx\n",
-					nd_set->cookie2,
-					nsl_get_isetcookie(ndd, nd_label));
-			return ERR_PTR(-EAGAIN);
-		}
 	}
+	if (!nsl_validate_blk_isetcookie(ndd, nd_label, nd_set->cookie2))
+		return ERR_PTR(-EAGAIN);
 
 	nsblk = kzalloc(sizeof(*nsblk), GFP_KERNEL);
 	if (!nsblk)

drivers/nvdimm/nd.h

@@ -177,6 +177,10 @@ static inline void nsl_set_lbasize(struct nvdimm_drvdata *ndd,
 	nd_label->lbasize = __cpu_to_le64(lbasize);
 }
 
+bool nsl_validate_blk_isetcookie(struct nvdimm_drvdata *ndd,
+				 struct nd_namespace_label *nd_label,
+				 u64 isetcookie);
+
 struct nd_region_data {
 	int ns_count;
 	int ns_active;