libnvdimm, dimm: clear 'locked' status on successful DIMM enable

If we successfully enable a DIMM then it must not be locked and we can
clear the label-read failure condition. Otherwise, we need to reload the
entire bus provider driver to achieve the same effect, and that can
disrupt unrelated DIMMs and namespaces.

Fixes: 9d62ed9651 ("libnvdimm: handle locked label storage areas")
Cc: <stable@vger.kernel.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/nvdimm/dimm_devs.c

@@ -200,6 +200,13 @@ void nvdimm_set_locked(struct device *dev)
 	set_bit(NDD_LOCKED, &nvdimm->flags);
 }
 
+void nvdimm_clear_locked(struct device *dev)
+{
+	struct nvdimm *nvdimm = to_nvdimm(dev);
+
+	clear_bit(NDD_LOCKED, &nvdimm->flags);
+}
+
 static void nvdimm_release(struct device *dev)
 {
 	struct nvdimm *nvdimm = to_nvdimm(dev);