Linux 5.2 commit dcf49dbc8077) adds a 'recurse' flag for keyring searches.

--- a/libcfs/libcfs/crypto/keyring.c
+++ b/libcfs/libcfs/crypto/keyring.c
@@ -138,7 +138,11 @@ static struct key *search_llcrypt_keyrin
 	 */
 	key_ref_t keyref = make_key_ref(keyring, true /* possessed */);
 
+#ifdef HAVE_KEYRING_SEARCH_4ARGS
 	keyref = keyring_search(keyref, type, description, false);
+#else
+	keyref = keyring_search(keyref, type, description);
+#endif
 	if (IS_ERR(keyref)) {
 		if (PTR_ERR(keyref) == -EAGAIN || /* not found */
 		    PTR_ERR(keyref) == -EKEYREVOKED) /* recently invalidated */