diff --git a/sys/dev/nvme/nvme_private.h b/sys/dev/nvme/nvme_private.h
--- a/sys/dev/nvme/nvme_private.h
+++ b/sys/dev/nvme/nvme_private.h
@@ -119,8 +119,8 @@
 	struct nvme_command		cmd;
 	struct nvme_qpair		*qpair;
 	struct memdesc			payload;
-	bool				payload_valid;
-	bool				timeout;
+	bool				payload_valid : 1,
+					timeout : 1;
 	nvme_cb_fn_t			cb_fn;
 	void				*cb_arg;
 	int32_t				retries;