diff --git a/Assemble.c b/Assemble.c
index bfc879c..ee0346a 100644
--- a/Assemble.c
+++ b/Assemble.c
@@ -1598,7 +1598,7 @@ int assemble_container_content(struct supertype *st, int mdfd,
 			if (!err) {
 				if (!mdmon_running(st->container_dev))
 					start_mdmon(st->container_dev);
-				ping_monitor(devnum2devname(st->container_dev));
+				ping_monitor_by_id(st->container_dev);
 			}
 			break;
 		}
diff --git a/Create.c b/Create.c
index 6349f86..9f34425 100644
--- a/Create.c
+++ b/Create.c
@@ -929,7 +929,7 @@ int Create(struct supertype *st, char *mddev,
 			if (need_mdmon)
 				start_mdmon(st->container_dev);
 
-			ping_monitor(devnum2devname(st->container_dev));
+			ping_monitor_by_id(st->container_dev);
 			close(container_fd);
 		}
 		wait_for(chosen_name, mdfd);
diff --git a/Grow.c b/Grow.c
index 40e693e..b639585 100644
--- a/Grow.c
+++ b/Grow.c
@@ -3416,7 +3416,7 @@ int Grow_continue(int mdfd, struct supertype *st, struct mdinfo *info,
 
 		if (!mdmon_running(st->container_dev))
 			start_mdmon(st->container_dev);
-		ping_monitor(devnum2devname(st->container_dev));
+		ping_monitor_by_id(st->container_dev);
 
 
 		if (info->reshape_active == 2) {
diff --git a/Incremental.c b/Incremental.c
index 300bdca..7218060 100644
--- a/Incremental.c
+++ b/Incremental.c
@@ -438,7 +438,7 @@ int Incremental(char *devname, int verbose, int runstop,
 	/* 7/ Is there enough devices to possibly start the array? */
 	/* 7a/ if not, finish with success. */
 	if (info.array.level == LEVEL_CONTAINER) {
-		char *devname = NULL;
+		int devnum;
 		/* Try to assemble within the container */
 		map_unlock(&map);
 		sysfs_uevent(&info, "change");
@@ -448,7 +448,7 @@ int Incremental(char *devname, int verbose, int runstop,
 				chosen_name, info.array.working_disks);
 		wait_for(chosen_name, mdfd);
 		if (st->ss->external)
-			devname = devnum2devname(fd2devnum(mdfd));
+			devnum = fd2devnum(mdfd);
 		close(mdfd);
 		sysfs_free(sra);
 		rv = Incremental(chosen_name, verbose, runstop,
@@ -460,10 +460,8 @@ int Incremental(char *devname, int verbose, int runstop,
 			rv = 0;
 		/* after spare is added, ping monitor for external metadata
 		 * so that it can eg. try to rebuild degraded array */
-		if (st->ss->external) {
-			ping_monitor(devname);
-			free(devname);
-		}
+		if (st->ss->external)
+			ping_monitor_by_id(devnum);
 		return rv;
 	}
 
diff --git a/Manage.c b/Manage.c
index a679c24..5fd7014 100644
--- a/Manage.c
+++ b/Manage.c
@@ -932,7 +932,7 @@ int Manage_subdevs(char *devname, int fd,
 					sysfs_free(sra);
 					return 1;
 				}
-				ping_monitor(devnum2devname(devnum));
+				ping_monitor_by_id(devnum);
 				sysfs_free(sra);
 				close(container_fd);
 			} else {
diff --git a/Monitor.c b/Monitor.c
index d3795b1..3f211b5 100644
--- a/Monitor.c
+++ b/Monitor.c
@@ -975,7 +975,7 @@ int Wait(char *dev)
 				if (is_subarray(&e->metadata_version[9]))
 					ping_monitor(&e->metadata_version[9]);
 				else
-					ping_monitor(devnum2devname(devnum));
+					ping_monitor_by_id(devnum);
 			}
 			free_mdstat(ms);
 			return rv;
diff --git a/msg.c b/msg.c
index a1f4bc6..a10c930 100644
--- a/msg.c
+++ b/msg.c
@@ -213,6 +213,20 @@ int ping_monitor(char *devname)
 	return err;
 }
 
+/* ping monitor using device number */
+int ping_monitor_by_id(int devnum)
+{
+	int err = -1;
+	char *container = devnum2devname(devnum);
+
+	if (container) {
+		err = ping_monitor(container);
+		free(container);
+	}
+
+	return err;
+}
+
 static char *ping_monitor_version(char *devname)
 {
 	int sfd = connect_monitor(devname);
diff --git a/msg.h b/msg.h
index 91a7798..c6d037d 100644
--- a/msg.h
+++ b/msg.h
@@ -27,6 +27,7 @@ extern int ack(int fd, int tmo);
 extern int wait_reply(int fd, int tmo);
 extern int connect_monitor(char *devname);
 extern int ping_monitor(char *devname);
+extern int ping_monitor_by_id(int devnum);
 extern int block_subarray(struct mdinfo *sra);
 extern int unblock_subarray(struct mdinfo *sra, const int unfreeze);
 extern int block_monitor(char *container, const int freeze);