dm-ioctl: report an error if a device has no table

When we send a message to a device that has no table, the return code was
not set. The code would return "2", which is not considered a valid return value.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Reviewed-by: Benjamin Marzinski <bmarzins@redhat.com>

Author: Mikulas Patocka

drivers/md/dm-ioctl.c

@@ -1938,8 +1938,11 @@ static int target_message(struct file *filp, struct dm_ioctl *param, size_t para
 		goto out_argv;
 
 	table = dm_get_live_table(md, &srcu_idx);
-	if (!table)
+	if (!table) {
+		DMERR("The device has no table.");
+		r = -EINVAL;
 		goto out_table;
+	}
 
 	if (dm_deleting_md(md)) {
 		r = -ENXIO;