diff --git a/drivers/infiniband/hw/mlx4/mcg.c b/drivers/infiniband/hw/mlx4/mcg.c
index ebdca2b280ab..8f7ad07915b0 100644
--- a/drivers/infiniband/hw/mlx4/mcg.c
+++ b/drivers/infiniband/hw/mlx4/mcg.c
@@ -96,7 +96,7 @@ struct ib_sa_mcmember_data {
 	u8		scope_join_state;
 	u8		proxy_join;
 	u8		reserved[2];
-};
+} __packed __aligned(4);
 
 struct mcast_group {
 	struct ib_sa_mcmember_data rec;