diff --git a/drivers/infiniband/hw/mthca/mthca_memfree.h b/drivers/infiniband/hw/mthca/mthca_memfree.h
index f9a2e65e2ff5..61d5bbba293a 100644
--- a/drivers/infiniband/hw/mthca/mthca_memfree.h
+++ b/drivers/infiniband/hw/mthca/mthca_memfree.h
@@ -68,7 +68,7 @@ struct mthca_icm_table {
 	int               lowmem;
 	int               coherent;
 	struct mutex      mutex;
-	struct mthca_icm *icm[];
+	struct mthca_icm *icm[] __counted_by(num_icm);
 };
 
 struct mthca_icm_iter {