IB/iser: Use helper for container_of

Nicer this way.

Signed-off-by: Sagi Grimberg <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>
diff --git a/drivers/infiniband/ulp/iser/iser_initiator.c b/drivers/infiniband/ulp/iser/iser_initiator.c
index 21f28c8..21148b6 100644
--- a/drivers/infiniband/ulp/iser/iser_initiator.c
+++ b/drivers/infiniband/ulp/iser/iser_initiator.c
@@ -559,8 +559,7 @@
 			 unsigned long rx_xfer_len,
 			 struct ib_conn *ib_conn)
 {
-	struct iser_conn *iser_conn = container_of(ib_conn, struct iser_conn,
-						   ib_conn);
+	struct iser_conn *iser_conn = to_iser_conn(ib_conn);
 	struct iscsi_hdr *hdr;
 	char *data;
 	u64 rx_dma;