net/smc: use a constant for control message length

The sizeof(struct smc_cdc_msg) evaluates to 48 bytes instead of the
required 44 bytes. We need to use the constant value of
SMC_WR_TX_SIZE to set and check the control message length.
Signed-off-by: Karsten Graul <kgraul@linux.vnet.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc/smc_cdc.c

@@ -269,7 +269,7 @@ static void smc_cdc_rx_handler(struct ib_wc *wc, void *buf)
 
 	if (wc->byte_len < offsetof(struct smc_cdc_msg, reserved))
 		return; /* short message */
-	if (cdc->len != sizeof(*cdc))
+	if (cdc->len != SMC_WR_TX_SIZE)
 		return; /* invalid message */
 	smc_cdc_msg_recv(cdc, link, wc->wr_id);
 }

net/smc/smc_core.c

@@ -465,7 +465,7 @@ int smc_conn_create(struct smc_sock *smc, __be32 peer_in_addr,
 		rc = smc_link_determine_gid(conn->lgr);
 	}
 	conn->local_tx_ctrl.common.type = SMC_CDC_MSG_TYPE;
-	conn->local_tx_ctrl.len = sizeof(struct smc_cdc_msg);
+	conn->local_tx_ctrl.len = SMC_WR_TX_SIZE;
 #ifndef KERNEL_HAS_ATOMIC64
 	spin_lock_init(&conn->acurs_lock);
 #endif