net/smc: call smc_cdc_msg_send() under send_lock

Call smc_cdc_msg_send() under the connection send_lock to make sure all
send operations for one connection are serialized.
Signed-off-by: NKarsten Graul <kgraul@linux.ibm.com>
Signed-off-by: NUrsula Braun <ubraun@linux.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/smc/smc_cdc.c

@@ -125,7 +125,10 @@ static int smcr_cdc_get_slot_and_msg_send(struct smc_connection *conn)
 	if (rc)
 		return rc;
 
-	return smc_cdc_msg_send(conn, wr_buf, pend);
+	spin_lock_bh(&conn->send_lock);
+	rc = smc_cdc_msg_send(conn, wr_buf, pend);
+	spin_unlock_bh(&conn->send_lock);
+	return rc;
 }
 
 int smc_cdc_get_slot_and_msg_send(struct smc_connection *conn)