[bug report] dpaa_eth: add support for DPAA Ethernet

[Dan Carpenter <dan.carpenter@oracle.com>]

Hello Madalin Bucur,

The patch 9ad1a3749333: "dpaa_eth: add support for DPAA Ethernet"
from Nov 15, 2016, leads to the following static checker warning:

	drivers/net/ethernet/freescale/dpaa/dpaa_eth.c:1082 dpaa_eth_init_tx_port()
	warn: 'port' was already freed.

drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
  1058  static void dpaa_eth_init_tx_port(struct fman_port *port, struct dpaa_fq *errq,
  1059                                    struct dpaa_fq *defq,
  1060                                    struct dpaa_buffer_layout *buf_layout)
  1061  {
  1062          struct fman_buffer_prefix_content buf_prefix_content;
  1063          struct fman_port_params params;
  1064          int err;
  1065  
  1066          memset(&params, 0, sizeof(params));
  1067          memset(&buf_prefix_content, 0, sizeof(buf_prefix_content));
  1068  
  1069          buf_prefix_content.priv_data_size = buf_layout->priv_data_size;
  1070          buf_prefix_content.pass_prs_result = true;
  1071          buf_prefix_content.pass_hash_result = true;
  1072          buf_prefix_content.pass_time_stamp = false;
  1073          buf_prefix_content.data_align = DPAA_FD_DATA_ALIGNMENT;
  1074  
  1075          params.specific_params.non_rx_params.err_fqid = errq->fqid;
  1076          params.specific_params.non_rx_params.dflt_fqid = defq->fqid;
  1077  
  1078          err = fman_port_config(port, &params);

fman_port_config() frees port on error.  This is the wrong thing to do
and a layering violation.  We should just return an error.

But the callers also need to be modified to check for errors etc...  So
it's not easy to fix all the bugs because there are too many.

  1079          if (err)
  1080                  pr_err("%s: fman_port_config failed\n", __func__);
  1081  
  1082          err = fman_port_cfg_buf_prefix_content(port, &buf_prefix_content);

Use after free.

  1083          if (err)
  1084                  pr_err("%s: fman_port_cfg_buf_prefix_content failed\n",
  1085                         __func__);
  1086  
  1087          err = fman_port_init(port);
  1088          if (err)
  1089                  pr_err("%s: fm_port_init failed\n", __func__);
  1090  }


regards,
dan carpenter