[bug report] {net, IB}/mlx5: Manage port association for multiport RoCE

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

Hello Daniel Jurgens,

The patch 32f69e4be269: "{net, IB}/mlx5: Manage port association for
multiport RoCE" from Jan 4, 2018, leads to the following static
checker warning:

	drivers/infiniband/hw/mlx5/main.c:3285 mlx5_ib_init_multiport_master()
	warn: iterator 'mpi->list.next' changed during iteration

drivers/infiniband/hw/mlx5/main.c
  3285                  list_for_each_entry(mpi, &mlx5_ib_unaffiliated_port_list,
                                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
We're iterating through the unafiliated list.

  3286                                      list) {
  3287                          if (dev->sys_image_guid == mpi->sys_image_guid &&
  3288                              (mlx5_core_native_port_num(mpi->mdev) - 1) == i) {
  3289                                  bound = mlx5_ib_bind_slave_port(dev, mpi);

The mlx5_ib_bind_slave_port() function returns true on success and
false on failure.  On the failure path it calls:

	mlx5_ib_unbind_slave_port(ibdev, mpi);

Which adds our "mpi" as the last item on the unaffiliated list.  I don't
think anything good can come from adding a list item to a list twice.

  3290                          }
  3291  
  3292                          if (bound) {
  3293                                  dev_dbg(mpi->mdev->device,
  3294                                          "removing port from unaffiliated list.\n");
  3295                                  mlx5_ib_dbg(dev, "port %d bound\n", i + 1);
  3296                                  list_del(&mpi->list);
  3297                                  break;
  3298                          }
  3299                  }
  3300                  if (!bound)
  3301                          mlx5_ib_dbg(dev, "no free port found for port %d\n",
  3302                                      i + 1);

regards,
dan carpenter