Re: [dpdk-dev] [PATCH v2 2/3] net/vmxnet3: fix vmxnet3 dev_uninit() hot-unplug

[Chas Williams <3chas3@gmail.com>]

On Wed, Sep 19, 2018 at 8:58 AM Luca Boccassi <bluca@debian.org> wrote:
>
> The vmxnet3 driver can't call back into dev_close(), and possibly
> dev_stop(), in dev_uninit().  When dev_uninit() is called, anything
> that those routines would want to clean up has already been released.
> Further, for complete cleanup, it is necessary to release any of the
> queue resources during dev_close().
> This allows a vmxnet3 device to be hot-unplugged without leaking
> queues.
>
> Fixes: dfaff37fc46d ("vmxnet3: import new vmxnet3 poll mode driver implementation")
> Cc: stable@dpdk.org
>
> Signed-off-by: Brian Russell <brussell@brocade.com>
> Signed-off-by: Luca Boccassi <bluca@debian.org>
> ---
> v2: add back extra close() call in uninit() for buggy applications as
>     requested by the reviewers, and add debug log noting the issue
>
>  drivers/net/vmxnet3/vmxnet3_ethdev.c | 35 +++++++++++++++++++++++-----
>  1 file changed, 29 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/net/vmxnet3/vmxnet3_ethdev.c b/drivers/net/vmxnet3/vmxnet3_ethdev.c
> index f1596ab19d..98e5d01890 100644
> --- a/drivers/net/vmxnet3/vmxnet3_ethdev.c
> +++ b/drivers/net/vmxnet3/vmxnet3_ethdev.c
> @@ -354,8 +354,10 @@ eth_vmxnet3_dev_uninit(struct rte_eth_dev *eth_dev)
>         if (rte_eal_process_type() != RTE_PROC_PRIMARY)
>                 return 0;

This should probably be EPERM as well.  Out of scope though.

>
> -       if (hw->adapter_stopped == 0)
> +       if (hw->adapter_stopped == 0) {
> +               PMD_INIT_LOG(DEBUG, "Device has not been closed.");
>                 vmxnet3_dev_close(eth_dev);

This just seems wrong.  You have called uninit() will the driver is
still busy.  Instead of "fixing" the state of the driver, return EBUSY
here.

> +       }
>
>         eth_dev->dev_ops = NULL;
>         eth_dev->rx_pkt_burst = NULL;
> @@ -802,7 +804,7 @@ vmxnet3_dev_stop(struct rte_eth_dev *dev)
>         PMD_INIT_FUNC_TRACE();
>
>         if (hw->adapter_stopped == 1) {
> -               PMD_INIT_LOG(DEBUG, "Device already closed.");
> +               PMD_INIT_LOG(DEBUG, "Device already stopped.");
>                 return;
>         }
>
> @@ -826,7 +828,6 @@ vmxnet3_dev_stop(struct rte_eth_dev *dev)
>         /* reset the device */
>         VMXNET3_WRITE_BAR1_REG(hw, VMXNET3_REG_CMD, VMXNET3_CMD_RESET_DEV);
>         PMD_INIT_LOG(DEBUG, "Device reset.");
> -       hw->adapter_stopped = 0;
>
>         vmxnet3_dev_clear_queues(dev);
>
> @@ -836,6 +837,30 @@ vmxnet3_dev_stop(struct rte_eth_dev *dev)
>         link.link_speed = ETH_SPEED_NUM_10G;
>         link.link_autoneg = ETH_LINK_FIXED;
>         rte_eth_linkstatus_set(dev, &link);
> +
> +       hw->adapter_stopped = 1;
> +}
> +
> +static void
> +vmxnet3_free_queues(struct rte_eth_dev *dev)
> +{
> +       int i;
> +
> +       PMD_INIT_FUNC_TRACE();
> +
> +       for (i = 0; i < dev->data->nb_rx_queues; i++) {
> +               void *rxq = dev->data->rx_queues[i];
> +
> +               vmxnet3_dev_rx_queue_release(rxq);
> +       }
> +       dev->data->nb_rx_queues = 0;
> +
> +       for (i = 0; i < dev->data->nb_tx_queues; i++) {
> +               void *txq = dev->data->tx_queues[i];
> +
> +               vmxnet3_dev_tx_queue_release(txq);
> +       }
> +       dev->data->nb_tx_queues = 0;
>  }
>
>  /*
> @@ -844,12 +869,10 @@ vmxnet3_dev_stop(struct rte_eth_dev *dev)
>  static void
>  vmxnet3_dev_close(struct rte_eth_dev *dev)
>  {
> -       struct vmxnet3_hw *hw = dev->data->dev_private;
> -
>         PMD_INIT_FUNC_TRACE();
>
>         vmxnet3_dev_stop(dev);
> -       hw->adapter_stopped = 1;
> +       vmxnet3_free_queues(dev);
>  }
>
>  static void
> --
> 2.18.0
>