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

[Luca Boccassi <bluca@debian.org>]

On Wed, 2018-09-19 at 11:47 -0400, Chas Williams wrote:
> 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.

At this point that's out of scope too - it doesn't affect the ability
to hotplug or not.
So please send another patch and discuss it further with Louis, who
requested to drop that change.

> > +       }
> > 
> >         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
> > 

-- 
Kind regards,
Luca Boccassi