Re: [dpdk-dev] [PATCH 3/3] net/mlx5: rebuild flows on updating RETA

[Yongseok Koh <yskoh@mellanox.com>]

Hi Nelio,

On Fri, Mar 17, 2017 at 02:11:43AM -0700, Nélio Laranjeiro wrote:
> On Thu, Mar 16, 2017 at 03:40:56PM -0700, Yongseok Koh wrote:
> > Currently mlx5_dev_rss_reta_update() just updates tables in the host,
> > therefore it isn't immediately effective until restarting the device by
> > calling mlx5_dev_stop()/mlx5_dev_start() to update the changes in the
> > device side. This patch adds rebuilding the device-specific datastructure
> > and applying it to the device right away.
> >
> > Signed-off-by: Yongseok Koh <yskoh@mellanox.com>
> > ---
> >  drivers/net/mlx5/mlx5_rss.c | 3 +++
> >  1 file changed, 3 insertions(+)
> >
> > diff --git a/drivers/net/mlx5/mlx5_rss.c b/drivers/net/mlx5/mlx5_rss.c
> > index 0702f1a63..30e59faa5 100644
> > --- a/drivers/net/mlx5/mlx5_rss.c
> > +++ b/drivers/net/mlx5/mlx5_rss.c
> > @@ -357,8 +357,11 @@ mlx5_dev_rss_reta_update(struct rte_eth_dev *dev,
> >        int ret;
> >        struct priv *priv = dev->data->dev_private;
> > 
> > +     mlx5_dev_stop(dev);
> >        priv_lock(priv);
> >        ret = priv_dev_rss_reta_update(priv, reta_conf, reta_size);
> >        priv_unlock(priv);
> > +     if (!ret)
> > +             ret = (unsigned int)mlx5_dev_start(dev);
> >        return -ret;
> >  }
> > --
> > 2.11.0
> >
> 
> Hi Yongseok,
> 
> I don't understand why you need the cast for the returned value of
> mlx5_dev_start() as it already returns an int and your final variable is
> also an int.

For some reason, in mlx5 PMD code, priv_* calls return positive error numbers
and corresponding mlx5_* APIs return negative values by adding (-) sign the the
return value from priv_* calls.

To follow this tacit rule in the existing code, I casted the return value to
unsigned.

Thanks,
Yongseok