[dpdk-dev] [PATCH 3/3] net/mlx5: adjust removal error

[Matan Azrad]

Hi Adrien,
Thanks for this too.

> -----Original Message-----
> From: Adrien Mazarguil [mailto:adrien.mazarguil at 6wind.com]
> Sent: Friday, November 3, 2017 3:06 PM
> To: Matan Azrad <matan at mellanox.com>
> Cc: Gaetan Rivet <gaetan.rivet at 6wind.com>; dev at dpdk.org
> Subject: Re: [PATCH 3/3] net/mlx5: adjust removal error
> 
> On Thu, Nov 02, 2017 at 03:42:04PM +0000, Matan Azrad wrote:
> > Fail-safe PMD expects to get -ENODEV error value if sub PMD control
> > command fails because of device removal.
> >
> > Make control callbacks return with -ENODEV when the device has
> > disappeared.
> >
> > Signed-off-by: Matan Azrad <matan at mellanox.com>
> 
> In short I have the same comments as on the mlx4 patch about usage
> consistency, this also applies to mlx5; mlx5_removed() should be only used
> by the public callbacks from struct eth_dev_ops.
> 
> There's an additional difficulty with this PMD, you need to take into account
> the fact it provides secondary process support (mlx5_dev_sec_ops).
> I think secondary processes do not have any IBV context available for
> mlx5_removed() to query, which should resolve to a no-op in this case.
> Make sure secondary processes do not crash whatever happens.
> 
Will check it, thanks!

> See below for coding style and other issues.
> 
> > ---
> >  drivers/net/mlx5/mlx5.h        |  1 +
> >  drivers/net/mlx5/mlx5_ethdev.c | 39
> +++++++++++++++++++++++++++++++++++----
> >  drivers/net/mlx5/mlx5_flow.c   |  2 ++
> >  drivers/net/mlx5/mlx5_rss.c    |  4 ++++
> >  drivers/net/mlx5/mlx5_rxq.c    | 12 ++++++++++--
> >  drivers/net/mlx5/mlx5_stats.c  |  6 +++++-
> >  drivers/net/mlx5/mlx5_txq.c    |  2 ++
> >  7 files changed, 59 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/net/mlx5/mlx5.h b/drivers/net/mlx5/mlx5.h index
> > e6a69b8..0dd104a 100644
> > --- a/drivers/net/mlx5/mlx5.h
> > +++ b/drivers/net/mlx5/mlx5.h
> > @@ -208,6 +208,7 @@ int mlx5_ibv_device_to_pci_addr(const struct
> > ibv_device *,  int mlx5_set_link_up(struct rte_eth_dev *dev);  void
> > priv_dev_select_tx_function(struct priv *priv, struct rte_eth_dev
> > *dev);  void priv_dev_select_rx_function(struct priv *priv, struct
> > rte_eth_dev *dev);
> > +int mlx5_removed(const struct priv *priv);
> >
> >  /* mlx5_mac.c */
> >
> > diff --git a/drivers/net/mlx5/mlx5_ethdev.c
> > b/drivers/net/mlx5/mlx5_ethdev.c index c31ea4b..bf61cd6 100644
> > --- a/drivers/net/mlx5/mlx5_ethdev.c
> > +++ b/drivers/net/mlx5/mlx5_ethdev.c
> > @@ -394,6 +394,8 @@ struct priv *
> >
> >  	ret = priv_sysfs_write(priv, name, value_str, (sizeof(value_str) - 1));
> >  	if (ret == -1) {
> > +		if (mlx5_removed(priv))
> > +			errno = ENODEV;
> >  		DEBUG("cannot write %s `%s' (%lu) to sysfs: %s",
> >  		      name, value_str, value, strerror(errno));
> >  		return -1;
> > @@ -925,13 +927,17 @@ struct priv *
> >  {
> >  	struct utsname utsname;
> >  	int ver[3];
> > +	int ret;
> >
> >  	if (uname(&utsname) == -1 ||
> >  	    sscanf(utsname.release, "%d.%d.%d",
> >  		   &ver[0], &ver[1], &ver[2]) != 3 ||
> >  	    KERNEL_VERSION(ver[0], ver[1], ver[2]) < KERNEL_VERSION(4, 9,
> 0))
> > -		return mlx5_link_update_unlocked_gset(dev,
> wait_to_complete);
> > -	return mlx5_link_update_unlocked_gs(dev, wait_to_complete);
> > +		ret = mlx5_link_update_unlocked_gset(dev,
> wait_to_complete);
> > +	ret =  mlx5_link_update_unlocked_gs(dev, wait_to_complete);
> 
> Besides the extra space after "ret =", I think this doesn't work as intended. A
> "else" statement is necessary.
> 
Will fix it, thanks!

> > +	if (ret && mlx5_removed(mlx5_get_priv(dev)))
> > +		return -ENODEV;
> > +	return ret;
> >  }
> >
> >  /**
> > @@ -978,6 +984,8 @@ struct priv *
> >  	     strerror(ret));
> >  	priv_unlock(priv);
> >  	assert(ret >= 0);
> > +	if (mlx5_removed(priv))
> > +		return -ENODEV;
> >  	return -ret;
> >  }
> >
> > @@ -1029,6 +1037,8 @@ struct priv *
> >  out:
> >  	priv_unlock(priv);
> >  	assert(ret >= 0);
> > +	if (mlx5_removed(priv))
> > +		return -ENODEV;
> >  	return -ret;
> >  }
> >
> > @@ -1083,6 +1093,8 @@ struct priv *
> >  out:
> >  	priv_unlock(priv);
> >  	assert(ret >= 0);
> > +	if (mlx5_removed(priv))
> > +		return -ENODEV;
> >  	return -ret;
> >  }
> >
> > @@ -1364,13 +1376,13 @@ struct priv *
> >  	if (up) {
> >  		err = priv_set_flags(priv, ~IFF_UP, IFF_UP);
> >  		if (err)
> > -			return err;
> > +			return errno == ENODEV ? -ENODEV : err;
> 
> There is a documentation issue here since the mlx5 PMD didn't get all the
> errno consistency fixes that mlx4 got, however err is documented as being -1
> in case of error, whereas priv_dev_set_link() returns a positive errno value
> instead and mlx5_set_link_down/up() should return only negative errno
> values but are documented as returning positive ones.
> 
> Anyway to keep it short: currently in mlx5, priv_*() => positive errno and the
> public-facing mlx5_*() => negative errno, hence you should return a positive
> ENODEV here.
> 

Ok.

> You could avoid this mess by patching the public callbacks only and not
> internal functions like this one.
> 
> >  		priv_dev_select_tx_function(priv, dev);
> >  		priv_dev_select_rx_function(priv, dev);
> >  	} else {
> >  		err = priv_set_flags(priv, ~IFF_UP, ~IFF_UP);
> >  		if (err)
> > -			return err;
> > +			return errno == ENODEV ? -ENODEV : err;
> 
> Same here.
> 
> >  		dev->rx_pkt_burst = removed_rx_burst;
> >  		dev->tx_pkt_burst = removed_tx_burst;
> >  	}
> > @@ -1474,3 +1486,22 @@ struct priv *
> >  		dev->rx_pkt_burst = mlx5_rx_burst;
> >  	}
> >  }
> > +
> > +/**
> > + * Check if mlx5 device was removed.
> > + *
> 
> "mlx5" is redundant.
> 
> As with mlx4, a short paragraph should describe where this function is
> supposed to be used.
> 
> > + * @param priv
> > + *   Pointer to private structure.
> > + *
> > + * @return
> > + *   -ENODEV when device is removed and rte_errno is set, otherwise 0.
> > + */
> > +int
> > +mlx5_removed(const struct priv *priv) {
> > +	struct ibv_device_attr device_attr;
> > +
> > +	if (ibv_query_device(priv->ctx, &device_attr) == EIO)
> > +		return -(rte_errno = ENODEV);
> 
> Coding rules prohibit this kind of affectation, see mlx4 comments.
> 
> > +	return 0;
> > +}
> > diff --git a/drivers/net/mlx5/mlx5_flow.c
> > b/drivers/net/mlx5/mlx5_flow.c index 5f49bf5..448c0a3 100644
> > --- a/drivers/net/mlx5/mlx5_flow.c
> > +++ b/drivers/net/mlx5/mlx5_flow.c
> > @@ -3068,6 +3068,8 @@ struct rte_flow *
> >  		priv_lock(priv);
> >  		ret = priv_fdir_ctrl_func(priv, filter_op, arg);
> >  		priv_unlock(priv);
> > +		if (ret && mlx5_removed(priv))
> > +			ret = ENODEV;
> >  		break;
> >  	default:
> >  		ERROR("%p: filter type (%d) not supported", diff --git
> > a/drivers/net/mlx5/mlx5_rss.c b/drivers/net/mlx5/mlx5_rss.c index
> > f3de46d..1ad9269 100644
> > --- a/drivers/net/mlx5/mlx5_rss.c
> > +++ b/drivers/net/mlx5/mlx5_rss.c
> > @@ -250,6 +250,8 @@
> >  	priv_lock(priv);
> >  	ret = priv_dev_rss_reta_query(priv, reta_conf, reta_size);
> >  	priv_unlock(priv);
> > +	if (ret && mlx5_removed(priv))
> > +		return -ENODEV;
> >  	return -ret;
> >  }
> >
> > @@ -282,5 +284,7 @@
> >  		mlx5_dev_stop(dev);
> >  		mlx5_dev_start(dev);
> >  	}
> > +	if (ret && mlx5_removed(priv))
> > +		return -ENODEV;
> >  	return -ret;
> >  }
> > diff --git a/drivers/net/mlx5/mlx5_rxq.c b/drivers/net/mlx5/mlx5_rxq.c
> > index a1f382b..c9a549d 100644
> > --- a/drivers/net/mlx5/mlx5_rxq.c
> > +++ b/drivers/net/mlx5/mlx5_rxq.c
> > @@ -278,6 +278,8 @@
> >  	(*priv->rxqs)[idx] = &rxq_ctrl->rxq;
> >  out:
> >  	priv_unlock(priv);
> > +	if (mlx5_removed(priv))
> > +		return -ENODEV;
> >  	return -ret;
> >  }
> >
> > @@ -485,8 +487,11 @@
> >  	}
> >  exit:
> >  	priv_unlock(priv);
> > -	if (ret)
> > +	if (ret) {
> >  		WARN("unable to arm interrupt on rx queue %d",
> rx_queue_id);
> > +		if (mlx5_removed(priv))
> > +			return -ENODEV;
> > +	}
> >  	return -ret;
> >  }
> >
> > @@ -537,9 +542,12 @@
> >  	if (rxq_ibv)
> >  		mlx5_priv_rxq_ibv_release(priv, rxq_ibv);
> >  	priv_unlock(priv);
> > -	if (ret)
> > +	if (ret) {
> >  		WARN("unable to disable interrupt on rx queue %d",
> >  		     rx_queue_id);
> > +		if (mlx5_removed(priv))
> > +			return -ENODEV;
> > +	}
> >  	return -ret;
> >  }
> >
> > diff --git a/drivers/net/mlx5/mlx5_stats.c
> > b/drivers/net/mlx5/mlx5_stats.c index 5e225d3..33b2a60 100644
> > --- a/drivers/net/mlx5/mlx5_stats.c
> > +++ b/drivers/net/mlx5/mlx5_stats.c
> > @@ -438,13 +438,17 @@ struct mlx5_counter_ctrl {
> >  		stats_n = priv_ethtool_get_stats_n(priv);
> >  		if (stats_n < 0) {
> >  			priv_unlock(priv);
> > -			return -1;
> > +			ret = -1;
> > +			goto error;
> >  		}
> >  		if (xstats_ctrl->stats_n != stats_n)
> >  			priv_xstats_init(priv);
> >  		ret = priv_xstats_get(priv, stats);
> >  		priv_unlock(priv);
> >  	}
> > +error:
> > +	if (ret < 0 && mlx5_removed(priv))
> > +		return -ENODEV;
> >  	return ret;
> >  }
> >
> > diff --git a/drivers/net/mlx5/mlx5_txq.c b/drivers/net/mlx5/mlx5_txq.c
> > index fbb2630..a0101cb 100644
> > --- a/drivers/net/mlx5/mlx5_txq.c
> > +++ b/drivers/net/mlx5/mlx5_txq.c
> > @@ -186,6 +186,8 @@
> >  	(*priv->txqs)[idx] = &txq_ctrl->txq;
> >  out:
> >  	priv_unlock(priv);
> > +	if (mlx5_removed(priv))
> > +		return -ENODEV;
> >  	return -ret;
> >  }
> >
> > --
> > 1.8.3.1
> >
> 
> --
> Adrien Mazarguil
> 6WIND