Messages in this thread | | | Date | Thu, 22 Jul 2021 02:35:49 +0300 | From | Vladimir Oltean <> | Subject | Re: [PATCH v2 1/2] net: dsa: ensure linearized SKBs in case of tail taggers |
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On Wed, Jul 21, 2021 at 11:56:41PM +0200, Lino Sanfilippo wrote: > The function skb_put() that is used by tail taggers to make room for the > DSA tag must only be called for linearized SKBS. However in case that the > slave device inherited features like NETIF_F_HW_SG or NETIF_F_FRAGLIST the > SKB passed to the slaves transmit function may not be linearized. > Avoid those SKBs by clearing the NETIF_F_HW_SG and NETIF_F_FRAGLIST flags > for tail taggers. > Furthermore since the tagging protocol can be changed at runtime move the > code for setting up the slaves features into dsa_slave_setup_tagger(). > > Suggested-by: Vladimir Oltean <olteanv@gmail.com> > Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de> > --- > net/dsa/slave.c | 14 +++++++++----- > 1 file changed, 9 insertions(+), 5 deletions(-) > > diff --git a/net/dsa/slave.c b/net/dsa/slave.c > index 22ce11cd770e..ae2a648ed9be 100644 > --- a/net/dsa/slave.c > +++ b/net/dsa/slave.c > @@ -1808,6 +1808,7 @@ void dsa_slave_setup_tagger(struct net_device *slave) > struct dsa_slave_priv *p = netdev_priv(slave); > const struct dsa_port *cpu_dp = dp->cpu_dp; > struct net_device *master = cpu_dp->master; > + const struct dsa_switch *ds = dp->ds; > > slave->needed_headroom = cpu_dp->tag_ops->needed_headroom; > slave->needed_tailroom = cpu_dp->tag_ops->needed_tailroom; > @@ -1819,6 +1820,14 @@ void dsa_slave_setup_tagger(struct net_device *slave) > slave->needed_tailroom += master->needed_tailroom; > > p->xmit = cpu_dp->tag_ops->xmit; > + > + slave->features = master->vlan_features | NETIF_F_HW_TC; > + if (ds->ops->port_vlan_add && ds->ops->port_vlan_del) > + slave->features |= NETIF_F_HW_VLAN_CTAG_FILTER; > + slave->hw_features |= NETIF_F_HW_TC; > + slave->features |= NETIF_F_LLTX; > + if (slave->needed_tailroom) > + slave->features &= ~(NETIF_F_SG | NETIF_F_FRAGLIST); > } > > static struct lock_class_key dsa_slave_netdev_xmit_lock_key; > @@ -1881,11 +1890,6 @@ int dsa_slave_create(struct dsa_port *port) > if (slave_dev == NULL) > return -ENOMEM; > > - slave_dev->features = master->vlan_features | NETIF_F_HW_TC; > - if (ds->ops->port_vlan_add && ds->ops->port_vlan_del) > - slave_dev->features |= NETIF_F_HW_VLAN_CTAG_FILTER; > - slave_dev->hw_features |= NETIF_F_HW_TC; > - slave_dev->features |= NETIF_F_LLTX; > slave_dev->ethtool_ops = &dsa_slave_ethtool_ops; > if (!is_zero_ether_addr(port->mac)) > ether_addr_copy(slave_dev->dev_addr, port->mac); > -- > 2.32.0 >
I would have probably changed the code in dsa_slave_create just like this:
- slave->features = master->vlan_features | NETIF_F_HW_TC; + slave->features = NETIF_F_HW_TC; ... - slave_dev->vlan_features = master->vlan_features;
and in dsa_slave_setup_tagger:
+ vlan_features = master->vlan_features; + slave->features &= ~vlan_features; + if (slave->needed_tailroom) + vlan_features &= ~(NETIF_F_SG | NETIF_F_FRAGLIST); + slave->features |= vlan_features; + slave->vlan_features = vlan_features;
no need to move around NETIF_F_HW_TC and NETIF_F_LLTX. Makes sense?
And I would probably add:
Fixes: 91da11f870f0 ("net: Distributed Switch Architecture protocol support")
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