Re: [PATCH net-next v2 2/4] swdevice: add new api to set and del bridge port attributes

[Jiri Pirko <jiri@resnulli.us>]

Thu, Dec 11, 2014 at 06:59:15PM CET, roopa@cumulusnetworks.com wrote:
>On 12/11/14, 9:11 AM, Jiri Pirko wrote:
>>Thu, Dec 11, 2014 at 05:52:10PM CET, roopa@cumulusnetworks.com wrote:
>>>On 12/10/14, 1:37 AM, Jiri Pirko wrote:
>>>>Wed, Dec 10, 2014 at 10:05:18AM CET, roopa@cumulusnetworks.com wrote:
>>>>>From: Roopa Prabhu <roopa@cumulusnetworks.com>
>>>>>
>>>>>This patch adds two new api's netdev_switch_port_bridge_setlink
>>>>>and netdev_switch_port_bridge_dellink to offload bridge port attributes
>>>>>to switch asic
>>>>>
>>>>>(The names of the apis look odd with 'switch_port_bridge',
>>>>>but am more inclined to change the prefix of the api to something else.
>>>>>Will take any suggestions).
>>>>>
>>>>>The api's look at the NETIF_F_HW_NETFUNC_OFFLOAD feature flag to
>>>>>pass bridge port attributes to the port device.
>>>>>
>>>>>If the device has the NETIF_F_HW_NETFUNC_OFFLOAD, but does not support
>>>>>the bridge port attribute offload ndo, call bridge port attribute ndo's on
>>>>>the lowerdevs if supported. This is one way to pass bridge port attributes
>>>>>through stacked netdevs (example when bridge port is a bond and bond slaves
>>>>>are switch ports).
>>>>>
>>>>>Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
>>>>>---
>>>>>include/net/switchdev.h   |    5 +++-
>>>>>net/switchdev/switchdev.c |   70 +++++++++++++++++++++++++++++++++++++++++++++
>>>>>2 files changed, 74 insertions(+), 1 deletion(-)
>>>>>
>>>>>diff --git a/include/net/switchdev.h b/include/net/switchdev.h
>>>>>index 8a6d164..22676b6 100644
>>>>>--- a/include/net/switchdev.h
>>>>>+++ b/include/net/switchdev.h
>>>>>@@ -17,7 +17,10 @@
>>>>>int netdev_switch_parent_id_get(struct net_device *dev,
>>>>>				struct netdev_phys_item_id *psid);
>>>>>int netdev_switch_port_stp_update(struct net_device *dev, u8 state);
>>>>>-
>>>>>+int netdev_switch_port_bridge_setlink(struct net_device *dev,
>>>>>+				struct nlmsghdr *nlh, u16 flags);
>>>>>+int netdev_switch_port_bridge_dellink(struct net_device *dev,
>>>>>+				struct nlmsghdr *nlh, u16 flags);
>>>>>#else
>>>>>
>>>>>static inline int netdev_switch_parent_id_get(struct net_device *dev,
>>>>>diff --git a/net/switchdev/switchdev.c b/net/switchdev/switchdev.c
>>>>>index d162b21..62317e1 100644
>>>>>--- a/net/switchdev/switchdev.c
>>>>>+++ b/net/switchdev/switchdev.c
>>>>>@@ -50,3 +50,73 @@ int netdev_switch_port_stp_update(struct net_device *dev, u8 state)
>>>>>	return ops->ndo_switch_port_stp_update(dev, state);
>>>>>}
>>>>>EXPORT_SYMBOL(netdev_switch_port_stp_update);
>>>>>+
>>>>>+/**
>>>>>+ *	netdev_switch_port_bridge_setlink - Notify switch device port of bridge
>>>>>+ *	port attributes
>>>>>+ *
>>>>>+ *	@dev: port device
>>>>>+ *	@nlh: netlink msg with bridge port attributes
>>>>>+ *
>>>>>+ *	Notify switch device port of bridge port attributes
>>>>>+ */
>>>>>+int netdev_switch_port_bridge_setlink(struct net_device *dev,
>>>>>+									  struct nlmsghdr *nlh, u16 flags)
>>>>>+{
>>>>>+	const struct net_device_ops *ops = dev->netdev_ops;
>>>>>+	struct net_device *lower_dev;
>>>>>+	struct list_head *iter;
>>>>>+	int ret = 0, err = 0;
>>>>>+
>>>>>+	if (!(dev->features & NETIF_F_HW_NETFUNC_OFFLOAD))
>>>>>+		return err;
>>>>>+
>>>>>+	if (ops->ndo_bridge_setlink) {
>>>>>+	    WARN_ON(!ops->ndo_switch_parent_id_get);
>>>>>+	    return ops->ndo_bridge_setlink(dev, nlh, flags);
>>>>	You have to change ndo_bridge_setlink in netdevice.h first.
>>>>	Otherwise when only this patch is applied (during bisection)
>>>>	this won't compile.
>>>ack, will fix it and keep that in mind next time.
>>>>>+	}
>>>>>+
>>>>>+	netdev_for_each_lower_dev(dev, lower_dev, iter) {
>>>>	I do not understand why to iterate over lower devices. At this
>>>>	stage we don't know a thing about this upper or its lowers. Let
>>>>	the uppers (/masters) to decide if this needs to be propagated
>>>>	or not.
>>>Jiri, In the stacked devices case, there is no way to propagate the bridge
>>>port attributes to switch device driver today (vlan and other bridge port
>>>attributes). Can you tell me if there is a way ?. no, ndo_vlan* ndo's are not
>>>useful here. Nor we should go and implement ndo_bridge_setlink* in all
>>>devices that can be bridge ports.
>>
>>Hmm. I just think that is cleaner to implement ndo_bridge_setlink in
>>bonding for example and let it propagate the the call to slaves.
>No, that will require bridge attribute support in all drivers. And that is no
>good.

Not all drivers, just all masters which want to support this. Like bond,
team, macvlan etc. That would be the same as for
ndo_vlan_rx_add_vid/ndo_vlan_rx_kill_vid/ndo_change_mtu etc. I do not
see any problem in that. It is much much clearer over big hammer iterate
over lowers in my opinion.


>>Let every "upper" to handle ndo_bridge_setlink their way. Sometimes it
>>might not make sense to propagate to "lowers".
>
>This does not really propagate to lowers. It is just trying to get to a
>switch port and from there to the switch driver.
>Example, bond driver does not need to care if its a bridge port. It will
>simply pass the call to its slave which
>might be a switch port.
>
>bond driver does not care if its a bridge port. But the switch driver cares,
>because it knows that the bond was created with switch ports.
>
>
>>
>>>And this allows a switch driver to receive these callbacks if it has marked
>>>the switch port with an offload flag. Your way of using the switch port to
>>>get to the switch driver does not help in these cases.
>>I do not follow how this is related to this case (stacked layout).
>>
>>>The other option is to use the 'switch device (not port)' to get to the
>>>switch driver.
>>
>>That would not help this case (stacked layout) I believe.
>>
>>
>>>This patch shows that you can still do this with the ndo ops.
>>>>>+		err = netdev_switch_port_bridge_setlink(lower_dev, nlh, flags);
>>>>>+		if (err)
>>>>>+			ret = err;
>>>>>+    }
>>>>  ^^^^^ Indent is off. This should be catched by scripts/checkpatch.pl.
>>>>
>>>>>+
>>>>>+	return ret;
>>>>>+}
>>>>>+EXPORT_SYMBOL(netdev_switch_port_bridge_setlink);
>>>>>+
>>>>>+/**
>>>>>+ *	netdev_switch_port_bridge_dellink - Notify switch device port of bridge
>>>>>+ *	attribute delete
>>>>>+ *
>>>>>+ *	@dev: port device
>>>>>+ *	@nlh: netlink msg with bridge port attributes
>>>>>+ *
>>>>>+ *	Notify switch device port of bridge port attribute delete
>>>>>+ */
>>>>>+int netdev_switch_port_bridge_dellink(struct net_device *dev,
>>>>>+									  struct nlmsghdr *nlh, u16 flags)
>>>>>+{
>>>>>+	const struct net_device_ops *ops = dev->netdev_ops;
>>>>>+	struct net_device *lower_dev;
>>>>>+	struct list_head *iter;
>>>>>+	int ret = 0, err = 0;
>>>>>+
>>>>>+	if (!(dev->features & NETIF_F_HW_NETFUNC_OFFLOAD))
>>>>>+		return err;
>>>>>+
>>>>>+	if (ops->ndo_bridge_dellink) {
>>>>>+		WARN_ON(!ops->ndo_switch_parent_id_get);
>>>>>+		return ops->ndo_bridge_dellink(dev, nlh, flags);
>>>>>+	}
>>>>>+
>>>>>+	netdev_for_each_lower_dev(dev, lower_dev, iter) {
>>>>>+		err = netdev_switch_port_bridge_dellink(lower_dev, nlh, flags);
>>>>>+		if (err)
>>>>>+			ret = err;
>>>>>+	}
>>>>>+
>>>>>+	return ret;
>>>>>+}
>>>>>+EXPORT_SYMBOL(netdev_switch_port_bridge_dellink);
>>>>>-- 
>>>>>1.7.10.4
>>>>>
>>--
>>To unsubscribe from this list: send the line "unsubscribe netdev" in
>>the body of a message to majordomo@vger.kernel.org
>>More majordomo info at  http://vger.kernel.org/majordomo-info.html
>