commit 5aed85cec29882d1c4b4b2a01cb75a99efdbe4ed
author Florian Fainelli <f.fainelli@gmail.com> Wed Aug 27 17:04:52 2014 -0700
committer David S. Miller <davem@davemloft.net> Wed Aug 27 22:59:40 2014 -0700
tree c2a68a4275a8aefb66c4d1e359d76704c6894817
parent 0d8bcdd383b8865e752a7e8edb4712c2e3902052

net: dsa: allow switches to work without tagging

In case switch port tagging is disabled (voluntarily, or the switch just
does not support it), allow us to continue using the defined set of
dsa_device_ops in net/dsa/slave.c.

We introduce dsa_protocol_is_tagged() to check whether we need to
override skb->protocol and go through the DSA-specifif packet_type
function, or if we just go on and receive the SKB through the normal
path.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/netdevice.h

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 1875dc7..4298013 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1784,10 +1784,10 @@
 static inline bool netdev_uses_dsa(struct net_device *dev)
 {
 #ifdef CONFIG_NET_DSA
-	return dev->dsa_ptr != NULL;
-#else
-	return false;
+	if (dev->dsa_ptr != NULL)
+		return dsa_uses_tagged_protocol(dev->dsa_ptr);
 #endif
+	return false;
 }
 
 /**

include/net/dsa.h

diff --git a/include/net/dsa.h b/include/net/dsa.h
index dc35745..1035f64 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -198,4 +198,9 @@
 	return (void *)(ds + 1);
 }
 
+static inline bool dsa_uses_tagged_protocol(struct dsa_switch_tree *dst)
+{
+	return dst->tag_protocol != 0;
+}
+
 #endif

net/dsa/slave.c

diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index 03d2894..241c2a1 100644
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -181,6 +181,17 @@
 	return dst->ops->xmit(skb, dev);
 }
 
+static netdev_tx_t dsa_slave_notag_xmit(struct sk_buff *skb,
+					struct net_device *dev)
+{
+	struct dsa_slave_priv *p = netdev_priv(dev);
+
+	skb->dev = p->parent->dst->master_netdev;
+	dev_queue_xmit(skb);
+
+	return NETDEV_TX_OK;
+}
+
 
 /* ethtool operations *******************************************************/
 static int
@@ -314,6 +325,11 @@
 	.ndo_do_ioctl		= dsa_slave_ioctl,
 };
 
+static const struct dsa_device_ops notag_netdev_ops = {
+	.xmit	= dsa_slave_notag_xmit,
+	.rcv	= NULL,
+};
+
 static void dsa_slave_adjust_link(struct net_device *dev)
 {
 	struct dsa_slave_priv *p = netdev_priv(dev);
@@ -415,7 +431,8 @@
 		break;
 #endif
 	default:
-		BUG();
+		ds->dst->ops = &notag_netdev_ops;
+		break;
 	}
 
 	SET_NETDEV_DEV(slave_dev, parent);