net: dsa: reduce number of protocol hooks

DSA is currently registering one packet_type function per EtherType it
needs to intercept in the receive path of a DSA-enabled Ethernet device.
Right now we have three of them: trailer, DSA and eDSA, and there might
be more in the future, this will not scale to the addition of new
protocols.

This patch proceeds with adding a new layer of abstraction and two new
functions:

dsa_switch_rcv() which will dispatch into the tag-protocol specific
receive function implemented by net/dsa/tag_*.c

dsa_slave_xmit() which will dispatch into the tag-protocol specific
transmit function implemented by net/dsa/tag_*.c

When we do create the per-port slave network devices, we iterate over
the switch protocol to assign the DSA-specific receive and transmit
operations.

A new fake ethertype value is used: ETH_P_XDSA to illustrate the fact
that this is no longer going to look like ETH_P_DSA or ETH_P_TRAILER
like it used to be.

This allows us to greatly simplify the check in eth_type_trans() and
always override the skb->protocol with ETH_P_XDSA for Ethernet switches
tagged protocol, while also reducing the number repetitive slave
netdevice_ops assignments.

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

1 files changed, 4 insertions, 4 deletions

diff --git a/net/dsa/tag_dsa.c b/net/dsa/tag_dsa.c
index cacce1e22f9c..d7dbc5bda5c0 100644
--- a/net/dsa/tag_dsa.c
+++ b/net/dsa/tag_dsa.c
@@ -16,7 +16,7 @@
 
 #define DSA_HLEN	4
 
-netdev_tx_t dsa_xmit(struct sk_buff *skb, struct net_device *dev)
+static netdev_tx_t dsa_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct dsa_slave_priv *p = netdev_priv(dev);
 	u8 *dsa_header;
@@ -186,7 +186,7 @@ out:
 	return 0;
 }
 
-struct packet_type dsa_packet_type __read_mostly = {
-	.type	= cpu_to_be16(ETH_P_DSA),
-	.func	= dsa_rcv,
+const struct dsa_device_ops dsa_netdev_ops = {
+	.xmit	= dsa_xmit,
+	.rcv	= dsa_rcv,
 };