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>

10 files changed, 68 insertions, 105 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 039b23786c22..1875dc71422a 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1781,24 +1781,13 @@ void dev_net_set(struct net_device *dev, struct net *net)
 #endif
 }
 
-static inline bool netdev_uses_dsa_tags(struct net_device *dev)
+static inline bool netdev_uses_dsa(struct net_device *dev)
 {
-#ifdef CONFIG_NET_DSA_TAG_DSA
-        if (dev->dsa_ptr != NULL)
-                return dsa_uses_dsa_tags(dev->dsa_ptr);
-#endif
-
-        return 0;
-}
-
-static inline bool netdev_uses_trailer_tags(struct net_device *dev)
-{
-#ifdef CONFIG_NET_DSA_TAG_TRAILER
-        if (dev->dsa_ptr != NULL)
-                return dsa_uses_trailer_tags(dev->dsa_ptr);
+#ifdef CONFIG_NET_DSA
+        return dev->dsa_ptr != NULL;
+#else
+        return false;
 #endif
-
-        return 0;
 }
 
 /**
@@ -1933,6 +1922,13 @@ struct udp_offload {
         struct offload_callbacks callbacks;
 };
 
+struct dsa_device_ops {
+        netdev_tx_t (*xmit)(struct sk_buff *skb, struct net_device *dev);
+        int (*rcv)(struct sk_buff *skb, struct net_device *dev,
+                   struct packet_type *pt, struct net_device *orig_dev);
+};
+
+
 /* often modified stats are per cpu, other are shared (netdev->stats) */
 struct pcpu_sw_netstats {
         u64     rx_packets;
diff --git a/include/net/dsa.h b/include/net/dsa.h
index 6efce384451e..6e26f1e4d8ce 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -59,6 +59,8 @@ struct dsa_platform_data {
         struct dsa_chip_data    *chip;
 };
 
+struct dsa_device_ops;
+
 struct dsa_switch_tree {
         /*
          * Configuration data for the platform device that owns
@@ -71,6 +73,7 @@ struct dsa_switch_tree {
          * protocol to use.
          */
         struct net_device       *master_netdev;
+        const struct dsa_device_ops     *ops;
         __be16                  tag_protocol;
 
         /*
@@ -186,21 +189,4 @@ static inline void *ds_to_priv(struct dsa_switch *ds)
         return (void *)(ds + 1);
 }
 
-/*
- * The original DSA tag format and some other tag formats have no
- * ethertype, which means that we need to add a little hack to the
- * networking receive path to make sure that received frames get
- * the right ->protocol assigned to them when one of those tag
- * formats is in use.
- */
-static inline bool dsa_uses_dsa_tags(struct dsa_switch_tree *dst)
-{
-        return !!(dst->tag_protocol == htons(ETH_P_DSA));
-}
-
-static inline bool dsa_uses_trailer_tags(struct dsa_switch_tree *dst)
-{
-        return !!(dst->tag_protocol == htons(ETH_P_TRAILER));
-}
-
 #endif
diff --git a/include/uapi/linux/if_ether.h b/include/uapi/linux/if_ether.h
index 0f8210b8e0bc..aa63ed023c2b 100644
--- a/include/uapi/linux/if_ether.h
+++ b/include/uapi/linux/if_ether.h
@@ -128,6 +128,7 @@
 #define ETH_P_PHONET    0x00F5          /* Nokia Phonet frames          */
 #define ETH_P_IEEE802154 0x00F6         /* IEEE802.15.4 frame           */
 #define ETH_P_CAIF      0x00F7          /* ST-Ericsson CAIF protocol    */
+#define ETH_P_XDSA      0x00F8          /* Multiplexed DSA protocol     */
 
 /*
  *      This is an Ethernet frame header.
diff --git a/net/dsa/dsa.c b/net/dsa/dsa.c
index 0a49632fac47..92e71d2a2ccd 100644
--- a/net/dsa/dsa.c
+++ b/net/dsa/dsa.c
@@ -608,6 +608,24 @@ static void dsa_shutdown(struct platform_device *pdev)
 {
 }
 
+static int dsa_switch_rcv(struct sk_buff *skb, struct net_device *dev,
+                          struct packet_type *pt, struct net_device *orig_dev)
+{
+        struct dsa_switch_tree *dst = dev->dsa_ptr;
+
+        if (unlikely(dst == NULL)) {
+                kfree_skb(skb);
+                return 0;
+        }
+
+        return dst->ops->rcv(skb, dev, pt, orig_dev);
+}
+
+struct packet_type dsa_pack_type __read_mostly = {
+        .type   = cpu_to_be16(ETH_P_XDSA),
+        .func   = dsa_switch_rcv,
+};
+
 static const struct of_device_id dsa_of_match_table[] = {
         { .compatible = "marvell,dsa", },
         {}
@@ -633,30 +651,15 @@ static int __init dsa_init_module(void)
         if (rc)
                 return rc;
 
-#ifdef CONFIG_NET_DSA_TAG_DSA
-        dev_add_pack(&dsa_packet_type);
-#endif
-#ifdef CONFIG_NET_DSA_TAG_EDSA
-        dev_add_pack(&edsa_packet_type);
-#endif
-#ifdef CONFIG_NET_DSA_TAG_TRAILER
-        dev_add_pack(&trailer_packet_type);
-#endif
+        dev_add_pack(&dsa_pack_type);
+
         return 0;
 }
 module_init(dsa_init_module);
 
 static void __exit dsa_cleanup_module(void)
 {
-#ifdef CONFIG_NET_DSA_TAG_TRAILER
-        dev_remove_pack(&trailer_packet_type);
-#endif
-#ifdef CONFIG_NET_DSA_TAG_EDSA
-        dev_remove_pack(&edsa_packet_type);
-#endif
-#ifdef CONFIG_NET_DSA_TAG_DSA
-        dev_remove_pack(&dsa_packet_type);
-#endif
+        dev_remove_pack(&dsa_pack_type);
         platform_driver_unregister(&dsa_driver);
 }
 module_exit(dsa_cleanup_module);
diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h
index d4cf5cc747e3..218d75d16f6f 100644
--- a/net/dsa/dsa_priv.h
+++ b/net/dsa/dsa_priv.h
@@ -45,16 +45,13 @@ struct net_device *dsa_slave_create(struct dsa_switch *ds,
                                     int port, char *name);
 
 /* tag_dsa.c */
-netdev_tx_t dsa_xmit(struct sk_buff *skb, struct net_device *dev);
-extern struct packet_type dsa_packet_type;
+extern const struct dsa_device_ops dsa_netdev_ops;
 
 /* tag_edsa.c */
-netdev_tx_t edsa_xmit(struct sk_buff *skb, struct net_device *dev);
-extern struct packet_type edsa_packet_type;
+extern const struct dsa_device_ops edsa_netdev_ops;
 
 /* tag_trailer.c */
-netdev_tx_t trailer_xmit(struct sk_buff *skb, struct net_device *dev);
-extern struct packet_type trailer_packet_type;
+extern const struct dsa_device_ops trailer_netdev_ops;
 
 
 #endif
diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index 45a1e34c89e0..ad1a913533aa 100644
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -171,6 +171,14 @@ static int dsa_slave_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
         return -EOPNOTSUPP;
 }
 
+static netdev_tx_t dsa_slave_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+        struct dsa_slave_priv *p = netdev_priv(dev);
+        struct dsa_switch_tree *dst = p->parent->dst;
+
+        return dst->ops->xmit(skb, dev);
+}
+
 
 /* ethtool operations *******************************************************/
 static int
@@ -293,42 +301,16 @@ static const struct ethtool_ops dsa_slave_ethtool_ops = {
         .get_sset_count         = dsa_slave_get_sset_count,
 };
 
-#ifdef CONFIG_NET_DSA_TAG_DSA
-static const struct net_device_ops dsa_netdev_ops = {
+static const struct net_device_ops dsa_slave_netdev_ops = {
         .ndo_init               = dsa_slave_init,
         .ndo_open               = dsa_slave_open,
         .ndo_stop               = dsa_slave_close,
-        .ndo_start_xmit         = dsa_xmit,
+        .ndo_start_xmit         = dsa_slave_xmit,
         .ndo_change_rx_flags    = dsa_slave_change_rx_flags,
         .ndo_set_rx_mode        = dsa_slave_set_rx_mode,
         .ndo_set_mac_address    = dsa_slave_set_mac_address,
         .ndo_do_ioctl           = dsa_slave_ioctl,
 };
-#endif
-#ifdef CONFIG_NET_DSA_TAG_EDSA
-static const struct net_device_ops edsa_netdev_ops = {
-        .ndo_init               = dsa_slave_init,
-        .ndo_open               = dsa_slave_open,
-        .ndo_stop               = dsa_slave_close,
-        .ndo_start_xmit         = edsa_xmit,
-        .ndo_change_rx_flags    = dsa_slave_change_rx_flags,
-        .ndo_set_rx_mode        = dsa_slave_set_rx_mode,
-        .ndo_set_mac_address    = dsa_slave_set_mac_address,
-        .ndo_do_ioctl           = dsa_slave_ioctl,
-};
-#endif
-#ifdef CONFIG_NET_DSA_TAG_TRAILER
-static const struct net_device_ops trailer_netdev_ops = {
-        .ndo_init               = dsa_slave_init,
-        .ndo_open               = dsa_slave_open,
-        .ndo_stop               = dsa_slave_close,
-        .ndo_start_xmit         = trailer_xmit,
-        .ndo_change_rx_flags    = dsa_slave_change_rx_flags,
-        .ndo_set_rx_mode        = dsa_slave_set_rx_mode,
-        .ndo_set_mac_address    = dsa_slave_set_mac_address,
-        .ndo_do_ioctl           = dsa_slave_ioctl,
-};
-#endif
 
 /* slave device setup *******************************************************/
 struct net_device *
@@ -349,21 +331,22 @@ dsa_slave_create(struct dsa_switch *ds, struct device *parent,
         slave_dev->ethtool_ops = &dsa_slave_ethtool_ops;
         eth_hw_addr_inherit(slave_dev, master);
         slave_dev->tx_queue_len = 0;
+        slave_dev->netdev_ops = &dsa_slave_netdev_ops;
 
         switch (ds->dst->tag_protocol) {
 #ifdef CONFIG_NET_DSA_TAG_DSA
         case htons(ETH_P_DSA):
-                slave_dev->netdev_ops = &dsa_netdev_ops;
+                ds->dst->ops = &dsa_netdev_ops;
                 break;
 #endif
 #ifdef CONFIG_NET_DSA_TAG_EDSA
         case htons(ETH_P_EDSA):
-                slave_dev->netdev_ops = &edsa_netdev_ops;
+                ds->dst->ops = &edsa_netdev_ops;
                 break;
 #endif
 #ifdef CONFIG_NET_DSA_TAG_TRAILER
         case htons(ETH_P_TRAILER):
-                slave_dev->netdev_ops = &trailer_netdev_ops;
+                ds->dst->ops = &trailer_netdev_ops;
                 break;
 #endif
         default:
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,
 };
diff --git a/net/dsa/tag_edsa.c b/net/dsa/tag_edsa.c
index e70c43c25e64..6b30abe89183 100644
--- a/net/dsa/tag_edsa.c
+++ b/net/dsa/tag_edsa.c
@@ -17,7 +17,7 @@
 #define DSA_HLEN        4
 #define EDSA_HLEN       8
 
-netdev_tx_t edsa_xmit(struct sk_buff *skb, struct net_device *dev)
+static netdev_tx_t edsa_xmit(struct sk_buff *skb, struct net_device *dev)
 {
         struct dsa_slave_priv *p = netdev_priv(dev);
         u8 *edsa_header;
@@ -205,7 +205,7 @@ out:
         return 0;
 }
 
-struct packet_type edsa_packet_type __read_mostly = {
-        .type   = cpu_to_be16(ETH_P_EDSA),
-        .func   = edsa_rcv,
+const struct dsa_device_ops edsa_netdev_ops = {
+        .xmit   = edsa_xmit,
+        .rcv    = edsa_rcv,
 };
diff --git a/net/dsa/tag_trailer.c b/net/dsa/tag_trailer.c
index 94bc260d015d..5fe9444842c5 100644
--- a/net/dsa/tag_trailer.c
+++ b/net/dsa/tag_trailer.c
@@ -14,7 +14,7 @@
 #include <linux/slab.h>
 #include "dsa_priv.h"
 
-netdev_tx_t trailer_xmit(struct sk_buff *skb, struct net_device *dev)
+static netdev_tx_t trailer_xmit(struct sk_buff *skb, struct net_device *dev)
 {
         struct dsa_slave_priv *p = netdev_priv(dev);
         struct sk_buff *nskb;
@@ -114,7 +114,7 @@ out:
         return 0;
 }
 
-struct packet_type trailer_packet_type __read_mostly = {
-        .type   = cpu_to_be16(ETH_P_TRAILER),
-        .func   = trailer_rcv,
+const struct dsa_device_ops trailer_netdev_ops = {
+        .xmit   = trailer_xmit,
+        .rcv    = trailer_rcv,
 };
diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c
index f405e0592407..5cebca134585 100644
--- a/net/ethernet/eth.c
+++ b/net/ethernet/eth.c
@@ -181,11 +181,8 @@ __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev)
          * variants has been configured on the receiving interface,
          * and if so, set skb->protocol without looking at the packet.
          */
-        if (unlikely(netdev_uses_dsa_tags(dev)))
-                return htons(ETH_P_DSA);
-
-        if (unlikely(netdev_uses_trailer_tags(dev)))
-                return htons(ETH_P_TRAILER);
+        if (unlikely(netdev_uses_dsa(dev)))
+                return htons(ETH_P_XDSA);
 
         if (likely(ntohs(eth->h_proto) >= ETH_P_802_3_MIN))
                 return eth->h_proto;