Commit 3e8a72d1 authored by Florian Fainelli's avatar Florian Fainelli Committed by David S. Miller
Browse files

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: default avatarFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 8663dc20

include/linux/netdevice.h

+12 −16
Original line number Diff line number Diff line
@@ -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;

include/net/dsa.h

+3 −17
Original line number Diff line number Diff line
@@ -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

include/uapi/linux/if_ether.h

+1 −0
Original line number Diff line number Diff line
@@ -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.

net/dsa/dsa.c

+21 −18
Original line number Diff line number Diff line
@@ -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);

net/dsa/dsa_priv.h

+3 −6
Original line number Diff line number Diff line
@@ -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

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