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Commit 6d81f41c authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

dummy: percpu stats and lockless xmit 



Converts dummy network device driver to :

- percpu stats

- 64bit stats

- lockless xmit (NETIF_F_LLTX)

- performance features added (NETIF_F_SG | NETIF_F_FRAGLIST |
NETIF_F_TSO | NETIF_F_NO_CSUM | NETIF_F_HIGHDMA)

Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 745e20f1

drivers/net/dummy.c

+55 −3
Original line number Diff line number Diff line
@@ -36,6 +36,7 @@ 
#include <linux/moduleparam.h>

#include <linux/rtnetlink.h>

#include <net/rtnetlink.h>

#include <linux/u64_stats_sync.h>



static int numdummies = 1;
@@ -55,21 +56,69 @@ static void set_multicast_list(struct net_device *dev) 
{

}



struct pcpu_dstats {

	u64			tx_packets;

	u64			tx_bytes;

	struct u64_stats_sync	syncp;

};



static struct rtnl_link_stats64 *dummy_get_stats64(struct net_device *dev,

						   struct rtnl_link_stats64 *stats)

{

	int i;



	for_each_possible_cpu(i) {

		const struct pcpu_dstats *dstats;

		u64 tbytes, tpackets;

		unsigned int start;



		dstats = per_cpu_ptr(dev->dstats, i);

		do {

			start = u64_stats_fetch_begin(&dstats->syncp);

			tbytes = dstats->tx_bytes;

			tpackets = dstats->tx_packets;

		} while (u64_stats_fetch_retry(&dstats->syncp, start));

		stats->tx_bytes += tbytes;

		stats->tx_packets += tpackets;

	}

	return stats;

}



static netdev_tx_t dummy_xmit(struct sk_buff *skb, struct net_device *dev)

{

	dev->stats.tx_packets++;

	dev->stats.tx_bytes += skb->len;

	struct pcpu_dstats *dstats = this_cpu_ptr(dev->dstats);



	u64_stats_update_begin(&dstats->syncp);

	dstats->tx_packets++;

	dstats->tx_bytes += skb->len;

	u64_stats_update_end(&dstats->syncp);



	dev_kfree_skb(skb);

	return NETDEV_TX_OK;

}



static int dummy_dev_init(struct net_device *dev)

{

	dev->dstats = alloc_percpu(struct pcpu_dstats);

	if (!dev->dstats)

		return -ENOMEM;



	return 0;

}



static void dummy_dev_free(struct net_device *dev)

{

	free_percpu(dev->dstats);

	free_netdev(dev);

}



static const struct net_device_ops dummy_netdev_ops = {

	.ndo_init		= dummy_dev_init,

	.ndo_start_xmit		= dummy_xmit,

	.ndo_validate_addr	= eth_validate_addr,

	.ndo_set_multicast_list = set_multicast_list,

	.ndo_set_mac_address	= dummy_set_address,

	.ndo_get_stats64	= dummy_get_stats64,

};



static void dummy_setup(struct net_device *dev)
@@ -78,14 +127,17 @@ static void dummy_setup(struct net_device *dev) 


	/* Initialize the device structure. */

	dev->netdev_ops = &dummy_netdev_ops;

	dev->destructor = free_netdev;

	dev->destructor = dummy_dev_free;



	/* Fill in device structure with ethernet-generic values. */

	dev->tx_queue_len = 0;

	dev->flags |= IFF_NOARP;

	dev->flags &= ~IFF_MULTICAST;

	dev->features	|= NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_TSO;

	dev->features	|= NETIF_F_NO_CSUM | NETIF_F_HIGHDMA | NETIF_F_LLTX;

	random_ether_addr(dev->dev_addr);

}



static int dummy_validate(struct nlattr *tb[], struct nlattr *data[])

{

	if (tb[IFLA_ADDRESS]) {

include/linux/netdevice.h

+1 −0
Original line number Diff line number Diff line
@@ -1057,6 +1057,7 @@ struct net_device { 
		void				*ml_priv;

		struct pcpu_lstats __percpu	*lstats; /* loopback stats */

		struct pcpu_tstats __percpu	*tstats; /* tunnel stats */

		struct pcpu_dstats __percpu	*dstats; /* dummy stats */

	};

	/* GARP */

	struct garp_port	*garp_port;