android_kernel_motorola_sm6225/drivers/net/veth.c
Daniel Lezcano c15853f2c1 veth: fix dev refcount race
When deleting the veth driver, veth_close calls netif_carrier_off
for the two extremities of the network device. netif_carrier_off on
the peer device will fire an event and hold a reference on the peer
device. Just after, the peer is unregistered taking the rtnl_lock while
the linkwatch_event is scheduled. If __linkwatch_run_queue does not
occurs before the unregistering, unregister_netdevice will wait for
the dev refcount to reach zero holding the rtnl_lock and linkwatch_event
will wait for the rtnl_lock and hold the dev refcount.

Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-02-20 00:21:47 -08:00

497 lines
9.8 KiB
C

/*
* drivers/net/veth.c
*
* Copyright (C) 2007 OpenVZ http://openvz.org, SWsoft Inc
*
* Author: Pavel Emelianov <xemul@openvz.org>
* Ethtool interface from: Eric W. Biederman <ebiederm@xmission.com>
*
*/
#include <linux/list.h>
#include <linux/netdevice.h>
#include <linux/ethtool.h>
#include <linux/etherdevice.h>
#include <net/dst.h>
#include <net/xfrm.h>
#include <linux/veth.h>
#define DRV_NAME "veth"
#define DRV_VERSION "1.0"
struct veth_net_stats {
unsigned long rx_packets;
unsigned long tx_packets;
unsigned long rx_bytes;
unsigned long tx_bytes;
unsigned long tx_dropped;
};
struct veth_priv {
struct net_device *peer;
struct net_device *dev;
struct list_head list;
struct veth_net_stats *stats;
unsigned ip_summed;
};
static LIST_HEAD(veth_list);
/*
* ethtool interface
*/
static struct {
const char string[ETH_GSTRING_LEN];
} ethtool_stats_keys[] = {
{ "peer_ifindex" },
};
static int veth_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
{
cmd->supported = 0;
cmd->advertising = 0;
cmd->speed = SPEED_10000;
cmd->duplex = DUPLEX_FULL;
cmd->port = PORT_TP;
cmd->phy_address = 0;
cmd->transceiver = XCVR_INTERNAL;
cmd->autoneg = AUTONEG_DISABLE;
cmd->maxtxpkt = 0;
cmd->maxrxpkt = 0;
return 0;
}
static void veth_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
{
strcpy(info->driver, DRV_NAME);
strcpy(info->version, DRV_VERSION);
strcpy(info->fw_version, "N/A");
}
static void veth_get_strings(struct net_device *dev, u32 stringset, u8 *buf)
{
switch(stringset) {
case ETH_SS_STATS:
memcpy(buf, &ethtool_stats_keys, sizeof(ethtool_stats_keys));
break;
}
}
static int veth_get_sset_count(struct net_device *dev, int sset)
{
switch (sset) {
case ETH_SS_STATS:
return ARRAY_SIZE(ethtool_stats_keys);
default:
return -EOPNOTSUPP;
}
}
static void veth_get_ethtool_stats(struct net_device *dev,
struct ethtool_stats *stats, u64 *data)
{
struct veth_priv *priv;
priv = netdev_priv(dev);
data[0] = priv->peer->ifindex;
}
static u32 veth_get_rx_csum(struct net_device *dev)
{
struct veth_priv *priv;
priv = netdev_priv(dev);
return priv->ip_summed == CHECKSUM_UNNECESSARY;
}
static int veth_set_rx_csum(struct net_device *dev, u32 data)
{
struct veth_priv *priv;
priv = netdev_priv(dev);
priv->ip_summed = data ? CHECKSUM_UNNECESSARY : CHECKSUM_NONE;
return 0;
}
static u32 veth_get_tx_csum(struct net_device *dev)
{
return (dev->features & NETIF_F_NO_CSUM) != 0;
}
static int veth_set_tx_csum(struct net_device *dev, u32 data)
{
if (data)
dev->features |= NETIF_F_NO_CSUM;
else
dev->features &= ~NETIF_F_NO_CSUM;
return 0;
}
static struct ethtool_ops veth_ethtool_ops = {
.get_settings = veth_get_settings,
.get_drvinfo = veth_get_drvinfo,
.get_link = ethtool_op_get_link,
.get_rx_csum = veth_get_rx_csum,
.set_rx_csum = veth_set_rx_csum,
.get_tx_csum = veth_get_tx_csum,
.set_tx_csum = veth_set_tx_csum,
.get_sg = ethtool_op_get_sg,
.set_sg = ethtool_op_set_sg,
.get_strings = veth_get_strings,
.get_sset_count = veth_get_sset_count,
.get_ethtool_stats = veth_get_ethtool_stats,
};
/*
* xmit
*/
static int veth_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct net_device *rcv = NULL;
struct veth_priv *priv, *rcv_priv;
struct veth_net_stats *stats;
int length, cpu;
skb_orphan(skb);
priv = netdev_priv(dev);
rcv = priv->peer;
rcv_priv = netdev_priv(rcv);
cpu = smp_processor_id();
stats = per_cpu_ptr(priv->stats, cpu);
if (!(rcv->flags & IFF_UP))
goto outf;
skb->pkt_type = PACKET_HOST;
skb->protocol = eth_type_trans(skb, rcv);
if (dev->features & NETIF_F_NO_CSUM)
skb->ip_summed = rcv_priv->ip_summed;
dst_release(skb->dst);
skb->dst = NULL;
skb->mark = 0;
secpath_reset(skb);
nf_reset(skb);
length = skb->len;
stats->tx_bytes += length;
stats->tx_packets++;
stats = per_cpu_ptr(rcv_priv->stats, cpu);
stats->rx_bytes += length;
stats->rx_packets++;
netif_rx(skb);
return 0;
outf:
kfree_skb(skb);
stats->tx_dropped++;
return 0;
}
/*
* general routines
*/
static struct net_device_stats *veth_get_stats(struct net_device *dev)
{
struct veth_priv *priv;
struct net_device_stats *dev_stats;
int cpu;
struct veth_net_stats *stats;
priv = netdev_priv(dev);
dev_stats = &dev->stats;
dev_stats->rx_packets = 0;
dev_stats->tx_packets = 0;
dev_stats->rx_bytes = 0;
dev_stats->tx_bytes = 0;
dev_stats->tx_dropped = 0;
for_each_online_cpu(cpu) {
stats = per_cpu_ptr(priv->stats, cpu);
dev_stats->rx_packets += stats->rx_packets;
dev_stats->tx_packets += stats->tx_packets;
dev_stats->rx_bytes += stats->rx_bytes;
dev_stats->tx_bytes += stats->tx_bytes;
dev_stats->tx_dropped += stats->tx_dropped;
}
return dev_stats;
}
static int veth_open(struct net_device *dev)
{
struct veth_priv *priv;
priv = netdev_priv(dev);
if (priv->peer == NULL)
return -ENOTCONN;
if (priv->peer->flags & IFF_UP) {
netif_carrier_on(dev);
netif_carrier_on(priv->peer);
}
return 0;
}
static int veth_dev_init(struct net_device *dev)
{
struct veth_net_stats *stats;
struct veth_priv *priv;
stats = alloc_percpu(struct veth_net_stats);
if (stats == NULL)
return -ENOMEM;
priv = netdev_priv(dev);
priv->stats = stats;
return 0;
}
static void veth_dev_free(struct net_device *dev)
{
struct veth_priv *priv;
priv = netdev_priv(dev);
free_percpu(priv->stats);
free_netdev(dev);
}
static void veth_setup(struct net_device *dev)
{
ether_setup(dev);
dev->hard_start_xmit = veth_xmit;
dev->get_stats = veth_get_stats;
dev->open = veth_open;
dev->ethtool_ops = &veth_ethtool_ops;
dev->features |= NETIF_F_LLTX;
dev->init = veth_dev_init;
dev->destructor = veth_dev_free;
}
static void veth_change_state(struct net_device *dev)
{
struct net_device *peer;
struct veth_priv *priv;
priv = netdev_priv(dev);
peer = priv->peer;
if (netif_carrier_ok(peer)) {
if (!netif_carrier_ok(dev))
netif_carrier_on(dev);
} else {
if (netif_carrier_ok(dev))
netif_carrier_off(dev);
}
}
static int veth_device_event(struct notifier_block *unused,
unsigned long event, void *ptr)
{
struct net_device *dev = ptr;
if (dev->open != veth_open)
goto out;
switch (event) {
case NETDEV_CHANGE:
veth_change_state(dev);
break;
}
out:
return NOTIFY_DONE;
}
static struct notifier_block veth_notifier_block __read_mostly = {
.notifier_call = veth_device_event,
};
/*
* netlink interface
*/
static int veth_validate(struct nlattr *tb[], struct nlattr *data[])
{
if (tb[IFLA_ADDRESS]) {
if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
return -EINVAL;
if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
return -EADDRNOTAVAIL;
}
return 0;
}
static struct rtnl_link_ops veth_link_ops;
static int veth_newlink(struct net_device *dev,
struct nlattr *tb[], struct nlattr *data[])
{
int err;
struct net_device *peer;
struct veth_priv *priv;
char ifname[IFNAMSIZ];
struct nlattr *peer_tb[IFLA_MAX + 1], **tbp;
/*
* create and register peer first
*
* struct ifinfomsg is at the head of VETH_INFO_PEER, but we
* skip it since no info from it is useful yet
*/
if (data != NULL && data[VETH_INFO_PEER] != NULL) {
struct nlattr *nla_peer;
nla_peer = data[VETH_INFO_PEER];
err = nla_parse(peer_tb, IFLA_MAX,
nla_data(nla_peer) + sizeof(struct ifinfomsg),
nla_len(nla_peer) - sizeof(struct ifinfomsg),
ifla_policy);
if (err < 0)
return err;
err = veth_validate(peer_tb, NULL);
if (err < 0)
return err;
tbp = peer_tb;
} else
tbp = tb;
if (tbp[IFLA_IFNAME])
nla_strlcpy(ifname, tbp[IFLA_IFNAME], IFNAMSIZ);
else
snprintf(ifname, IFNAMSIZ, DRV_NAME "%%d");
peer = rtnl_create_link(dev->nd_net, ifname, &veth_link_ops, tbp);
if (IS_ERR(peer))
return PTR_ERR(peer);
if (tbp[IFLA_ADDRESS] == NULL)
random_ether_addr(peer->dev_addr);
err = register_netdevice(peer);
if (err < 0)
goto err_register_peer;
netif_carrier_off(peer);
/*
* register dev last
*
* note, that since we've registered new device the dev's name
* should be re-allocated
*/
if (tb[IFLA_ADDRESS] == NULL)
random_ether_addr(dev->dev_addr);
if (tb[IFLA_IFNAME])
nla_strlcpy(dev->name, tb[IFLA_IFNAME], IFNAMSIZ);
else
snprintf(dev->name, IFNAMSIZ, DRV_NAME "%%d");
if (strchr(dev->name, '%')) {
err = dev_alloc_name(dev, dev->name);
if (err < 0)
goto err_alloc_name;
}
err = register_netdevice(dev);
if (err < 0)
goto err_register_dev;
netif_carrier_off(dev);
/*
* tie the deviced together
*/
priv = netdev_priv(dev);
priv->dev = dev;
priv->peer = peer;
list_add(&priv->list, &veth_list);
priv = netdev_priv(peer);
priv->dev = peer;
priv->peer = dev;
INIT_LIST_HEAD(&priv->list);
return 0;
err_register_dev:
/* nothing to do */
err_alloc_name:
unregister_netdevice(peer);
return err;
err_register_peer:
free_netdev(peer);
return err;
}
static void veth_dellink(struct net_device *dev)
{
struct veth_priv *priv;
struct net_device *peer;
priv = netdev_priv(dev);
peer = priv->peer;
if (!list_empty(&priv->list))
list_del(&priv->list);
priv = netdev_priv(peer);
if (!list_empty(&priv->list))
list_del(&priv->list);
unregister_netdevice(dev);
unregister_netdevice(peer);
}
static const struct nla_policy veth_policy[VETH_INFO_MAX + 1];
static struct rtnl_link_ops veth_link_ops = {
.kind = DRV_NAME,
.priv_size = sizeof(struct veth_priv),
.setup = veth_setup,
.validate = veth_validate,
.newlink = veth_newlink,
.dellink = veth_dellink,
.policy = veth_policy,
.maxtype = VETH_INFO_MAX,
};
/*
* init/fini
*/
static __init int veth_init(void)
{
register_netdevice_notifier(&veth_notifier_block);
return rtnl_link_register(&veth_link_ops);
}
static __exit void veth_exit(void)
{
rtnl_link_unregister(&veth_link_ops);
unregister_netdevice_notifier(&veth_notifier_block);
}
module_init(veth_init);
module_exit(veth_exit);
MODULE_DESCRIPTION("Virtual Ethernet Tunnel");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS_RTNL_LINK(DRV_NAME);