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|
// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2018, Intel Corporation. */
/* This provides a net_failover interface for paravirtual drivers to
* provide an alternate datapath by exporting APIs to create and
* destroy a upper 'net_failover' netdev. The upper dev manages the
* original paravirtual interface as a 'standby' netdev and uses the
* generic failover infrastructure to register and manage a direct
* attached VF as a 'primary' netdev. This enables live migration of
* a VM with direct attached VF by failing over to the paravirtual
* datapath when the VF is unplugged.
*
* Some of the netdev management routines are based on bond/team driver as
* this driver provides active-backup functionality similar to those drivers.
*/
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/ethtool.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/netdevice.h>
#include <linux/netpoll.h>
#include <linux/rtnetlink.h>
#include <linux/if_vlan.h>
#include <linux/pci.h>
#include <net/sch_generic.h>
#include <uapi/linux/if_arp.h>
#include <net/net_failover.h>
static bool net_failover_xmit_ready(struct net_device *dev)
{
return netif_running(dev) && netif_carrier_ok(dev);
}
static int net_failover_open(struct net_device *dev)
{
struct net_failover_info *nfo_info = netdev_priv(dev);
struct net_device *primary_dev, *standby_dev;
int err;
primary_dev = rtnl_dereference(nfo_info->primary_dev);
if (primary_dev) {
err = dev_open(primary_dev);
if (err)
goto err_primary_open;
}
standby_dev = rtnl_dereference(nfo_info->standby_dev);
if (standby_dev) {
err = dev_open(standby_dev);
if (err)
goto err_standby_open;
}
if ((primary_dev && net_failover_xmit_ready(primary_dev)) ||
(standby_dev && net_failover_xmit_ready(standby_dev))) {
netif_carrier_on(dev);
netif_tx_wake_all_queues(dev);
}
return 0;
err_standby_open:
dev_close(primary_dev);
err_primary_open:
netif_tx_disable(dev);
return err;
}
static int net_failover_close(struct net_device *dev)
{
struct net_failover_info *nfo_info = netdev_priv(dev);
struct net_device *slave_dev;
netif_tx_disable(dev);
slave_dev = rtnl_dereference(nfo_info->primary_dev);
if (slave_dev)
dev_close(slave_dev);
slave_dev = rtnl_dereference(nfo_info->standby_dev);
if (slave_dev)
dev_close(slave_dev);
return 0;
}
static netdev_tx_t net_failover_drop_xmit(struct sk_buff *skb,
struct net_device *dev)
{
atomic_long_inc(&dev->tx_dropped);
dev_kfree_skb_any(skb);
return NETDEV_TX_OK;
}
static netdev_tx_t net_failover_start_xmit(struct sk_buff *skb,
struct net_device *dev)
{
struct net_failover_info *nfo_info = netdev_priv(dev);
struct net_device *xmit_dev;
/* Try xmit via primary netdev followed by standby netdev */
xmit_dev = rcu_dereference_bh(nfo_info->primary_dev);
if (!xmit_dev || !net_failover_xmit_ready(xmit_dev)) {
xmit_dev = rcu_dereference_bh(nfo_info->standby_dev);
if (!xmit_dev || !net_failover_xmit_ready(xmit_dev))
return net_failover_drop_xmit(skb, dev);
}
skb->dev = xmit_dev;
skb->queue_mapping = qdisc_skb_cb(skb)->slave_dev_queue_mapping;
return dev_queue_xmit(skb);
}
static u16 net_failover_select_queue(struct net_device *dev,
struct sk_buff *skb,
struct net_device *sb_dev,
select_queue_fallback_t fallback)
{
struct net_failover_info *nfo_info = netdev_priv(dev);
struct net_device *primary_dev;
u16 txq;
primary_dev = rcu_dereference(nfo_info->primary_dev);
if (primary_dev) {
const struct net_device_ops *ops = primary_dev->netdev_ops;
if (ops->ndo_select_queue)
txq = ops->ndo_select_queue(primary_dev, skb,
sb_dev, fallback);
else
txq = fallback(primary_dev, skb);
qdisc_skb_cb(skb)->slave_dev_queue_mapping = skb->queue_mapping;
return txq;
}
txq = skb_rx_queue_recorded(skb) ? skb_get_rx_queue(skb) : 0;
/* Save the original txq to restore before passing to the driver */
qdisc_skb_cb(skb)->slave_dev_queue_mapping = skb->queue_mapping;
if (unlikely(txq >= dev->real_num_tx_queues)) {
do {
txq -= dev->real_num_tx_queues;
} while (txq >= dev->real_num_tx_queues);
}
return txq;
}
/* fold stats, assuming all rtnl_link_stats64 fields are u64, but
* that some drivers can provide 32bit values only.
*/
static void net_failover_fold_stats(struct rtnl_link_stats64 *_res,
const struct rtnl_link_stats64 *_new,
const struct rtnl_link_stats64 *_old)
{
const u64 *new = (const u64 *)_new;
const u64 *old = (const u64 *)_old;
u64 *res = (u64 *)_res;
int i;
for (i = 0; i < sizeof(*_res) / sizeof(u64); i++) {
u64 nv = new[i];
u64 ov = old[i];
s64 delta = nv - ov;
/* detects if this particular field is 32bit only */
if (((nv | ov) >> 32) == 0)
delta = (s64)(s32)((u32)nv - (u32)ov);
/* filter anomalies, some drivers reset their stats
* at down/up events.
*/
if (delta > 0)
res[i] += delta;
}
}
static void net_failover_get_stats(struct net_device *dev,
struct rtnl_link_stats64 *stats)
{
struct net_failover_info *nfo_info = netdev_priv(dev);
const struct rtnl_link_stats64 *new;
struct rtnl_link_stats64 temp;
struct net_device *slave_dev;
spin_lock(&nfo_info->stats_lock);
memcpy(stats, &nfo_info->failover_stats, sizeof(*stats));
rcu_read_lock();
slave_dev = rcu_dereference(nfo_info->primary_dev);
if (slave_dev) {
new = dev_get_stats(slave_dev, &temp);
net_failover_fold_stats(stats, new, &nfo_info->primary_stats);
memcpy(&nfo_info->primary_stats, new, sizeof(*new));
}
slave_dev = rcu_dereference(nfo_info->standby_dev);
if (slave_dev) {
new = dev_get_stats(slave_dev, &temp);
net_failover_fold_stats(stats, new, &nfo_info->standby_stats);
memcpy(&nfo_info->standby_stats, new, sizeof(*new));
}
rcu_read_unlock();
memcpy(&nfo_info->failover_stats, stats, sizeof(*stats));
spin_unlock(&nfo_info->stats_lock);
}
static int net_failover_change_mtu(struct net_device *dev, int new_mtu)
{
struct net_failover_info *nfo_info = netdev_priv(dev);
struct net_device *primary_dev, *standby_dev;
int ret = 0;
primary_dev = rcu_dereference(nfo_info->primary_dev);
if (primary_dev) {
ret = dev_set_mtu(primary_dev, new_mtu);
if (ret)
return ret;
}
standby_dev = rcu_dereference(nfo_info->standby_dev);
if (standby_dev) {
ret = dev_set_mtu(standby_dev, new_mtu);
if (ret) {
if (primary_dev)
dev_set_mtu(primary_dev, dev->mtu);
return ret;
}
}
dev->mtu = new_mtu;
return 0;
}
static void net_failover_set_rx_mode(struct net_device *dev)
{
struct net_failover_info *nfo_info = netdev_priv(dev);
struct net_device *slave_dev;
rcu_read_lock();
slave_dev = rcu_dereference(nfo_info->primary_dev);
if (slave_dev) {
dev_uc_sync_multiple(slave_dev, dev);
dev_mc_sync_multiple(slave_dev, dev);
}
slave_dev = rcu_dereference(nfo_info->standby_dev);
if (slave_dev) {
dev_uc_sync_multiple(slave_dev, dev);
dev_mc_sync_multiple(slave_dev, dev);
}
rcu_read_unlock();
}
static int net_failover_vlan_rx_add_vid(struct net_device *dev, __be16 proto,
u16 vid)
{
struct net_failover_info *nfo_info = netdev_priv(dev);
struct net_device *primary_dev, *standby_dev;
int ret = 0;
primary_dev = rcu_dereference(nfo_info->primary_dev);
if (primary_dev) {
ret = vlan_vid_add(primary_dev, proto, vid);
if (ret)
return ret;
}
standby_dev = rcu_dereference(nfo_info->standby_dev);
if (standby_dev) {
ret = vlan_vid_add(standby_dev, proto, vid);
if (ret)
if (primary_dev)
vlan_vid_del(primary_dev, proto, vid);
}
return ret;
}
static int net_failover_vlan_rx_kill_vid(struct net_device *dev, __be16 proto,
u16 vid)
{
struct net_failover_info *nfo_info = netdev_priv(dev);
struct net_device *slave_dev;
slave_dev = rcu_dereference(nfo_info->primary_dev);
if (slave_dev)
vlan_vid_del(slave_dev, proto, vid);
slave_dev = rcu_dereference(nfo_info->standby_dev);
if (slave_dev)
vlan_vid_del(slave_dev, proto, vid);
return 0;
}
static const struct net_device_ops failover_dev_ops = {
.ndo_open = net_failover_open,
.ndo_stop = net_failover_close,
.ndo_start_xmit = net_failover_start_xmit,
.ndo_select_queue = net_failover_select_queue,
.ndo_get_stats64 = net_failover_get_stats,
.ndo_change_mtu = net_failover_change_mtu,
.ndo_set_rx_mode = net_failover_set_rx_mode,
.ndo_vlan_rx_add_vid = net_failover_vlan_rx_add_vid,
.ndo_vlan_rx_kill_vid = net_failover_vlan_rx_kill_vid,
.ndo_validate_addr = eth_validate_addr,
.ndo_features_check = passthru_features_check,
};
#define FAILOVER_NAME "net_failover"
#define FAILOVER_VERSION "0.1"
static void nfo_ethtool_get_drvinfo(struct net_device *dev,
struct ethtool_drvinfo *drvinfo)
{
strlcpy(drvinfo->driver, FAILOVER_NAME, sizeof(drvinfo->driver));
strlcpy(drvinfo->version, FAILOVER_VERSION, sizeof(drvinfo->version));
}
static int nfo_ethtool_get_link_ksettings(struct net_device *dev,
struct ethtool_link_ksettings *cmd)
{
struct net_failover_info *nfo_info = netdev_priv(dev);
struct net_device *slave_dev;
slave_dev = rtnl_dereference(nfo_info->primary_dev);
if (!slave_dev || !net_failover_xmit_ready(slave_dev)) {
slave_dev = rtnl_dereference(nfo_info->standby_dev);
if (!slave_dev || !net_failover_xmit_ready(slave_dev)) {
cmd->base.duplex = DUPLEX_UNKNOWN;
cmd->base.port = PORT_OTHER;
cmd->base.speed = SPEED_UNKNOWN;
return 0;
}
}
return __ethtool_get_link_ksettings(slave_dev, cmd);
}
static const struct ethtool_ops failover_ethtool_ops = {
.get_drvinfo = nfo_ethtool_get_drvinfo,
.get_link = ethtool_op_get_link,
.get_link_ksettings = nfo_ethtool_get_link_ksettings,
};
/* Called when slave dev is injecting data into network stack.
* Change the associated network device from lower dev to failover dev.
* note: already called with rcu_read_lock
*/
static rx_handler_result_t net_failover_handle_frame(struct sk_buff **pskb)
{
struct sk_buff *skb = *pskb;
struct net_device *dev = rcu_dereference(skb->dev->rx_handler_data);
struct net_failover_info *nfo_info = netdev_priv(dev);
struct net_device *primary_dev, *standby_dev;
primary_dev = rcu_dereference(nfo_info->primary_dev);
standby_dev = rcu_dereference(nfo_info->standby_dev);
if (primary_dev && skb->dev == standby_dev)
return RX_HANDLER_EXACT;
skb->dev = dev;
return RX_HANDLER_ANOTHER;
}
static void net_failover_compute_features(struct net_device *dev)
{
netdev_features_t vlan_features = FAILOVER_VLAN_FEATURES &
NETIF_F_ALL_FOR_ALL;
netdev_features_t enc_features = FAILOVER_ENC_FEATURES;
unsigned short max_hard_header_len = ETH_HLEN;
unsigned int dst_release_flag = IFF_XMIT_DST_RELEASE |
IFF_XMIT_DST_RELEASE_PERM;
struct net_failover_info *nfo_info = netdev_priv(dev);
struct net_device *primary_dev, *standby_dev;
primary_dev = rcu_dereference(nfo_info->primary_dev);
if (primary_dev) {
vlan_features =
netdev_increment_features(vlan_features,
primary_dev->vlan_features,
FAILOVER_VLAN_FEATURES);
enc_features =
netdev_increment_features(enc_features,
primary_dev->hw_enc_features,
FAILOVER_ENC_FEATURES);
dst_release_flag &= primary_dev->priv_flags;
if (primary_dev->hard_header_len > max_hard_header_len)
max_hard_header_len = primary_dev->hard_header_len;
}
standby_dev = rcu_dereference(nfo_info->standby_dev);
if (standby_dev) {
vlan_features =
netdev_increment_features(vlan_features,
standby_dev->vlan_features,
FAILOVER_VLAN_FEATURES);
enc_features =
netdev_increment_features(enc_features,
standby_dev->hw_enc_features,
FAILOVER_ENC_FEATURES);
dst_release_flag &= standby_dev->priv_flags;
if (standby_dev->hard_header_len > max_hard_header_len)
max_hard_header_len = standby_dev->hard_header_len;
}
dev->vlan_features = vlan_features;
dev->hw_enc_features = enc_features | NETIF_F_GSO_ENCAP_ALL;
dev->hard_header_len = max_hard_header_len;
dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
if (dst_release_flag == (IFF_XMIT_DST_RELEASE |
IFF_XMIT_DST_RELEASE_PERM))
dev->priv_flags |= IFF_XMIT_DST_RELEASE;
netdev_change_features(dev);
}
static void net_failover_lower_state_changed(struct net_device *slave_dev,
struct net_device *primary_dev,
struct net_device *standby_dev)
{
struct netdev_lag_lower_state_info info;
if (netif_carrier_ok(slave_dev))
info.link_up = true;
else
info.link_up = false;
if (slave_dev == primary_dev) {
if (netif_running(primary_dev))
info.tx_enabled = true;
else
info.tx_enabled = false;
} else {
if ((primary_dev && netif_running(primary_dev)) ||
(!netif_running(standby_dev)))
info.tx_enabled = false;
else
info.tx_enabled = true;
}
netdev_lower_state_changed(slave_dev, &info);
}
static int net_failover_slave_pre_register(struct net_device *slave_dev,
struct net_device *failover_dev)
{
struct net_device *standby_dev, *primary_dev;
struct net_failover_info *nfo_info;
bool slave_is_standby;
nfo_info = netdev_priv(failover_dev);
standby_dev = rtnl_dereference(nfo_info->standby_dev);
primary_dev = rtnl_dereference(nfo_info->primary_dev);
slave_is_standby = slave_dev->dev.parent == failover_dev->dev.parent;
if (slave_is_standby ? standby_dev : primary_dev) {
netdev_err(failover_dev, "%s attempting to register as slave dev when %s already present\n",
slave_dev->name,
slave_is_standby ? "standby" : "primary");
return -EINVAL;
}
/* We want to allow only a direct attached VF device as a primary
* netdev. As there is no easy way to check for a VF device, restrict
* this to a pci device.
*/
if (!slave_is_standby && (!slave_dev->dev.parent ||
!dev_is_pci(slave_dev->dev.parent)))
return -EINVAL;
if (failover_dev->features & NETIF_F_VLAN_CHALLENGED &&
vlan_uses_dev(failover_dev)) {
netdev_err(failover_dev, "Device %s is VLAN challenged and failover device has VLAN set up\n",
failover_dev->name);
return -EINVAL;
}
return 0;
}
static int net_failover_slave_register(struct net_device *slave_dev,
struct net_device *failover_dev)
{
struct net_device *standby_dev, *primary_dev;
struct net_failover_info *nfo_info;
bool slave_is_standby;
u32 orig_mtu;
int err;
/* Align MTU of slave with failover dev */
orig_mtu = slave_dev->mtu;
err = dev_set_mtu(slave_dev, failover_dev->mtu);
if (err) {
netdev_err(failover_dev, "unable to change mtu of %s to %u register failed\n",
slave_dev->name, failover_dev->mtu);
goto done;
}
dev_hold(slave_dev);
if (netif_running(failover_dev)) {
err = dev_open(slave_dev);
if (err && (err != -EBUSY)) {
netdev_err(failover_dev, "Opening slave %s failed err:%d\n",
slave_dev->name, err);
goto err_dev_open;
}
}
netif_addr_lock_bh(failover_dev);
dev_uc_sync_multiple(slave_dev, failover_dev);
dev_mc_sync_multiple(slave_dev, failover_dev);
netif_addr_unlock_bh(failover_dev);
err = vlan_vids_add_by_dev(slave_dev, failover_dev);
if (err) {
netdev_err(failover_dev, "Failed to add vlan ids to device %s err:%d\n",
slave_dev->name, err);
goto err_vlan_add;
}
nfo_info = netdev_priv(failover_dev);
standby_dev = rtnl_dereference(nfo_info->standby_dev);
primary_dev = rtnl_dereference(nfo_info->primary_dev);
slave_is_standby = slave_dev->dev.parent == failover_dev->dev.parent;
if (slave_is_standby) {
rcu_assign_pointer(nfo_info->standby_dev, slave_dev);
standby_dev = slave_dev;
dev_get_stats(standby_dev, &nfo_info->standby_stats);
} else {
rcu_assign_pointer(nfo_info->primary_dev, slave_dev);
primary_dev = slave_dev;
dev_get_stats(primary_dev, &nfo_info->primary_stats);
failover_dev->min_mtu = slave_dev->min_mtu;
failover_dev->max_mtu = slave_dev->max_mtu;
}
net_failover_lower_state_changed(slave_dev, primary_dev, standby_dev);
net_failover_compute_features(failover_dev);
call_netdevice_notifiers(NETDEV_JOIN, slave_dev);
netdev_info(failover_dev, "failover %s slave:%s registered\n",
slave_is_standby ? "standby" : "primary", slave_dev->name);
return 0;
err_vlan_add:
dev_uc_unsync(slave_dev, failover_dev);
dev_mc_unsync(slave_dev, failover_dev);
dev_close(slave_dev);
err_dev_open:
dev_put(slave_dev);
dev_set_mtu(slave_dev, orig_mtu);
done:
return err;
}
static int net_failover_slave_pre_unregister(struct net_device *slave_dev,
struct net_device *failover_dev)
{
struct net_device *standby_dev, *primary_dev;
struct net_failover_info *nfo_info;
nfo_info = netdev_priv(failover_dev);
primary_dev = rtnl_dereference(nfo_info->primary_dev);
standby_dev = rtnl_dereference(nfo_info->standby_dev);
if (slave_dev != primary_dev && slave_dev != standby_dev)
return -ENODEV;
return 0;
}
static int net_failover_slave_unregister(struct net_device *slave_dev,
struct net_device *failover_dev)
{
struct net_device *standby_dev, *primary_dev;
struct net_failover_info *nfo_info;
bool slave_is_standby;
nfo_info = netdev_priv(failover_dev);
primary_dev = rtnl_dereference(nfo_info->primary_dev);
standby_dev = rtnl_dereference(nfo_info->standby_dev);
vlan_vids_del_by_dev(slave_dev, failover_dev);
dev_uc_unsync(slave_dev, failover_dev);
dev_mc_unsync(slave_dev, failover_dev);
dev_close(slave_dev);
nfo_info = netdev_priv(failover_dev);
dev_get_stats(failover_dev, &nfo_info->failover_stats);
slave_is_standby = slave_dev->dev.parent == failover_dev->dev.parent;
if (slave_is_standby) {
RCU_INIT_POINTER(nfo_info->standby_dev, NULL);
} else {
RCU_INIT_POINTER(nfo_info->primary_dev, NULL);
if (standby_dev) {
failover_dev->min_mtu = standby_dev->min_mtu;
failover_dev->max_mtu = standby_dev->max_mtu;
}
}
dev_put(slave_dev);
net_failover_compute_features(failover_dev);
netdev_info(failover_dev, "failover %s slave:%s unregistered\n",
slave_is_standby ? "standby" : "primary", slave_dev->name);
return 0;
}
static int net_failover_slave_link_change(struct net_device *slave_dev,
struct net_device *failover_dev)
{
struct net_device *primary_dev, *standby_dev;
struct net_failover_info *nfo_info;
nfo_info = netdev_priv(failover_dev);
primary_dev = rtnl_dereference(nfo_info->primary_dev);
standby_dev = rtnl_dereference(nfo_info->standby_dev);
if (slave_dev != primary_dev && slave_dev != standby_dev)
return -ENODEV;
if ((primary_dev && net_failover_xmit_ready(primary_dev)) ||
(standby_dev && net_failover_xmit_ready(standby_dev))) {
netif_carrier_on(failover_dev);
netif_tx_wake_all_queues(failover_dev);
} else {
dev_get_stats(failover_dev, &nfo_info->failover_stats);
netif_carrier_off(failover_dev);
netif_tx_stop_all_queues(failover_dev);
}
net_failover_lower_state_changed(slave_dev, primary_dev, standby_dev);
return 0;
}
static int net_failover_slave_name_change(struct net_device *slave_dev,
struct net_device *failover_dev)
{
struct net_device *primary_dev, *standby_dev;
struct net_failover_info *nfo_info;
nfo_info = netdev_priv(failover_dev);
primary_dev = rtnl_dereference(nfo_info->primary_dev);
standby_dev = rtnl_dereference(nfo_info->standby_dev);
if (slave_dev != primary_dev && slave_dev != standby_dev)
return -ENODEV;
/* We need to bring up the slave after the rename by udev in case
* open failed with EBUSY when it was registered.
*/
dev_open(slave_dev);
return 0;
}
static struct failover_ops net_failover_ops = {
.slave_pre_register = net_failover_slave_pre_register,
.slave_register = net_failover_slave_register,
.slave_pre_unregister = net_failover_slave_pre_unregister,
.slave_unregister = net_failover_slave_unregister,
.slave_link_change = net_failover_slave_link_change,
.slave_name_change = net_failover_slave_name_change,
.slave_handle_frame = net_failover_handle_frame,
};
/**
* net_failover_create - Create and register a failover instance
*
* @dev: standby netdev
*
* Creates a failover netdev and registers a failover instance for a standby
* netdev. Used by paravirtual drivers that use 3-netdev model.
* The failover netdev acts as a master device and controls 2 slave devices -
* the original standby netdev and a VF netdev with the same MAC gets
* registered as primary netdev.
*
* Return: pointer to failover instance
*/
struct failover *net_failover_create(struct net_device *standby_dev)
{
struct device *dev = standby_dev->dev.parent;
struct net_device *failover_dev;
struct failover *failover;
int err;
/* Alloc at least 2 queues, for now we are going with 16 assuming
* that VF devices being enslaved won't have too many queues.
*/
failover_dev = alloc_etherdev_mq(sizeof(struct net_failover_info), 16);
if (!failover_dev) {
dev_err(dev, "Unable to allocate failover_netdev!\n");
return ERR_PTR(-ENOMEM);
}
dev_net_set(failover_dev, dev_net(standby_dev));
SET_NETDEV_DEV(failover_dev, dev);
failover_dev->netdev_ops = &failover_dev_ops;
failover_dev->ethtool_ops = &failover_ethtool_ops;
/* Initialize the device options */
failover_dev->priv_flags |= IFF_UNICAST_FLT | IFF_NO_QUEUE;
failover_dev->priv_flags &= ~(IFF_XMIT_DST_RELEASE |
IFF_TX_SKB_SHARING);
/* don't acquire failover netdev's netif_tx_lock when transmitting */
failover_dev->features |= NETIF_F_LLTX;
/* Don't allow failover devices to change network namespaces. */
failover_dev->features |= NETIF_F_NETNS_LOCAL;
failover_dev->hw_features = FAILOVER_VLAN_FEATURES |
NETIF_F_HW_VLAN_CTAG_TX |
NETIF_F_HW_VLAN_CTAG_RX |
NETIF_F_HW_VLAN_CTAG_FILTER;
failover_dev->hw_features |= NETIF_F_GSO_ENCAP_ALL;
failover_dev->features |= failover_dev->hw_features;
memcpy(failover_dev->dev_addr, standby_dev->dev_addr,
failover_dev->addr_len);
failover_dev->min_mtu = standby_dev->min_mtu;
failover_dev->max_mtu = standby_dev->max_mtu;
err = register_netdev(failover_dev);
if (err) {
dev_err(dev, "Unable to register failover_dev!\n");
goto err_register_netdev;
}
netif_carrier_off(failover_dev);
failover = failover_register(failover_dev, &net_failover_ops);
if (IS_ERR(failover))
goto err_failover_register;
return failover;
err_failover_register:
unregister_netdev(failover_dev);
err_register_netdev:
free_netdev(failover_dev);
return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(net_failover_create);
/**
* net_failover_destroy - Destroy a failover instance
*
* @failover: pointer to failover instance
*
* Unregisters any slave netdevs associated with the failover instance by
* calling failover_slave_unregister().
* unregisters the failover instance itself and finally frees the failover
* netdev. Used by paravirtual drivers that use 3-netdev model.
*
*/
void net_failover_destroy(struct failover *failover)
{
struct net_failover_info *nfo_info;
struct net_device *failover_dev;
struct net_device *slave_dev;
if (!failover)
return;
failover_dev = rcu_dereference(failover->failover_dev);
nfo_info = netdev_priv(failover_dev);
netif_device_detach(failover_dev);
rtnl_lock();
slave_dev = rtnl_dereference(nfo_info->primary_dev);
if (slave_dev)
failover_slave_unregister(slave_dev);
slave_dev = rtnl_dereference(nfo_info->standby_dev);
if (slave_dev)
failover_slave_unregister(slave_dev);
failover_unregister(failover);
unregister_netdevice(failover_dev);
rtnl_unlock();
free_netdev(failover_dev);
}
EXPORT_SYMBOL_GPL(net_failover_destroy);
static __init int
net_failover_init(void)
{
return 0;
}
module_init(net_failover_init);
static __exit
void net_failover_exit(void)
{
}
module_exit(net_failover_exit);
MODULE_DESCRIPTION("Failover driver for Paravirtual drivers");
MODULE_LICENSE("GPL v2");
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