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bonding: avoid NETDEV_CHANGEMTU event when unregistering slave

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As Hongjun/Nicolas summarized in their original patch:

"
When a device changes from one netns to another, it's first unregistered,
then the netns reference is updated and the dev is registered in the new
netns. Thus, when a slave moves to another netns, it is first
unregistered. This triggers a NETDEV_UNREGISTER event which is caught by
the bonding driver. The driver calls bond_release(), which calls
dev_set_mtu() and thus triggers NETDEV_CHANGEMTU (the device is still in
the old netns).
"

This is a very special case, because the device is being unregistered
no one should still care about the NETDEV_CHANGEMTU event triggered
at this point, we can avoid broadcasting this event on this path,
and avoid touching inetdev_event()/addrconf_notify() path.

It requires to export __dev_set_mtu() to bonding driver.

Reported-by: Hongjun Li <hongjun.li@6wind.com>
Reported-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Cc: Jay Vosburgh <j.vosburgh@gmail.com>
Cc: Veaceslav Falico <vfalico@gmail.com>
Cc: Andy Gospodarek <andy@greyhouse.net>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
WANG Cong 2017-07-06 15:01:57 -07:00 committed by David S. Miller
parent 5dc314f8de
commit f51048c3e0
3 changed files with 12 additions and 7 deletions
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15
drivers/net/bonding/bond_main.c
View file

@ -1820,7 +1820,7 @@ err_undo_flags:
*/
static int __bond_release_one(struct net_device *bond_dev,
struct net_device *slave_dev,
bool all)
bool all, bool unregister)
{
struct bonding *bond = netdev_priv(bond_dev);
struct slave *slave, *oldcurrent;
@ -1965,7 +1965,10 @@ static int __bond_release_one(struct net_device *bond_dev,
dev_set_mac_address(slave_dev, (struct sockaddr *)&ss);
}
dev_set_mtu(slave_dev, slave->original_mtu);
if (unregister)
__dev_set_mtu(slave_dev, slave->original_mtu);
else
dev_set_mtu(slave_dev, slave->original_mtu);
slave_dev->priv_flags &= ~IFF_BONDING;
@ -1977,7 +1980,7 @@ static int __bond_release_one(struct net_device *bond_dev,
/* A wrapper used because of ndo_del_link */
int bond_release(struct net_device *bond_dev, struct net_device *slave_dev)
{
return __bond_release_one(bond_dev, slave_dev, false);
return __bond_release_one(bond_dev, slave_dev, false, false);
}
/* First release a slave and then destroy the bond if no more slaves are left.
@ -1989,7 +1992,7 @@ static int bond_release_and_destroy(struct net_device *bond_dev,
struct bonding *bond = netdev_priv(bond_dev);
int ret;
ret = bond_release(bond_dev, slave_dev);
ret = __bond_release_one(bond_dev, slave_dev, false, true);
if (ret == 0 && !bond_has_slaves(bond)) {
bond_dev->priv_flags |= IFF_DISABLE_NETPOLL;
netdev_info(bond_dev, "Destroying bond %s\n",
@ -3060,7 +3063,7 @@ static int bond_slave_netdev_event(unsigned long event,
if (bond_dev->type != ARPHRD_ETHER)
bond_release_and_destroy(bond_dev, slave_dev);
else
bond_release(bond_dev, slave_dev);
__bond_release_one(bond_dev, slave_dev, false, true);
break;
case NETDEV_UP:
case NETDEV_CHANGE:
@ -4252,7 +4255,7 @@ static void bond_uninit(struct net_device *bond_dev)
/* Release the bonded slaves */
bond_for_each_slave(bond, slave, iter)
__bond_release_one(bond_dev, slave->dev, true);
__bond_release_one(bond_dev, slave->dev, true, true);
netdev_info(bond_dev, "Released all slaves\n");
arr = rtnl_dereference(bond->slave_arr);

1
include/linux/netdevice.h
View file

@ -3284,6 +3284,7 @@ void __dev_notify_flags(struct net_device *, unsigned int old_flags,
int dev_change_name(struct net_device *, const char *);
int dev_set_alias(struct net_device *, const char *, size_t);
int dev_change_net_namespace(struct net_device *, struct net *, const char *);
int __dev_set_mtu(struct net_device *, int);
int dev_set_mtu(struct net_device *, int);
void dev_set_group(struct net_device *, int);
int dev_set_mac_address(struct net_device *, struct sockaddr *);

3
net/core/dev.c
View file

@ -6765,7 +6765,7 @@ int dev_change_flags(struct net_device *dev, unsigned int flags)
}
EXPORT_SYMBOL(dev_change_flags);
static int __dev_set_mtu(struct net_device *dev, int new_mtu)
int __dev_set_mtu(struct net_device *dev, int new_mtu)
{
const struct net_device_ops *ops = dev->netdev_ops;
@ -6775,6 +6775,7 @@ static int __dev_set_mtu(struct net_device *dev, int new_mtu)
dev->mtu = new_mtu;
return 0;
}
EXPORT_SYMBOL(__dev_set_mtu);
/**
* dev_set_mtu - Change maximum transfer unit