Commit f51048c3 authored by WANG Cong's avatar WANG Cong Committed by David S. Miller
Browse files

bonding: avoid NETDEV_CHANGEMTU event when unregistering slave 



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: default avatarHongjun Li <hongjun.li@6wind.com>
Reported-by: default avatarNicolas 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: default avatarCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 5dc314f8

drivers/net/bonding/bond_main.c

+9 −6
Original line number Diff line number Diff line
@@ -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;
@@ -1965,6 +1965,9 @@ static int __bond_release_one(struct net_device *bond_dev, 
		dev_set_mac_address(slave_dev, (struct sockaddr *)&ss);

	}



	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);

include/linux/netdevice.h

+1 −0
Original line number Diff line number Diff line
@@ -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 *);

net/core/dev.c

+2 −1
Original line number Diff line number Diff line
@@ -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

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