From: WANG Cong <xiyou.wangcong@gmail.com>
Date: Thu, 6 Jul 2017 15:01:57 -0700
Subject: bonding: avoid NETDEV_CHANGEMTU event when unregistering slave
Patch-mainline: v4.13-rc1
Git-commit: f51048c3e07b68c90b21a77541fc4b208f9244d7
References: bsc#1109837
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>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
drivers/net/bonding/bond_main.c | 15 +++++++++------
include/linux/netdevice.h | 1 +
net/core/dev.c | 3 ++-
3 files changed, 12 insertions(+), 7 deletions(-)
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1821,7 +1821,7 @@ 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;
@@ -1966,7 +1966,10 @@ static int __bond_release_one(struct net
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;
@@ -1978,7 +1981,7 @@ static int __bond_release_one(struct net
/* 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.
@@ -1990,7 +1993,7 @@ static int bond_release_and_destroy(str
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",
@@ -3065,7 +3068,7 @@ static int bond_slave_netdev_event(unsig
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:
@@ -4262,7 +4265,7 @@ static void bond_uninit(struct net_devic
/* 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);
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3284,6 +3284,7 @@ void __dev_notify_flags(struct net_devic
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 *);
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6766,7 +6766,7 @@ int dev_change_flags(struct net_device *
}
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;
@@ -6776,6 +6776,7 @@ static int __dev_set_mtu(struct net_devi
dev->mtu = new_mtu;
return 0;
}
+EXPORT_SYMBOL(__dev_set_mtu);
/**
* dev_set_mtu - Change maximum transfer unit