On 6/17/25 00:28, Jay Vosburgh wrote: > Remove the ability to disable use_carrier in bonding, and remove > all code related to the old link state check that utilizes ethtool or > ioctl to determine the link state of an interface in a bond. > > To avoid acquiring RTNL many times per second, bonding's miimon > link monitor inspects link state under RCU, but not under RTNL. However, > ethtool implementations in drivers may sleep, and therefore the ethtool or > ioctl strategy is unsuitable for use with calls into driver ethtool > functions. > > The use_carrier option was introduced in 2003, to provide > backwards compatibility for network device drivers that did not support > the then-new netif_carrier_ok/on/off system. Today, device drivers are > expected to support netif_carrier_*, and the use_carrier backwards > compatibility logic is no longer necessary. > > Bonding now always behaves as if use_carrier=1, which relies on > netif_carrier_ok() to determine the link state of interfaces. This has > been the default setting for use_carrier since its introduction. For > backwards compatibility, the option itself remains, but may only be set to > 1, and queries will always return 1. > > Reported-by: syzbot+b8c48ea38ca27d150063@xxxxxxxxxxxxxxxxxxxxxxxxx > Closes: https://syzkaller.appspot.com/bug?extid=b8c48ea38ca27d150063 > Link: https://lore.kernel.org/lkml/000000000000eb54bf061cfd666a@xxxxxxxxxx/ > Link: https://lore.kernel.org/netdev/20240718122017.d2e33aaac43a.I10ab9c9ded97163aef4e4de10985cd8f7de60d28@changeid/ > Link: http://lore.kernel.org/netdev/aEt6LvBMwUMxmUyx@mini-arch > Signed-off-by: Jay Vosburgh <jv@xxxxxxxxxxxxx> > > --- > Documentation/networking/bonding.rst | 79 +++---------------- > drivers/net/bonding/bond_main.c | 113 ++------------------------- > drivers/net/bonding/bond_netlink.c | 11 +-- > drivers/net/bonding/bond_options.c | 7 +- > drivers/net/bonding/bond_sysfs.c | 6 +- > include/net/bonding.h | 1 - > 6 files changed, 25 insertions(+), 192 deletions(-) > [snip] > diff --git a/drivers/net/bonding/bond_netlink.c b/drivers/net/bonding/bond_netlink.c > index ac5e402c34bc..98f9bef61474 100644 > --- a/drivers/net/bonding/bond_netlink.c > +++ b/drivers/net/bonding/bond_netlink.c > @@ -258,13 +258,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], > return err; > } > if (data[IFLA_BOND_USE_CARRIER]) { > - int use_carrier = nla_get_u8(data[IFLA_BOND_USE_CARRIER]); > - > - bond_opt_initval(&newval, use_carrier); > - err = __bond_opt_set(bond, BOND_OPT_USE_CARRIER, &newval, > - data[IFLA_BOND_USE_CARRIER], extack); > - if (err) > - return err; > + if (nla_get_u8(data[IFLA_BOND_USE_CARRIER]) != 1) you can set extack to send back an error to the user that use_carrier is now obsolete > + return -EINVAL; > } > if (data[IFLA_BOND_ARP_INTERVAL]) { > int arp_interval = nla_get_u32(data[IFLA_BOND_ARP_INTERVAL]); > @@ -676,7 +671,7 @@ static int bond_fill_info(struct sk_buff *skb, > bond->params.peer_notif_delay * bond->params.miimon)) > goto nla_put_failure; > > - if (nla_put_u8(skb, IFLA_BOND_USE_CARRIER, bond->params.use_carrier)) > + if (nla_put_u8(skb, IFLA_BOND_USE_CARRIER, 1)) > goto nla_put_failure; > > if (nla_put_u32(skb, IFLA_BOND_ARP_INTERVAL, bond->params.arp_interval))
