# Re: \[PATCH net-next\] bonding: Remove support for use\_carrier - From: Nikolay Aleksandrov \ - Date: 2025-09-03 09:52:21 - List: netdev - Page: https://ratatoskr.run/netdev/2025/09/8534365 - Thread: https://ratatoskr.run/netdev/2025/08/8534281/t.md ```text On 8/30/25 03:08, Jay Vosburgh wrote: > Remove the implementation of use_carrier, the link monitoring > method that utilizes ethtool or ioctl to determine the link state of an > interface in a bond. Bonding will always behaves as if use_carrier=1, > which relies on netif_carrier_ok() to determine the link state of > interfaces. > > To avoid acquiring RTNL many times per second, bonding inspects > link state under RCU, but not under RTNL. However, ethtool > implementations in drivers may sleep, and therefore this 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. Device drivers are now > expected to support netif_carrier_*, and the use_carrier backwards > compatibility logic is no longer necessary. > > The option itself remains, but when queried always returns 1, > and may only be set to 1. > > Link: https://lore.kernel.org/lkml/000000000000eb54bf061cfd666a@google.com/ > Link: https://lore.kernel.org/netdev/20240718122017.d2e33aaac43a.I10ab9c9ded97163aef4e4de10985cd8f7de60d28@changeid/ > Signed-off-by: Jay Vosburgh > > --- > > Note: Deliberately omitting a Fixes tag to avoid removing functionality > in older kernels that may be in use. > > Documentation/networking/bonding.rst | 79 +++---------------- > drivers/net/bonding/bond_main.c | 113 ++------------------------- > drivers/net/bonding/bond_netlink.c | 14 ++-- > drivers/net/bonding/bond_options.c | 7 +- > drivers/net/bonding/bond_sysfs.c | 6 +- > include/net/bonding.h | 1 - > 6 files changed, 28 insertions(+), 192 deletions(-) > Reviewed-by: Nikolay Aleksandrov ```