Re: [PATCH RFC net-next] bonding: Remove support for use_carrier

[Joe Damato <jdamato@fastly.com>]

On Sun, Jul 21, 2024 at 11:28:23PM -0700, David Wei wrote:
> On 2024-07-21 10:07, 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.  The ability to set or query the use_carrier option
> > remains, but bonding now 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.
> > 
> > Link: https://lore.kernel.org/lkml/000000000000eb54bf061cfd666a@google.com/
> > Link: https://lore.kernel.org/netdev/20240718122017.d2e33aaac43a.I10ab9c9ded97163aef4e4de10985cd8f7de60d28@changeid/
> > Signed-off-by: Jay Vosburgh <jv@jvosburgh.net>
> > 
> > ---
> > 
> > 	I've done some sniff testing and this seems to behave as
> > expected, except that writing 0 to the sysfs use_carrier fails.  Netlink
> > permits setting use_carrier to any value but always returns 1; sysfs and
> > netlink should behave consistently.
> 
> Net-next is closed until 28 July. Please resubmit then.

AFAICT, the subject line is marked as RFC (although it is a bit
confusing as it mentions both PATCH and RFC), but my understanding
is that RFCs are accepted at any time.