Subject: Re: [net-next PATCH] net: rtnetlink: Enslave device before bringing it up

From: David Ahern <[email-masked]>
Date: Wed, 29 May 2019 09:41:07 -0600

On 5/29/19 7:51 AM, Phil Sutter wrote:
> Unlike with bridges, one can't add an interface to a bond and set it up
> at the same time:
> 
> | # ip link set dummy0 down
> | # ip link set dummy0 master bond0 up
> | Error: Device can not be enslaved while up.
> 
> Of all drivers with ndo_add_slave callback, bond and team decline if
> IFF_UP flag is set, vrf cycles the interface (i.e., sets it down and
> immediately up again) and the others just don't care.
> 
> Support the common notion of setting the interface up after enslaving it
> by sorting the operations accordingly.
> 
> Signed-off-by: Phil Sutter <[email-masked]>
> ---
>  net/core/rtnetlink.c | 14 +++++++-------
>  1 file changed, 7 insertions(+), 7 deletions(-)
> 

I agree with the intent - enslave before up.

Not sure how likely this is, but it does break the case:
ip li set dummy0 master bond0 down