Re: [PATCH net-next] net: shaper: Reject zero weight in shaper config

[Mohsin Bashir <mohsin.bashr@gmail.com>]

On 4/13/26 2:50 PM, Jakub Kicinski wrote:
> On Fri, 10 Apr 2026 15:51:23 -0700 Mohsin Bashir wrote:
>> A zero weight is meaningless for DWRR scheduling and can cause
>> starvation of the affected node. Add a min-value constraint to
>> the weight attribute in the net_shaper netlink spec so that zero
>> is rejected at the netlink policy level.
>>
>> Found while prototyping a new driver, existing drivers are not
>> affected.
> 
> AI review points out that if the netlink attr is not present core will
> leave the DWRR weight as 0 in the struct. I guess we need to think this
> thru a little more carefully. What should the "default" weight be?
> What if user specifies weights only for subset of leaves?
> 
> This part of the uAPI seems under-defined.
> 
> Maybe a better adjustment would be to make core set the weight to 1
> automatically if the user has not defined it? Only when sending it to
> the driver tho, because we'd still want it to not be reported back to
> user space. Not sure how hairy it'd get code-wise.

Interesting!!
Let me look at the big picture here and re-spin.