Re: [PATCH net-next v7 01/16] net: Add queue-create operation

[Stanislav Fomichev <stfomichev@gmail.com>]

On 01/15, Daniel Borkmann wrote:
> Add a ynl netdev family operation called queue-create that creates a
> new queue on a netdevice:
> 
>       name: queue-create
>       attribute-set: queue
>       flags: [admin-perm]
>       do:
>         request:
>           attributes:
>             - ifindex
>             - type
>             - lease
>         reply: &queue-create-op
>           attributes:
>             - id
> 
> This is a generic operation such that it can be extended for various
> use cases in future. Right now it is mandatory to specify ifindex,
> the queue type which is enforced to rx and a lease. The newly created
> queue id is returned to the caller.
> 
> A queue from a virtual device can have a lease which refers to another
> queue from a physical device. This is useful for memory providers
> and AF_XDP operations which take an ifindex and queue id to allow
> applications to bind against virtual devices in containers. The lease
> couples both queues together and allows to proxy the operations from
> a virtual device in a container to the physical device.
> 
> In future, the nested lease attribute can be lifted and made optional
> for other use-cases such as dynamic queue creation for physical
> netdevs. The lack of lease and the specification of the physical
> device as an ifindex will imply that we need a real queue to be
> allocated. Similarly, the queue type enforcement to rx can then be
> lifted as well to support tx.
> 
> An early implementation had only driver-specific integration [0], but
> in order for other virtual devices to reuse, it makes sense to have
> this as a generic API in core net.
> 
> For leasing queues, the virtual netdev must have real_num_rx_queue
> less than num_rx_queues at the time of calling queue-create. The
> queue-type must be rx as only rx queues are supported for leasing
> for now. We also enforce that the queue-create ifindex must point
> to a virtual device, and that the nested lease attribute's ifindex
> must point to a physical device. The nested lease attribute set
> contains a netns-id attribute which is currently only intended for
> dumping as part of the queue-get operation. Also, it is modeled as
> an s32 type similarly as done elsewhere in the stack.
> 
> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
> Co-developed-by: David Wei <dw@davidwei.uk>
> Signed-off-by: David Wei <dw@davidwei.uk>
> Link: https://bpfconf.ebpf.io/bpfconf2025/bpfconf2025_material/lsfmmbpf_2025_netkit_borkmann.pdf [0]

Acked-by: Stanislav Fomichev <sdf@fomichev.me>