Re: [PATCH net-next v4 0/2] Add OVS packet family YNL spec and unicast notification support

[Minxi Hou <houminxi@gmail.com>]

Sashiko flagged a few things on this series, noting my analysis here
for the record.

The dp-ifindex field is typed as u32 in the spec while the kernel
struct uses "int".  All three existing OVS specs (ovs_datapath,
ovs_flow, ovs_vport) also use u32 for this field, so I kept it
consistent.

key/actions/egress-tun-key are typed as binary rather than nest.
This is documented in the commit message and inline comments --
the nested attribute-sets belong to ovs_flow's spec, and YNL does
not support cross-spec references.

The execute operation does not carry uns-admin-perm in the spec.
The kernel sets GENL_UNS_ADMIN_PERM on it, but none of the existing
OVS specs declare admin-perm flags on any of their operations either
(ovs_datapath new/del/set, ovs_flow new/del/set, ovs_vport new/del/set
all have GENL_UNS_ADMIN_PERM in the kernel but omit it in the YAML).

ntf_bind() will raise OSError if the socket was already bound.
ntf_subscribe() has the same constraint -- both expect to be called
before any operation that triggers autobind.