Re: [PATCH] netlink: specs: add specification for NBD

[Hristo Venev <hristo@venev.name>]

On Tue, 2026-02-17 at 12:17 +0000, Donald Hunter wrote:
> There are yamllint errors:
> 
> make -C tools/net/ynl lint
> make: Entering directory '/home/donaldh/net-next/tools/net/ynl'
> yamllint ../../../Documentation/netlink/specs
> ../../../Documentation/netlink/specs/nbd.yaml
>   159:81    error    line too long (104 > 80 characters)  (line-
> length)
>   169:6     error    syntax error: expected <block end>, but found
> '<block mapping start>' (syntax)
>   170:7     error    wrong indentation: expected 5 but found 6 
> (indentation)

Thanks, I will fix the lint errors in v2.

> > +doc: See :file:`drivers/block/nbd.c`
> 
> Prefer to see a meaningful doc string here.

I will add more proper documentation in v2. I couldn't find any
existing documentation of this netlink interface, so I guess I will
write it myself.

> > +attribute-sets:
> > +  -
> > +    name: nbd-attrs
> > +    name-prefix: nbd-attr-
> > +    doc: Configuration policy attributes, used for CONNECT
> > +    attributes:
> > +      -
> > +        name: unspec
> > +        value: 0
> > +        type: unused
> 
> No need for unspec in the attribute list, ynl codegen does the right
> thing.

For me `pyynl.ynl_gen_c --mode uapi --header` no longer generates
`NBD_ATTR_UNSPEC` if I remove this. Is there a YNL property to specify
the name of the zero value of the attribute set? If not, should I
remove it anyway, changing the generated header?

> > +    name: device-item-attrs
> > +    name-prefix: nbd-device-item-
> > +    doc: |
> > +      This is the format for multiple devices with
> > :code:`NBD_ATTR_DEVICE_LIST`
> > +
> > +      .. code-block::
> > +
> > +        [NBD_ATTR_DEVICE_LIST]
> > +          [NBD_DEVICE_ITEM]
> > +            [NBD_DEVICE_INDEX]
> > +            [NBD_DEVICE_CONNECTED]
> > +    attributes:
> > +      -
> > +        name: unspec
> > +        value: 0
> > +        type: unused
> 
> Not required.

The same question applies here.

> > +    name: device-attrs
> > +    name-prefix: nbd-device-
> > +    attr-max-name: nbd-device-attr-max
> > +    attributes:
> > +      -
> > +        name: unspec
> > +        value: 0
> > +        type: unused
> 
> Not required.

The same question applies here.

> > +    name: sock-item-attrs
> > +    name-prefix: nbd-sock-item-
> > +    doc: |
> > +      This is the format for multiple sockets with
> > :code:`NBD_ATTR_SOCKETS`
> > +
> > +      .. code-block::
> > +
> > +        [NBD_ATTR_SOCKETS]
> > +          [NBD_SOCK_ITEM]
> > +            [NBD_SOCK_FD]
> > +          [NBD_SOCK_ITEM]
> > +            [NBD_SOCK_FD]
> > +    attributes:
> > +      -
> > +        name: unspec
> > +        value: 0
> > +        type: unused
> 
> Not required.

The same question applies here.

> > +    name: sock-attrs
> > +    name-prefix: nbd-sock-
> > +    attributes:
> > +      -
> > +        name: unspec
> > +        value: 0
> > +        type: unused
> 
> Not required.

The same question applies here.

> > +operations:
> > +  enum-model: unified
> > +  name-prefix: nbd-cmd-
> > +  list:
> > +    -
> > +      name: unspec
> > +      value: 0
> > +      doc: NBD_CMD_UNSPEC

A similar question applies here. If I remove this, `pyynl.ynl_gen_c
--mode uapi --header` no longer generates `NBD_CMD_UNSPEC`. Is there a
YNL property to generate it? If not, should I remove it anyway?

> > +    -
> > +      name: connect
> > +      doc: See :file:`drivers/block/nbd.c`,
> > :code:`nbd_genl_connect()`
> 
> Prefer to see meaningful doc string (same for other ops)

I guess I will have to document the four operations in v2 as well.

> > +      attribute-set: nbd-attrs
> > +      dont-validate: [strict]
>
> nbd.c has strict & dump, should this be [strict, dump] ? (same for
> other ops)

The NBD operations don't have `dump`, only `do`, so adding `dump` to
`dont-validate` does not change the output of `pyynl.ynl_gen_c --mode
kernel --source`. Should I add it anyway?