Re: [PATCH] qapi: net/tap: deprecate vhostforce option

[Markus Armbruster <armbru@redhat.com>]

Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> writes:

> This option simply duplicates the @vhost option since long ago
> (10 years!)
> commit 1e7398a140f7a6 ("vhost: enable vhost without without MSI-X").

This isn't obvious to me.

As far as I can see, their only use is in net_init_tap_one():

    if (tap->has_vhost ? tap->vhost :
        vhostfdname || (tap->has_vhostforce && tap->vhostforce)) {

Can you take this apart for me?

> Let's finally deprecate it.
>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
> ---
>  docs/about/deprecated.rst | 7 +++++++
>  qapi/net.json             | 6 +++++-
>  2 files changed, 12 insertions(+), 1 deletion(-)
>
> diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst
> index d50645a071..d14cb37480 100644
> --- a/docs/about/deprecated.rst
> +++ b/docs/about/deprecated.rst
> @@ -516,6 +516,13 @@ Stream ``reconnect`` (since 9.2)
>  The ``reconnect`` option only allows specifying second granularity timeouts,
>  which is not enough for all types of use cases, use ``reconnect-ms`` instead.
>  
> +TAP ``vhostforce`` (since 10.2)
> +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> +
> +The ``vhostforce`` option just duplicates the main ``vhost`` option.
> +Use ``vhost`` alone.

Would "Use instead ``vhost`` instead" be clearer?

> +
> +
>  VFIO device options
>  '''''''''''''''''''
>  
> diff --git a/qapi/net.json b/qapi/net.json
> index 78bcc9871e..d1216bb60a 100644
> --- a/qapi/net.json
> +++ b/qapi/net.json
> @@ -353,6 +353,10 @@
>  # @poll-us: maximum number of microseconds that could be spent on busy
>  #     polling for tap (since 2.7)
>  #
> +# Features:
> +#
> +# @deprecated: Member @vhostforce is deprecated.  Simply use @vhost.

@deprecated text is commonly of the form "FOO is deprecated.  Use BAR
instead."

Recommend "Use @vhost instead."

> +#
>  # Since: 1.2
>  ##
>  { 'struct': 'NetdevTapOptions',
> @@ -369,7 +373,7 @@
>      '*vhost':      'bool',
>      '*vhostfd':    'str',
>      '*vhostfds':   'str',
> -    '*vhostforce': 'bool',
> +    '*vhostforce': { 'type': 'bool', 'features': [ 'deprecated' ] },
>      '*queues':     'uint32',
>      '*poll-us':    'uint32'} }