Re: [PATCH net-next] ethtool: add netlink support for rss set

[Jakub Kicinski <kuba@kernel.org>]

On Thu,  9 Mar 2023 14:05:44 -0800 Sudheer Mogilappagari wrote:
> Add netlink based support for "ethtool -X <dev>" command by
> implementing ETHTOOL_MSG_RSS_SET netlink message. This is
> equivalent to functionality provided via ETHTOOL_SRSSH in
> ioctl path. It allows creation and deletion of RSS context
> and modifying RSS table, hash key and hash function of an
> interface.
> 
> Functionality is backward compatible with the one available
> in ioctl path but enables addition of new RSS context based
> parameters in future.

RSS contexts are somewhat under-defined, so I'd prefer to wait
until we actually need to extend the API before going to netlink.
I think I told you as much when you posted initial code for RSS?

> diff --git a/include/uapi/linux/ethtool_netlink.h b/include/uapi/linux/ethtool_netlink.h
> index d39ce21381c5..56c4e8570dc6 100644
> --- a/include/uapi/linux/ethtool_netlink.h
> +++ b/include/uapi/linux/ethtool_netlink.h
> @@ -52,6 +52,7 @@ enum {
>  	ETHTOOL_MSG_PSE_GET,
>  	ETHTOOL_MSG_PSE_SET,
>  	ETHTOOL_MSG_RSS_GET,
> +	ETHTOOL_MSG_RSS_SET,
>  	ETHTOOL_MSG_PLCA_GET_CFG,
>  	ETHTOOL_MSG_PLCA_SET_CFG,
>  	ETHTOOL_MSG_PLCA_GET_STATUS,

You certainly can't add entries half way thru an enum in uAPI..