Re: [PATCH net-next v2 06/12] net: ethtool: optionally skip rtnl_lock in cable test handlers

[Jacob Keller <jacob.e.keller@intel.com>]

On 6/4/2026 5:29 PM, Jakub Kicinski wrote:
> Skip rtnl_lock in cable test handlers. This is really a noop since
> no ops locked device supports these.
> 

It would stop being a noop if an ops-locked driver ever implemented
these in the future.. but I can guess that even if that happens the
cable test bits don't really need the global RTNL serialization anyways
making this ok.

Makes sense.

Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>

> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> ---
>  net/ethtool/cabletest.c | 12 ++++--------
>  1 file changed, 4 insertions(+), 8 deletions(-)
> 
> diff --git a/net/ethtool/cabletest.c b/net/ethtool/cabletest.c
> index 8d375dac2a40..9c22d4c767c6 100644
> --- a/net/ethtool/cabletest.c
> +++ b/net/ethtool/cabletest.c
> @@ -73,8 +73,7 @@ int ethnl_act_cable_test(struct sk_buff *skb, struct genl_info *info)
>  
>  	dev = req_info.dev;
>  
> -	rtnl_lock();
> -	netdev_lock_ops(dev);
> +	netdev_lock_ops_compat(dev);
>  	phydev = ethnl_req_get_phydev(&req_info, tb,
>  				      ETHTOOL_A_CABLE_TEST_HEADER,
>  				      info->extack);
> @@ -101,8 +100,7 @@ int ethnl_act_cable_test(struct sk_buff *skb, struct genl_info *info)
>  		ethnl_cable_test_started(phydev, ETHTOOL_MSG_CABLE_TEST_NTF);
>  
>  out_unlock:
> -	netdev_unlock_ops(dev);
> -	rtnl_unlock();
> +	netdev_unlock_ops_compat(dev);
>  	ethnl_parse_header_dev_put(&req_info);
>  	return ret;
>  }
> @@ -342,8 +340,7 @@ int ethnl_act_cable_test_tdr(struct sk_buff *skb, struct genl_info *info)
>  	if (ret)
>  		goto out_dev_put;
>  
> -	rtnl_lock();
> -	netdev_lock_ops(dev);
> +	netdev_lock_ops_compat(dev);
>  	phydev = ethnl_req_get_phydev(&req_info, tb,
>  				      ETHTOOL_A_CABLE_TEST_TDR_HEADER,
>  				      info->extack);
> @@ -371,8 +368,7 @@ int ethnl_act_cable_test_tdr(struct sk_buff *skb, struct genl_info *info)
>  					 ETHTOOL_MSG_CABLE_TEST_TDR_NTF);
>  
>  out_unlock:
> -	netdev_unlock_ops(dev);
> -	rtnl_unlock();
> +	netdev_unlock_ops_compat(dev);
>  out_dev_put:
>  	ethnl_parse_header_dev_put(&req_info);
>  	return ret;