Re: [PATCH net-next v6 2/9] net: ethtool: add hds_config member in ethtool_netdev_state

[Jakub Kicinski <kuba@kernel.org>]

On Wed, 18 Dec 2024 14:45:23 +0000 Taehee Yoo wrote:
> When tcp-data-split is UNKNOWN mode, drivers arbitrarily handle it.
> For example, bnxt_en driver automatically enables if at least one of
> LRO/GRO/JUMBO is enabled.
> If tcp-data-split is UNKNOWN and LRO is enabled, a driver returns
> ENABLES of tcp-data-split, not UNKNOWN.
> So, `ethtool -g eth0` shows tcp-data-split is enabled.
> 
> The problem is in the setting situation.
> In the ethnl_set_rings(), it first calls get_ringparam() to get the
> current driver's config.
> At that moment, if driver's tcp-data-split config is UNKNOWN, it returns
> ENABLE if LRO/GRO/JUMBO is enabled.
> Then, it sets values from the user and driver's current config to
> kernel_ethtool_ringparam.
> Last it calls .set_ringparam().
> The driver, especially bnxt_en driver receives
> ETHTOOL_TCP_DATA_SPLIT_ENABLED.
> But it can't distinguish whether it is set by the user or just the
> current config.
> 
> When user updates ring parameter, the new hds_config value is updated
> and current hds_config value is stored to old_hdsconfig.
> Driver's .set_ringparam() callback can distinguish a passed
> tcp-data-split value is came from user explicitly.
> If .set_ringparam() is failed, hds_config is rollbacked immediately.
> 
> Suggested-by: Jakub Kicinski <kuba@kernel.org>
> Signed-off-by: Taehee Yoo <ap420073@gmail.com>

Reviewed-by: Jakub Kicinski <kuba@kernel.org>