Re: [PATCH net-next v3 4/8] net: qualcomm: ipqess: Add Ethtool ops to IPQESS port netdevices

[Simon Horman <horms@kernel.org>]

On Tue, Nov 14, 2023 at 11:55:54AM +0100, Romain Gantois wrote:
> The IPQESS driver registers one netdevice for each front-facing switch
> port. Add support for several ethtool operations to these netdevices.
> 
> Signed-off-by: Romain Gantois <romain.gantois@bootlin.com>

Hi Romain,

some more minor feedback from my side.

> ---
>  drivers/net/ethernet/qualcomm/ipqess/Makefile |   2 +-
>  .../ethernet/qualcomm/ipqess/ipqess_ethtool.c | 245 ++++++++++++++++++
>  .../ethernet/qualcomm/ipqess/ipqess_port.c    |   1 +
>  .../ethernet/qualcomm/ipqess/ipqess_port.h    |   3 +
>  4 files changed, 250 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/net/ethernet/qualcomm/ipqess/ipqess_ethtool.c

...

> diff --git a/drivers/net/ethernet/qualcomm/ipqess/ipqess_ethtool.c b/drivers/net/ethernet/qualcomm/ipqess/ipqess_ethtool.c

...

> +static int ipqess_port_set_eee(struct net_device *dev, struct ethtool_eee *eee)
> +{
> +	struct ipqess_port *port = netdev_priv(dev);
> +	int ret;
> +	u32 lpi_en = QCA8K_REG_EEE_CTRL_LPI_EN(port->index);
> +	struct qca8k_priv *priv = port->sw->priv;
> +	u32 lpi_ctl1;

nit: Please consider using reverse xmas tree - longest line to shortest -
     for local variable declarations in networking code.

> +
> +	/* Port's PHY and MAC both need to be EEE capable */
> +	if (!dev->phydev || !port->pl)
> +		return -ENODEV;
> +
> +	mutex_lock(&priv->reg_mutex);
> +	lpi_ctl1 = qca8k_read(priv, QCA8K_REG_EEE_CTRL, &lpi_ctl1);
> +	if (lpi_ctl1 < 0) {

lpi_ctl1 is unsigned, it can never be less than zero.

As flagged by Smatch and Coccinelle.

I think this should probably be (completely untested!):

	ret = qca8k_read(priv, QCA8K_REG_EEE_CTRL, &lpi_ctl1);
	if (ret < 0) {

Which would also resolve the issue immediately below too.

> +		mutex_unlock(&priv->reg_mutex);
> +		return ret;

It seems that ret is used uninitialised here.

Flagged by clang-16 W=1 builds.

> +	}

...