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

From: Simon Horman <horms@kernel.org>
To: Romain Gantois <romain.gantois@bootlin.com>
Cc: davem@davemloft.net, Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Jakub Kicinski <kuba@kernel.org>,
	Eric Dumazet <edumazet@google.com>,
	Paolo Abeni <pabeni@redhat.com>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	devicetree@vger.kernel.org, thomas.petazzoni@bootlin.com,
	Andrew Lunn <andrew@lunn.ch>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Heiner Kallweit <hkallweit1@gmail.com>,
	Russell King <linux@armlinux.org.uk>,
	linux-arm-kernel@lists.infradead.org,
	Vladimir Oltean <vladimir.oltean@nxp.com>,
	Luka Perkov <luka.perkov@sartura.hr>,
	Robert Marko <robert.marko@sartura.hr>,
	Andy Gross <agross@kernel.org>,
	Bjorn Andersson <andersson@kernel.org>,
	Konrad Dybcio <konrad.dybcio@somainline.org>
Subject: Re: [PATCH net-next v3 4/8] net: qualcomm: ipqess: Add Ethtool ops to IPQESS port netdevices
Date: Wed, 15 Nov 2023 18:18:58 +0000	[thread overview]
Message-ID: <20231115181858.GY74656@kernel.org> (raw)
In-Reply-To: <20231114105600.1012056-5-romain.gantois@bootlin.com>

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.

> +	}

...

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