netdev - Re: [PATCH v2 07/12] can: Add support for serdev LIN adapters

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Message-ID: <20240504131331.GL3167983@kernel.org>
Date: Sat, 4 May 2024 14:13:31 +0100
From: Simon Horman <horms@...nel.org>
To: Christoph Fritz <christoph.fritz@...dev.de>
Cc: Oliver Hartkopp <socketcan@...tkopp.net>,
	Marc Kleine-Budde <mkl@...gutronix.de>,
	Vincent Mailhol <mailhol.vincent@...adoo.fr>,
	"David S . Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>, Jiri Kosina <jikos@...nel.org>,
	Benjamin Tissoires <bentiss@...nel.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Jiri Slaby <jirislaby@...nel.org>,
	Sebastian Reichel <sre@...nel.org>,
	Linus Walleij <linus.walleij@...aro.org>,
	Andreas Lauser <andreas.lauser@...cedes-benz.com>,
	Jonathan Corbet <corbet@....net>,
	Pavel Pisa <pisa@....felk.cvut.cz>, linux-can@...r.kernel.org,
	netdev@...r.kernel.org, devicetree@...r.kernel.org,
	linux-input@...r.kernel.org, linux-serial@...r.kernel.org
Subject: Re: [PATCH v2 07/12] can: Add support for serdev LIN adapters

On Thu, May 02, 2024 at 09:55:29AM +0200, Christoph Fritz wrote:
> This commit introduces LIN-Bus support for UART devices equipped with
> LIN transceivers, utilizing the Serial Device Bus (serdev) interface.
> 
> For more details on an adapter, visit: https://hexdev.de/hexlin#tty
> 
> Signed-off-by: Christoph Fritz <christoph.fritz@...dev.de>

...

> diff --git a/drivers/net/can/lin-serdev.c b/drivers/net/can/lin-serdev.c

...

> +static int linser_probe(struct serdev_device *serdev)
> +{
> +	struct linser_priv *priv;
> +	int ret;
> +
> +	priv = devm_kzalloc(&serdev->dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	ret = kfifo_alloc(&priv->rx_fifo, LINSER_RX_FIFO_SIZE, GFP_KERNEL);
> +	if (ret)
> +		return ret;
> +
> +	INIT_DELAYED_WORK(&priv->rx_work, linser_process_delayed);
> +
> +	priv->serdev = serdev;
> +	serdev_device_set_drvdata(serdev, priv);
> +	serdev_device_set_client_ops(serdev, &linser_ops);
> +
> +	ret = serdev_device_open(serdev);
> +	if (ret) {
> +		dev_err(&serdev->dev, "Unable to open device\n");
> +		goto err_open;
> +	}
> +
> +	serdev_device_set_flow_control(serdev, false);
> +	serdev_device_set_break_detection(serdev, true);
> +	linser_derive_timings(priv, LIN_DEFAULT_BAUDRATE);
> +
> +	mutex_init(&priv->resp_lock);
> +
> +	priv->lin_dev = register_lin(&serdev->dev, &linser_lindev_ops);
> +	if (IS_ERR_OR_NULL(priv->lin_dev)) {
> +		ret = PTR_ERR(priv->lin_dev);

As per my feedback on an earlier patch in the series,
in the case where priv->lin_dev is NULL,
this will result in the function returning 0.
Is that ok?

Flagged by Smatch

> +		goto err_register_lin;
> +	}
> +
> +	serdev_device_close(serdev);
> +	priv->is_stopped = true;
> +
> +	return 0;
> +
> +err_register_lin:
> +	serdev_device_close(serdev);
> +err_open:
> +	kfifo_free(&priv->rx_fifo);
> +	return ret;
> +}

...