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

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Date: Wed, 08 May 2024 10:37:54 +0200
From: Christoph Fritz <christoph.fritz@...dev.de>
To: Simon Horman <horms@...nel.org>
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 Sat, 2024-05-04 at 14:13 +0100, Simon Horman wrote:
> 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

IS_ERR_OR_NULL() gets IS_ERR() in upcoming v4

Thanks
  -- Christoph

> 
> > +		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;
> > +}
> 
> ...