Re: [PATCH v11] leds: trigger: implement a tty trigger

From: Pavel Machek <pavel@ucw.cz>
To: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-kernel@vger.kernel.org, Johan Hovold <johan@kernel.org>,
	Jacek Anaszewski <jacek.anaszewski@gmail.com>,
	linux-serial@vger.kernel.org, Jiri Slaby <jslaby@suse.com>,
	kernel@pengutronix.de, linux-leds@vger.kernel.org,
	Dan Murphy <dmurphy@ti.com>
Subject: Re: [PATCH v11] leds: trigger: implement a tty trigger
Date: Thu, 18 Feb 2021 14:37:33 +0100	[thread overview]
Message-ID: <20210218133733.GB12948@duo.ucw.cz> (raw)
In-Reply-To: <20210113173018.bq2fkea2o3yp6rf6@pengutronix.de>

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Hi!

Close, but see below:

> +static ssize_t ttyname_store(struct device *dev,
> +			     struct device_attribute *attr, const char *buf,
> +			     size_t size)
> +{
> +	struct ledtrig_tty_data *trigger_data = led_trigger_get_drvdata(dev);
> +	char *ttyname;
> +	ssize_t ret = size;
> +	bool running;
> +
> +	if (size > 0 && buf[size - 1] == '\n')
> +		size -= 1;
> +
> +	if (size) {
> +		ttyname = kmemdup_nul(buf, size, GFP_KERNEL);
> +		if (!ttyname) {
> +			ret = -ENOMEM;
> +			goto out_unlock;

Unlock without a lock:

> +out_unlock:
> +	mutex_unlock(&trigger_data->mutex);
> +
> +	if (ttyname && !running)
> +		ledtrig_tty_restart(trigger_data);
> +
> +	return ret;
> +}

> +
> +		tty = tty_kopen_shared(devno);
> +		if (IS_ERR(tty) || !tty)
> +			/* What to do? retry or abort */
> +			goto out;

Abort would make sense to me.

> +	if (icount.rx != trigger_data->rx ||
> +	    icount.tx != trigger_data->tx) {
> +		led_set_brightness(trigger_data->led_cdev, LED_ON);

Please use _sync version.

Best regards,
								Pavel
-- 
http://www.livejournal.com/~pavelmachek

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