On Fri 2020-10-30 12:44:30, Marek Behún wrote:
> Use bit fields members in struct led_netdev_data instead of one mode
> member and set_bit/clear_bit/test_bit functions. These functions are
> suitable for longer or variable length bit arrays.

They also provide atomicity guarantees. If you can explain why this is
safe, we can do this, but it needs _way_ better changelog.

								Pavel

> Signed-off-by: Marek Behún <kabel@kernel.org>
> ---
>  drivers/leds/trigger/ledtrig-netdev.c | 69 ++++++++++++---------------
>  1 file changed, 30 insertions(+), 39 deletions(-)
> 
> diff --git a/drivers/leds/trigger/ledtrig-netdev.c b/drivers/leds/trigger/ledtrig-netdev.c
> index 4f6b73e3b491..8f013b6df4fa 100644
> --- a/drivers/leds/trigger/ledtrig-netdev.c
> +++ b/drivers/leds/trigger/ledtrig-netdev.c
> @@ -49,11 +49,11 @@ struct led_netdev_data {
>  	atomic_t interval;
>  	unsigned int last_activity;
>  
> -	unsigned long mode;
> -#define NETDEV_LED_LINK	0
> -#define NETDEV_LED_TX	1
> -#define NETDEV_LED_RX	2
> -#define NETDEV_LED_MODE_LINKUP	3
> +	unsigned link:1;
> +	unsigned tx:1;
> +	unsigned rx:1;
> +
> +	unsigned linkup:1;
>  };
>  
>  enum netdev_led_attr {
> @@ -73,10 +73,10 @@ static void set_baseline_state(struct led_netdev_data *trigger_data)
>  	if (!led_cdev->blink_brightness)
>  		led_cdev->blink_brightness = led_cdev->max_brightness;
>  
> -	if (!test_bit(NETDEV_LED_MODE_LINKUP, &trigger_data->mode))
> +	if (!trigger_data->linkup)
>  		led_set_brightness(led_cdev, LED_OFF);
>  	else {
> -		if (test_bit(NETDEV_LED_LINK, &trigger_data->mode))
> +		if (trigger_data->link)
>  			led_set_brightness(led_cdev,
>  					   led_cdev->blink_brightness);
>  		else
> @@ -85,8 +85,7 @@ static void set_baseline_state(struct led_netdev_data *trigger_data)
>  		/* If we are looking for RX/TX start periodically
>  		 * checking stats
>  		 */
> -		if (test_bit(NETDEV_LED_TX, &trigger_data->mode) ||
> -		    test_bit(NETDEV_LED_RX, &trigger_data->mode))
> +		if (trigger_data->tx || trigger_data->rx)
>  			schedule_delayed_work(&trigger_data->work, 0);
>  	}
>  }
> @@ -131,10 +130,10 @@ static ssize_t device_name_store(struct device *dev,
>  		trigger_data->net_dev =
>  		    dev_get_by_name(&init_net, trigger_data->device_name);
>  
> -	clear_bit(NETDEV_LED_MODE_LINKUP, &trigger_data->mode);
> +	trigger_data->linkup = 0;
>  	if (trigger_data->net_dev != NULL)
>  		if (netif_carrier_ok(trigger_data->net_dev))
> -			set_bit(NETDEV_LED_MODE_LINKUP, &trigger_data->mode);
> +			trigger_data->linkup = 1;
>  
>  	trigger_data->last_activity = 0;
>  
> @@ -150,23 +149,24 @@ static ssize_t netdev_led_attr_show(struct device *dev, char *buf,
>  	enum netdev_led_attr attr)
>  {
>  	struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev);
> -	int bit;
> +	int val;
>  
>  	switch (attr) {
>  	case NETDEV_ATTR_LINK:
> -		bit = NETDEV_LED_LINK;
> +		val = trigger_data->link;
>  		break;
>  	case NETDEV_ATTR_TX:
> -		bit = NETDEV_LED_TX;
> +		val = trigger_data->tx;
>  		break;
>  	case NETDEV_ATTR_RX:
> -		bit = NETDEV_LED_RX;
> +		val = trigger_data->rx;
>  		break;
>  	default:
> -		return -EINVAL;
> +		/* unreachable */
> +		break;
>  	}
>  
> -	return sprintf(buf, "%u\n", test_bit(bit, &trigger_data->mode));
> +	return sprintf(buf, "%u\n", val);
>  }
>  
>  static ssize_t netdev_led_attr_store(struct device *dev, const char *buf,
> @@ -175,33 +175,28 @@ static ssize_t netdev_led_attr_store(struct device *dev, const char *buf,
>  	struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev);
>  	unsigned long state;
>  	int ret;
> -	int bit;
>  
>  	ret = kstrtoul(buf, 0, &state);
>  	if (ret)
>  		return ret;
>  
> +	cancel_delayed_work_sync(&trigger_data->work);
> +
>  	switch (attr) {
>  	case NETDEV_ATTR_LINK:
> -		bit = NETDEV_LED_LINK;
> +		trigger_data->link = state;
>  		break;
>  	case NETDEV_ATTR_TX:
> -		bit = NETDEV_LED_TX;
> +		trigger_data->tx = state;
>  		break;
>  	case NETDEV_ATTR_RX:
> -		bit = NETDEV_LED_RX;
> +		trigger_data->rx = state;
>  		break;
>  	default:
> -		return -EINVAL;
> +		/* unreachable */
> +		break;
>  	}
>  
> -	cancel_delayed_work_sync(&trigger_data->work);
> -
> -	if (state)
> -		set_bit(bit, &trigger_data->mode);
> -	else
> -		clear_bit(bit, &trigger_data->mode);
> -
>  	set_baseline_state(trigger_data);
>  
>  	return size;
> @@ -315,7 +310,7 @@ static int netdev_trig_notify(struct notifier_block *nb,
>  
>  	spin_lock_bh(&trigger_data->lock);
>  
> -	clear_bit(NETDEV_LED_MODE_LINKUP, &trigger_data->mode);
> +	trigger_data->linkup = 0;
>  	switch (evt) {
>  	case NETDEV_CHANGENAME:
>  	case NETDEV_REGISTER:
> @@ -331,7 +326,7 @@ static int netdev_trig_notify(struct notifier_block *nb,
>  	case NETDEV_UP:
>  	case NETDEV_CHANGE:
>  		if (netif_carrier_ok(dev))
> -			set_bit(NETDEV_LED_MODE_LINKUP, &trigger_data->mode);
> +			trigger_data->linkup = 1;
>  		break;
>  	}
>  
> @@ -360,21 +355,17 @@ static void netdev_trig_work(struct work_struct *work)
>  	}
>  
>  	/* If we are not looking for RX/TX then return  */
> -	if (!test_bit(NETDEV_LED_TX, &trigger_data->mode) &&
> -	    !test_bit(NETDEV_LED_RX, &trigger_data->mode))
> +	if (!trigger_data->tx && !trigger_data->rx)
>  		return;
>  
>  	dev_stats = dev_get_stats(trigger_data->net_dev, &temp);
> -	new_activity =
> -	    (test_bit(NETDEV_LED_TX, &trigger_data->mode) ?
> -		dev_stats->tx_packets : 0) +
> -	    (test_bit(NETDEV_LED_RX, &trigger_data->mode) ?
> -		dev_stats->rx_packets : 0);
> +	new_activity = (trigger_data->tx ? dev_stats->tx_packets : 0) +
> +		       (trigger_data->rx ? dev_stats->rx_packets : 0);
>  
>  	if (trigger_data->last_activity != new_activity) {
>  		led_stop_software_blink(trigger_data->led_cdev);
>  
> -		invert = test_bit(NETDEV_LED_LINK, &trigger_data->mode);
> +		invert = trigger_data->link;
>  		interval = jiffies_to_msecs(
>  				atomic_read(&trigger_data->interval));
>  		/* base state is ON (link present) */
> -- 
> 2.26.2

-- 
http://www.livejournal.com/~pavelmachek