[PATCH v2] leds: trigger: netdev: skip setting baseline state in activate if hw-controlled

[PATCH v2] leds: trigger: netdev: skip setting baseline state in activate if hw-controlled

[Heiner Kallweit]

The current codes uses the sw_control path in set_baseline_state() when
called from netdev_trig_activate() even if we're hw-controlled. This
may result in errors when led_set_brightness() is called because we may
not have set_brightness led ops (if hw doesn't support setting a LED
to ON). In addition this path may schedule trigger_data->work what
doesn't make sense when being hw-controlled.

Therefore set trigger_data->hw_control = true before calling
set_device_name() from netdev_trig_activate(). In this call chain we
have to prevent set_baseline_state() from being called, because this
would call hw_control_set(). Use led_cdev->trigger_data == NULL as
indicator for being called from netdev_trig_activate().

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
v2:
- improve commit message
---
 drivers/leds/trigger/ledtrig-netdev.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/leds/trigger/ledtrig-netdev.c b/drivers/leds/trigger/ledtrig-netdev.c
index 7ed2d0b64..b58396600 100644
--- a/drivers/leds/trigger/ledtrig-netdev.c
+++ b/drivers/leds/trigger/ledtrig-netdev.c
@@ -251,7 +251,11 @@ static int set_device_name(struct led_netdev_data *trigger_data,
 
 	trigger_data->last_activity = 0;
 
-	set_baseline_state(trigger_data);
+	/* skip if we're called from netdev_trig_activate() and hw_control is true */
+	if (!trigger_data->hw_control ||
+	    led_get_trigger_data(trigger_data->led_cdev))
+		set_baseline_state(trigger_data);
+
 	mutex_unlock(&trigger_data->lock);
 	rtnl_unlock();
 
@@ -568,8 +572,8 @@ static int netdev_trig_activate(struct led_classdev *led_cdev)
 		if (dev) {
 			const char *name = dev_name(dev);
 
-			set_device_name(trigger_data, name, strlen(name));
 			trigger_data->hw_control = true;
+			set_device_name(trigger_data, name, strlen(name));
 
 			rc = led_cdev->hw_control_get(led_cdev, &mode);
 			if (!rc)
-- 
2.43.0

Re: [PATCH v2] leds: trigger: netdev: skip setting baseline state in activate if hw-controlled

[Lee Jones]

On Mon, 18 Dec 2023, Heiner Kallweit wrote:

> The current codes uses the sw_control path in set_baseline_state() when
> called from netdev_trig_activate() even if we're hw-controlled. This
> may result in errors when led_set_brightness() is called because we may
> not have set_brightness led ops (if hw doesn't support setting a LED

"LED"

> to ON). In addition this path may schedule trigger_data->work what

s/what/which/

> doesn't make sense when being hw-controlled.
> 
> Therefore set trigger_data->hw_control = true before calling
> set_device_name() from netdev_trig_activate(). In this call chain we
> have to prevent set_baseline_state() from being called, because this
> would call hw_control_set(). Use led_cdev->trigger_data == NULL as
> indicator for being called from netdev_trig_activate().
> 
> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
> ---
> v2:
> - improve commit message
> ---
>  drivers/leds/trigger/ledtrig-netdev.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/leds/trigger/ledtrig-netdev.c b/drivers/leds/trigger/ledtrig-netdev.c
> index 7ed2d0b64..b58396600 100644
> --- a/drivers/leds/trigger/ledtrig-netdev.c
> +++ b/drivers/leds/trigger/ledtrig-netdev.c
> @@ -251,7 +251,11 @@ static int set_device_name(struct led_netdev_data *trigger_data,
>  
>  	trigger_data->last_activity = 0;
>  
> -	set_baseline_state(trigger_data);
> +	/* skip if we're called from netdev_trig_activate() and hw_control is true */

Nit: Sentences start with an uppercase char.

> +	if (!trigger_data->hw_control ||
> +	    led_get_trigger_data(trigger_data->led_cdev))

Nit: Place this all on a single line.

> +		set_baseline_state(trigger_data);
> +
>  	mutex_unlock(&trigger_data->lock);
>  	rtnl_unlock();
>  
> @@ -568,8 +572,8 @@ static int netdev_trig_activate(struct led_classdev *led_cdev)
>  		if (dev) {
>  			const char *name = dev_name(dev);
>  
> -			set_device_name(trigger_data, name, strlen(name));
>  			trigger_data->hw_control = true;
> +			set_device_name(trigger_data, name, strlen(name));
>  
>  			rc = led_cdev->hw_control_get(led_cdev, &mode);
>  			if (!rc)
> -- 
> 2.43.0
> 
> 

-- 
Lee Jones [李琼斯]