Hello Lee! What are the next steps? Should I make any changes, or are we waiting for test results from the mailing list members? Sorry for the ping. On Wed, Sep 04, 2024 at 01:39:30AM +0300, Dmitry Rokosov wrote: > This allows to setup ordered workqueue for leds events. This may be > useful, because default 'system_wq' does not guarantee execution order > of each work_struct, thus for several brightness update requests (for > multiple leds), real brightness switch could be in random order. > > Yes, for sysfs-based leds we have flush_work() call inside > brightness_store() operation, but it's blocking call, so userspace > caller can be blocked at a long time, which means leds animation stream > can be broken. > > Ordered workqueue has the same behaviour as system_wq + flush_work(), > but all scheduled works are async and userspace caller is not blocked, > which it better for userspace animation scheduling. > > Signed-off-by: Alexey Romanov <avromanov@xxxxxxxxxxxxxxxxx> > Signed-off-by: Dmitry Rokosov <ddrokosov@xxxxxxxxxxxxxxxxx> > --- > Changes v2 since v1 at [1]: > - replace "leds" with "LEDs" in the log message > > Links: > [1] https://lore.kernel.org/all/20240820155407.32729-1-ddrokosov@xxxxxxxxxxxxxxxxx/ > --- > drivers/leds/led-class.c | 12 +++++++++++- > drivers/leds/led-core.c | 6 +++--- > include/linux/leds.h | 1 + > 3 files changed, 15 insertions(+), 4 deletions(-) > > diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c > index c66d1bead0a4..b5e28ad54f7f 100644 > --- a/drivers/leds/led-class.c > +++ b/drivers/leds/led-class.c > @@ -25,6 +25,8 @@ > static DEFINE_MUTEX(leds_lookup_lock); > static LIST_HEAD(leds_lookup_list); > > +static struct workqueue_struct *leds_wq; > + > static ssize_t brightness_show(struct device *dev, > struct device_attribute *attr, char *buf) > { > @@ -57,7 +59,6 @@ static ssize_t brightness_store(struct device *dev, > if (state == LED_OFF) > led_trigger_remove(led_cdev); > led_set_brightness(led_cdev, state); > - flush_work(&led_cdev->set_brightness_work); > > ret = size; > unlock: > @@ -548,6 +549,8 @@ int led_classdev_register_ext(struct device *parent, > > led_update_brightness(led_cdev); > > + led_cdev->wq = leds_wq; > + > led_init_core(led_cdev); > > #ifdef CONFIG_LEDS_TRIGGERS > @@ -666,12 +669,19 @@ EXPORT_SYMBOL_GPL(devm_led_classdev_unregister); > > static int __init leds_init(void) > { > + leds_wq = alloc_ordered_workqueue("leds", 0); > + if (!leds_wq) { > + pr_err("failed to create LEDs ordered workqueue\n"); > + return -ENOMEM; > + } > + > return class_register(&leds_class); > } > > static void __exit leds_exit(void) > { > class_unregister(&leds_class); > + destroy_workqueue(leds_wq); > } > > subsys_initcall(leds_init); > diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c > index 89c9806cc97f..9769ac49be20 100644 > --- a/drivers/leds/led-core.c > +++ b/drivers/leds/led-core.c > @@ -266,7 +266,7 @@ void led_blink_set_nosleep(struct led_classdev *led_cdev, unsigned long delay_on > led_cdev->delayed_delay_on = delay_on; > led_cdev->delayed_delay_off = delay_off; > set_bit(LED_SET_BLINK, &led_cdev->work_flags); > - schedule_work(&led_cdev->set_brightness_work); > + queue_work(led_cdev->wq, &led_cdev->set_brightness_work); > return; > } > > @@ -297,7 +297,7 @@ void led_set_brightness(struct led_classdev *led_cdev, unsigned int brightness) > */ > if (!brightness) { > set_bit(LED_BLINK_DISABLE, &led_cdev->work_flags); > - schedule_work(&led_cdev->set_brightness_work); > + queue_work(led_cdev->wq, &led_cdev->set_brightness_work); > } else { > set_bit(LED_BLINK_BRIGHTNESS_CHANGE, > &led_cdev->work_flags); > @@ -333,7 +333,7 @@ void led_set_brightness_nopm(struct led_classdev *led_cdev, unsigned int value) > set_bit(LED_SET_BRIGHTNESS_OFF, &led_cdev->work_flags); > } > > - schedule_work(&led_cdev->set_brightness_work); > + queue_work(led_cdev->wq, &led_cdev->set_brightness_work); > } > EXPORT_SYMBOL_GPL(led_set_brightness_nopm); > > diff --git a/include/linux/leds.h b/include/linux/leds.h > index 6300313c46b7..7c9f1cb12ab9 100644 > --- a/include/linux/leds.h > +++ b/include/linux/leds.h > @@ -169,6 +169,7 @@ struct led_classdev { > int new_blink_brightness; > void (*flash_resume)(struct led_classdev *led_cdev); > > + struct workqueue_struct *wq; /* LED workqueue */ > struct work_struct set_brightness_work; > int delayed_set_value; > unsigned long delayed_delay_on; > -- > 2.43.0 > -- Thank you, Dmitry
