Re: [PATCH] leds: avoid races with workqueue

[Pavel Machek <pavel-+ZI9xUNit7I@public.gmane.org>]

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On Thu 2019-05-02 21:28:06, Jacek Anaszewski wrote:
> On 5/2/19 9:13 PM, Pavel Machek wrote:
> >Hi!
> >
> >>>>>+++ b/drivers/leds/led-class.c
> >>>>>@@ -57,6 +57,7 @@ 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);
> >>>>
> >>>>Is this really required here? It creates non-uniform brightness
> >>>>setting behavior depending on whether it is set from sysfs or
> >>>>by in-kernel call to led_set_brightness().
> >>>
> >>>This fixes the echo 0 > brightness; echo 1 > brightness. It has to be
> >>>at a place where we can sleep.
> >>>
> >>>If you have better idea, it is welcome, but it would be good to fix
> >>>the bug.
> >>
> >>Currently not, so I applied the patch in this shape.
> >
> >Thanks!
> >
> >This is actually something that makes sense for stable.. perhaps the
> >bots can pick it up.
> 
> I was thinking of it, but finally decided to submit this patch
> to linux-stable when it will prove not having side effects.
> 
> But if you think it is ready for stable then I can add
> relevant "Fixes" tag. Do you think that below will be an appropriate
> base to refer to?
> 
> Fixes 1afcadfcd184 ("leds: core: Use set_brightness_work for the blocking
> op")

Yes, that looks right. If you can add fixes: and cc: stable tags, the
rest should happen automagically.

Thanks!
									Pavel



-- 
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