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SubjectRe: [PATCH] leds: Add mutex protection in brightness_show()
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Date
Hi,

On 11/09/2016 01:38 PM, Pavel Machek wrote:
> Hi!
>
>> Initially the claim about no need for lock in brightness_show()
>> was valid as the function was just returning unchanged
>> LED brightness. After the addition of led_update_brightness() this
>
> The claim was probably wrong from the day one, unless brightness is of
> type "atomic_t".
>
> /* Ensures consistent access to the LED Flash Class device */
> struct mutex led_access;
> };
>
> This should really list fields that are protected by led_access.

Originally it was introduced to facilitate disabling LED subsystem
sysfs interface, i.e. it protects flags property of
struct led_classdev.

--
Best regards,
Jacek Anaszewski

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