led: core: Fix blink_brightness setting race
authorHans de Goede <hdegoede@redhat.com>
Sun, 23 Oct 2016 19:47:26 +0000 (21:47 +0200)
committerJacek Anaszewski <j.anaszewski@samsung.com>
Tue, 22 Nov 2016 11:07:05 +0000 (12:07 +0100)
commiteb1610b4c273370f491c5e194e5a56e3470d81e8
treeae3eaaea3b20831c561e6897f936da2f1c7652b5
parenta9c6ce57ec2f136d08141e8220a0ffaca216f7b0
led: core: Fix blink_brightness setting race

All 3 of led_timer_func, led_set_brightness and led_set_software_blink
set blink_brightness. If led_timer_func or led_set_software_blink race
with led_set_brightness they may end up overwriting the new
blink_brightness. The new atomic work_flags does not protect against
this as it just protects the flags and not blink_brightness.

This commit introduces a new new_blink_brightness value which gets
set by led_set_brightness and read by led_timer_func on LED on, fixing
this.

Dealing with the new brightness at LED on time, makes the new
brightness apply sooner, which also fixes a led_set_brightness which
happens while a oneshot blink which ends in LED on is running not
getting applied.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>
drivers/leds/led-core.c
include/linux/leds.h