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authorHans de Goede <hdegoede@redhat.com>2016-11-08 14:38:46 +0100
committerJacek Anaszewski <j.anaszewski@samsung.com>2016-11-22 12:07:05 +0100
commita9c6ce57ec2f136d08141e8220a0ffaca216f7b0 (patch)
treef7a577053e7c3453ae8939d87b903dde4754b2e7 /drivers/leds
parentleds: Add user LED driver for NIC78bx device (diff)
downloadlinux-a9c6ce57ec2f136d08141e8220a0ffaca216f7b0.tar.xz
linux-a9c6ce57ec2f136d08141e8220a0ffaca216f7b0.zip
led: core: Use atomic bit-field for the blink-flags
All the LED_BLINK* flags are accessed read-modify-write from e.g. led_set_brightness and led_blink_set_oneshot while both set_brightness_work and the blink_timer may be running. If these race then the modify step done by one of them may be lost, switch the LED_BLINK* flags to a new atomic work_flags bit-field to avoid this race. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Diffstat (limited to 'drivers/leds')
-rw-r--r--drivers/leds/led-class.c1
-rw-r--r--drivers/leds/led-core.c52
2 files changed, 28 insertions, 25 deletions
diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index d946eb166781..326ee6e925a2 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -204,6 +204,7 @@ int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
dev_warn(parent, "Led %s renamed to %s due to name collision",
led_cdev->name, dev_name(led_cdev->dev));
+ led_cdev->work_flags = 0;
#ifdef CONFIG_LEDS_TRIGGERS
init_rwsem(&led_cdev->trigger_lock);
#endif
diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c
index 3bce44893021..bd6bb4d44f05 100644
--- a/drivers/leds/led-core.c
+++ b/drivers/leds/led-core.c
@@ -53,12 +53,13 @@ static void led_timer_function(unsigned long data)
if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) {
led_set_brightness_nosleep(led_cdev, LED_OFF);
- led_cdev->flags &= ~LED_BLINK_SW;
+ clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
return;
}
- if (led_cdev->flags & LED_BLINK_ONESHOT_STOP) {
- led_cdev->flags &= ~(LED_BLINK_ONESHOT_STOP | LED_BLINK_SW);
+ if (test_and_clear_bit(LED_BLINK_ONESHOT_STOP,
+ &led_cdev->work_flags)) {
+ clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
return;
}
@@ -73,10 +74,9 @@ static void led_timer_function(unsigned long data)
* Do it only if there is no pending blink brightness
* change, to avoid overwriting the new value.
*/
- if (!(led_cdev->flags & LED_BLINK_BRIGHTNESS_CHANGE))
+ if (!test_and_clear_bit(LED_BLINK_BRIGHTNESS_CHANGE,
+ &led_cdev->work_flags))
led_cdev->blink_brightness = brightness;
- else
- led_cdev->flags &= ~LED_BLINK_BRIGHTNESS_CHANGE;
brightness = LED_OFF;
delay = led_cdev->blink_delay_off;
}
@@ -87,13 +87,15 @@ static void led_timer_function(unsigned long data)
* the final blink state so that the led is toggled each delay_on +
* delay_off milliseconds in worst case.
*/
- if (led_cdev->flags & LED_BLINK_ONESHOT) {
- if (led_cdev->flags & LED_BLINK_INVERT) {
+ if (test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags)) {
+ if (test_bit(LED_BLINK_INVERT, &led_cdev->work_flags)) {
if (brightness)
- led_cdev->flags |= LED_BLINK_ONESHOT_STOP;
+ set_bit(LED_BLINK_ONESHOT_STOP,
+ &led_cdev->work_flags);
} else {
if (!brightness)
- led_cdev->flags |= LED_BLINK_ONESHOT_STOP;
+ set_bit(LED_BLINK_ONESHOT_STOP,
+ &led_cdev->work_flags);
}
}
@@ -106,10 +108,9 @@ static void set_brightness_delayed(struct work_struct *ws)
container_of(ws, struct led_classdev, set_brightness_work);
int ret = 0;
- if (led_cdev->flags & LED_BLINK_DISABLE) {
+ if (test_and_clear_bit(LED_BLINK_DISABLE, &led_cdev->work_flags)) {
led_cdev->delayed_set_value = LED_OFF;
led_stop_software_blink(led_cdev);
- led_cdev->flags &= ~LED_BLINK_DISABLE;
}
ret = __led_set_brightness(led_cdev, led_cdev->delayed_set_value);
@@ -152,7 +153,7 @@ static void led_set_software_blink(struct led_classdev *led_cdev,
return;
}
- led_cdev->flags |= LED_BLINK_SW;
+ set_bit(LED_BLINK_SW, &led_cdev->work_flags);
mod_timer(&led_cdev->blink_timer, jiffies + 1);
}
@@ -161,7 +162,7 @@ static void led_blink_setup(struct led_classdev *led_cdev,
unsigned long *delay_on,
unsigned long *delay_off)
{
- if (!(led_cdev->flags & LED_BLINK_ONESHOT) &&
+ if (!test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags) &&
led_cdev->blink_set &&
!led_cdev->blink_set(led_cdev, delay_on, delay_off))
return;
@@ -188,8 +189,8 @@ void led_blink_set(struct led_classdev *led_cdev,
{
del_timer_sync(&led_cdev->blink_timer);
- led_cdev->flags &= ~LED_BLINK_ONESHOT;
- led_cdev->flags &= ~LED_BLINK_ONESHOT_STOP;
+ clear_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags);
+ clear_bit(LED_BLINK_ONESHOT_STOP, &led_cdev->work_flags);
led_blink_setup(led_cdev, delay_on, delay_off);
}
@@ -200,17 +201,17 @@ void led_blink_set_oneshot(struct led_classdev *led_cdev,
unsigned long *delay_off,
int invert)
{
- if ((led_cdev->flags & LED_BLINK_ONESHOT) &&
+ if (test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags) &&
timer_pending(&led_cdev->blink_timer))
return;
- led_cdev->flags |= LED_BLINK_ONESHOT;
- led_cdev->flags &= ~LED_BLINK_ONESHOT_STOP;
+ set_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags);
+ clear_bit(LED_BLINK_ONESHOT_STOP, &led_cdev->work_flags);
if (invert)
- led_cdev->flags |= LED_BLINK_INVERT;
+ set_bit(LED_BLINK_INVERT, &led_cdev->work_flags);
else
- led_cdev->flags &= ~LED_BLINK_INVERT;
+ clear_bit(LED_BLINK_INVERT, &led_cdev->work_flags);
led_blink_setup(led_cdev, delay_on, delay_off);
}
@@ -221,7 +222,7 @@ void led_stop_software_blink(struct led_classdev *led_cdev)
del_timer_sync(&led_cdev->blink_timer);
led_cdev->blink_delay_on = 0;
led_cdev->blink_delay_off = 0;
- led_cdev->flags &= ~LED_BLINK_SW;
+ clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
}
EXPORT_SYMBOL_GPL(led_stop_software_blink);
@@ -232,17 +233,18 @@ void led_set_brightness(struct led_classdev *led_cdev,
* If software blink is active, delay brightness setting
* until the next timer tick.
*/
- if (led_cdev->flags & LED_BLINK_SW) {
+ if (test_bit(LED_BLINK_SW, &led_cdev->work_flags)) {
/*
* If we need to disable soft blinking delegate this to the
* work queue task to avoid problems in case we are called
* from hard irq context.
*/
if (brightness == LED_OFF) {
- led_cdev->flags |= LED_BLINK_DISABLE;
+ set_bit(LED_BLINK_DISABLE, &led_cdev->work_flags);
schedule_work(&led_cdev->set_brightness_work);
} else {
- led_cdev->flags |= LED_BLINK_BRIGHTNESS_CHANGE;
+ set_bit(LED_BLINK_BRIGHTNESS_CHANGE,
+ &led_cdev->work_flags);
led_cdev->blink_brightness = brightness;
}
return;