[PATCH] iio:light:tsl2563: Replace cancel_delayed_work() with cancel_delayed_work_sync().

[PATCH] iio:light:tsl2563: Replace cancel_delayed_work() with cancel_delayed_work_sync().

[Tetsuo Handa]

Since cancel_delayed_work(&chip->poweroff_work) does not guarantee that
tsl2563_poweroff_work() is not running, tsl2563_set_power(chip, 0) can be
called from tsl2563_poweroff_work() after tsl2563_get_power(chip) and
tsl2563_set_power(chip, 1) are called. Use _sync version in order to make
sure that tsl2563_poweroff_work() is no longer running.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
---
 drivers/iio/light/tsl2563.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/light/tsl2563.c b/drivers/iio/light/tsl2563.c
index 4d89ac3a5bbc..bbb577459fb9 100644
--- a/drivers/iio/light/tsl2563.c
+++ b/drivers/iio/light/tsl2563.c
@@ -310,7 +310,7 @@ static int tsl2563_get_adc(struct tsl2563_chip *chip)
 		goto out;
 
 	if (!chip->int_enabled) {
-		cancel_delayed_work(&chip->poweroff_work);
+		cancel_delayed_work_sync(&chip->poweroff_work);
 
 		if (!tsl2563_get_power(chip)) {
 			ret = tsl2563_set_power(chip, 1);
@@ -638,7 +638,7 @@ static int tsl2563_write_interrupt_config(struct iio_dev *indio_dev,
 		chip->intr &= ~0x30;
 		chip->intr |= 0x10;
 		/* ensure the chip is actually on */
-		cancel_delayed_work(&chip->poweroff_work);
+		cancel_delayed_work_sync(&chip->poweroff_work);
 		if (!tsl2563_get_power(chip)) {
 			ret = tsl2563_set_power(chip, 1);
 			if (ret)
-- 
2.18.4

Re: [PATCH] iio:light:tsl2563: Replace cancel_delayed_work() with cancel_delayed_work_sync().

[Jonathan Cameron]

On Mon, 13 Jun 2022 00:04:00 +0900
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> wrote:

> Since cancel_delayed_work(&chip->poweroff_work) does not guarantee that
> tsl2563_poweroff_work() is not running, tsl2563_set_power(chip, 0) can be
> called from tsl2563_poweroff_work() after tsl2563_get_power(chip) and
> tsl2563_set_power(chip, 1) are called. Use _sync version in order to make
> sure that tsl2563_poweroff_work() is no longer running.
> 
> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Makes sense to me.

Applied to the togreg branch of iio.git.

Technically this may be a fix (at very least it removes some undesirable
behaviour) but I'm not proposing that we should backport it to stable.

Thanks,

Jonathan

> ---
>  drivers/iio/light/tsl2563.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iio/light/tsl2563.c b/drivers/iio/light/tsl2563.c
> index 4d89ac3a5bbc..bbb577459fb9 100644
> --- a/drivers/iio/light/tsl2563.c
> +++ b/drivers/iio/light/tsl2563.c
> @@ -310,7 +310,7 @@ static int tsl2563_get_adc(struct tsl2563_chip *chip)
>  		goto out;
>  
>  	if (!chip->int_enabled) {
> -		cancel_delayed_work(&chip->poweroff_work);
> +		cancel_delayed_work_sync(&chip->poweroff_work);
>  
>  		if (!tsl2563_get_power(chip)) {
>  			ret = tsl2563_set_power(chip, 1);
> @@ -638,7 +638,7 @@ static int tsl2563_write_interrupt_config(struct iio_dev *indio_dev,
>  		chip->intr &= ~0x30;
>  		chip->intr |= 0x10;
>  		/* ensure the chip is actually on */
> -		cancel_delayed_work(&chip->poweroff_work);
> +		cancel_delayed_work_sync(&chip->poweroff_work);
>  		if (!tsl2563_get_power(chip)) {
>  			ret = tsl2563_set_power(chip, 1);
>  			if (ret)