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[PATCH v2] iio: stmpe-adc: Fix wait_for_completion_timeout return value check

Miaoqian Lin posted 1 patch 4 years ago 
drivers/iio/adc/stmpe-adc.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
[PATCH v2] iio: stmpe-adc: Fix wait_for_completion_timeout return value check
Posted by Miaoqian Lin 4 years ago 
wait_for_completion_timeout() returns unsigned long not long.
it returns 0 if timed out, and positive if completed.
The check for <= 0 is ambiguous and should be == 0 here
indicating timeout which is the only error case

Fixes: e813dde6f833 ("iio: stmpe-adc: Use wait_for_completion_timeout")
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
---
changes in v2:
- Fix same issue in stmpe_read_temp.
---
 drivers/iio/adc/stmpe-adc.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/iio/adc/stmpe-adc.c b/drivers/iio/adc/stmpe-adc.c
index d2d405388499..83e0ac4467ca 100644
--- a/drivers/iio/adc/stmpe-adc.c
+++ b/drivers/iio/adc/stmpe-adc.c
@@ -61,7 +61,7 @@ struct stmpe_adc {
 static int stmpe_read_voltage(struct stmpe_adc *info,
 		struct iio_chan_spec const *chan, int *val)
 {
-	long ret;
+	unsigned long ret;
 
 	mutex_lock(&info->lock);
 
@@ -79,7 +79,7 @@ static int stmpe_read_voltage(struct stmpe_adc *info,
 
 	ret = wait_for_completion_timeout(&info->completion, STMPE_ADC_TIMEOUT);
 
-	if (ret <= 0) {
+	if (ret == 0) {
 		stmpe_reg_write(info->stmpe, STMPE_REG_ADC_INT_STA,
 				STMPE_ADC_CH(info->channel));
 		mutex_unlock(&info->lock);
@@ -96,7 +96,7 @@ static int stmpe_read_voltage(struct stmpe_adc *info,
 static int stmpe_read_temp(struct stmpe_adc *info,
 		struct iio_chan_spec const *chan, int *val)
 {
-	long ret;
+	unsigned long ret;
 
 	mutex_lock(&info->lock);
 
@@ -114,7 +114,7 @@ static int stmpe_read_temp(struct stmpe_adc *info,
 
 	ret = wait_for_completion_timeout(&info->completion, STMPE_ADC_TIMEOUT);
 
-	if (ret <= 0) {
+	if (ret == 0) {
 		mutex_unlock(&info->lock);
 		return -ETIMEDOUT;
 	}
-- 
2.17.1
RE: [PATCH v2] iio: stmpe-adc: Fix wait_for_completion_timeout return value check
Posted by Sa, Nuno 4 years ago 

> -----Original Message-----
> From: Miaoqian Lin <linmq006@gmail.com>
> Sent: Tuesday, April 12, 2022 3:56 AM
> To: Jonathan Cameron <jic23@kernel.org>; Lars-Peter Clausen
> <lars@metafoo.de>; Maxime Coquelin
> <mcoquelin.stm32@gmail.com>; Alexandre Torgue
> <alexandre.torgue@foss.st.com>; Kees Cook
> <keescook@chromium.org>; Miaoqian Lin <linmq006@gmail.com>;
> Philippe Schenker <philippe.schenker@toradex.com>; linux-
> iio@vger.kernel.org; linux-stm32@st-md-mailman.stormreply.com;
> linux-arm-kernel@lists.infradead.org; linux-kernel@vger.kernel.org
> Subject: [PATCH v2] iio: stmpe-adc: Fix wait_for_completion_timeout
> return value check
> 
> [External]
> 
> wait_for_completion_timeout() returns unsigned long not long.
> it returns 0 if timed out, and positive if completed.
> The check for <= 0 is ambiguous and should be == 0 here
> indicating timeout which is the only error case
> 
> Fixes: e813dde6f833 ("iio: stmpe-adc: Use
> wait_for_completion_timeout")
> Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
> ---
> changes in v2:
> - Fix same issue in stmpe_read_temp.
> ---

Reviewed-by: Nuno Sá <nuno.sa@analog.com>

(I guess the subject also needs tweaking for the preferred format)

>  drivers/iio/adc/stmpe-adc.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/iio/adc/stmpe-adc.c b/drivers/iio/adc/stmpe-adc.c
> index d2d405388499..83e0ac4467ca 100644
> --- a/drivers/iio/adc/stmpe-adc.c
> +++ b/drivers/iio/adc/stmpe-adc.c
> @@ -61,7 +61,7 @@ struct stmpe_adc {
>  static int stmpe_read_voltage(struct stmpe_adc *info,
>  		struct iio_chan_spec const *chan, int *val)
>  {
> -	long ret;
> +	unsigned long ret;
> 
>  	mutex_lock(&info->lock);
> 
> @@ -79,7 +79,7 @@ static int stmpe_read_voltage(struct stmpe_adc
> *info,
> 
>  	ret = wait_for_completion_timeout(&info->completion,
> STMPE_ADC_TIMEOUT);
> 
> -	if (ret <= 0) {
> +	if (ret == 0) {
>  		stmpe_reg_write(info->stmpe,
> STMPE_REG_ADC_INT_STA,
>  				STMPE_ADC_CH(info->channel));
>  		mutex_unlock(&info->lock);
> @@ -96,7 +96,7 @@ static int stmpe_read_voltage(struct stmpe_adc
> *info,
>  static int stmpe_read_temp(struct stmpe_adc *info,
>  		struct iio_chan_spec const *chan, int *val)
>  {
> -	long ret;
> +	unsigned long ret;
> 
>  	mutex_lock(&info->lock);
> 
> @@ -114,7 +114,7 @@ static int stmpe_read_temp(struct stmpe_adc
> *info,
> 
>  	ret = wait_for_completion_timeout(&info->completion,
> STMPE_ADC_TIMEOUT);
> 
> -	if (ret <= 0) {
> +	if (ret == 0) {
>  		mutex_unlock(&info->lock);
>  		return -ETIMEDOUT;
>  	}
> --
> 2.17.1
[PATCH v3] iio: adc: stmpe-adc: Fix wait_for_completion_timeout return value check
Posted by Miaoqian Lin 4 years ago 
wait_for_completion_timeout() returns unsigned long not long.
it returns 0 if timed out, and positive if completed.
The check for <= 0 is ambiguous and should be == 0 here
indicating timeout which is the only error case

Fixes: e813dde6f833 ("iio: stmpe-adc: Use wait_for_completion_timeout")
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
---
changes in v2:
- Fix same issue in stmpe_read_temp.
---
changes in v3:
- update the patch subject.
---
 drivers/iio/adc/stmpe-adc.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/iio/adc/stmpe-adc.c b/drivers/iio/adc/stmpe-adc.c
index d2d405388499..83e0ac4467ca 100644
--- a/drivers/iio/adc/stmpe-adc.c
+++ b/drivers/iio/adc/stmpe-adc.c
@@ -61,7 +61,7 @@ struct stmpe_adc {
 static int stmpe_read_voltage(struct stmpe_adc *info,
 		struct iio_chan_spec const *chan, int *val)
 {
-	long ret;
+	unsigned long ret;
 
 	mutex_lock(&info->lock);
 
@@ -79,7 +79,7 @@ static int stmpe_read_voltage(struct stmpe_adc *info,
 
 	ret = wait_for_completion_timeout(&info->completion, STMPE_ADC_TIMEOUT);
 
-	if (ret <= 0) {
+	if (ret == 0) {
 		stmpe_reg_write(info->stmpe, STMPE_REG_ADC_INT_STA,
 				STMPE_ADC_CH(info->channel));
 		mutex_unlock(&info->lock);
@@ -96,7 +96,7 @@ static int stmpe_read_voltage(struct stmpe_adc *info,
 static int stmpe_read_temp(struct stmpe_adc *info,
 		struct iio_chan_spec const *chan, int *val)
 {
-	long ret;
+	unsigned long ret;
 
 	mutex_lock(&info->lock);
 
@@ -114,7 +114,7 @@ static int stmpe_read_temp(struct stmpe_adc *info,
 
 	ret = wait_for_completion_timeout(&info->completion, STMPE_ADC_TIMEOUT);
 
-	if (ret <= 0) {
+	if (ret == 0) {
 		mutex_unlock(&info->lock);
 		return -ETIMEDOUT;
 	}
-- 
2.17.1
Re: [PATCH v3] iio: adc: stmpe-adc: Fix wait_for_completion_timeout return value check
Posted by Philippe Schenker 4 years ago 
On Tue, 2022-04-12 at 06:51 +0000, Miaoqian Lin wrote:
> wait_for_completion_timeout() returns unsigned long not long.
> it returns 0 if timed out, and positive if completed.
> The check for <= 0 is ambiguous and should be == 0 here
> indicating timeout which is the only error case
> 
> Fixes: e813dde6f833 ("iio: stmpe-adc: Use
> wait_for_completion_timeout")
> Signed-off-by: Miaoqian Lin <linmq006@gmail.com>

Reviewed-by: Philippe Schenker <philippe.schenker@toradex.com>

> ---
> changes in v2:
> - Fix same issue in stmpe_read_temp.
> ---
> changes in v3:
> - update the patch subject.
> ---
>  drivers/iio/adc/stmpe-adc.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/iio/adc/stmpe-adc.c b/drivers/iio/adc/stmpe-adc.c
> index d2d405388499..83e0ac4467ca 100644
> --- a/drivers/iio/adc/stmpe-adc.c
> +++ b/drivers/iio/adc/stmpe-adc.c
> @@ -61,7 +61,7 @@ struct stmpe_adc {
>  static int stmpe_read_voltage(struct stmpe_adc *info,
>                 struct iio_chan_spec const *chan, int *val)
>  {
> -       long ret;
> +       unsigned long ret;
>  
>         mutex_lock(&info->lock);
>  
> @@ -79,7 +79,7 @@ static int stmpe_read_voltage(struct stmpe_adc
> *info,
>  
>         ret = wait_for_completion_timeout(&info->completion,
> STMPE_ADC_TIMEOUT);
>  
> -       if (ret <= 0) {
> +       if (ret == 0) {
>                 stmpe_reg_write(info->stmpe, STMPE_REG_ADC_INT_STA,
>                                 STMPE_ADC_CH(info->channel));
>                 mutex_unlock(&info->lock);
> @@ -96,7 +96,7 @@ static int stmpe_read_voltage(struct stmpe_adc
> *info,
>  static int stmpe_read_temp(struct stmpe_adc *info,
>                 struct iio_chan_spec const *chan, int *val)
>  {
> -       long ret;
> +       unsigned long ret;
>  
>         mutex_lock(&info->lock);
>  
> @@ -114,7 +114,7 @@ static int stmpe_read_temp(struct stmpe_adc *info,
>  
>         ret = wait_for_completion_timeout(&info->completion,
> STMPE_ADC_TIMEOUT);
>  
> -       if (ret <= 0) {
> +       if (ret == 0) {
>                 mutex_unlock(&info->lock);
>                 return -ETIMEDOUT;
>         }

Patchew 2.1-devel-ea86937

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