diff mbox

[3/3] HID: cp2112: fix broken gpio_direction_input callback

Message ID 1509621164-28830-3-git-send-email-sebastien.szymanski@armadeus.com (mailing list archive)
State New, archived
Headers show

Commit Message

Sébastien Szymanski Nov. 2, 2017, 11:12 a.m. UTC
When everything goes smoothly, ret is set to 0 which makes the function
to return EIO error.

Fixes: 8e9faa15469e ("HID: cp2112: fix gpio-callback error handling")
Signed-off-by: Sébastien Szymanski <sebastien.szymanski@armadeus.com>
---
 drivers/hid/hid-cp2112.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

Comments

Benjamin Tissoires Nov. 6, 2017, 8:11 a.m. UTC | #1
On Nov 02 2017 or thereabouts, Sébastien Szymanski wrote:
> When everything goes smoothly, ret is set to 0 which makes the function
> to return EIO error.
> 
> Fixes: 8e9faa15469e ("HID: cp2112: fix gpio-callback error handling")
> Signed-off-by: Sébastien Szymanski <sebastien.szymanski@armadeus.com>
> ---
>  drivers/hid/hid-cp2112.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/hid/hid-cp2112.c b/drivers/hid/hid-cp2112.c
> index 28e3c18..f7754a6 100644
> --- a/drivers/hid/hid-cp2112.c
> +++ b/drivers/hid/hid-cp2112.c
> @@ -205,12 +205,13 @@ static int cp2112_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
>  	ret = hid_hw_raw_request(hdev, CP2112_GPIO_CONFIG, buf,
>  				 CP2112_GPIO_CONFIG_LENGTH, HID_FEATURE_REPORT,
>  				 HID_REQ_SET_REPORT);
> -	if (ret < 0) {
> +	if (ret != CP2112_GPIO_CONFIG_LENGTH) {

Ack for this.

>  		hid_err(hdev, "error setting GPIO config: %d\n", ret);
>  		goto exit;
>  	}
>  
> -	ret = 0;
> +	mutex_unlock(&dev->lock);
> +	return 0;

Wouldn't it be better to just turn
- return ret < 0 ? ret : -EIO;
into
+ return ret <= 0 ? ret : -EIO;
at the end of the function?

I'd rather keep the same exit path in both cases, error or success.

Cheers,
Benjamin


>  
>  exit:
>  	mutex_unlock(&dev->lock);
> -- 
> 2.7.3
> 
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Sébastien Szymanski Nov. 6, 2017, 1:58 p.m. UTC | #2
On 11/06/2017 09:11 AM, Benjamin Tissoires wrote:
> On Nov 02 2017 or thereabouts, Sébastien Szymanski wrote:
>> When everything goes smoothly, ret is set to 0 which makes the function
>> to return EIO error.
>>
>> Fixes: 8e9faa15469e ("HID: cp2112: fix gpio-callback error handling")
>> Signed-off-by: Sébastien Szymanski <sebastien.szymanski@armadeus.com>
>> ---
>>  drivers/hid/hid-cp2112.c | 5 +++--
>>  1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/hid/hid-cp2112.c b/drivers/hid/hid-cp2112.c
>> index 28e3c18..f7754a6 100644
>> --- a/drivers/hid/hid-cp2112.c
>> +++ b/drivers/hid/hid-cp2112.c
>> @@ -205,12 +205,13 @@ static int cp2112_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
>>  	ret = hid_hw_raw_request(hdev, CP2112_GPIO_CONFIG, buf,
>>  				 CP2112_GPIO_CONFIG_LENGTH, HID_FEATURE_REPORT,
>>  				 HID_REQ_SET_REPORT);
>> -	if (ret < 0) {
>> +	if (ret != CP2112_GPIO_CONFIG_LENGTH) {
> 
> Ack for this.

As explained in the interface specification, the device doesn't answer
to set reports, so the transfer should be CP2112_GPIO_CONFIG_LENGTH (5)
bytes.

> 
>>  		hid_err(hdev, "error setting GPIO config: %d\n", ret);
>>  		goto exit;
>>  	}
>>  
>> -	ret = 0;
>> +	mutex_unlock(&dev->lock);
>> +	return 0;
> 
> Wouldn't it be better to just turn
> - return ret < 0 ? ret : -EIO;
> into
> + return ret <= 0 ? ret : -EIO;
> at the end of the function?

Well, the commit I mentioned in the Fixes tag, changes from

- return ret <= 0 ? ret : -EIO;

to

+ return ret < 0 ? ret : -EIO;

because ret being 0 could mean that one of the hid_hw_raw_request
returned 0.

Regards,

> 
> I'd rather keep the same exit path in both cases, error or success.
> 
> Cheers,
> Benjamin
> 
> 
>>  
>>  exit:
>>  	mutex_unlock(&dev->lock);
>> -- 
>> 2.7.3
>>
Benjamin Tissoires Nov. 6, 2017, 5:43 p.m. UTC | #3
On Nov 06 2017 or thereabouts, Sébastien Szymanski wrote:
> On 11/06/2017 09:11 AM, Benjamin Tissoires wrote:
> > On Nov 02 2017 or thereabouts, Sébastien Szymanski wrote:
> >> When everything goes smoothly, ret is set to 0 which makes the function
> >> to return EIO error.
> >>
> >> Fixes: 8e9faa15469e ("HID: cp2112: fix gpio-callback error handling")
> >> Signed-off-by: Sébastien Szymanski <sebastien.szymanski@armadeus.com>
> >> ---
> >>  drivers/hid/hid-cp2112.c | 5 +++--
> >>  1 file changed, 3 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/drivers/hid/hid-cp2112.c b/drivers/hid/hid-cp2112.c
> >> index 28e3c18..f7754a6 100644
> >> --- a/drivers/hid/hid-cp2112.c
> >> +++ b/drivers/hid/hid-cp2112.c
> >> @@ -205,12 +205,13 @@ static int cp2112_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
> >>  	ret = hid_hw_raw_request(hdev, CP2112_GPIO_CONFIG, buf,
> >>  				 CP2112_GPIO_CONFIG_LENGTH, HID_FEATURE_REPORT,
> >>  				 HID_REQ_SET_REPORT);
> >> -	if (ret < 0) {
> >> +	if (ret != CP2112_GPIO_CONFIG_LENGTH) {
> > 
> > Ack for this.
> 
> As explained in the interface specification, the device doesn't answer
> to set reports, so the transfer should be CP2112_GPIO_CONFIG_LENGTH (5)
> bytes.
> 
> > 
> >>  		hid_err(hdev, "error setting GPIO config: %d\n", ret);
> >>  		goto exit;
> >>  	}
> >>  
> >> -	ret = 0;
> >> +	mutex_unlock(&dev->lock);
> >> +	return 0;
> > 
> > Wouldn't it be better to just turn
> > - return ret < 0 ? ret : -EIO;
> > into
> > + return ret <= 0 ? ret : -EIO;
> > at the end of the function?
> 
> Well, the commit I mentioned in the Fixes tag, changes from
> 
> - return ret <= 0 ? ret : -EIO;
> 
> to
> 
> + return ret < 0 ? ret : -EIO;
> 
> because ret being 0 could mean that one of the hid_hw_raw_request
> returned 0.

True.

So, commit 8e9faa15469e basically makes all transfert return -EIO and
should be reverted, right?

IMO, your commit should be:
if (ret != CP2112_GPIO_CONFIG_LENGTH) {
	hid_err(hdev, "error setting GPIO config: %d\n", ret);
	if (ret >= 0)
		ret = -EIO;
	goto exit;
}

ret = 0;
exit:
mutex_unlock(&dev->lock);
return ret;

How does that sound?

Cheers,
Benjamin

> 
> Regards,
> 
> > 
> > I'd rather keep the same exit path in both cases, error or success.
> > 
> > Cheers,
> > Benjamin
> > 
> > 
> >>  
> >>  exit:
> >>  	mutex_unlock(&dev->lock);
> >> -- 
> >> 2.7.3
> >>
> 
> 
> -- 
> Sébastien Szymanski
> Software engineer, Armadeus Systems
> Tel: +33 (0)9 72 29 41 44
> Fax: +33 (0)9 72 28 79 26
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diff mbox

Patch

diff --git a/drivers/hid/hid-cp2112.c b/drivers/hid/hid-cp2112.c
index 28e3c18..f7754a6 100644
--- a/drivers/hid/hid-cp2112.c
+++ b/drivers/hid/hid-cp2112.c
@@ -205,12 +205,13 @@  static int cp2112_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
 	ret = hid_hw_raw_request(hdev, CP2112_GPIO_CONFIG, buf,
 				 CP2112_GPIO_CONFIG_LENGTH, HID_FEATURE_REPORT,
 				 HID_REQ_SET_REPORT);
-	if (ret < 0) {
+	if (ret != CP2112_GPIO_CONFIG_LENGTH) {
 		hid_err(hdev, "error setting GPIO config: %d\n", ret);
 		goto exit;
 	}
 
-	ret = 0;
+	mutex_unlock(&dev->lock);
+	return 0;
 
 exit:
 	mutex_unlock(&dev->lock);