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From: Dan Carpenter <dan.carpenter@oracle.com>
To: walter harms <wharms@bfs.de>
Cc: Jonathan Cameron <jic23@kernel.org>,
	Grant Likely <grant.likely@linaro.org>,
	Rob Herring <robh+dt@kernel.org>, Josh Wu <josh.wu@atmel.com>,
	Alexandre Belloni <alexandre.belloni@free-electrons.com>,
	Nicolas Ferre <nicolas.ferre@atmel.com>,
	Maxime Ripard <maxime.ripard@free-electrons.com>,
	Lars-Peter Clausen <lars@metafoo.de>,
	Thomas Meyer <thomas@m3y3r.de>,
	Wei Yongjun <yongjun_wei@trendmicro.com.cn>,
	Sachin Kamat <sachin.kamat@linaro.org>,
	linux-iio@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: Re: [patch] iio: adc: at91: signedness bug in at91_adc_get_trigger_value_by_name()
Date: Wed, 11 Jun 2014 08:12:21 +0000	[thread overview]
Message-ID: <20140611081220.GP5500@mwanda> (raw)
In-Reply-To: <53980711.5030604@bfs.de>

On Wed, Jun 11, 2014 at 09:36:49AM +0200, walter harms wrote:
> 
> 
> Am 11.06.2014 08:53, schrieb Dan Carpenter:
> > The function returns a u8 so the -ENOMEM is truncated to a positive
> > value.  The caller tests for zero returns and treats them as an error
> > so I have changed the -ENOMEM to 0.
> > 
> > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> > 
> > diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c
> > index 3b5bacd..5ebe33d 100644
> > --- a/drivers/iio/adc/at91_adc.c
> > +++ b/drivers/iio/adc/at91_adc.c
> > @@ -525,7 +525,7 @@ static u8 at91_adc_get_trigger_value_by_name(struct iio_dev *idev,
> >  				idev->id,
> >  				triggers[i].name);
> >  		if (!name)
> > -			return -ENOMEM;
> > +			return 0;
> >  
> >  		if (strcmp(trigger_name, name) = 0) {
> >  			value = triggers[i].value;
> 
> 
> hi Dan,
> LXR says there is only 1 caller (and he is checking for ENOMON)
                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
No, it's not?  It's checking for zero.

> perhaps it is better to change  the return value to int.

In theory, it's always better to preserve the error code but in real
life, this memory allocation is going to succeed.  I'm not able to
compile this code, and that change is quite a bit more involved, but
I'll send it anyway.

regards,
dan carpenter


WARNING: multiple messages have this Message-ID (diff)
From: Dan Carpenter <dan.carpenter@oracle.com>
To: walter harms <wharms@bfs.de>
Cc: Jonathan Cameron <jic23@kernel.org>,
	Grant Likely <grant.likely@linaro.org>,
	Rob Herring <robh+dt@kernel.org>, Josh Wu <josh.wu@atmel.com>,
	Alexandre Belloni <alexandre.belloni@free-electrons.com>,
	Nicolas Ferre <nicolas.ferre@atmel.com>,
	Maxime Ripard <maxime.ripard@free-electrons.com>,
	Lars-Peter Clausen <lars@metafoo.de>,
	Thomas Meyer <thomas@m3y3r.de>,
	Wei Yongjun <yongjun_wei@trendmicro.com.cn>,
	Sachin Kamat <sachin.kamat@linaro.org>,
	linux-iio@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: Re: [patch] iio: adc: at91: signedness bug in at91_adc_get_trigger_value_by_name()
Date: Wed, 11 Jun 2014 11:12:21 +0300	[thread overview]
Message-ID: <20140611081220.GP5500@mwanda> (raw)
In-Reply-To: <53980711.5030604@bfs.de>

On Wed, Jun 11, 2014 at 09:36:49AM +0200, walter harms wrote:
> 
> 
> Am 11.06.2014 08:53, schrieb Dan Carpenter:
> > The function returns a u8 so the -ENOMEM is truncated to a positive
> > value.  The caller tests for zero returns and treats them as an error
> > so I have changed the -ENOMEM to 0.
> > 
> > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> > 
> > diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c
> > index 3b5bacd..5ebe33d 100644
> > --- a/drivers/iio/adc/at91_adc.c
> > +++ b/drivers/iio/adc/at91_adc.c
> > @@ -525,7 +525,7 @@ static u8 at91_adc_get_trigger_value_by_name(struct iio_dev *idev,
> >  				idev->id,
> >  				triggers[i].name);
> >  		if (!name)
> > -			return -ENOMEM;
> > +			return 0;
> >  
> >  		if (strcmp(trigger_name, name) == 0) {
> >  			value = triggers[i].value;
> 
> 
> hi Dan,
> LXR says there is only 1 caller (and he is checking for ENOMON)
                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
No, it's not?  It's checking for zero.

> perhaps it is better to change  the return value to int.

In theory, it's always better to preserve the error code but in real
life, this memory allocation is going to succeed.  I'm not able to
compile this code, and that change is quite a bit more involved, but
I'll send it anyway.

regards,
dan carpenter


  reply	other threads:[~2014-06-11  8:12 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-06-11  6:53 [patch] iio: adc: at91: signedness bug in at91_adc_get_trigger_value_by_name() Dan Carpenter
2014-06-11  6:53 ` Dan Carpenter
2014-06-11  7:36 ` walter harms
2014-06-11  7:36   ` walter harms
2014-06-11  8:12   ` Dan Carpenter [this message]
2014-06-11  8:12     ` Dan Carpenter
2014-06-11  8:27     ` walter harms
2014-06-11  8:27       ` walter harms
2014-06-11  8:13   ` [patch v2] " Dan Carpenter
2014-06-11  8:13     ` Dan Carpenter
2014-06-11 14:41     ` Alexandre Belloni
2014-06-11 14:41       ` Alexandre Belloni
2014-06-14 14:38       ` Jonathan Cameron
2014-06-14 14:38         ` Jonathan Cameron

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