| Message ID | 20220227164357.84742-1-trix@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | iio: adc: mt6360: strengthen return check of mt6360_adc_read_channel | expand |
Le 27/02/2022 à 17:43, trix-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org a écrit : > From: Tom Rix <trix-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> > > Clang static analysis reports this issue > mt6360-adc.c:277:20: warning: Assigned value is > garbage or undefined > data.values[i++] = val; > ^ ~~~ > > val is set by a successful call to m6360_adc_read_channel(). > A negative return is checked but within m6360_adc_read_channel, > a non zero check is done. > Strengthen the check to non zero. Hi, my understanding of m6360_adc_read_channel() is that on success, it returns IIO_VAL_INT (i.e. 1). So, I think that with your patch, we will now always fail because 'ret' is never 0 at this point. CJ > > Signed-off-by: Tom Rix <trix-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> > --- > drivers/iio/adc/mt6360-adc.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/iio/adc/mt6360-adc.c b/drivers/iio/adc/mt6360-adc.c > index 07c0e67683910..9fb6dc305a392 100644 > --- a/drivers/iio/adc/mt6360-adc.c > +++ b/drivers/iio/adc/mt6360-adc.c > @@ -269,7 +269,7 @@ static irqreturn_t mt6360_adc_trigger_handler(int irq, void *p) > memset(&data, 0, sizeof(data)); > for_each_set_bit(bit, indio_dev->active_scan_mask, indio_dev->masklength) { > ret = mt6360_adc_read_channel(mad, bit, &val); > - if (ret < 0) { > + if (ret) { > dev_warn(&indio_dev->dev, "Failed to get channel %d conversion val\n", bit); > goto out; > }
On Sun, 27 Feb 2022 18:01:47 +0100 Christophe JAILLET <christophe.jaillet@wanadoo.fr> wrote: > Le 27/02/2022 à 17:43, trix-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org a > écrit : > > From: Tom Rix <trix-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> > > > > Clang static analysis reports this issue > > mt6360-adc.c:277:20: warning: Assigned value is > > garbage or undefined > > data.values[i++] = val; > > ^ ~~~ > > > > val is set by a successful call to m6360_adc_read_channel(). > > A negative return is checked but within m6360_adc_read_channel, > > a non zero check is done. > > Strengthen the check to non zero. > > Hi, my understanding of m6360_adc_read_channel() is that on success, it > returns IIO_VAL_INT (i.e. 1). > > So, I think that with your patch, we will now always fail because 'ret' > is never 0 at this point. Firstly I'm glad you were more awake than me Christophe as I missed that entirely. :( So two ways we could deal with the warning (which is valid given there is no way clang could sensibly tell that all those if (ret) actually mean if (ret < 0). I don't like changing them to if (ret < 0) inside _adc_read_channel() because generally it ends up cleaner to just do if (ret) based handling for regmap calls. So we could just assign a default to val that is never used or we could change that function to return 0 on success and adjust the other call site to return IIO_VAL_INT if there isn't an error. The second one would make the other caller rather messier so I'd suggest just giving val a default and adding a comment saying it's for warning suppression purposes... Jonathan > > CJ > > > > > Signed-off-by: Tom Rix <trix-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> > > --- > > drivers/iio/adc/mt6360-adc.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/iio/adc/mt6360-adc.c b/drivers/iio/adc/mt6360-adc.c > > index 07c0e67683910..9fb6dc305a392 100644 > > --- a/drivers/iio/adc/mt6360-adc.c > > +++ b/drivers/iio/adc/mt6360-adc.c > > @@ -269,7 +269,7 @@ static irqreturn_t mt6360_adc_trigger_handler(int irq, void *p) > > memset(&data, 0, sizeof(data)); > > for_each_set_bit(bit, indio_dev->active_scan_mask, indio_dev->masklength) { > > ret = mt6360_adc_read_channel(mad, bit, &val); > > - if (ret < 0) { > > + if (ret) { > > dev_warn(&indio_dev->dev, "Failed to get channel %d conversion val\n", bit); > > goto out; > > } >
diff --git a/drivers/iio/adc/mt6360-adc.c b/drivers/iio/adc/mt6360-adc.c index 07c0e67683910..9fb6dc305a392 100644 --- a/drivers/iio/adc/mt6360-adc.c +++ b/drivers/iio/adc/mt6360-adc.c @@ -269,7 +269,7 @@ static irqreturn_t mt6360_adc_trigger_handler(int irq, void *p) memset(&data, 0, sizeof(data)); for_each_set_bit(bit, indio_dev->active_scan_mask, indio_dev->masklength) { ret = mt6360_adc_read_channel(mad, bit, &val); - if (ret < 0) { + if (ret) { dev_warn(&indio_dev->dev, "Failed to get channel %d conversion val\n", bit); goto out; }