Re: [PATCH v2] staging: iio: ad7816: Switch to the gpio descriptor interface

[Dan Carpenter]

On Wed, Oct 17, 2018 at 10:58:23AM -0400, Sasha Levin wrote:
> On Wed, Oct 17, 2018 at 08:17:20PM +0530, Nishad Kamdar wrote:
> > +	chip->rdwr_pin = devm_gpiod_get(&spi_dev->dev, "rdwr", GPIOD_IN);
> > +	if (IS_ERR(chip->rdwr_pin)) {
> > +		ret = PTR_ERR(chip->rdwr_pin);
> > +		dev_err(&spi_dev->dev, "Failed to request rdwr GPIO: %d\n",
> > +			ret);
> > 		return ret;
> > 	}
> > -	gpio_direction_input(chip->rdwr_pin);
> > -	ret = devm_gpio_request(&spi_dev->dev, chip->convert_pin,
> > -				spi_get_device_id(spi_dev)->name);
> > -	if (ret) {
> > -		dev_err(&spi_dev->dev, "Fail to request convert gpio PIN %d.\n",
> > -			chip->convert_pin);
> > +	chip->convert_pin = devm_gpiod_get(&spi_dev->dev, "convert", GPIOD_IN);
> > +	if (IS_ERR(chip->convert_pin)) {
> > +		ret = PTR_ERR(chip->convert_pin);
> > +		dev_err(&spi_dev->dev, "Failed to request convert GPIO: %d\n",
> > +			ret);
> > 		return ret;
> > 	}
> > -	gpio_direction_input(chip->convert_pin);
> > -	ret = devm_gpio_request(&spi_dev->dev, chip->busy_pin,
> > -				spi_get_device_id(spi_dev)->name);
> > -	if (ret) {
> > -		dev_err(&spi_dev->dev, "Fail to request busy gpio PIN %d.\n",
> > -			chip->busy_pin);
> > +	chip->busy_pin = devm_gpiod_get(&spi_dev->dev, "busy", GPIOD_IN);
> > +	if (IS_ERR(chip->busy_pin)) {
> > +		ret = PTR_ERR(chip->busy_pin);
> > +		dev_err(&spi_dev->dev, "Failed to request busy GPIO: %d\n",
> > +			ret);
> > 		return ret;
> > 	}
> 
> Hm, from what I can tell devm_gpio_request() is allocating some memory,
> which makes this a series of 4 allocations.
> 
> What happens if the fourth allocation fails? Do we leak the first three?

These are devm_ allocations.  They are freed when &spi_dev->dev is
released.

regards,
dan carpenter