Re: [PATCH 0/2] fix fwnode_irq_get_byname() returnvalue

[Andy Shevchenko]

On Tue, Oct 25, 2022 at 11:50:24AM +0300, Matti Vaittinen wrote:
> The fix fwnode_irq_get_byname() may have returned zero if mapping the
> IRQ fails. This contradicts the documentation. Furthermore, returning
> zero or errno on error is unepected and can easily lead to problems
> like:
> 
> int probe(foo)
> {
> ...
> 	ret = fwnode_irq_get_byname(...);
> 	if (ret < 0)
> 		return ret;
> ...
> }
> 
> or
> 
> int probe(foo)
> {
> ...
> 	ret = fwnode_irq_get_byname(...);
> 	if (ret <= 0)
> 		return ret;
> ...
> }
> 
> which are both likely to be wrong. First treats zero as successful call and
> misses the IRQ mapping failure. Second returns zero from probe even though
> it detects the IRQ mapping failure correvtly.
> 
> Here we change the fwnode_irq_get_byname() to always return a negative
> errno upon failure. I have also audited following callers:
> 
> drivers/i2c/i2c-smbus.c
> drivers/iio/accel/adxl355_core.c
> drivers/iio/gyro/fxas21002c_core.c
> drivers/iio/imu/adis16480.c
> drivers/iio/imu/bmi160/bmi160_core.c
> drivers/iio/imu/bmi160/bmi160_core.c
> 
> and it seems to me these calls will be Ok after the change. The
> i2c-smbus.c will gain a functional change (bugfix?) as after this patch
> the probe will return -EINVAL should the IRQ mapping fail. The series
> will also adjust the return value check for zero to be omitted.

Thanks for doing this, no major comments except worrying about fwnode_irq_get()
which is left untouched an hence different error domain for the same
family of API.

For these patches:
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>


-- 
With Best Regards,
Andy Shevchenko