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Date:   Fri, 12 May 2023 10:52:38 +0300
From:   Matti Vaittinen <mazziesaccount@gmail.com>
To:     Matti Vaittinen <mazziesaccount@gmail.com>,
        Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Cc:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Daniel Scally <djrscally@gmail.com>,
        Heikki Krogerus <heikki.krogerus@linux.intel.com>,
        Sakari Ailus <sakari.ailus@linux.intel.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Wolfram Sang <wsa@kernel.org>,
        Matti Vaittinen <mazziesaccount@gmail.com>,
        Jonathan Cameron <jic23@kernel.org>,
        Lars-Peter Clausen <lars@metafoo.de>,
        Akhil R <akhilrajeev@nvidia.com>, linux-acpi@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-i2c@vger.kernel.org,
        linux-iio@vger.kernel.org
Subject: [PATCH v3 0/3] fix fwnode_irq_get_byname() returnvalue
Message-ID: <cover.1683875389.git.mazziesaccount@gmail.com>
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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)
{
=2E..
	ret =3D fwnode_irq_get_byname(...);
	if (ret < 0)
		return ret;
=2E..
}

or

int probe(foo)
{
=2E..
	ret =3D fwnode_irq_get_byname(...);
	if (ret <=3D 0)
		return ret;
=2E..
}

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 (v6.4-rc1):

drivers/i2c/i2c-smbus.c
drivers/iio/accel/adxl355_core.c
drivers/iio/accel/kionix-kx022a.c
drivers/iio/adc/ad4130.c
drivers/iio/adc/max11410.c
drivers/iio/addac/ad74115.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 and kionix-kx022a.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.

---

Matti Vaittinen (3):
  drivers: fwnode: fix fwnode_irq_get_byname()
  i2c: i2c-smbus: fwnode_irq_get_byname() return value fix
  iio: kx022a fix irq getting

 drivers/base/property.c           | 9 +++++++--
 drivers/i2c/i2c-smbus.c           | 2 +-
 drivers/iio/accel/kionix-kx022a.c | 2 +-
 3 files changed, 9 insertions(+), 4 deletions(-)


base-commit: ac9a78681b921877518763ba0e89202254349d1b
--=20
2.40.1


--=20
Matti Vaittinen, Linux device drivers
ROHM Semiconductors, Finland SWDC
Kiviharjunlenkki 1E
90220 OULU
FINLAND

~~~ "I don't think so," said Rene Descartes. Just then he vanished ~~~
Simon says - in Latin please.
~~~ "non cogito me" dixit Rene Descarte, deinde evanescavit ~~~
Thanks to Simon Glass for the translation =3D]=20

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