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[v4,0/7] fix fwnode_irq_get[_byname()] returnvalue

Message ID cover.1684220962.git.mazziesaccount@gmail.com
Headers show
Series fix fwnode_irq_get[_byname()] returnvalue | expand

Message

Matti Vaittinen May 16, 2023, 7:12 a.m. UTC
The fwnode_irq_get() and the fwnode_irq_get_byname() may have returned
zero if mapping the IRQ fails. This contradicts the
fwnode_irq_get_byname() 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() and the fwnode_irq_get_byname() to
always return a negative errno upon failure.

I have audited following callers (v6.4-rc2):

fwnode_irq_get_byname():
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

fwnode_irq_get():
drivers/gpio/gpio-dwapb.c
drivers/iio/chemical/scd30_serial.c
drivers/iio/proximity/mb1232.c
drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
drivers/net/mdio/fwnode_mdio.c
drivers/pinctrl/pinctrl-ingenic.c
drivers/pinctrl/pinctrl-microchip-sgpio.c
drivers/pinctrl/pinctrl-pistachio.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.

NOTES:

Changes are compile-tested only.

drivers/pinctrl/nuvoton/pinctrl-wpcm450.c
will also gain a functional change. The pinctrl-wpcm450.c change is easy
to see - after this series the device-tree mapping failures will be
handled as any other errors - probe will be aborted with -EINVAL. Other
feasible option could be treating other errors in IRQ getting same way
as the DT mapping failures - just silently skip the IRQ. Please see
comment in the respective patch.

drivers/iio/cdc/ad7150.c
will gain functional change as well. Here the logic is less
straightforward but boils down to the same question as with the
pinctrl-wpcm450.c. Should all the IRQ getting errors jump to same
'no-IRQ' branch as the DT mapping error, or should the DT mapping error
abort the probe with error same way as other IRQ getting failures do?

Revision history:
v3 => v4:
 - Change also the fwnode_irq_get() as was suggested by Jonathan.
Changelog v2 => v3:
 - rebase/resend/add kx022a fix.
Changelog v1 => v2:
 - minor styling

---


Matti Vaittinen (7):
  drivers: fwnode: fix fwnode_irq_get[_byname]()
  iio: mb1232: relax return value check for IRQ get
  net-next: mb1232: relax return value check for IRQ get
  pinctrl: wpcm450: elax return value check for IRQ get
  pinctrl: ingenic: relax return value check for IRQ get
  pinctrl: pistachio: relax return value check for IRQ get
  iio: cdc: ad7150: Functional change

 drivers/base/property.c                         | 12 +++++++++---
 drivers/iio/cdc/ad7150.c                        |  3 +--
 drivers/iio/proximity/mb1232.c                  |  4 ++--
 drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c |  4 ++--
 drivers/pinctrl/nuvoton/pinctrl-wpcm450.c       |  2 --
 drivers/pinctrl/pinctrl-ingenic.c               |  2 --
 drivers/pinctrl/pinctrl-pistachio.c             |  6 ------
 7 files changed, 14 insertions(+), 19 deletions(-)


base-commit: f1fcbaa18b28dec10281551dfe6ed3a3ed80e3d6

Comments

Paul Cercueil May 16, 2023, 7:49 a.m. UTC | #1
Hi Matti,

Le mardi 16 mai 2023 à 10:13 +0300, Matti Vaittinen a écrit :
> fwnode_irq_get[_byname]() were changed to not return 0 anymore.
> 
> Drop check for return value 0.
> 
> Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>

Reviewed-by: Paul Cercueil <paul@crapouillou.net>

Cheers,
-Paul

> 
> ---
> 
> The first patch of the series changes the fwnode_irq_get() so this
> depends
> on the first patch of the series and should not be applied alone.
> ---
>  drivers/pinctrl/pinctrl-ingenic.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/drivers/pinctrl/pinctrl-ingenic.c
> b/drivers/pinctrl/pinctrl-ingenic.c
> index 2f220a47b749..86e71ad703a5 100644
> --- a/drivers/pinctrl/pinctrl-ingenic.c
> +++ b/drivers/pinctrl/pinctrl-ingenic.c
> @@ -4201,8 +4201,6 @@ static int __init ingenic_gpio_probe(struct
> ingenic_pinctrl *jzpc,
>         err = fwnode_irq_get(fwnode, 0);
>         if (err < 0)
>                 return err;
> -       if (!err)
> -               return -EINVAL;
>         jzgc->irq = err;
>  
>         girq = &jzgc->gc.irq;
> -- 
> 2.40.1
> 
>
Matti Vaittinen May 17, 2023, 1:09 p.m. UTC | #2
On 5/17/23 15:43, Linus Walleij wrote:
> On Tue, May 16, 2023 at 9:12 AM Matti Vaittinen
> <mazziesaccount@gmail.com> wrote:
> 
>> The fwnode_irq_get() and the fwnode_irq_get_byname() may have returned
>> zero if mapping the IRQ fails. This contradicts the
>> fwnode_irq_get_byname() documentation. Furthermore, returning zero or
>> errno on error is unepected and can easily lead to problems
>> like:
> 
> Also, zero is not really a valid IRQ, it means NO_IRQ:
> https://lwn.net/Articles/470820/
> 
> I'll apply the pinctrl patches.

Thanks Linus. I guess you noticed but please wait until the patch 1/7 
gets in as the pinctrl patches won't do "the right thing" without it. 
(Just ensuring we are on a same page ;) )

Yours,
	-- Matti