If gpio_set_transitory fails, we should free the gpio again. Most
notably, the flag FLAG_REQUESTED has previously been set in
gpiod_request_commit, and should be reset on failure.
Signed-off-by: Boerge Struempfel <[email protected]>
---
drivers/gpio/gpiolib-sysfs.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c
index 6f309a3b2d9a..12d853845bb8 100644
--- a/drivers/gpio/gpiolib-sysfs.c
+++ b/drivers/gpio/gpiolib-sysfs.c
@@ -474,14 +474,17 @@ static ssize_t export_store(const struct class *class,
goto done;
status = gpiod_set_transitory(desc, false);
- if (!status) {
- status = gpiod_export(desc, true);
- if (status < 0)
- gpiod_free(desc);
- else
- set_bit(FLAG_SYSFS, &desc->flags);
+ if (status) {
+ gpiod_free(desc);
+ goto done;
}
+ status = gpiod_export(desc, true);
+ if (status < 0)
+ gpiod_free(desc);
+ else
+ set_bit(FLAG_SYSFS, &desc->flags);
+
done:
if (status)
pr_debug("%s: status %d\n", __func__, status);
--
2.42.0
On Thu, Nov 23, 2023 at 3:30 PM Boerge Struempfel
<[email protected]> wrote:
>
> If gpio_set_transitory fails, we should free the gpio again. Most
We refer to functions as func() in the text and comments (note parentheses).
GPIO
> notably, the flag FLAG_REQUESTED has previously been set in
> gpiod_request_commit, and should be reset on failure.
Same about func().
...
Seems the correct fix, but you may also add that no existing user is
returning anything except 0 or ENOTSUPP that is converted to 0 in
GPIOLIB core code. Hence no Fixes tag is needed, but still possible if
maintainers want it.
--
With Best Regards,
Andy Shevchenko
Hi Andy
thank you for your feedback
On Thu, Nov 23, 2023 at 3:25 PM Andy Shevchenko
<[email protected]> wrote:
>
> On Thu, Nov 23, 2023 at 3:30 PM Boerge Struempfel
> <[email protected]> wrote:
> >
> > If gpio_set_transitory fails, we should free the gpio again. Most
>
> We refer to functions as func() in the text and comments (note parentheses).
>
> GPIO
Thanks for letting me know, I will update the the commit message in
regards to this.
>
> > notably, the flag FLAG_REQUESTED has previously been set in
> > gpiod_request_commit, and should be reset on failure.
>
> Same about func().
>
> ...
>
> Seems the correct fix, but you may also add that no existing user is
> returning anything except 0 or ENOTSUPP that is converted to 0 in
> GPIOLIB core code. Hence no Fixes tag is needed, but still possible if
> maintainers want it.
>
You are right. For now, all mainline users are returning 0. We only found
this due to downstream-specific code. I'll add a comment about this not
affecting any existing users to the commit message.
> --
> With Best Regards,
> Andy Shevchenko
Hi Andy,
On Thu, Nov 23, 2023 at 4:01 PM Börge Strümpfel
<[email protected]> wrote:
>
> Hi Andy
>
> thank you for your feedback
>
> On Thu, Nov 23, 2023 at 3:25 PM Andy Shevchenko
> <[email protected]> wrote:
> >
> > On Thu, Nov 23, 2023 at 3:30 PM Boerge Struempfel
> > <[email protected]> wrote:
> > >
> > > If gpio_set_transitory fails, we should free the gpio again. Most
> >
> > We refer to functions as func() in the text and comments (note parentheses).
> >
> > GPIO
>
> Thanks for letting me know, I will update the the commit message in
> regards to this.
>
> >
> > > notably, the flag FLAG_REQUESTED has previously been set in
> > > gpiod_request_commit, and should be reset on failure.
> >
> > Same about func().
> >
> > ...
> >
> > Seems the correct fix, but you may also add that no existing user is
> > returning anything except 0 or ENOTSUPP that is converted to 0 in
> > GPIOLIB core code. Hence no Fixes tag is needed, but still possible if
> > maintainers want it.
> >
>
> You are right. For now, all mainline users are returning 0. We only found
> this due to downstream-specific code. I'll add a comment about this not
> affecting any existing users to the commit message.
>
A small update:
I looked through the possible users again, and there seems to be at least
the possibility for some other return values. The reason for this is, that
the .set_config() of the specific gpio driver is called during the
gpiod_set_transitory() call. For example the .set_config() of gpio-aspeed
might in certain (somewhat unlikely) cases return -EPROBE_DEFER as
well as -EINVAL.
However I don't think, that these conditional paths can be reached on a
properly configured system.
Kind Regards,
Börge Strümpfel