linux-kernel - Re: [PATCH v1 1/1] gpiolib: Return label, if set, for IRQ only line

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Date: Thu, 9 May 2024 16:58:44 +0300
From: Andy Shevchenko <andy.shevchenko@...il.com>
To: Bartosz Golaszewski <brgl@...ev.pl>
Cc: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
	Bartosz Golaszewski <bartosz.golaszewski@...aro.org>,
	Linus Walleij <linus.walleij@...aro.org>,
	linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 1/1] gpiolib: Return label, if set, for IRQ only line

Thu, May 09, 2024 at 03:15:05PM +0200, Bartosz Golaszewski kirjoitti:
> On Wed, May 8, 2024 at 4:47 PM Andy Shevchenko
> <andriy.shevchenko@...ux.intel.com> wrote:
> >
> > If line has been locked as IRQ without requesting,
> > still check its label and return it, if not NULL.
> >
> > Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> > ---
> >  drivers/gpio/gpiolib.c | 12 ++++++------
> >  1 file changed, 6 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> > index db536ec9734d..1f1673552767 100644
> > --- a/drivers/gpio/gpiolib.c
> > +++ b/drivers/gpio/gpiolib.c
> > @@ -105,16 +105,16 @@ const char *gpiod_get_label(struct gpio_desc *desc)
> >         unsigned long flags;
> >
> >         flags = READ_ONCE(desc->flags);
> > -       if (test_bit(FLAG_USED_AS_IRQ, &flags) &&
> > -           !test_bit(FLAG_REQUESTED, &flags))
> > -               return "interrupt";
> > -
> > -       if (!test_bit(FLAG_REQUESTED, &flags))
> > -               return NULL;
> >
> >         label = srcu_dereference_check(desc->label, &desc->srcu,
> >                                        srcu_read_lock_held(&desc->srcu));
> >
> > +       if (test_bit(FLAG_USED_AS_IRQ, &flags))
> > +               return label->str ?: "interrupt";
> > +
> > +       if (!test_bit(FLAG_REQUESTED, &flags))
> > +               return NULL;
> > +
> >         return label->str;
> >  }
> 
> What good would it be if gpiochip_dup_line_label() returns NULL for
> unrequested lines anyway?

Then it should be handled differently in those cases. So, consider it as
a preparatory patch which doesn't change current behaviour.

(Yes, I have some hack patches locally which do something useful, but they are
not ready. In any case this one looks to me as a good cleanup on its own for
the sake of readability of the code and reduced amount of checks.)

-- 
With Best Regards,
Andy Shevchenko