diff mbox series

[v2,2/6] gpio: cdev: prepare gpio_desc_to_lineinfo() for being called from atomic

Message ID 20241010-gpio-notify-in-kernel-events-v2-2-b560411f7c59@linaro.org
State Superseded
Headers show
Series gpio: notify user-space about config changes in the kernel | expand

Commit Message

Bartosz Golaszewski Oct. 10, 2024, 9:10 a.m. UTC 
From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

In order to prepare gpio_desc_to_lineinfo() to being called from atomic
context, add a new argument - bool atomic - which, if set, indicates
that no sleeping functions must be called (currently: only
pinctrl_gpio_can_use_line()).

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
---
 drivers/gpio/gpiolib-cdev.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

Comments

Kent Gibson Oct. 14, 2024, 1:58 a.m. UTC | #1 
On Thu, Oct 10, 2024 at 11:10:23AM +0200, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
>
> In order to prepare gpio_desc_to_lineinfo() to being called from atomic
> context, add a new argument - bool atomic - which, if set, indicates
> that no sleeping functions must be called (currently: only
> pinctrl_gpio_can_use_line()).
>
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> ---
>  drivers/gpio/gpiolib-cdev.c | 16 ++++++++++------
>  1 file changed, 10 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
> index b0050250ac3a..8c48a53b4fa8 100644
> --- a/drivers/gpio/gpiolib-cdev.c
> +++ b/drivers/gpio/gpiolib-cdev.c
> @@ -2361,7 +2361,7 @@ static void gpio_v2_line_info_changed_to_v1(
>  #endif /* CONFIG_GPIO_CDEV_V1 */
>
>  static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
> -				  struct gpio_v2_line_info *info)
> +				  struct gpio_v2_line_info *info, bool atomic)
>  {
>  	unsigned long dflags;
>  	const char *label;
> @@ -2402,9 +2402,13 @@ static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
>  	    test_bit(FLAG_USED_AS_IRQ, &dflags) ||
>  	    test_bit(FLAG_EXPORT, &dflags) ||
>  	    test_bit(FLAG_SYSFS, &dflags) ||
> -	    !gpiochip_line_is_valid(guard.gc, info->offset) ||
> -	    !pinctrl_gpio_can_use_line(guard.gc, info->offset))
> +	    !gpiochip_line_is_valid(guard.gc, info->offset))
>  		info->flags |= GPIO_V2_LINE_FLAG_USED;
> +
> +	if (!atomic) {
> +		if (!pinctrl_gpio_can_use_line(guard.gc, info->offset))
> +			info->flags |= GPIO_V2_LINE_FLAG_USED;
> +	}
>

Should be else if.

Cheers,
Kent.

>  	if (test_bit(FLAG_IS_OUT, &dflags))
>  		info->flags |= GPIO_V2_LINE_FLAG_OUTPUT;
> @@ -2502,7 +2506,7 @@ static int lineinfo_get_v1(struct gpio_chardev_data *cdev, void __user *ip,
>  			return -EBUSY;
>  	}
>
> -	gpio_desc_to_lineinfo(desc, &lineinfo_v2);
> +	gpio_desc_to_lineinfo(desc, &lineinfo_v2, false);
>  	gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo);
>
>  	if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
> @@ -2539,7 +2543,7 @@ static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip,
>  		if (test_and_set_bit(lineinfo.offset, cdev->watched_lines))
>  			return -EBUSY;
>  	}
> -	gpio_desc_to_lineinfo(desc, &lineinfo);
> +	gpio_desc_to_lineinfo(desc, &lineinfo, false);
>  	supinfo_to_lineinfo(desc, &lineinfo);
>
>  	if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
> @@ -2632,7 +2636,7 @@ static int lineinfo_changed_notify(struct notifier_block *nb,
>  	memset(&chg, 0, sizeof(chg));
>  	chg.event_type = action;
>  	chg.timestamp_ns = ktime_get_ns();
> -	gpio_desc_to_lineinfo(desc, &chg.info);
> +	gpio_desc_to_lineinfo(desc, &chg.info, false);
>  	supinfo_to_lineinfo(desc, &chg.info);
>
>  	ret = kfifo_in_spinlocked(&cdev->events, &chg, 1, &cdev->wait.lock);
>
> --
> 2.43.0
>
Bartosz Golaszewski Oct. 14, 2024, 7:45 a.m. UTC | #2 
On Mon, Oct 14, 2024 at 3:58 AM Kent Gibson <warthog618@gmail.com> wrote:
>
> On Thu, Oct 10, 2024 at 11:10:23AM +0200, Bartosz Golaszewski wrote:
> > From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> >
> > In order to prepare gpio_desc_to_lineinfo() to being called from atomic
> > context, add a new argument - bool atomic - which, if set, indicates
> > that no sleeping functions must be called (currently: only
> > pinctrl_gpio_can_use_line()).
> >
> > Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> > ---
> >       unsigned long dflags;
> >       const char *label;
> > @@ -2402,9 +2402,13 @@ static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
> >           test_bit(FLAG_USED_AS_IRQ, &dflags) ||
> >           test_bit(FLAG_EXPORT, &dflags) ||
> >           test_bit(FLAG_SYSFS, &dflags) ||
> > -         !gpiochip_line_is_valid(guard.gc, info->offset) ||
> > -         !pinctrl_gpio_can_use_line(guard.gc, info->offset))
> > +         !gpiochip_line_is_valid(guard.gc, info->offset))
> >               info->flags |= GPIO_V2_LINE_FLAG_USED;
> > +
> > +     if (!atomic) {
> > +             if (!pinctrl_gpio_can_use_line(guard.gc, info->offset))
> > +                     info->flags |= GPIO_V2_LINE_FLAG_USED;
> > +     }
> >
>
> Should be else if.
>

If we're not atomic, let's call pinctrl_gpio_can_use_line() and update
the flag accordingly. If we're in atomic, just don't do it. In any
case do the rest. Looks good to me, am I missing something?

Bart

>
> >       if (test_bit(FLAG_IS_OUT, &dflags))
> >               info->flags |= GPIO_V2_LINE_FLAG_OUTPUT;
> > @@ -2502,7 +2506,7 @@ static int lineinfo_get_v1(struct gpio_chardev_data *cdev, void __user *ip,
> >                       return -EBUSY;
> >       }
> >
Kent Gibson Oct. 14, 2024, 8:32 a.m. UTC | #3 
On Mon, Oct 14, 2024 at 09:45:19AM +0200, Bartosz Golaszewski wrote:
> On Mon, Oct 14, 2024 at 3:58 AM Kent Gibson <warthog618@gmail.com> wrote:
> >
> > On Thu, Oct 10, 2024 at 11:10:23AM +0200, Bartosz Golaszewski wrote:
> > > From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> > >
> > > In order to prepare gpio_desc_to_lineinfo() to being called from atomic
> > > context, add a new argument - bool atomic - which, if set, indicates
> > > that no sleeping functions must be called (currently: only
> > > pinctrl_gpio_can_use_line()).
> > >
> > > Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> > > ---
> > >       unsigned long dflags;
> > >       const char *label;
> > > @@ -2402,9 +2402,13 @@ static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
> > >           test_bit(FLAG_USED_AS_IRQ, &dflags) ||
> > >           test_bit(FLAG_EXPORT, &dflags) ||
> > >           test_bit(FLAG_SYSFS, &dflags) ||
> > > -         !gpiochip_line_is_valid(guard.gc, info->offset) ||
> > > -         !pinctrl_gpio_can_use_line(guard.gc, info->offset))
> > > +         !gpiochip_line_is_valid(guard.gc, info->offset))
> > >               info->flags |= GPIO_V2_LINE_FLAG_USED;
> > > +
> > > +     if (!atomic) {
> > > +             if (!pinctrl_gpio_can_use_line(guard.gc, info->offset))
> > > +                     info->flags |= GPIO_V2_LINE_FLAG_USED;
> > > +     }
> > >
> >
> > Should be else if.
> >
>
> If we're not atomic, let's call pinctrl_gpio_can_use_line() and update
> the flag accordingly. If we're in atomic, just don't do it. In any
> case do the rest. Looks good to me, am I missing something?
>

Previously the preceding if short circuits and doesn't perform the
pinctl check if ANY of the preceding checks are true.
The pinctrl check should be in an else-if to get the same behaviour.

I am refering to the if (!atomic), btw, not the if in its body.
(that is why my comment is placed after the closing bracket)

Cheers,
Kent.
Bartosz Golaszewski Oct. 14, 2024, 8:41 a.m. UTC | #4 
On Mon, Oct 14, 2024 at 10:32 AM Kent Gibson <warthog618@gmail.com> wrote:
>
> On Mon, Oct 14, 2024 at 09:45:19AM +0200, Bartosz Golaszewski wrote:
> > On Mon, Oct 14, 2024 at 3:58 AM Kent Gibson <warthog618@gmail.com> wrote:
> > >
> > > On Thu, Oct 10, 2024 at 11:10:23AM +0200, Bartosz Golaszewski wrote:
> > > > From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> > > >
> > > > In order to prepare gpio_desc_to_lineinfo() to being called from atomic
> > > > context, add a new argument - bool atomic - which, if set, indicates
> > > > that no sleeping functions must be called (currently: only
> > > > pinctrl_gpio_can_use_line()).
> > > >
> > > > Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> > > > ---
> > > >       unsigned long dflags;
> > > >       const char *label;
> > > > @@ -2402,9 +2402,13 @@ static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
> > > >           test_bit(FLAG_USED_AS_IRQ, &dflags) ||
> > > >           test_bit(FLAG_EXPORT, &dflags) ||
> > > >           test_bit(FLAG_SYSFS, &dflags) ||
> > > > -         !gpiochip_line_is_valid(guard.gc, info->offset) ||
> > > > -         !pinctrl_gpio_can_use_line(guard.gc, info->offset))
> > > > +         !gpiochip_line_is_valid(guard.gc, info->offset))
> > > >               info->flags |= GPIO_V2_LINE_FLAG_USED;
> > > > +
> > > > +     if (!atomic) {
> > > > +             if (!pinctrl_gpio_can_use_line(guard.gc, info->offset))
> > > > +                     info->flags |= GPIO_V2_LINE_FLAG_USED;
> > > > +     }
> > > >
> > >
> > > Should be else if.
> > >
> >
> > If we're not atomic, let's call pinctrl_gpio_can_use_line() and update
> > the flag accordingly. If we're in atomic, just don't do it. In any
> > case do the rest. Looks good to me, am I missing something?
> >
>
> Previously the preceding if short circuits and doesn't perform the
> pinctl check if ANY of the preceding checks are true.
> The pinctrl check should be in an else-if to get the same behaviour.
>
> I am refering to the if (!atomic), btw, not the if in its body.
> (that is why my comment is placed after the closing bracket)
>

Ok, got it.

Bartosz
diff mbox series

Patch

diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
index b0050250ac3a..8c48a53b4fa8 100644
--- a/drivers/gpio/gpiolib-cdev.c
+++ b/drivers/gpio/gpiolib-cdev.c
@@ -2361,7 +2361,7 @@  static void gpio_v2_line_info_changed_to_v1(
 #endif /* CONFIG_GPIO_CDEV_V1 */
 
 static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
-				  struct gpio_v2_line_info *info)
+				  struct gpio_v2_line_info *info, bool atomic)
 {
 	unsigned long dflags;
 	const char *label;
@@ -2402,9 +2402,13 @@  static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
 	    test_bit(FLAG_USED_AS_IRQ, &dflags) ||
 	    test_bit(FLAG_EXPORT, &dflags) ||
 	    test_bit(FLAG_SYSFS, &dflags) ||
-	    !gpiochip_line_is_valid(guard.gc, info->offset) ||
-	    !pinctrl_gpio_can_use_line(guard.gc, info->offset))
+	    !gpiochip_line_is_valid(guard.gc, info->offset))
 		info->flags |= GPIO_V2_LINE_FLAG_USED;
+	
+	if (!atomic) {
+		if (!pinctrl_gpio_can_use_line(guard.gc, info->offset))
+			info->flags |= GPIO_V2_LINE_FLAG_USED;
+	}
 
 	if (test_bit(FLAG_IS_OUT, &dflags))
 		info->flags |= GPIO_V2_LINE_FLAG_OUTPUT;
@@ -2502,7 +2506,7 @@  static int lineinfo_get_v1(struct gpio_chardev_data *cdev, void __user *ip,
 			return -EBUSY;
 	}
 
-	gpio_desc_to_lineinfo(desc, &lineinfo_v2);
+	gpio_desc_to_lineinfo(desc, &lineinfo_v2, false);
 	gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo);
 
 	if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
@@ -2539,7 +2543,7 @@  static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip,
 		if (test_and_set_bit(lineinfo.offset, cdev->watched_lines))
 			return -EBUSY;
 	}
-	gpio_desc_to_lineinfo(desc, &lineinfo);
+	gpio_desc_to_lineinfo(desc, &lineinfo, false);
 	supinfo_to_lineinfo(desc, &lineinfo);
 
 	if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
@@ -2632,7 +2636,7 @@  static int lineinfo_changed_notify(struct notifier_block *nb,
 	memset(&chg, 0, sizeof(chg));
 	chg.event_type = action;
 	chg.timestamp_ns = ktime_get_ns();
-	gpio_desc_to_lineinfo(desc, &chg.info);
+	gpio_desc_to_lineinfo(desc, &chg.info, false);
 	supinfo_to_lineinfo(desc, &chg.info);
 
 	ret = kfifo_in_spinlocked(&cdev->events, &chg, 1, &cdev->wait.lock);