[PATCH] gpio: Skip over NULL and (empty string) line names

[PATCH] gpio: Skip over NULL and (empty string) line names

[Linus Walleij]

The core will warn if we try to assign the name ''
(empty string) to two lines. Actively ignore NULL
and empty string in the name assignment loop.

Reported-by: Guillaume Tucker <guillaume.tucker@collabora.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
 drivers/gpio/gpiolib.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 26c75499d549..d07da3ffd140 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -343,6 +343,10 @@ static int gpiochip_set_desc_names(struct gpio_chip *gc)
 	for (i = 0; i != gc->ngpio; ++i) {
 		struct gpio_desc *gpiod;
 
+		/* Skip NULL or '(empty string)' names */
+		if (!gc->names[i] || !strlen(gc->names[i]))
+			continue;
+
 		gpiod = gpio_name_to_desc(gc->names[i]);
 		if (gpiod && (gpiod->gdev == gdev)) {
 			dev_err(&gdev->dev,
@@ -352,8 +356,12 @@ static int gpiochip_set_desc_names(struct gpio_chip *gc)
 	}
 
 	/* Then add all names to the GPIO descriptors */
-	for (i = 0; i != gc->ngpio; ++i)
+	for (i = 0; i != gc->ngpio; ++i) {
+		/* Skip NULL or '(empty string)' names */
+		if (!gc->names[i] || !strlen(gc->names[i]))
+			continue;
 		gdev->descs[i].name = gc->names[i];
+	}
 
 	return 0;
 }
@@ -404,6 +412,9 @@ static int devprop_gpiochip_set_names(struct gpio_chip *chip)
 	for (i = 0; i < count; i++) {
 		struct gpio_desc *gpiod;
 
+		/* Skip NULL or '(empty string)' names */
+		if (!names[i] || !strlen(names[i]))
+			continue;
 		gpiod = gpio_name_to_desc(names[i]);
 		if (gpiod && (gpiod->gdev == gdev)) {
 			dev_err(&gdev->dev,
-- 
2.28.0

Re: [PATCH] gpio: Skip over NULL and (empty string) line names

[Andy Shevchenko]

On Tue, Dec 15, 2020 at 2:41 PM Linus Walleij <linus.walleij@linaro.org> wrote:
>
> The core will warn if we try to assign the name ''
> (empty string) to two lines. Actively ignore NULL
> and empty string in the name assignment loop.

> +               if (!gc->names[i] || !strlen(gc->names[i]))

> +               if (!gc->names[i] || !strlen(gc->names[i]))

> +               if (!names[i] || !strlen(names[i]))

Can we replace strlen() calls by a simple check of the first byte?

names[i][0]


-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH] gpio: Skip over NULL and (empty string) line names

[Andy Shevchenko]

On Fri, Dec 18, 2020 at 6:05 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
> On Tue, Dec 15, 2020 at 2:41 PM Linus Walleij <linus.walleij@linaro.org> wrote:
> >
> > The core will warn if we try to assign the name ''
> > (empty string) to two lines. Actively ignore NULL
> > and empty string in the name assignment loop.
>
> > +               if (!gc->names[i] || !strlen(gc->names[i]))
>
> > +               if (!gc->names[i] || !strlen(gc->names[i]))
>
> > +               if (!names[i] || !strlen(names[i]))
>
> Can we replace strlen() calls by a simple check of the first byte?
>
> names[i][0]

Unfinished example...

        if (!names[i] || names[i][0] == '\0')


-- 
With Best Regards,
Andy Shevchenko