From: Bartosz Golaszewski Date: Sat, 15 Feb 2025 10:08:47 +0000 (+0100) Subject: gpiolib: read descriptor flags once in gpiolib_dbg_show() X-Git-Tag: v6.15-rc1~179^2~80 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=11067f50458a5bb3b72f83c508e03f321e0c0c34;p=thirdparty%2Flinux.git gpiolib: read descriptor flags once in gpiolib_dbg_show() For consistency with most other code that can access requested descriptors: read the flags once atomically and then test individual bits from the helper variable. This avoids any potential discrepancies should flags change during the debug print. Link: https://lore.kernel.org/r/20250215100847.30136-1-brgl@bgdev.pl Signed-off-by: Bartosz Golaszewski --- diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 9103384f4a5e7..e8678a6c82ea3 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -5111,6 +5111,7 @@ static void gpiolib_dbg_show(struct seq_file *s, struct gpio_device *gdev) unsigned int gpio = gdev->base; struct gpio_desc *desc; struct gpio_chip *gc; + unsigned long flags; int value; guard(srcu)(&gdev->srcu); @@ -5123,12 +5124,13 @@ static void gpiolib_dbg_show(struct seq_file *s, struct gpio_device *gdev) for_each_gpio_desc(gc, desc) { guard(srcu)(&desc->gdev->desc_srcu); - is_irq = test_bit(FLAG_USED_AS_IRQ, &desc->flags); - if (is_irq || test_bit(FLAG_REQUESTED, &desc->flags)) { + flags = READ_ONCE(desc->flags); + is_irq = test_bit(FLAG_USED_AS_IRQ, &flags); + if (is_irq || test_bit(FLAG_REQUESTED, &flags)) { gpiod_get_direction(desc); - is_out = test_bit(FLAG_IS_OUT, &desc->flags); + is_out = test_bit(FLAG_IS_OUT, &flags); value = gpio_chip_get_value(gc, desc); - active_low = test_bit(FLAG_ACTIVE_LOW, &desc->flags); + active_low = test_bit(FLAG_ACTIVE_LOW, &flags); seq_printf(s, " gpio-%-3u (%-20.20s|%-20.20s) %s %s %s%s\n", gpio, desc->name ?: "", gpiod_get_label(desc), is_out ? "out" : "in ",