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From: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
To: Linus Walleij <linusw@kernel.org>,
	Bartosz Golaszewski <brgl@kernel.org>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Kent Gibson <warthog618@gmail.com>,
	Adrian Ambrozewicz <aambrozewicz@nvidia.com>
Cc: linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org,
	Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Subject: [PATCH v2 3/5] gpiolib: clear debounce period before the "requested" flag
Date: Mon, 09 Nov 2026 11:27:07 +0100	[thread overview]
Message-ID: <20261109-gpio-desc-flags-atomic-v2-3-c4c54b476628@oss.qualcomm.com> (raw)
In-Reply-To: <20261109-gpio-desc-flags-atomic-v2-0-c4c54b476628@oss.qualcomm.com>

The debounce_period_us field is protected by the GPIOD_FLAG_REQUESTED
flag, so it should be cleared before the flag, else it could potentially
race with a new request.

Suggested-by: Kent Gibson <warthog618@gmail.com>
Closes: https://lore.kernel.org/all/20261105042905.GB8436@rigel/
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
---
 drivers/gpio/gpiolib.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 63b65b646fbcfa9ea0f724d1d3e1ac22ba28f638..af2d67d977f4925558ab77c34b37c3c29bd12a6f 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -2693,6 +2693,10 @@ void gpiod_free_commit(struct gpio_desc *desc)
 		if (guard.gc->free)
 			guard.gc->free(guard.gc, gpiod_hwgpio(desc));
 
+#ifdef CONFIG_GPIO_CDEV
+		WRITE_ONCE(desc->debounce_period_us, 0);
+#endif
+
 		clear_bit(GPIOD_FLAG_ACTIVE_LOW, &flags);
 		clear_bit(GPIOD_FLAG_REQUESTED, &flags);
 		clear_bit(GPIOD_FLAG_OPEN_DRAIN, &flags);
@@ -2710,9 +2714,6 @@ void gpiod_free_commit(struct gpio_desc *desc)
 #endif
 		desc_set_label(desc, NULL);
 		WRITE_ONCE(desc->flags, flags);
-#ifdef CONFIG_GPIO_CDEV
-		WRITE_ONCE(desc->debounce_period_us, 0);
-#endif
 		gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_RELEASED);
 	}
 }

-- 
2.47.3


  parent reply	other threads:[~2026-11-09 10:27 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-11-09 10:27 [PATCH v2 0/5] gpiolib: improve concurrent access to the flags field of struct gpio_desc Bartosz Golaszewski
2026-11-09 10:27 ` [PATCH v2 1/5] gpiolib: don't overwrite the entire flags field in gpiod_get_direction() Bartosz Golaszewski
2026-11-09 10:27 ` [PATCH v2 2/5] gpio: shared: use atomic set_bit() for descriptor flags Bartosz Golaszewski
2026-11-09 10:27 ` Bartosz Golaszewski [this message]
2026-11-09 10:27 ` [PATCH v2 4/5] gpiolib: don't overwrite the entire flags field in gpiod_free_commit() Bartosz Golaszewski
2026-11-09 21:53   ` Andy Shevchenko
2026-11-09 10:27 ` [PATCH v2 5/5] gpio: cdev: don't overwrite the whole flags field when configuring lines Bartosz Golaszewski
2026-11-09 21:58   ` Andy Shevchenko

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