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>,
stable@vger.kernel.org
Subject: [PATCH 4/5] gpiolib: don't overwrite the entire flags field in gpiod_free_commit()
Date: Wed, 04 Nov 2026 16:36:59 +0100 [thread overview]
Message-ID: <20261104-gpio-desc-flags-atomic-v1-4-e23cedf619ba@oss.qualcomm.com> (raw)
In-Reply-To: <20261104-gpio-desc-flags-atomic-v1-0-e23cedf619ba@oss.qualcomm.com>
Use gpiod_update_flags() to clear all request-related flags in one go
instead of risking racing with concurrent users and overwriting any
changes they could have done between READ_ONCE() and WRITE_ONCE().
Cc: stable@vger.kernel.org
Fixes: 35b545332b80 ("gpio: remove gpio_lock")
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
---
drivers/gpio/gpiolib.c | 26 +++++++++++++-------------
1 file changed, 13 insertions(+), 13 deletions(-)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 63b65b646fbcfa9ea0f724d1d3e1ac22ba28f638..28d4cf0cef70f437dc4271f82975d09dc55125ea 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -2693,23 +2693,23 @@ void gpiod_free_commit(struct gpio_desc *desc)
if (guard.gc->free)
guard.gc->free(guard.gc, gpiod_hwgpio(desc));
- clear_bit(GPIOD_FLAG_ACTIVE_LOW, &flags);
- clear_bit(GPIOD_FLAG_REQUESTED, &flags);
- clear_bit(GPIOD_FLAG_OPEN_DRAIN, &flags);
- clear_bit(GPIOD_FLAG_OPEN_SOURCE, &flags);
- clear_bit(GPIOD_FLAG_PULL_UP, &flags);
- clear_bit(GPIOD_FLAG_PULL_DOWN, &flags);
- clear_bit(GPIOD_FLAG_BIAS_DISABLE, &flags);
- clear_bit(GPIOD_FLAG_EDGE_RISING, &flags);
- clear_bit(GPIOD_FLAG_EDGE_FALLING, &flags);
- clear_bit(GPIOD_FLAG_EVENT_CLOCK_REALTIME, &flags);
- clear_bit(GPIOD_FLAG_EVENT_CLOCK_HTE, &flags);
- clear_bit(GPIOD_FLAG_IS_HOGGED, &flags);
#ifdef CONFIG_OF_DYNAMIC
WRITE_ONCE(desc->hog, NULL);
#endif
desc_set_label(desc, NULL);
- WRITE_ONCE(desc->flags, flags);
+ gpiod_update_flags(desc,
+ BIT(GPIOD_FLAG_ACTIVE_LOW) |
+ BIT(GPIOD_FLAG_REQUESTED) |
+ BIT(GPIOD_FLAG_OPEN_DRAIN) |
+ BIT(GPIOD_FLAG_OPEN_SOURCE) |
+ BIT(GPIOD_FLAG_PULL_UP) |
+ BIT(GPIOD_FLAG_PULL_DOWN) |
+ BIT(GPIOD_FLAG_BIAS_DISABLE) |
+ BIT(GPIOD_FLAG_EDGE_RISING) |
+ BIT(GPIOD_FLAG_EDGE_FALLING) |
+ BIT(GPIOD_FLAG_EVENT_CLOCK_REALTIME) |
+ BIT(GPIOD_FLAG_EVENT_CLOCK_HTE) |
+ BIT(GPIOD_FLAG_IS_HOGGED), 0);
#ifdef CONFIG_GPIO_CDEV
WRITE_ONCE(desc->debounce_period_us, 0);
#endif
--
2.47.3
next prev parent reply other threads:[~2026-11-04 15:37 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-04 15:36 [PATCH 0/5] gpiolib: improve concurrent access to the flags field of struct gpio_desc Bartosz Golaszewski
2026-11-04 15:36 ` [PATCH 1/5] gpiolib: don't overwrite the entire flags field in gpiod_get_direction() Bartosz Golaszewski
2026-11-04 15:36 ` [PATCH 2/5] gpio: shared: use atomic set_bit() for descriptor flags Bartosz Golaszewski
2026-11-04 15:36 ` [PATCH 3/5] gpiolib: provide gpiod_update_flags() Bartosz Golaszewski
2026-11-04 15:36 ` Bartosz Golaszewski [this message]
2026-11-04 15:37 ` [PATCH 5/5] gpio: cdev: don't overwrite the whole flags field when configuring lines Bartosz Golaszewski
2026-11-04 21:55 ` Andy Shevchenko
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