diff mbox series

[12/22] gpio: sysfs: extend the critical section for unregistering sysfs devices

Message ID 20240130124828.14678-13-brgl@bgdev.pl
State Superseded
Headers show
Series gpio: rework locking and object life-time control | expand

Commit Message

Bartosz Golaszewski Jan. 30, 2024, 12:48 p.m. UTC 
From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Checking the gdev->mockdev pointer for NULL must be part of the critical
section.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
---
 drivers/gpio/gpiolib-sysfs.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

Comments

Linus Walleij Jan. 31, 2024, 8:06 p.m. UTC | #1 
On Tue, Jan 30, 2024 at 1:48 PM Bartosz Golaszewski <brgl@bgdev.pl> wrote:

> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
>
> Checking the gdev->mockdev pointer for NULL must be part of the critical
> section.
>
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

(Unrelated: I don't quite understand why it has to be a member of the
gpio_device if mockdev/sysfs isn't enabled, something for us to fix
another day.)

Yours,
Linus Walleij
diff mbox series

Patch

diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c
index 1cc707685f87..5da316ea9cc7 100644
--- a/drivers/gpio/gpiolib-sysfs.c
+++ b/drivers/gpio/gpiolib-sysfs.c
@@ -1,6 +1,7 @@ 
 // SPDX-License-Identifier: GPL-2.0
 
 #include <linux/bitops.h>
+#include <linux/cleanup.h>
 #include <linux/device.h>
 #include <linux/idr.h>
 #include <linux/init.h>
@@ -768,15 +769,15 @@  void gpiochip_sysfs_unregister(struct gpio_device *gdev)
 	struct gpio_desc *desc;
 	struct gpio_chip *chip = gdev->chip;
 
-	if (!gdev->mockdev)
-		return;
+	scoped_guard(mutex, &sysfs_lock) {
+		if (!gdev->mockdev)
+			return;
 
-	device_unregister(gdev->mockdev);
+		device_unregister(gdev->mockdev);
 
-	/* prevent further gpiod exports */
-	mutex_lock(&sysfs_lock);
-	gdev->mockdev = NULL;
-	mutex_unlock(&sysfs_lock);
+		/* prevent further gpiod exports */
+		gdev->mockdev = NULL;
+	}
 
 	/* unregister gpiod class devices owned by sysfs */
 	for_each_gpio_desc_with_flag(chip, desc, FLAG_SYSFS) {