linux-kernel - [PATCH v1 1/1] gpiolib: sysfs: Do unexport GPIO when user asks for it

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Date:   Mon, 14 Aug 2023 14:26:15 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <brgl@...ev.pl>,
        Andy Shevchenko <andy@...nel.org>,
        Marek Behún <kabel@...nel.org>
Subject: [PATCH v1 1/1] gpiolib: sysfs: Do unexport GPIO when user asks for it

It seems that sysfs interface implicitly relied on the gpiod_free()
to unexport the line. This is not good and prone to regressions.
Fix it by explicitly calling gpiod_unexport().

Fixes: b0ce9ce408b6 ("gpiolib: Do not unexport GPIO on freeing")
Reported-by: Marek Behún <kabel@...nel.org>
Closes: https://lore.kernel.org/r/20230808102828.4a9eac09@dellmb
Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Tested-by: Marek Behún <kabel@...nel.org>
---
 drivers/gpio/gpiolib-sysfs.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c
index 530dfd19d7b5..50503a4525eb 100644
--- a/drivers/gpio/gpiolib-sysfs.c
+++ b/drivers/gpio/gpiolib-sysfs.c
@@ -515,8 +515,9 @@ static ssize_t unexport_store(const struct class *class,
 	 * they may be undone on its behalf too.
 	 */
 	if (test_and_clear_bit(FLAG_SYSFS, &desc->flags)) {
+		gpiod_unexport(desc);
+		gpiod_free(desc);
 		status = 0;
-		gpiod_free(desc);
 	}
 done:
 	if (status)
@@ -781,8 +782,10 @@ void gpiochip_sysfs_unregister(struct gpio_device *gdev)
 	mutex_unlock(&sysfs_lock);
 
 	/* unregister gpiod class devices owned by sysfs */
-	for_each_gpio_desc_with_flag(chip, desc, FLAG_SYSFS)
+	for_each_gpio_desc_with_flag(chip, desc, FLAG_SYSFS) {
+		gpiod_unexport(desc);
 		gpiod_free(desc);
+	}
 }
 
 static int __init gpiolib_sysfs_init(void)
-- 
2.40.0.1.gaa8946217a0b