[PATCH] gpio: zynq: fix runtime PM leak on request error path

[Ridham Khurana]

pm_runtime_get_sync() leaves the usage counter incremented even when it
fails, and zynq_gpio_request() returns the error without dropping it.

gpiolib does not call ->free() when ->request() fails, so zynq_gpio_free(),
which holds the only matching pm_runtime_put(), never runs. The reference
is leaked and the controller can no longer runtime-suspend, so its clock
stays enabled.

Switch to pm_runtime_resume_and_get(), which only increments the usage
counter on success.

Fixes: 3242ba117e9b ("gpio: Add driver for Zynq GPIO controller")
Cc: stable at vger.kernel.org
Signed-off-by: Ridham Khurana <khurana.ridham222 at gmail.com>
---
Build-tested on arm64 with CONFIG_GPIO_ZYNQ=m. Not tested on Zynq hardware.

 drivers/gpio/gpio-zynq.c | 10 +---------
 1 file changed, 1 insertion(+), 9 deletions(-)

diff --git a/drivers/gpio/gpio-zynq.c b/drivers/gpio/gpio-zynq.c
index 15a79d9a2e9e..13e4c5f0e297 100644
--- a/drivers/gpio/gpio-zynq.c
+++ b/drivers/gpio/gpio-zynq.c
@@ -798,15 +798,7 @@ static int zynq_gpio_runtime_resume(struct device *dev)
 
 static int zynq_gpio_request(struct gpio_chip *chip, unsigned int offset)
 {
-	int ret;
-
-	ret = pm_runtime_get_sync(chip->parent);
-
-	/*
-	 * If the device is already active pm_runtime_get() will return 1 on
-	 * success, but gpio_request still needs to return 0.
-	 */
-	return ret < 0 ? ret : 0;
+	return pm_runtime_resume_and_get(chip->parent);
 }
 
 static void zynq_gpio_free(struct gpio_chip *chip, unsigned int offset)
-- 
2.47.3