From 33a68e86fd7741f782c71a0daa9111b352e94445 Mon Sep 17 00:00:00 2001 From: Linus Walleij Date: Thu, 11 Feb 2016 10:28:44 +0100 Subject: [PATCH] gpio: reference count the gpio device for each desc Every time a descriptor is retrieved from the gpiolib, we issue module_get() to reference count the module supplying the GPIOs. We also need to call device_get() and device_put() as we also reference the backing gpio_device when doing this. Since the sysfs GPIO interface is using gpiod_get() this will also reference count the sysfs requests until all GPIOs are unexported. Signed-off-by: Linus Walleij --- drivers/gpio/gpiolib.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 0738f9a51633..646dea4f96ff 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -1205,6 +1205,8 @@ int gpiod_request(struct gpio_desc *desc, const char *label) status = __gpiod_request(desc, label); if (status < 0) module_put(gdev->owner); + else + get_device(&gdev->dev); } if (status) @@ -1248,10 +1250,12 @@ static bool __gpiod_free(struct gpio_desc *desc) void gpiod_free(struct gpio_desc *desc) { - if (desc && __gpiod_free(desc)) + if (desc && desc->gdev && __gpiod_free(desc)) { module_put(desc->gdev->owner); - else + put_device(&desc->gdev->dev); + } else { WARN_ON(extra_checks); + } } /**