gpiolib: irqchip: prevent driver unloading if gpio is used as irq only

Now nothing prevents GPIO driver from being unloaded if its gpios
were requested as GPIO IRQs only (without calling gpio_request()).

Hence, add calls of try_module_get()/module_put() into
gpiochip_irq_reqres/relres() to track such scenario properly.

Cc: Johan Hovold <johan@kernel.org>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index b1b08b3fa626ac5d42126b8bdb46211c5c03ea11..debd7c56187de949bb04d797070a45522ebafbbe 100644 (file)
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -522,10 +522,14 @@ static int gpiochip_irq_reqres(struct irq_data *d)
 {
        struct gpio_chip *chip = irq_data_get_irq_chip_data(d);
 
+       if (!try_module_get(chip->owner))
+               return -ENODEV;
+
        if (gpiochip_lock_as_irq(chip, d->hwirq)) {
                chip_err(chip,
                        "unable to lock HW IRQ %lu for IRQ\n",
                        d->hwirq);
+               module_put(chip->owner);
                return -EINVAL;
        }
        return 0;
@@ -536,6 +540,7 @@ static void gpiochip_irq_relres(struct irq_data *d)
        struct gpio_chip *chip = irq_data_get_irq_chip_data(d);
 
        gpiochip_unlock_as_irq(chip, d->hwirq);
+       module_put(chip->owner);
 }
 
 static int gpiochip_to_irq(struct gpio_chip *chip, unsigned offset)