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Rework this function to: - not warn on desc == NULL as this is a use-case on which most free functions silently return - put the references to desc->gdev and desc->gdev->owner unconditionally so that the release callback actually gets called when the remaining references are dropped by external GPIO users Signed-off-by: Bartosz Golaszewski --- v1 -> v2: - add a comment about why we can't use VALIDATE_DESC_VOID() v2 -> v3: - we must drop the reference to the owner module before we drop the one to the gpio_device as the latter may be removed if this is the last reference and we'll end up calling module_put() on freed memory drivers/gpio/gpiolib.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 251c875b5c34..76e0c38026c3 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -2167,12 +2167,18 @@ static bool gpiod_free_commit(struct gpio_desc *desc) void gpiod_free(struct gpio_desc *desc) { - if (desc && desc->gdev && gpiod_free_commit(desc)) { - module_put(desc->gdev->owner); - gpio_device_put(desc->gdev); - } else { + /* + * We must not use VALIDATE_DESC_VOID() as the underlying gdev->chip + * may already be NULL but we still want to put the references. + */ + if (!desc) + return; + + if (!gpiod_free_commit(desc)) WARN_ON(extra_checks); - } + + module_put(desc->gdev->owner); + gpio_device_put(desc->gdev); } /**