6.4-stable review patch. If anyone has any objections, please let me know.
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From: Bartosz Golaszewski bartosz.golaszewski@linaro.org
[ Upstream commit 3386fb86ecdef0d39ee3306aea8ec290e61b934f ]
After we remove a GPIO chip that still has some requested descriptors, gpiod_free_commit() will fail and we will never put the references to the GPIO device and the owning module in gpiod_free().
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 bartosz.golaszewski@linaro.org Reviewed-by: Linus Walleij linus.walleij@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 5be8ad61523eb..6e7701f80929f 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -2175,12 +2175,18 @@ 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); }
/**