[PATCH AUTOSEL 5.15 40/41] gpio: grgpio: Fix device removing

Sasha Levin
2022-06-28T02:24:49Z

From: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

[ Upstream commit c1c2a15c2b5379ea8e44dcdcc298e3de42076ba0 ]

If a platform device's remove callback returns non-zero, the device core
emits a warning and still removes the device and calls the devm cleanup
callbacks.

So it's not save to not unregister the gpiochip because on the next request
to a GPIO the driver accesses kfree()'d memory. Also if an IRQ triggers,
the freed memory is accessed.

Instead rely on the GPIO framework to ensure that after gpiochip_remove()
all GPIOs are freed and so the corresponding IRQs are unmapped.

This is a preparation for making platform remove callbacks return void.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpio/gpio-grgpio.c | 14 +-------------
1 file changed, 1 insertion(+), 13 deletions(-)

diff --git a/drivers/gpio/gpio-grgpio.c b/drivers/gpio/gpio-grgpio.c
index f954359c9544..46f6158d1c71 100644
--- a/drivers/gpio/gpio-grgpio.c
+++ b/drivers/gpio/gpio-grgpio.c
@@ -435,25 +435,13 @@ static int grgpio_probe(struct platform_device *ofdev)
static int grgpio_remove(struct platform_device *ofdev)
{
struct grgpio_priv *priv = platform_get_drvdata(ofdev);
- int i;
- int ret = 0;
-
- if (priv->domain) {
- for (i = 0; i < GRGPIO_MAX_NGPIO; i++) {
- if (priv->uirqs[i].refcnt != 0) {
- ret = -EBUSY;
- goto out;
- }
- }
- }

gpiochip_remove(&priv->gc);

if (priv->domain)
irq_domain_remove(priv->domain);

-out:
- return ret;
+ return 0;
}

static const struct of_device_id grgpio_match[] = {
--
2.35.1