[PATCH v2 1/2] gpio: em: remove the gpiochip before removing the irq domain

From: Bartosz Golaszewski
Date: Thu Jul 11 2019 - 04:29:48 EST


From: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>

In commit 8764c4ca5049 ("gpio: em: use the managed version of
gpiochip_add_data()") we implicitly altered the ordering of resource
freeing: since gpiochip_remove() calls gpiochip_irqchip_remove()
internally, we now can potentially use the irq_domain after it was
destroyed in the remove() callback (as devm resources are freed after
remove() has returned).

Use devm_add_action_or_reset() to keep the ordering right and entirely
kill the remove() callback in the driver.

Reported-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Fixes: 8764c4ca5049 ("gpio: em: use the managed version of gpiochip_add_data()")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>
---
v1 -> v2:
- use devm_add_action_or_reset() to automatically remove the domain if
the underlying devm_add_action() fails

drivers/gpio/gpio-em.c | 33 +++++++++++++++------------------
1 file changed, 15 insertions(+), 18 deletions(-)

diff --git a/drivers/gpio/gpio-em.c b/drivers/gpio/gpio-em.c
index b6af705a4e5f..a87951293aaa 100644
--- a/drivers/gpio/gpio-em.c
+++ b/drivers/gpio/gpio-em.c
@@ -259,6 +259,13 @@ static const struct irq_domain_ops em_gio_irq_domain_ops = {
.xlate = irq_domain_xlate_twocell,
};

+static void em_gio_irq_domain_remove(void *data)
+{
+ struct irq_domain *domain = data;
+
+ irq_domain_remove(domain);
+}
+
static int em_gio_probe(struct platform_device *pdev)
{
struct em_gio_priv *p;
@@ -333,39 +340,30 @@ static int em_gio_probe(struct platform_device *pdev)
return -ENXIO;
}

+ ret = devm_add_action_or_reset(&pdev->dev, em_gio_irq_domain_remove,
+ p->irq_domain);
+ if (ret)
+ return ret;
+
if (devm_request_irq(&pdev->dev, irq[0]->start,
em_gio_irq_handler, 0, name, p)) {
dev_err(&pdev->dev, "failed to request low IRQ\n");
- ret = -ENOENT;
- goto err1;
+ return -ENOENT;
}

if (devm_request_irq(&pdev->dev, irq[1]->start,
em_gio_irq_handler, 0, name, p)) {
dev_err(&pdev->dev, "failed to request high IRQ\n");
- ret = -ENOENT;
- goto err1;
+ return -ENOENT;
}

ret = devm_gpiochip_add_data(&pdev->dev, gpio_chip, p);
if (ret) {
dev_err(&pdev->dev, "failed to add GPIO controller\n");
- goto err1;
+ return ret;
}

return 0;
-
-err1:
- irq_domain_remove(p->irq_domain);
- return ret;
-}
-
-static int em_gio_remove(struct platform_device *pdev)
-{
- struct em_gio_priv *p = platform_get_drvdata(pdev);
-
- irq_domain_remove(p->irq_domain);
- return 0;
}

static const struct of_device_id em_gio_dt_ids[] = {
@@ -376,7 +374,6 @@ MODULE_DEVICE_TABLE(of, em_gio_dt_ids);

static struct platform_driver em_gio_device_driver = {
.probe = em_gio_probe,
- .remove = em_gio_remove,
.driver = {
.name = "em_gio",
.of_match_table = em_gio_dt_ids,
--
2.21.0