[PATCH 38/42] crypto: stm32/crc32 - Convert to platform remove callback returning void

Uwe Kleine-König
2023-10-20T07:58:07Z

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is (mostly) ignored
and this typically results in resource leaks. To improve here there is a
quest to make the remove callback return void. In the first step of this
quest all drivers are converted to .remove_new() which already returns
void.

The driver adapted here suffered from this wrong assumption and had an
error paths resulting in resource leaks.

If pm_runtime_get() fails, the other resources held by the device must
still be freed. Only clk_disable() should be skipped as the
pm_runtime_get() failed to call clk_enable().

After this change the remove function returns zero unconditionally and
can trivially be converted to the prototype required for .remove_new().

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
---
drivers/crypto/stm32/stm32-crc32.c | 15 +++++----------
1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/drivers/crypto/stm32/stm32-crc32.c b/drivers/crypto/stm32/stm32-crc32.c
index 90a920e7f664..5d1067c8cb0d 100644
--- a/drivers/crypto/stm32/stm32-crc32.c
+++ b/drivers/crypto/stm32/stm32-crc32.c
@@ -379,16 +379,11 @@ static int stm32_crc_probe(struct platform_device *pdev)
return 0;
}

-static int stm32_crc_remove(struct platform_device *pdev)
+static void stm32_crc_remove(struct platform_device *pdev)
{
struct stm32_crc *crc = platform_get_drvdata(pdev);
int ret = pm_runtime_get_sync(crc->dev);

- if (ret < 0) {
- pm_runtime_put_noidle(crc->dev);
- return ret;
- }
-
spin_lock(&crc_list.lock);
list_del(&crc->list);
spin_unlock(&crc_list.lock);
@@ -401,9 +396,9 @@ static int stm32_crc_remove(struct platform_device *pdev)
pm_runtime_disable(crc->dev);
pm_runtime_put_noidle(crc->dev);

- clk_disable_unprepare(crc->clk);
-
- return 0;
+ if (ret >= 0)
+ clk_disable(crc->clk);
+ clk_unprepare(crc->clk);
}

static int __maybe_unused stm32_crc_suspend(struct device *dev)
@@ -472,7 +467,7 @@ MODULE_DEVICE_TABLE(of, stm32_dt_ids);

static struct platform_driver stm32_crc_driver = {
.probe = stm32_crc_probe,
- .remove = stm32_crc_remove,
+ .remove_new = stm32_crc_remove,
.driver = {
.name = DRIVER_NAME,
.pm = &stm32_crc_pm_ops,
--
2.42.0