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 ignored (apart
from emitting a warning) 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. Eventually after all drivers
are converted, .remove_new() will be renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
---
 drivers/firmware/qemu_fw_cfg.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
index 1448f61173b3..03da9a4354f8 100644
--- a/drivers/firmware/qemu_fw_cfg.c
+++ b/drivers/firmware/qemu_fw_cfg.c
@@ -731,7 +731,7 @@ static int fw_cfg_sysfs_probe(struct platform_device *pdev)
 	return err;
 }
 
-static int fw_cfg_sysfs_remove(struct platform_device *pdev)
+static void fw_cfg_sysfs_remove(struct platform_device *pdev)
 {
 	pr_debug("fw_cfg: unloading.\n");
 	fw_cfg_sysfs_cache_cleanup();
@@ -739,7 +739,6 @@ static int fw_cfg_sysfs_remove(struct platform_device *pdev)
 	fw_cfg_io_cleanup();
 	fw_cfg_kset_unregister_recursive(fw_cfg_fname_kset);
 	fw_cfg_kobj_cleanup(fw_cfg_sel_ko);
-	return 0;
 }
 
 static const struct of_device_id fw_cfg_sysfs_mmio_match[] = {
@@ -758,7 +757,7 @@ MODULE_DEVICE_TABLE(acpi, fw_cfg_sysfs_acpi_match);
 
 static struct platform_driver fw_cfg_sysfs_driver = {
 	.probe = fw_cfg_sysfs_probe,
-	.remove = fw_cfg_sysfs_remove,
+	.remove_new = fw_cfg_sysfs_remove,
 	.driver = {
 		.name = "fw_cfg",
 		.of_match_table = fw_cfg_sysfs_mmio_match,
-- 
2.43.0

On Wed, Dec 27, 2023 at 05:26:30PM +0100, Uwe Kleine-König wrote:
> 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 ignored (apart
> from emitting a warning) 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. Eventually after all drivers
> are converted, .remove_new() will be renamed to .remove().
> 
> Trivially convert this driver from always returning zero in the remove
> callback to the void returning variant.
> 
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

I don't mind.

Acked-by: Michael S. Tsirkin <mst@redhat.com>

> ---
>  drivers/firmware/qemu_fw_cfg.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
> index 1448f61173b3..03da9a4354f8 100644
> --- a/drivers/firmware/qemu_fw_cfg.c
> +++ b/drivers/firmware/qemu_fw_cfg.c
> @@ -731,7 +731,7 @@ static int fw_cfg_sysfs_probe(struct platform_device *pdev)
>  	return err;
>  }
>  
> -static int fw_cfg_sysfs_remove(struct platform_device *pdev)
> +static void fw_cfg_sysfs_remove(struct platform_device *pdev)
>  {
>  	pr_debug("fw_cfg: unloading.\n");
>  	fw_cfg_sysfs_cache_cleanup();
> @@ -739,7 +739,6 @@ static int fw_cfg_sysfs_remove(struct platform_device *pdev)
>  	fw_cfg_io_cleanup();
>  	fw_cfg_kset_unregister_recursive(fw_cfg_fname_kset);
>  	fw_cfg_kobj_cleanup(fw_cfg_sel_ko);
> -	return 0;
>  }
>  
>  static const struct of_device_id fw_cfg_sysfs_mmio_match[] = {
> @@ -758,7 +757,7 @@ MODULE_DEVICE_TABLE(acpi, fw_cfg_sysfs_acpi_match);
>  
>  static struct platform_driver fw_cfg_sysfs_driver = {
>  	.probe = fw_cfg_sysfs_probe,
> -	.remove = fw_cfg_sysfs_remove,
> +	.remove_new = fw_cfg_sysfs_remove,
>  	.driver = {
>  		.name = "fw_cfg",
>  		.of_match_table = fw_cfg_sysfs_mmio_match,
> -- 
> 2.43.0

On 27/12/23 17:26, Uwe Kleine-König wrote:
> 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 ignored (apart
> from emitting a warning) 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. Eventually after all drivers
> are converted, .remove_new() will be renamed to .remove().
> 
> Trivially convert this driver from always returning zero in the remove
> callback to the void returning variant.
> 
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> ---
>   drivers/firmware/qemu_fw_cfg.c | 5 ++---
>   1 file changed, 2 insertions(+), 3 deletions(-)

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>