[PATCH net-next] net: wan: fsl_qmc_hdlc: Convert to platform remove callback returning void

[PATCH net-next] net: wan: fsl_qmc_hdlc: Convert to platform remove callback returning void

[Uwe Kleine-König]

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>
---
Hello,

the drivers below of drivers/net were already converted to struct
platform_driver::remove_new during the v6.9-rc1 development cycle. This
driver was added for v6.9-rc1 and so missed during my conversion.

There are still more drivers to be converted, so there is from my side
no need to get this into v6.9, but the next merge window would be nice.

Best regards
Uwe

 drivers/net/wan/fsl_qmc_hdlc.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wan/fsl_qmc_hdlc.c b/drivers/net/wan/fsl_qmc_hdlc.c
index f69b1f579a0c..c5e7ca793c43 100644
--- a/drivers/net/wan/fsl_qmc_hdlc.c
+++ b/drivers/net/wan/fsl_qmc_hdlc.c
@@ -765,15 +765,13 @@ static int qmc_hdlc_probe(struct platform_device *pdev)
 	return ret;
 }
 
-static int qmc_hdlc_remove(struct platform_device *pdev)
+static void qmc_hdlc_remove(struct platform_device *pdev)
 {
 	struct qmc_hdlc *qmc_hdlc = platform_get_drvdata(pdev);
 
 	unregister_hdlc_device(qmc_hdlc->netdev);
 	free_netdev(qmc_hdlc->netdev);
 	qmc_hdlc_framer_exit(qmc_hdlc);
-
-	return 0;
 }
 
 static const struct of_device_id qmc_hdlc_id_table[] = {
@@ -788,7 +786,7 @@ static struct platform_driver qmc_hdlc_driver = {
 		.of_match_table = qmc_hdlc_id_table,
 	},
 	.probe = qmc_hdlc_probe,
-	.remove = qmc_hdlc_remove,
+	.remove_new = qmc_hdlc_remove,
 };
 module_platform_driver(qmc_hdlc_driver);
 
base-commit: 11cb68ad52ac78c81e33b806b531f097e68edfa2
-- 
2.43.0

Re: [PATCH net-next] net: wan: fsl_qmc_hdlc: Convert to platform remove callback returning void

[Herve Codina]

On Tue,  9 Apr 2024 11:12:04 +0200
Uwe Kleine-König <u.kleine-koenig@pengutronix.de> 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>
> ---
> Hello,
> 
> the drivers below of drivers/net were already converted to struct
> platform_driver::remove_new during the v6.9-rc1 development cycle. This
> driver was added for v6.9-rc1 and so missed during my conversion.
> 
> There are still more drivers to be converted, so there is from my side
> no need to get this into v6.9, but the next merge window would be nice.
> 
> Best regards
> Uwe
> 
>  drivers/net/wan/fsl_qmc_hdlc.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 

Acked-by: Herve Codina <herve.codina@bootlin.com>

Best regards,
Hervé

Re: [PATCH net-next] net: wan: fsl_qmc_hdlc: Convert to platform remove callback returning void

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Tue,  9 Apr 2024 11:12:04 +0200 you 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().
> 
> [...]

Here is the summary with links:
  - [net-next] net: wan: fsl_qmc_hdlc: Convert to platform remove callback returning void
    https://git.kernel.org/netdev/net-next/c/07409cf72844

You are awesome, thank you!
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