netdev - [PATCH net-next v2 1/4] net: ethernet: ti: am65-cpsw: Convert to platform remove callback returning void

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Message-ID: <20231128173823.867512-2-u.kleine-koenig@pengutronix.de>
Date: Tue, 28 Nov 2023 18:38:25 +0100
From: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
To: "David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>,
	Roger Quadros <rogerq@...nel.org>
Cc: Siddharth Vadapalli <s-vadapalli@...com>,
	Dan Carpenter <dan.carpenter@...aro.org>,
	netdev@...r.kernel.org,
	kernel@...gutronix.de
Subject: [PATCH net-next v2 1/4] net: ethernet: ti: am65-cpsw: Convert to platform remove callback returning void

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().

Replace the error path returning a non-zero value by an error message
and a comment that there is more to do. With that this patch results in
no change of behaviour in this driver apart from improving the error
message.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
---
 drivers/net/ethernet/ti/am65-cpsw-nuss.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
index 7992a76ed4d8..7651f90f51f2 100644
--- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
+++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
@@ -3028,7 +3028,7 @@ static int am65_cpsw_nuss_probe(struct platform_device *pdev)
 	return ret;
 }
 
-static int am65_cpsw_nuss_remove(struct platform_device *pdev)
+static void am65_cpsw_nuss_remove(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct am65_cpsw_common *common;
@@ -3037,8 +3037,14 @@ static int am65_cpsw_nuss_remove(struct platform_device *pdev)
 	common = dev_get_drvdata(dev);
 
 	ret = pm_runtime_resume_and_get(&pdev->dev);
-	if (ret < 0)
-		return ret;
+	if (ret < 0) {
+		/* Note, if this error path is taken, we're leaking some
+		 * resources.
+		 */
+		dev_err(&pdev->dev, "Failed to resume device (%pe)\n",
+			ERR_PTR(ret));
+		return;
+	}
 
 	am65_cpsw_unregister_devlink(common);
 	am65_cpsw_unregister_notifiers(common);
@@ -3056,7 +3062,6 @@ static int am65_cpsw_nuss_remove(struct platform_device *pdev)
 
 	pm_runtime_put_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
-	return 0;
 }
 
 static int am65_cpsw_nuss_suspend(struct device *dev)
@@ -3156,7 +3161,7 @@ static struct platform_driver am65_cpsw_nuss_driver = {
 		.pm = &am65_cpsw_nuss_dev_pm_ops,
 	},
 	.probe = am65_cpsw_nuss_probe,
-	.remove = am65_cpsw_nuss_remove,
+	.remove_new = am65_cpsw_nuss_remove,
 };
 
 module_platform_driver(am65_cpsw_nuss_driver);
-- 
2.42.0