netdev - [PATCH net-next v2 2/4] net: ethernet: ti: cpsw: Convert to platform remove callback returning void

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Message-ID: <20231128173823.867512-3-u.kleine-koenig@pengutronix.de>
Date: Tue, 28 Nov 2023 18:38:26 +0100
From: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
To: Roger Quadros <rogerq@...nel.org>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>
Cc: Siddharth Vadapalli <s-vadapalli@...com>,
	Ravi Gunasekaran <r-gunasekaran@...com>,
	Jesse Brandeburg <jesse.brandeburg@...el.com>,
	Rob Herring <robh@...nel.org>,
	Yunsheng Lin <linyunsheng@...wei.com>,
	Marek Majtyka <alardam@...il.com>,
	linux-omap@...r.kernel.org,
	netdev@...r.kernel.org,
	kernel@...gutronix.de
Subject: [PATCH net-next v2 2/4] net: ethernet: ti: 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/cpsw.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/ti/cpsw.c b/drivers/net/ethernet/ti/cpsw.c
index ca4d4548f85e..ea85c6dd5484 100644
--- a/drivers/net/ethernet/ti/cpsw.c
+++ b/drivers/net/ethernet/ti/cpsw.c
@@ -1722,14 +1722,20 @@ static int cpsw_probe(struct platform_device *pdev)
 	return ret;
 }
 
-static int cpsw_remove(struct platform_device *pdev)
+static void cpsw_remove(struct platform_device *pdev)
 {
 	struct cpsw_common *cpsw = platform_get_drvdata(pdev);
 	int i, ret;
 
 	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;
+	}
 
 	for (i = 0; i < cpsw->data.slaves; i++)
 		if (cpsw->slaves[i].ndev)
@@ -1740,7 +1746,6 @@ static int cpsw_remove(struct platform_device *pdev)
 	cpsw_remove_dt(pdev);
 	pm_runtime_put_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
-	return 0;
 }
 
 #ifdef CONFIG_PM_SLEEP
@@ -1795,7 +1800,7 @@ static struct platform_driver cpsw_driver = {
 		.of_match_table = cpsw_of_mtable,
 	},
 	.probe = cpsw_probe,
-	.remove = cpsw_remove,
+	.remove_new = cpsw_remove,
 };
 
 module_platform_driver(cpsw_driver);
-- 
2.42.0