linux-kernel - [PATCH AUTOSEL 6.4 01/40] serial: stm32: Ignore return value of uart_remove_one

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Date:   Sun, 23 Jul 2023 21:31:01 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Sasha Levin <sashal@...nel.org>, jslaby@...e.com,
        mcoquelin.stm32@...il.com, alexandre.torgue@...com,
        linux-serial@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: [PATCH AUTOSEL 6.4 01/40] serial: stm32: Ignore return value of uart_remove_one_port() in .remove()

From: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>

[ Upstream commit 6bd6cd29c92401a101993290051fa55078238a52 ]

Returning early from stm32_usart_serial_remove() results in a resource
leak as several cleanup functions are not called. The driver core ignores
the return value and there is no possibility to clean up later.

uart_remove_one_port() only returns non-zero if there is some
inconsistency (i.e. stm32_usart_driver.state[port->line].uart_port == NULL).
This should never happen, and even if it does it's a bad idea to exit
early in the remove callback without cleaning up.

This prepares changing the prototype of struct platform_driver::remove to
return void. See commit 5c5a7680e67b ("platform: Provide a remove callback
that returns no value") for further details about this quest.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
Link: https://lore.kernel.org/r/20230512173810.131447-2-u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/tty/serial/stm32-usart.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index 1e38fc9b10c11..e9e11a2596211 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -1755,13 +1755,10 @@ static int stm32_usart_serial_remove(struct platform_device *pdev)
 	struct uart_port *port = platform_get_drvdata(pdev);
 	struct stm32_port *stm32_port = to_stm32_port(port);
 	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
-	int err;
 	u32 cr3;
 
 	pm_runtime_get_sync(&pdev->dev);
-	err = uart_remove_one_port(&stm32_usart_driver, port);
-	if (err)
-		return(err);
+	uart_remove_one_port(&stm32_usart_driver, port);
 
 	pm_runtime_disable(&pdev->dev);
 	pm_runtime_set_suspended(&pdev->dev);
-- 
2.39.2