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Subject: Re: [PATCH v3] serial: samsung: Checks the return value of function
To:     Tamseel Shams <m.shams@samsung.com>,
        krzysztof.kozlowski@canonical.com, gregkh@linuxfoundation.org
Cc:     linux-arm-kernel@lists.infradead.org,
        linux-samsung-soc@vger.kernel.org, linux-serial@vger.kernel.org,
        linux-kernel@vger.kernel.org, alim.akhtar@samsung.com
References: <CGME20210706061710epcas5p2c11d1bf5afb14774c4d4db93f2b83b33@epcas5p2.samsung.com>
 <20210706061909.17555-1-m.shams@samsung.com>
From:   Jiri Slaby <jirislaby@kernel.org>
Message-ID: <9fedfbde-64e3-7ebf-576a-056819a0c1e0@kernel.org>
Date:   Wed, 7 Jul 2021 10:14:48 +0200
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On 06. 07. 21, 8:19, Tamseel Shams wrote:
> "uart_add_one_port" function call may fail and return
> some error code, so adding a check for return value.
> If it is returning some error code, then displaying the
> result, unregistering the driver and then returning from
> probe function with error code.
> 
> Signed-off-by: Tamseel Shams <m.shams@samsung.com>
> ---
> Changes since v1:
> 1. Added support to unregister driver on failure of "uart_add_one_port"
> function call.
> 2. Commit message updated.
> 
> Changes since v2:
> 1. Added support to unwind clocks on failure of "uart_add_one_port"
> function call.
> 
>   drivers/tty/serial/samsung_tty.c | 17 ++++++++++++++++-
>   1 file changed, 16 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c
> index 9fbc61151c2e..a3f3a17fb54b 100644
> --- a/drivers/tty/serial/samsung_tty.c
> +++ b/drivers/tty/serial/samsung_tty.c
> @@ -2253,7 +2253,11 @@ static int s3c24xx_serial_probe(struct platform_device *pdev)
>   	}
>   
>   	dev_dbg(&pdev->dev, "%s: adding port\n", __func__);
> -	uart_add_one_port(&s3c24xx_uart_drv, &ourport->port);
> +	ret = uart_add_one_port(&s3c24xx_uart_drv, &ourport->port);
> +	if (ret < 0) {
> +		dev_err(&pdev->dev, "Failed to add uart port, err %d\n", ret);
> +		goto add_port_error;
> +	}
>   	platform_set_drvdata(pdev, &ourport->port);
>   
>   	/*
> @@ -2272,6 +2276,17 @@ static int s3c24xx_serial_probe(struct platform_device *pdev)
>   	probe_index++;
>   
>   	return 0;
> +
> +add_port_error:
> +	ourport->port.mapbase = 0;
> +	clk_disable_unprepare(ourport->clk);
> +	clk_put(ourport->clk);
> +	if (!IS_ERR(ourport->baudclk)) {
> +		clk_disable_unprepare(ourport->baudclk);
> +		clk_put(ourport->baudclk);
> +	}


LGTM, now I only wonder why s3c24xx_serial_remove() does not put clocks?

> +	uart_unregister_driver(&s3c24xx_uart_drv);
> +	return ret;
>   }
>   
>   static int s3c24xx_serial_remove(struct platform_device *dev)
> 


-- 
js
suse labs