linux-kernel - Re: [PATCH serial v2] sc16is7xx: missing unregister/delete driver on error in sc16is7xx

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Date:   Mon, 11 Mar 2019 10:46:05 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Mao Wenan <maowenan@...wei.com>
Cc:     gregkh@...uxfoundation.org, jslaby@...e.com,
        linux-serial@...r.kernel.org, linux-kernel@...r.kernel.org,
        kernel-janitors@...r.kernel.org, vz@...ia.com
Subject: Re: [PATCH serial v2] sc16is7xx: missing unregister/delete driver on
 error in sc16is7xx_init()

On Sat, Mar 09, 2019 at 10:50:37AM +0800, Mao Wenan wrote:
> Add the missing uart_unregister_driver() and i2c_del_driver() before return
> from sc16is7xx_init() in the error handling case.
> 
> Reviewed-by: Vladimir Zapolskiy <vz@...ia.com>
> Signed-off-by: Mao Wenan <maowenan@...wei.com>
> ---
>  v1->v2: fix compile warning if CONFIG_SERIAL_SC16IS7XX_SPI is not exist.
>  drivers/tty/serial/sc16is7xx.c | 14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
> index 268098681856..b9e5941ce767 100644
> --- a/drivers/tty/serial/sc16is7xx.c
> +++ b/drivers/tty/serial/sc16is7xx.c
> @@ -1509,7 +1509,7 @@ static int __init sc16is7xx_init(void)
>  	ret = i2c_add_driver(&sc16is7xx_i2c_uart_driver);
>  	if (ret < 0) {
>  		pr_err("failed to init sc16is7xx i2c --> %d\n", ret);
> -		return ret;
> +		goto err_i2c;
>  	}
>  #endif
>  
> @@ -1517,10 +1517,20 @@ static int __init sc16is7xx_init(void)
>  	ret = spi_register_driver(&sc16is7xx_spi_uart_driver);
>  	if (ret < 0) {
>  		pr_err("failed to init sc16is7xx spi --> %d\n", ret);
> -		return ret;
> +		goto err_spi;
>  	}
>  #endif
>  	return ret;
> +
> +#ifdef CONFIG_SERIAL_SC16IS7XX_SPI
> +err_spi:
> +#endif
> +#ifdef CONFIG_SERIAL_SC16IS7XX_I2C
> +	i2c_del_driver(&sc16is7xx_i2c_uart_driver);
> +err_i2c:
> +#endif
> +	uart_unregister_driver(&sc16is7xx_uart);
> +	return ret;

This is quite ulgy.  Why not create two functions:

diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index 635178cf3eed..9986cb2479ad 100644
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -1491,6 +1491,21 @@ static struct i2c_driver sc16is7xx_i2c_uart_driver = {
 	.id_table	= sc16is7xx_i2c_id_table,
 };
 
+static int __init register_sc16is7xx_i2c(void)
+{
+	return i2c_add_driver(&sc16is7xx_i2c_uart_driver);
+}
+
+static void __exit del_sc16is7xx_i2c(void)
+{
+	i2c_del_driver(&sc16is7xx_i2c_uart_driver);
+}
+
+#else
+
+static int __init register_sc16is7xx_i2c(void) { return 0; }
+static void __exit del_sc16is7xx_i2c(void) {}
+
 #endif
 
 static int __init sc16is7xx_init(void)

Then you can remove all the ifdefs.

regards,
dan carpenter