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Date:   Wed, 23 Jun 2021 10:54:14 +0300
From:   Sakari Ailus <sakari.ailus@linux.intel.com>
To:     Yizhuo <yzhai003@ucr.edu>
Cc:     Mauro Carvalho Chehab <mchehab@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Juan Antonio Aldea-Armenteros <juant.aldea@gmail.com>,
        linux-media@vger.kernel.org, linux-staging@lists.linux.dev,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] media: atomisp: fix the uninitialized use and rename
 "retvalue"
Message-ID: <20210623075414.GF3@paasikivi.fi.intel.com>
References: <20210623055634.12603-1-yzhai003@ucr.edu>
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Hi Yizhuo,

On Wed, Jun 23, 2021 at 05:56:31AM +0000, Yizhuo wrote:
> Inside function mt9m114_detect(), variable "retvalue" could
> be uninitialized if mt9m114_read_reg() returns error, however, it
> is used in the later if statement, which is potentially unsafe.
> 
> The local variable "retvalue" is renamed to "model" to avoid
> confusion.
> 
> Signed-off-by: Yizhuo <yzhai003@ucr.edu>
> ---
>  drivers/staging/media/atomisp/i2c/atomisp-mt9m114.c | 11 +++++++----
>  1 file changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/staging/media/atomisp/i2c/atomisp-mt9m114.c b/drivers/staging/media/atomisp/i2c/atomisp-mt9m114.c
> index f5de81132177..fbd6c6cd84c8 100644
> --- a/drivers/staging/media/atomisp/i2c/atomisp-mt9m114.c
> +++ b/drivers/staging/media/atomisp/i2c/atomisp-mt9m114.c
> @@ -1533,16 +1533,19 @@ static struct v4l2_ctrl_config mt9m114_controls[] = {
>  static int mt9m114_detect(struct mt9m114_device *dev, struct i2c_client *client)
>  {
>  	struct i2c_adapter *adapter = client->adapter;
> -	u32 retvalue;
> +	u32 model;
> +	int ret;
>  
>  	if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) {
>  		dev_err(&client->dev, "%s: i2c error", __func__);
>  		return -ENODEV;
>  	}
> -	mt9m114_read_reg(client, MISENSOR_16BIT, (u32)MT9M114_PID, &retvalue);
> -	dev->real_model_id = retvalue;
> +	ret = mt9m114_read_reg(client, MISENSOR_16BIT, (u32)MT9M114_PID, &model);

This is over 80 characters.

You can also drop the cast, which also reduces the line length.

> +	if (ret)
> +		return ret;
> +	dev->real_model_id = model;
>  
> -	if (retvalue != MT9M114_MOD_ID) {
> +	if (model != MT9M114_MOD_ID) {
>  		dev_err(&client->dev, "%s: failed: client->addr = %x\n",
>  			__func__, client->addr);
>  		return -ENODEV;

-- 
Regards,

Sakari Ailus