Re: [PATCH -next v2] staging: greybus: camera: Switch to memdup_user_nul()

From: Dan Carpenter <dan.carpenter@oracle.com>
To: Yang Yingliang <yangyingliang@huawei.com>
Cc: linux-kernel@vger.kernel.org, linux-staging@lists.linux.dev,
	johan@kernel.org, elder@kernel.org, gregkh@linuxfoundation.org
Subject: Re: [PATCH -next v2] staging: greybus: camera: Switch to memdup_user_nul()
Date: Thu, 1 Apr 2021 10:43:32 +0300	[thread overview]
Message-ID: <20210401074332.GO2065@kadam> (raw)
In-Reply-To: <20210401031752.2861248-1-yangyingliang@huawei.com>

On Thu, Apr 01, 2021 at 11:17:52AM +0800, Yang Yingliang wrote:
> Use memdup_user_nul() helper instead of open-coding to
> simplify the code.
> 
> Reported-by: Hulk Robot <hulkci@huawei.com>
> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
> ---
>  drivers/staging/greybus/camera.c | 13 +++----------
>  1 file changed, 3 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/staging/greybus/camera.c b/drivers/staging/greybus/camera.c
> index b570e13394ac..2ecdc1bc5092 100644
> --- a/drivers/staging/greybus/camera.c
> +++ b/drivers/staging/greybus/camera.c
> @@ -1120,16 +1120,9 @@ static ssize_t gb_camera_debugfs_write(struct file *file,
>  	if (len > 1024)
>  		return -EINVAL;
>  
> -	kbuf = kmalloc(len + 1, GFP_KERNEL);
> -	if (!kbuf)
> -		return -ENOMEM;
> -
> -	if (copy_from_user(kbuf, buf, len)) {
> -		ret = -EFAULT;
> -		goto done;
> -	}
> -
> -	kbuf[len] = '\0';
> +	kbuf = memdup_user_nul(buf, len);
> +	if (IS_ERR(kbuf))
> +		return PTR_ERR(kbuf);;
                                    ^^
There is an extra semi-colon here.  Checkpatch actually catches this
sort of typo.

regards,
dan carpenter