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Subject: Re: [PATCH -next v2] staging: greybus: camera: Switch to
 memdup_user_nul()
To: Dan Carpenter <dan.carpenter@oracle.com>
CC: <linux-kernel@vger.kernel.org>, <linux-staging@lists.linux.dev>,
	<johan@kernel.org>, <elder@kernel.org>, <gregkh@linuxfoundation.org>
References: <20210401031752.2861248-1-yangyingliang@huawei.com>
 <20210401074332.GO2065@kadam> <20210401074719.GP2065@kadam>
From: Yang Yingliang <yangyingliang@huawei.com>
Message-ID: <b3a9b8ad-30b8-1716-1252-a6796b2c837a@huawei.com>
Date: Thu, 1 Apr 2021 17:20:07 +0800
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On 2021/4/1 15:47, Dan Carpenter wrote:
> On Thu, Apr 01, 2021 at 10:43:32AM +0300, Dan Carpenter wrote:
>> 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.
> So when someone makes a typo like this, my response is:
>
> 1) Let's add this to checkpatch (turns out it was already done)
> 2) Let's grep the kernel and fix the other instances.  The command would
> be something like: git grep ';;$' | grep '\.c:'
I search it in kernel and find some other instances like this, I can 
send some
patches to fix these.

Thanks,
Yang
>
> regards,
> dan carpenter
>
> .