Re: [PATCH 20/34] xen: convert put_page() to put_user_page*()

John Hubbard
2019-08-02T19:25:01Z

On 8/2/19 9:09 AM, Weiny, Ira wrote:
>>
>> On 02.08.19 07:48, John Hubbard wrote:
>>> On 8/1/19 9:36 PM, Juergen Gross wrote:
>>>> On 02.08.19 04:19, john.hubbard@gmail.com wrote:
>>>>> From: John Hubbard <jhubbard@nvidia.com>
>>> ...
>>> If that's not the case (both here, and in 3 or 4 other patches in this
>>> series, then as you said, I should add NULL checks to put_user_pages()
>>> and put_user_pages_dirty_lock().
>>
>> In this case it is not correct, but can easily be handled. The NULL case can
>> occur only in an error case with the pages array filled partially or not at all.
>>
>> I'd prefer something like the attached patch here.
>
> I'm not an expert in this code and have not looked at it carefully but that patch does seem to be the better fix than forcing NULL checks on everyone.
>

OK, I'll use Juergen's approach, and also check for that pattern in the
other patches.

thanks,
--
John Hubbard
NVIDIA