linux-kernel - Re: [PATCH] ioctl_userfaultfd.2: Corrections for returned .ioctls members

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Message-ID: <a2380fac-d173-50e3-963a-d7fc22b2da5d@gmail.com>
Date:   Tue, 22 Mar 2022 13:32:33 +0100
From:   "Alejandro Colomar (man-pages)" <alx.manpages@...il.com>
To:     Peter Xu <peterx@...hat.com>, Ian Abbott <abbotti@....co.uk>
Cc:     linux-man@...r.kernel.org,
        Michael Kerrisk <mtk.manpages@...il.com>,
        linux-kernel@...r.kernel.org,
        Axel Rasmussen <axelrasmussen@...gle.com>
Subject: Re: [PATCH] ioctl_userfaultfd.2: Corrections for returned .ioctls
 members

Hi Ian and Peter,

On 3/21/22 07:10, Peter Xu wrote:
> On Fri, Mar 18, 2022 at 07:13:43PM +0000, Ian Abbott wrote:
>> Support for the `UFFDIO_WRITEPROTECT` operation is not indicated in the
>> `ioctls` member of `struct uffdio_api`.  It is indicated in the `ioctls`
>> member of `struct uffdio_register` along with indications of support for
>> the `UFFDIO_COPY`, `UFFDIO_WAKE` and `UFFDIO_ZEROPAGE` operations (and
>> also the `UFFDIO_CONTINUE` operation supported since Linux 5.13 but
>> that is not documented by this man page yet.)
> 
> I thought it should have landed but indeed it's not.  Copying Axel.
> 
>>
>> Fixes: f559fa36a678 ("ioctl_userfaultfd.2: Add write-protect mode docs")
>> Signed-off-by: Ian Abbott <abbotti@....co.uk>

Patch applied.

> 
> The patch looks correct to me, thanks for fixing it.
> 
> Acked-by: Peter Xu <peterx@...hat.com>

And tag appended.

Thank you both!

Alex

> 
>> ---
>>   man2/ioctl_userfaultfd.2 | 27 ++++++++++++++++++++-------
>>   1 file changed, 20 insertions(+), 7 deletions(-)
>>
>> diff --git a/man2/ioctl_userfaultfd.2 b/man2/ioctl_userfaultfd.2
>> index 504f61d4b..e930af520 100644
>> --- a/man2/ioctl_userfaultfd.2
>> +++ b/man2/ioctl_userfaultfd.2
>> @@ -235,11 +235,6 @@ operation is supported.
>>   The
>>   .B UFFDIO_UNREGISTER
>>   operation is supported.
>> -.TP
>> -.B 1 << _UFFDIO_WRITEPROTECT
>> -The
>> -.B UFFDIO_WRITEPROTECT
>> -operation is supported.
>>   .PP
>>   This
>>   .BR ioctl (2)
>> @@ -333,8 +328,26 @@ If the operation is successful, the kernel modifies the
>>   bit-mask field to indicate which
>>   .BR ioctl (2)
>>   operations are available for the specified range.
>> -This returned bit mask is as for
>> -.BR UFFDIO_API .
>> +This returned bit mask can contain the following bits:
>> +.TP
>> +.B 1 << _UFFDIO_COPY
>> +The
>> +.B UFFDIO_COPY
>> +operation is supported.
>> +.TP
>> +.B 1 << _UFFDIO_WAKE
>> +The
>> +.B UFFDIO_WAKE
>> +operation is supported.
>> +.TP
>> +.B 1 << _UFFDIO_WRITEPROTECT
>> +The
>> +.B UFFDIO_WRITEPROTECT
>> +.TP
>> +.B 1 << _UFFDIO_ZEROPAGE
>> +The
>> +.B UFFDIO_ZEROPAGE
>> +operation is supported.
>>   .PP
>>   This
>>   .BR ioctl (2)
>> -- 
> 

-- 
Alejandro Colomar
Linux man-pages comaintainer; http://www.kernel.org/doc/man-pages/
http://www.alejandro-colomar.es/