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

[Peter Xu <peterx@redhat.com>]

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@mev.co.uk>

The patch looks correct to me, thanks for fixing it.

Acked-by: Peter Xu <peterx@redhat.com>

> ---
>  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)
> -- 

-- 
Peter Xu