Re: [PATCH 01/10] userfaultfd.2: briefly mention two-step feature handshake process

Mike Rapoport
2023-10-09T08:39:48Z

On Tue, Sep 19, 2023 at 12:01:57PM -0700, Axel Rasmussen wrote:
> This process is critical for programs which depend on extra features, so
> it's worth mentioning here.
>
> Future commits will much more fully describe it in ioctl_userfaultfd.2.
>
> Signed-off-by: Axel Rasmussen <axelrasmussen@google.com>

Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>

> ---
> man2/userfaultfd.2 | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/man2/userfaultfd.2 b/man2/userfaultfd.2
> index 40354065c..1b2af22f9 100644
> --- a/man2/userfaultfd.2
> +++ b/man2/userfaultfd.2
> @@ -200,8 +200,9 @@ the application must enable it using the
> .B UFFDIO_API
> .BR ioctl (2)
> operation.
> -This operation allows a handshake between the kernel and user space
> -to determine the API version and supported features.
> +This operation allows a two-step handshake between the kernel and user space
> +to determine what API version and features the kernel supports,
> +and then to enable those features user space wants.
> This operation must be performed before any of the other
> .BR ioctl (2)
> operations described below (or those operations fail with the
> --
> 2.42.0.459.ge4e396fd5e-goog
>
>

--
Sincerely yours,
Mike.