[v1] userfaultfd man page updates

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

Posted by Axel Rasmussen 2 years, 4 months ago

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>
---
 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

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

Posted by Mike Rapoport 2 years, 4 months ago

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.

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

Posted by Alejandro Colomar 2 years, 4 months ago

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>

Patch applied.  Thanks,
Alex

> ---
>  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
>