Re: [PATCH v5 06/22] liveupdate: luo_session: add sessions support

[Mike Rapoport]

On Fri, Nov 07, 2025 at 04:03:04PM -0500, Pasha Tatashin wrote:
> Introduce concept of "Live Update Sessions" within the LUO framework.
> LUO sessions provide a mechanism to group and manage `struct file *`
> instances (representing file descriptors) that need to be preserved
> across a kexec-based live update.
> 
> Each session is identified by a unique name and acts as a container
> for file objects whose state is critical to a userspace workload, such
> as a virtual machine or a high-performance database, aiming to maintain
> their functionality across a kernel transition.
> 
> This groundwork establishes the framework for preserving file-backed
> state across kernel updates, with the actual file data preservation
> mechanisms to be implemented in subsequent patches.
> 
> Signed-off-by: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx>
> ---
>  include/linux/liveupdate/abi/luo.h |  81 ++++++
>  include/uapi/linux/liveupdate.h    |   3 +
>  kernel/liveupdate/Makefile         |   3 +-
>  kernel/liveupdate/luo_core.c       |   9 +
>  kernel/liveupdate/luo_internal.h   |  39 +++
>  kernel/liveupdate/luo_session.c    | 405 +++++++++++++++++++++++++++++
>  6 files changed, 539 insertions(+), 1 deletion(-)
>  create mode 100644 kernel/liveupdate/luo_session.c
> 
> diff --git a/include/linux/liveupdate/abi/luo.h b/include/linux/liveupdate/abi/luo.h
> index 9483a294287f..37b9fecef3f7 100644
> --- a/include/linux/liveupdate/abi/luo.h
> +++ b/include/linux/liveupdate/abi/luo.h
> @@ -28,6 +28,11 @@
>   *     / {
>   *         compatible = "luo-v1";
>   *         liveupdate-number = <...>;
> + *
> + *         luo-session {
> + *             compatible = "luo-session-v1";
> + *             luo-session-head = <phys_addr_of_session_head_ser>;

'head' reads to me as list head rather than a header. I'd use 'hdr' for the
latter.

-- 
Sincerely yours,
Mike.