[PATCH v2 01/10] liveupdate: Pass user argument to file preserve and retrieve

[sashiko-bot at kernel.org]

> From: Pasha Tatashin <pasha.tatashin at soleen.com>
> 
> Allow userspace to pass a file-handler-specific argument structure when
> preserving or retrieving an FD via LUO. File handlers may need
> additional context during preservation or retrieval, such as a target
> FD, device location, or handler-specific parameters, without introducing
> separate ioctls for each file type. Whether the argument is required,
> optional, or unused is defined by the file handler.
> 
> Extend struct liveupdate_session_preserve_fd and
> struct liveupdate_session_retrieve_fd with a 64-bit arg field pointing
> to a handler-defined argument structure that begins with a 32-bit size
> field. Because IOCTL_OP validates a minimum size up to the token field,
> existing callers passing the 16-byte struct remain compatible and have
> arg zero-filled by copy_struct_from_user().
> [ ... ]
> so fail with -EBUSY if a non-zero argument is passed then, instead of
> silently ignoring it.
> 
> Signed-off-by: Pasha Tatashin <pasha.tatashin at soleen.com>
> Signed-off-by: David Matlack <dmatlack at google.com>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261022225035.377445-1-dmatlack@google.com?part=1