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Zhi Wang
e052daab94
Introduce safe Rust wrappers around struct fwctl_device and struct fwctl_uctx. This lets Rust drivers register fwctl devices and implement firmware RPC callbacks through a typed trait interface. The abstraction keeps lifetime and reference-count handling inside the wrapper, exposes pinned per-FD user contexts to drivers, and validates the layout assumptions required by the C fwctl allocation model. Allocation sizes are padded so the kmalloc-backed C allocations also satisfy Rust alignment requirements. Registration owns driver private data with a lifetime tied to the bound parent device and verifies the parent identity before registration. Callbacks access that data through a higher-ranked closure, preventing its erased lifetime from escaping, while Device remains only the refcounted fwctl object. This avoids requiring Rust drop glue from the fwctl_device release path after unregister or module teardown. RPC callbacks receive typed scope information, a mutable request/response buffer, and the userspace output-buffer size. Response pointer conversion, length validation, and raw output-length handling remain inside the abstraction. Add the Rust sources to the FWCTL MAINTAINERS entry and add myself as the maintainer for the Rust abstractions. Link: https://patch.msgid.link/r/[email protected] Co-developed-by: Danilo Krummrich <[email protected]> Signed-off-by: Danilo Krummrich <[email protected]> Signed-off-by: Zhi Wang <[email protected]> Reviewed-by: Alexandre Courbot <[email protected]> Signed-off-by: Jason Gunthorpe <[email protected]>