Re: [PATCH v2] rust: file: optimize rust symbol generation for FileDescriptorReservation

[Benno Lossin]

On Mon Mar 17, 2025 at 3:37 AM CET, Kunwu Chan wrote:
> From: Kunwu Chan <kunwu.chan@xxxxxxxxxxx>
>
> When build the kernel using the llvm-18.1.3-rust-1.85.0-x86_64
> with ARCH=arm64, the following symbols are generated:
>
> $ nm vmlinux | grep ' _R'.*FileDescriptorReservation | rustfilt
> ... T <kernel::fs::file::FileDescriptorReservation>::fd_install
> ... T <kernel::fs::file::FileDescriptorReservation>::get_unused_fd_flags
> ... T <kernel::fs::file::FileDescriptorReservation as core::ops::drop::Drop>::drop
>
> These Rust symbols are trivial wrappers around the C functions
> fd_install, put_unused_fd and put_task_struct. It
> doesn't make sense to go through a trivial wrapper for these
> functions, so mark them inline.
>
> Link: https://github.com/Rust-for-Linux/linux/issues/1145
> Suggested-by: Alice Ryhl <aliceryhl@xxxxxxxxxx>
> Co-developed-by: Grace Deng <Grace.Deng006@xxxxxxxxx>
> Signed-off-by: Grace Deng <Grace.Deng006@xxxxxxxxx>
> Signed-off-by: Kunwu Chan <kunwu.chan@xxxxxxxxxxx>

Reviewed-by: Benno Lossin <benno.lossin@xxxxxxxxx>

---
Cheers,
Benno


> ---
> Changes in v2:
>  - Add link and Suggested-by
>  - Mark 'reserved_fd' as inline
>  - Reword commit msg
> ---
>  rust/kernel/fs/file.rs | 4 ++++
>  1 file changed, 4 insertions(+)