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

From: Alice Ryhl
Date: Mon Mar 17 2025 - 06:27:11 EST


Adding Christian Brauner who originally merged the
rust/kernel/fs/file.rs file.

On Mon, Mar 17, 2025 at 10:37:02AM +0800, 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: Alice Ryhl <aliceryhl@xxxxxxxxxx>